Eduovisual
Immune System
Selective IgA deficiency: implications for transfusion
— Most common primary immunodeficiency in people of European ancestry (~1:300–1:700).
— Often asymptomatic and detected incidentally, frequently when a transfusion reaction prompts workup or routine screening reveals undetectable IgA.
— Classic stem: previously transfused patient or multiparous woman develops urticaria, bronchospasm, hypotension within minutes of starting blood, without fever.
— Recurrent sinopulmonary infections (otitis, sinusitis, bronchitis) with encapsulated organisms.
— Recurrent GI infections, especially Giardia.
— Coexisting autoimmune disease: celiac disease, SLE, RA, type 1 DM, ITP, autoimmune thyroiditis.
— Atopy: asthma, allergic rhinitis, food allergies.
— Anaphylaxis to blood products, IVIG, or even certain vaccines without other explanation.
— Failure of terminal B-cell differentiation into IgA-secreting plasma cells; T-cell help and IgM/IgG production remain intact.
— Reduced secretory IgA at mucosal surfaces → susceptibility at mucosal interfaces.
— Genetic overlap with CVID (common variable immunodeficiency); some SIgAD patients progress to CVID over years.
Board pearl: If a young adult presents with anaphylaxis on first-ever transfusion and a history of recurrent sinopulmonary infections plus celiac disease, the unifying diagnosis is selective IgA deficiency, and future products must be washed RBCs or from IgA-deficient donors.
— Asymptomatic incidental finding: Pre-op screening, celiac serology workup (false-negative tTG-IgA), or quantitative immunoglobulins drawn for autoimmune disease evaluation.
— Recurrent infection phenotype: Adult with ≥2 sinopulmonary infections per year, often with bronchiectasis on imaging if longstanding.
— Anaphylactic transfusion reaction phenotype: Urticaria, wheezing, hypotension, GI cramping within minutes of any IgA-containing product (RBCs, platelets, FFP, IVIG, even cryoprecipitate).
— Prior transfusions or pregnancies (sensitizing events for anti-IgA antibody formation; ~40% of SIgAD patients develop these antibodies).
— Prior reactions to IVIG, vaccines containing trace blood products, or breast milk in infancy (very rare).
— Family history of primary immunodeficiency, CVID, or unexplained recurrent infections — SIgAD has familial clustering.
— Celiac disease symptoms (chronic diarrhea, iron deficiency, weight loss) — present in ~10–15% of SIgAD patients.
— Autoimmune review of systems: joint pain (RA), photosensitive rash (SLE), thyroid symptoms.
— Atopic history: asthma, eczema, allergic rhinitis, food allergies (much higher prevalence than general population).
— Encapsulated organisms: S. pneumoniae, H. influenzae, Moraxella.
— GI: persistent or recurrent Giardia lamblia — ask about camping, well water, daycare exposure, chronic loose stools.
— Less commonly: severe viral gastroenteritis, Campylobacter.
— Diagnosis not made before age 4 because IgA matures slowly; transient low IgA is normal in infancy.
— In children <4 with low IgA, repeat at age 4 before labeling.
Key distinction: SIgAD patients with isolated low IgA usually have mild disease; those with concomitant IgG2/IgG4 subclass deficiency behave more like CVID and have more severe infections requiring closer follow-up and possibly immunoglobulin replacement consideration.
— Often completely normal.
— Possible findings reflecting comorbidities: nasal polyps or pale boggy turbinates (allergic rhinitis), wheezing (asthma), conjunctival pallor (iron-deficient celiac), dermatitis herpetiformis lesions (elbows, knees — celiac), digital clubbing (bronchiectasis from recurrent pneumonia).
— Tympanic membrane scarring from recurrent otitis.
— Onset within seconds to minutes of starting the product — earlier than most other reactions.
— Cutaneous: generalized urticaria, flushing, angioedema of lips/tongue.
— Respiratory: stridor, wheezing, hoarseness, hypoxia, tachypnea.
— Cardiovascular: hypotension, tachycardia, shock; can progress to cardiac arrest.
— GI: abdominal cramping, nausea, vomiting, diarrhea.
— Notably absent: FEVER. This is the discriminator from febrile non-hemolytic and acute hemolytic reactions.
— Vital signs every 5 minutes; trend BP, HR, SpO₂, mental status.
— Look for signs of distributive shock: warm extremities initially, narrow pulse pressure later, altered mentation.
— Check for hives vs. petechiae (the latter suggests hemolysis or DIC instead).
— Auscultate lungs for wheeze (anaphylaxis) vs. crackles (TRALI/TACO).
— Anaphylactic (IgA-related): minutes, hives + bronchospasm + hypotension, no fever.
— Febrile non-hemolytic: fever + chills, mild.
— Acute hemolytic: fever, flank/back pain, hemoglobinuria, DIC.
— TRALI: hypoxia + bilateral infiltrates within 6 hours.
— TACO: hypertension, JVD, pulmonary edema.
Step 3 management: When transfusion reaction is suspected — STOP the transfusion immediately, maintain IV access with normal saline through a new tubing, send the bag and recipient blood back to the blood bank, and treat anaphylaxis with IM epinephrine 0.3–0.5 mg, oxygen, IV fluids, antihistamines, and steroids.
— SIgAD criteria: serum IgA <7 mg/dL (undetectable), with normal IgG and IgM, in a patient ≥4 years old.
— "Partial IgA deficiency" = IgA below age-adjusted normal but ≥7 mg/dL; less clinical significance but still risk for transfusion reactions in severe partial cases.
— Anti-IgA antibody testing (sent to specialized reference labs): identifies patients with circulating anti-IgA who are at highest anaphylaxis risk.
— Not all SIgAD patients have anti-IgA antibodies; not all anti-IgA antibody carriers will react. But a history of severe transfusion anaphylaxis + low IgA = treat as high risk regardless of antibody titer.
— CBC with differential: look for cytopenias (autoimmune), eosinophilia (atopy).
— CMP: baseline renal/hepatic function, especially before IVIG candidates.
— Tissue transglutaminase IgA + total IgA together when screening for celiac — because IgA-based celiac serologies are falsely negative in SIgAD. In SIgAD, order tTG-IgG or deamidated gliadin peptide IgG instead.
— HIV testing: rule out secondary causes of hypogammaglobulinemia.
— SPEP/UPEP if older patient: rule out monoclonal gammopathy masking the picture.
— High-resolution chest CT if recurrent pneumonia or chronic cough — evaluate for bronchiectasis.
— Sinus CT for chronic sinusitis.
— Measure pre- and post-immunization titers to S. pneumoniae polysaccharide and tetanus to assess functional antibody response — abnormal results suggest evolving CVID rather than pure SIgAD and changes management.
Board pearl: Always pair total IgA with tTG-IgA when screening for celiac. If total IgA is undetectable, the tTG-IgA is uninterpretable — switch to IgG-based celiac serologies to avoid missing the diagnosis.
— Recurrent serious infections despite SIgAD diagnosis.
— Evolving cytopenias, granulomatous disease, or unexplained splenomegaly.
— Falling IgG over time → concern for progression to CVID.
— IgG subclass levels (IgG1–IgG4): isolated IgA + IgG2/IgG4 subclass deficiency behaves more like CVID; consider Ig replacement.
— B-cell and T-cell flow cytometry: quantify CD19+ B cells, CD4/CD8 T cells; in pure SIgAD, B-cell numbers are normal.
— Specific antibody responses post-vaccination (pneumococcal polysaccharide PPSV23, tetanus, diphtheria) — gold standard for functional humoral immunity.
— Genetic testing: not routine but useful when familial pattern or atypical features suggest a monogenic PID (e.g., TACI mutations shared with CVID).
— Anti-IgA antibody quantification (class-specific): IgG anti-IgA is the typical mediator of anaphylaxis; IgE anti-IgA also described.
— Tryptase level during/after a suspected transfusion anaphylaxis — supports anaphylactic mechanism (drawn within 1–2 hours of reaction, repeat baseline weeks later).
— Blood bank notation: once confirmed, patient must be flagged in the electronic medical record and blood bank database so future products are appropriately selected.
— Rule out secondary hypogammaglobulinemia: protein-losing enteropathy, nephrotic syndrome, drug effects (phenytoin, sulfasalazine, mycophenolate, rituximab), HIV, lymphoma.
— Drug-induced low IgA (especially phenytoin) is a classic Step 3 distractor — review the med list.
— Annual quantitative immunoglobulins to detect progression to CVID (occurs in a small minority).
— Reassess functional antibody responses if clinical picture worsens.
Key distinction: Pure SIgAD = normal IgG/IgM. If IgG also drops over time with poor vaccine responses, the diagnosis has evolved to CVID — management shifts to scheduled immunoglobulin replacement and closer infection/cancer surveillance.
— High risk: Prior anaphylactic transfusion reaction OR documented anti-IgA antibodies OR severe SIgAD with prior sensitizing exposure (transfusion, pregnancy, IVIG).
— Intermediate risk: Confirmed SIgAD without known anti-IgA antibodies but never previously transfused — uncertain risk; precaution still warranted for severe reactions.
— Low/uncertain risk: Partial IgA deficiency without prior reactions.
— First choice: Blood products from IgA-deficient donors (rare; obtained via national rare-donor registries — requires advance planning).
— Second choice: Washed RBCs — saline washing removes >99% of plasma IgA. Standard for RBC transfusion in high-risk SIgAD.
— Platelets: Washed platelets or platelets in platelet additive solution (PAS); apheresis platelets in PAS reduce plasma volume.
— FFP / cryoprecipitate: Must come from IgA-deficient donors — these products are plasma-rich and cannot be effectively washed.
— IVIG: Use IgA-depleted IVIG preparations if Ig replacement is required.
— Do not withhold life-saving transfusion. Use standard product with:
— Premedication: diphenhydramine, methylprednisolone, sometimes acetaminophen.
— Transfuse slowly with bedside epinephrine, airway equipment, and ICU-level monitoring.
— Continuous observation by physician.
— Document risk/benefit discussion.
— Patients with known SIgAD undergoing elective surgery with possible transfusion need: type & screen, blood bank notification ≥48 hours ahead, washed RBC availability arranged.
CCS pearl: On a CCS case with a known SIgAD patient needing surgery, order "type and crossmatch, washed RBCs" and consult blood bank in the preoperative orders. Anticipating the rare-product logistics is a graded action.
— Acute bacterial sinopulmonary infections: standard antibiotics (amoxicillin-clavulanate, doxycycline, respiratory fluoroquinolones for resistant pneumococcus).
— Recurrent infections: consider prophylactic antibiotics (e.g., azithromycin 3x/week or daily amoxicillin) in patients with bronchiectasis or ≥3–4 sinopulmonary infections/year.
— Giardia: tinidazole single dose or metronidazole 5–7 days; treat household contacts if symptomatic.
— Aggressive vaccination: annual influenza (inactivated), pneumococcal (PCV20 or PCV15 then PPSV23), COVID-19, RSV when indicated. Live vaccines generally safe in pure SIgAD but withheld if CVID-like progression.
— Not indicated for pure SIgAD — it does not replace IgA and carries severe anaphylaxis risk from contaminating IgA.
— Indicated only if there is concomitant IgG subclass deficiency or impaired specific antibody responses AND clinically significant infections.
— When used, choose IgA-depleted IVIG preparations (e.g., specific brands with very low residual IgA); pretreat with antihistamines/steroids; consider subcutaneous Ig (SCIG) which has lower anaphylaxis risk due to slower absorption.
— Diphenhydramine 25–50 mg IV.
— Methylprednisolone 100 mg IV (or hydrocortisone) 30–60 min prior.
— Acetaminophen 650 mg PO.
— Epinephrine and crash cart at bedside.
— Inhaled corticosteroids/bronchodilators for coexisting asthma.
— Gluten-free diet for celiac.
— Disease-specific therapy for autoimmune comorbidities.
Board pearl: Standard IVIG is contraindicated in SIgAD patients with anti-IgA antibodies because most preparations contain trace IgA — use IgA-depleted IVIG or subcutaneous Ig with appropriate premedication.
— Verify diagnosis and prior reaction history in the chart.
— Notify blood bank ≥48 hours before elective transfusion for IgA-deficient or washed product procurement.
— RBC washing reduces residual plasma IgA to negligible levels and takes ~1 hour — plan accordingly.
— Confirm 2 IV access points, baseline vitals, type & crossmatch, informed consent including discussion of anaphylaxis risk.
— Start slowly (initial 15 minutes at low rate); bedside nursing observation.
— Vital signs at 0, 15 min, then per protocol.
— Epinephrine, airway equipment, IV fluids immediately available.
— STOP transfusion immediately. Disconnect tubing at the IV catheter, not at the bag.
— Maintain IV access with normal saline through new tubing.
— IM epinephrine 0.3–0.5 mg (1:1000) mid-anterolateral thigh; repeat every 5–15 minutes as needed.
— High-flow oxygen; prepare for intubation if stridor/airway compromise.
— IV fluids 1–2 L NS bolus for hypotension; pressors (norepinephrine) if refractory.
— Adjuncts: diphenhydramine 50 mg IV, methylprednisolone 125 mg IV, H2 blocker (famotidine 20 mg IV), nebulized albuterol for bronchospasm.
— Send the blood bag, tubing, and a new sample of recipient blood to the blood bank.
— Order DAT, plasma free hemoglobin, urinalysis for hemoglobinuria, repeat type & screen, post-reaction tryptase — to exclude alternative reaction types.
— Continue close monitoring for biphasic anaphylaxis for at least 4–6 hours.
— Add allergy alert and blood bank flag in EMR: "IgA deficiency — washed/IgA-deficient products only."
— Provide patient with a MedicAlert bracelet and wallet card.
Step 3 management: The single most important first action in any suspected severe transfusion reaction is STOP the transfusion and keep the IV line open with saline — then assess, treat anaphylaxis with epinephrine, and notify the blood bank.
— Diagnosis is often made late in life, sometimes incidentally during workup for chronic sinusitis, bronchiectasis, or autoimmune disease.
— Higher cumulative risk of having been previously transfused or pregnant → higher prevalence of anti-IgA antibodies.
— Greater frequency of comorbidities requiring transfusion (GI bleeds, surgery, malignancy) — proactive blood bank planning is critical.
— Increased risk of medication-induced hypogammaglobulinemia confounding diagnosis: chronic phenytoin, sulfasalazine, rituximab (rheumatology/oncology patients) — always review the med list before labeling as primary SIgAD.
— Aggressive pneumococcal (PCV20 or PCV15→PPSV23 sequence), annual influenza, RSV (≥60), Tdap, herpes zoster (Shingrix, inactivated — safe), COVID-19 boosters.
— Avoid live attenuated influenza (LAIV) regardless of age in immunocompromised contexts.
— No dose adjustment of immunoglobulins based on renal function specifically, but IVIG can precipitate AKI (sucrose-stabilized preparations are highest risk — largely off market). Use sucrose-free, lower-osmolarity preparations.
— Hydrate well during IVIG infusion; monitor BUN/Cr.
— Adjust antibiotic dosing (e.g., levofloxacin, beta-lactams) for CrCl.
— Transfusion-transmitted hepatitis is a particular concern in chronically transfused patients — confirm donor screening, vaccinate against HAV/HBV.
— Coagulopathy from cirrhosis may require FFP — in SIgAD this means sourcing IgA-deficient FFP or accepting risk with premedication; prothrombin complex concentrates (PCC) are often preferable because they contain minimal plasma and therefore minimal IgA.
— Address transfusion preferences early; some patients with recurrent anaphylaxis opt for non-transfusion strategies (IV iron, EPO, tolerating lower Hgb thresholds).
Board pearl: In a cirrhotic SIgAD patient with active bleeding, 4-factor PCC is often preferred over FFP for urgent reversal because it delivers clotting factors with minimal plasma volume and minimal IgA exposure.
— Do not diagnose SIgAD before age 4 — IgA matures gradually; transient low IgA in toddlers often normalizes.
— Many children have transient IgA deficiency that resolves by school age.
— Repeat quantitative immunoglobulins at age 4 to confirm.
— Recurrent otitis media, sinusitis, and giardiasis are typical pediatric presentations.
— Routine childhood vaccinations: inactivated vaccines safe; live vaccines (MMR, varicella, rotavirus) generally safe in pure SIgAD unless CVID features develop.
— Screen for celiac disease with IgG-based serologies (tTG-IgG, DGP-IgG) because tTG-IgA is uninterpretable.
— Most SIgAD pregnancies are uncomplicated.
— Pregnancy is a sensitizing event — fetomaternal exchange can drive anti-IgA antibody development; document SIgAD status early and counsel about future transfusion risks.
— Anti-D (RhoGAM) administration in Rh-negative SIgAD mothers: anti-D immune globulin contains IgA and has been associated with anaphylaxis in SIgAD; use IgA-depleted preparations when available, or premedicate and observe.
— Plan delivery at a center with blood bank capability to source washed RBCs / IgA-deficient FFP in case of postpartum hemorrhage. Crossmatch in advance for high-risk deliveries (placenta previa, prior PPH, anticoagulation).
— Consider autologous blood donation in advance for elective C-section in known severe cases — though this is now uncommon.
— Iron optimization antenatally (oral or IV iron) to reduce transfusion need.
— Maternal SIgAD does not preclude breastfeeding; infants receive maternal IgG passively and produce their own IgA over time.
— Mothers can breastfeed safely; counseling should reassure.
— If a neonate of an SIgAD mother needs transfusion, no special precautions are required for the infant unless the infant is also confirmed SIgAD (rare/premature to diagnose).
Key distinction: In Rh-negative pregnant SIgAD patients, RhoGAM is not contraindicated — but use IgA-depleted anti-D preparations and administer in a monitored setting with epinephrine available.
— Anaphylactic transfusion reaction — most feared; can be fatal if unrecognized.
— Severe bacterial pneumonia, sepsis from encapsulated organisms.
— Chronic giardiasis with malabsorption, weight loss, and failure to thrive in children.
— Severe sinusitis with intracranial extension (rare).
— Bronchiectasis from repeated lower respiratory infections — leads to chronic productive cough, hemoptysis, progressive lung function decline.
— Chronic rhinosinusitis with nasal polyps.
— Chronic otitis media with conductive hearing loss in children.
— Malabsorption from undiagnosed/persistent celiac disease.
— Celiac disease (10–15%): screen all SIgAD patients with IgG-based serologies.
— SLE, RA, Sjögren syndrome, autoimmune thyroiditis (Hashimoto, Graves), type 1 diabetes, ITP, autoimmune hemolytic anemia, pernicious anemia, vitiligo, myasthenia gravis.
— Screen periodically based on symptoms; low threshold for autoimmune workup.
— Asthma, allergic rhinitis, eczema, food allergy — higher prevalence than general population; manage standardly.
— Slightly increased risk of GI lymphomas and gastric adenocarcinoma, particularly with concomitant celiac disease or progression to CVID.
— Counsel on smoking cessation and GI symptom vigilance.
— A minority of SIgAD patients progress to common variable immunodeficiency over years, marked by falling IgG and impaired vaccine responses → increased infection severity and need for Ig replacement.
— Anaphylaxis from IVIG, anti-D, or trace blood products in immune globulin preparations.
— Antibiotic-associated C. difficile in patients on frequent antibiotic courses.
Board pearl: Any SIgAD patient with chronic productive cough or recurrent pneumonia needs a high-resolution chest CT to evaluate for bronchiectasis — its presence changes long-term management to include airway clearance, chronic macrolide consideration, and pulmonology referral.
— Anaphylactic transfusion reaction with airway compromise, refractory hypotension, or need for vasopressors → ICU admission for monitoring at least 24 hours (biphasic anaphylaxis risk).
— Sepsis from any source in a patient with concomitant CVID-like immune dysfunction.
— Severe pneumonia with hypoxemia requiring NIV or intubation.
— Massive transfusion scenarios where rare-product logistics intersect with hemorrhagic shock.
— Allergy/Immunology: confirm diagnosis, evaluate for evolution to CVID, guide Ig replacement decisions, manage atopic comorbidities, provide patient education.
— Hematology / Transfusion Medicine: essential for transfusion planning, anti-IgA antibody testing, sourcing IgA-deficient products from rare-donor registries.
— Pulmonology: bronchiectasis management, chronic airway clearance, evaluation for nontuberculous mycobacteria.
— Gastroenterology: celiac biopsy confirmation, chronic diarrhea workup, nutritional support.
— Rheumatology: for autoimmune comorbidities.
— ENT: chronic sinusitis with surgical considerations.
— Pneumonia: use CURB-65 and PSI as usual but with lower threshold for admission given immune compromise.
— Acute giardiasis with severe dehydration: IV rehydration admission.
— Suspected transfusion reaction: keep patient monitored ≥4–6 hours; admit for observation if any hemodynamic instability or respiratory symptoms persisted.
— On transfer between units or facilities, explicitly communicate SIgAD status and blood product requirements — this is a recognized transition-of-care safety event when missed.
— Verify allergy/EMR alerts are active and visible across the institution.
— Reconcile blood bank records when patient moves between hospital systems.
CCS pearl: When admitting a known SIgAD patient, early consult orders to "Transfusion Medicine" and "Allergy/Immunology" plus an EMR allergy/precaution flag for "IgA deficiency — IgA-deficient or washed products only" are graded actions that demonstrate longitudinal Step 3 thinking.
— Low IgG plus low IgA and/or IgM, impaired vaccine responses.
— Recurrent sinopulmonary infections, autoimmunity, granulomatous disease, splenomegaly.
— Higher infection severity; requires scheduled Ig replacement.
— Key distinction: CVID has low IgG (the defining feature); SIgAD has normal IgG.
— Male infants, recurrent severe bacterial infections after 6 months as maternal antibodies wane.
— All immunoglobulin classes low, absent B cells on flow cytometry.
— Requires lifelong Ig replacement.
— High or normal IgM, low IgG and IgA. Recurrent pyogenic infections plus opportunistic infections (Pneumocystis, Cryptosporidium).
— Often X-linked (CD40L deficiency).
— Normal immunoglobulin levels but poor response to polysaccharide vaccines (pneumococcal).
— Diagnosed by pre-/post-vaccination titers.
— Total IgG normal but one or more subclasses low.
— IgG2 deficiency particularly affects polysaccharide responses.
— Can coexist with SIgAD → more severe phenotype.
— Low IgG in infants beyond physiologic nadir; usually self-resolves by 2–4 years.
— Pure low IgA + normal IgG/IgM + age ≥4 → SIgAD.
— Low IgG + low IgA + poor vaccine response in adult → CVID.
— Recurrent severe infections + absent B cells in infant male → XLA.
— Normal Ig levels but recurrent sinopulmonary infections → check specific antibody / subclass deficiency.
Key distinction: Both SIgAD and CVID can present with sinopulmonary infections and autoimmunity, but SIgAD has normal IgG. If serial IgG levels are falling, the patient is transitioning to CVID and now needs immunoglobulin replacement.
— Fever, flank/back pain, hemoglobinuria, DIC, AKI.
— Positive DAT, elevated plasma free hemoglobin, low haptoglobin.
— Usually clerical error; intravascular hemolysis.
— Fever + chills 1–6 hours into transfusion; mild.
— Cytokines from donor leukocytes; mitigated by leukoreduction.
— Treat with acetaminophen.
— Hives only, no systemic features.
— Pause transfusion, give diphenhydramine, resume if symptoms resolve.
— Key distinction from anaphylaxis: no hypotension, no airway involvement.
— Hypoxia + bilateral pulmonary infiltrates within 6 hours of transfusion; fever and hypotension common.
— Donor anti-HLA/anti-neutrophil antibodies; treat supportively, often requires intubation.
— Hypertension, JVD, pulmonary edema, dyspnea; older or cardiac patients.
— Treat with diuresis, slow transfusion rate.
— Days to weeks post-transfusion; mild hemolysis, falling Hgb, positive DAT.
— Drugs: phenytoin, valproate, carbamazepine, sulfasalazine, gold, penicillamine, mycophenolate, rituximab.
— Infections: HIV, EBV, CMV.
— Malignancy: thymoma (Good syndrome), CLL, multiple myeloma.
— Protein loss: nephrotic syndrome, protein-losing enteropathy, severe burns.
— Ataxia-telangiectasia: SIgAD + cerebellar ataxia + ocular telangiectasias + radiosensitivity + malignancy risk.
Board pearl: The discriminator between anaphylactic (IgA-related) and other transfusion reactions on Step 3 is the timing (minutes), the absence of fever, and the presence of bronchospasm + hypotension + urticaria. Fever in the first hour points to FNHTR or acute hemolysis instead.
— MedicAlert bracelet and wallet card stating "Selective IgA deficiency — requires washed or IgA-deficient blood products."
— EMR allergy flag and blood bank registry entry at every institution where the patient receives care.
— Patient and family education on transfusion risk and on need to disclose diagnosis before any surgery, pregnancy, or trauma care.
— Up-to-date inactivated vaccinations: annual influenza, pneumococcal (PCV20 or PCV15→PPSV23), Tdap every 10 years, HPV through age 26 (or up to 45 by shared decision), zoster (Shingrix) at age 50+, COVID-19 boosters, RSV ≥60 or per indication, HAV/HBV based on serology.
— Hand hygiene, water safety (avoid untreated water → Giardia), prudent antibiotic use.
— Prophylactic antibiotics (azithromycin) only for severe, recurrent infection phenotypes — typically under immunology guidance.
— Annual review for autoimmune disease symptoms; targeted testing as indicated.
— Celiac screening with IgG-based serologies at diagnosis and rescreen if new GI symptoms; biopsy confirmation if positive.
— TSH every 1–2 years to screen for thyroid autoimmunity.
— Periodic CBC for cytopenias.
— Pulmonology follow-up if bronchiectasis — airway clearance, sputum cultures (consider NTM), pulmonary rehab.
— Annual quantitative immunoglobulins (IgG, IgA, IgM) to detect evolution to CVID.
— Vaccine response testing if clinical picture worsens (rising infection frequency, falling IgG).
— Smoking cessation strongly emphasized — protects bronchiectasis risk.
— Influenza vaccination of household contacts.
— Pre-pregnancy counseling for women: transfusion planning, RhoGAM considerations.
Step 3 management: The longitudinal SIgAD care plan = lifelong blood bank precaution + annual immunoglobulin monitoring + autoimmune/celiac surveillance + aggressive vaccination + MedicAlert identification — frame it as a coordinated outpatient package.
— Annually: quantitative immunoglobulins (IgG/IgA/IgM), CBC, comprehensive metabolic panel, TSH, urinalysis. Review infection frequency and severity.
— Every 1–2 years: celiac screening with IgG-based serologies if not previously confirmed; review autoimmune symptoms.
— Allergy/Immunology visit annually or every 2 years for stable patients; more often during diagnostic workup or evolving disease.
— Pulmonary follow-up every 6–12 months for bronchiectasis with PFTs and sputum cultures.
— Post-transfusion reaction: observe ≥4–6 hours for biphasic anaphylaxis; trend tryptase if drawn; ensure documentation in chart and blood bank.
— Post-pneumonia: chest X-ray at 6–8 weeks to confirm resolution; consider HRCT if not resolving (rule out underlying bronchiectasis or NTM).
— Post-IVIG (if used): monitor renal function, hemoglobin (hemolysis), thrombosis symptoms.
— Always disclose SIgAD diagnosis to every healthcare provider, EMS, and dentist.
— Carry a wallet card and wear MedicAlert.
— Avoid sharing the diagnosis ambiguously — be specific about "blood transfusion anaphylaxis risk."
— Recognize early anaphylaxis symptoms: hives, throat tightness, wheezing, lightheadedness; call 911.
— Caution with OTC products containing trace blood derivatives (rare) and certain IVIG-derived therapies.
— Discuss family screening: first-degree relatives have higher SIgAD prevalence; counsel about testing if symptomatic.
— Daily airway clearance (oscillating PEP devices, chest physiotherapy).
— Annual sputum culture for typical organisms and nontuberculous mycobacteria.
— Consider macrolide maintenance (azithromycin 3x/week) in frequent exacerbators — first rule out NTM.
— When transferring care between providers or systems, ensure the SIgAD diagnosis, anti-IgA antibody status, prior reaction history, and current vaccination record travel with the patient.
CCS pearl: "Schedule follow-up: Allergy/Immunology in 4 weeks; primary care in 3 months with quantitative immunoglobulins" is a high-value chronic-care order set that embodies Step 3's longitudinal thinking.
— In a known SIgAD patient, consent must explicitly include the anaphylaxis risk and the plan to use washed or IgA-deficient products.
— In emergencies where rare products are unavailable, document a risk-benefit discussion with patient or surrogate; if patient is incapacitated, proceed under emergency exception with implied consent and use of all available mitigation (premedication, monitored setting).
— Failure to communicate SIgAD status across care transitions is a recognized sentinel event risk. EMR allergy flags, blood bank registries, and verbal handoff are all required redundancies.
— Standard "5 rights" of transfusion administration must be augmented with verification of product type (washed vs. standard) for SIgAD patients.
— On hospital transfer, send blood bank records with the patient and verify on arrival.
— Severe transfusion reactions are reportable to the hospital transfusion committee and often to FDA MedWatch or AABB hemovigilance systems.
— Documentation must include reaction onset, vitals, treatment, product details, and laboratory workup.
— Jehovah's Witness patients with SIgAD: dual constraints — religious refusal of blood products and immunologic intolerance. Discuss bloodless surgery techniques, IV iron, EPO, cell salvage (autologous, generally acceptable). Document advance directives.
— Pediatric SIgAD: parents must be educated and may need to advocate for the child during emergency care. Consider school nurse and emergency contact education.
— Family screening: offer testing to symptomatic first-degree relatives; do not test asymptomatic minors without clear indication (genetic ethics).
— IgA-deficient blood products are scarce national-registry resources. Coordinate with blood bank to avoid waste; consider autologous donation in advance for planned procedures when feasible.
— Always document allergy alerts, prior reactions, plan for future transfusion, and patient education in the chart.
— Discharge instructions after any reaction must include MedicAlert recommendation, follow-up plan, and emergency action plan.
Board pearl: A missed SIgAD allergy flag during a transfer that leads to standard-product transfusion and anaphylaxis is a classic root-cause-analysis vignette — the failure is at the handoff and EMR alert step, not at the bedside.
— Most common primary immunodeficiency in people of European ancestry; 1:300–1:700.
— Strong familial clustering; HLA-DR/DQ associations.
— Genetic overlap with CVID; some shared TACI/TNFRSF13B variants.
— Serum IgA <7 mg/dL, normal IgG and IgM, age ≥4 years, no secondary cause.
— Celiac disease (10–15%) — use IgG-based serologies.
— Giardia infections — chronic diarrhea, malabsorption.
— Autoimmune disease: SLE, RA, ITP, AIHA, type 1 DM, autoimmune thyroiditis, pernicious anemia.
— Atopy: asthma, allergic rhinitis, food allergies.
— Bronchiectasis with recurrent pneumonias.
— Anaphylaxis mechanism: anti-IgA antibodies (often IgG class) react with donor IgA.
— Onset: minutes after transfusion start.
— Distinctive feature: no fever.
— Product choice: IgA-deficient donor products → washed RBCs → premedicate + monitored standard product in emergencies.
— FFP/cryo cannot be washed effectively → must come from IgA-deficient donors.
— PCC preferred over FFP for urgent factor replacement.
— IgA-depleted IVIG or SCIG when Ig replacement needed.
— RhoGAM: use IgA-depleted preparations.
— Drugs lowering IgA: phenytoin, sulfasalazine, mycophenolate, rituximab.
— Ataxia-telangiectasia: SIgAD + cerebellar ataxia + ocular telangiectasias + AFP elevation + lymphoma risk.
— Good syndrome: thymoma + adult-onset hypogammaglobulinemia (different entity).
— Live vaccines generally safe in pure SIgAD (unlike severe T-cell deficiencies).
— Falling IgG over time → CVID transition → Ig replacement therapy.
Key distinction: SIgAD is the most common but mildest primary immunodeficiency; the high-stakes complication is transfusion anaphylaxis, not opportunistic infection.
— A 32-year-old woman receives 1 unit of RBCs for postpartum hemorrhage. Within 5 minutes, she develops generalized urticaria, wheezing, BP 80/50, no fever. Past history: recurrent sinusitis, celiac disease.
— Answer: Selective IgA deficiency with anti-IgA antibodies; stop transfusion, give IM epinephrine, use washed RBCs or IgA-deficient products for future transfusions.
— Adult with chronic diarrhea, iron deficiency, weight loss. tTG-IgA negative. Quantitative IgA undetectable.
— Answer: Repeat celiac workup with tTG-IgG or DGP-IgG; do not exclude celiac based on negative IgA-based serology.
— Patient with known SIgAD scheduled for elective hip replacement; estimated blood loss may require transfusion.
— Answer: Notify blood bank ≥48 hours in advance to arrange washed RBCs; type and crossmatch; ensure EMR allergy alert is active.
— Patient with recurrent infections is started on IVIG and develops anaphylaxis on first infusion. Workup reveals undetectable IgA.
— Answer: Discontinue standard IVIG; use IgA-depleted IVIG or subcutaneous Ig; premedicate.
— Rh-negative SIgAD pregnant woman at 28 weeks needs anti-D prophylaxis.
— Answer: Use IgA-depleted anti-D preparation; administer in monitored setting; do not withhold RhoGAM.
— Reaction within minutes with hives + bronchospasm + hypotension + no fever → IgA-mediated anaphylaxis.
— Reaction with fever + flank pain + dark urine → acute hemolytic.
— Reaction with fever + chills only → FNHTR.
— Hypoxia + bilateral infiltrates within 6 hours → TRALI.
— Hypertension + JVD + pulmonary edema → TACO.
— SIgAD patient now with falling IgG over years, worsening pneumonias, poor pneumococcal titers.
— Answer: Diagnose CVID; initiate immunoglobulin replacement therapy.
Board pearl: Master the transfusion-reaction matrix (timing + fever + airway + BP + UA findings) — Step 3 frequently tests SIgAD by hiding it inside a comparative transfusion-reaction stem.
— Diagnose: IgA <7 mg/dL, normal IgG/IgM, age ≥4, exclude drugs (phenytoin, sulfasalazine, MMF, rituximab) and secondary causes (HIV, thymoma, protein loss).
— Transfusion plan: IgA-deficient donor products first; washed RBCs for cellular products; PCC over FFP for urgent factor replacement; IgA-depleted IVIG/SCIG if Ig replacement is needed; in true emergencies, premedicate (steroids, antihistamines) and transfuse in a monitored setting with epinephrine at bedside.
— Reaction recognition: Anaphylaxis within minutes, hives + bronchospasm + hypotension, no fever → STOP transfusion, IM epinephrine 0.3–0.5 mg, NS through new tubing, return product to blood bank, observe ≥4–6 hours for biphasic reaction.
— Longitudinal care: Screen celiac with IgG-based serologies, evaluate for autoimmune disease (SLE, RA, thyroid, type 1 DM), aggressively vaccinate with inactivated vaccines, monitor annually for progression to CVID (falling IgG, poor vaccine responses), assess for bronchiectasis with HRCT if recurrent pneumonia, and ensure MedicAlert bracelet + EMR allergy flag + blood bank registry entry travel with the patient across every care transition.
Step 3 management: The single most testable action — for any SIgAD patient about to receive a blood product — is to notify the blood bank in advance and request washed RBCs or IgA-deficient donor products, with epinephrine and monitored-bed precautions in place.