B-cell defects Overview
X-linked Agammaglobulinemia (XLA), Brutons
Agammaglobulinemia
Common Variable Immunodeficiency (CVID)
Hyper IgM syndrome
IgA deficiency
IgG subclass deficiency
Transient
Hypogammaglobulinemia of Infancy
X-linked
lymphoproliferative disorder (XLP)
Mnemonic: Breasts Can Cake A Girl Too X-rated.
B-cell defects are the most common primary immunodeficiency
Presentation:
- recurrent infections with encapsulated bacteria.
- most viral infections are tolerated well
- Sino pulmonary infections.
- Organisms: S.pneumo, H.influ, S. Aureus, Pseudomonas, mycoplasma,
salmonella, shigella
- H/O failure to respond to Abxtreatment
- Enteroviral infections (CNS)
- Giardial infections (GI)
- NoFTT or early deaths unless complications
Evaluation of B-cell system:
Quantitative:
- QUIGs-check serum Ig concentrations. Check IgE if concerned about Hyper
IgE.
- B-cell Enumeration-via flow cytometry (B cell is precursor of plasma cells
which produce Ab’s)
Functionality:
- Check titers for immunizations eg tetanus, Hib, MMR, Prevnar, DTP.
Brief summaries:
XLA
- Males presenting at 6-9mo
- Recurrent sinopulminfxns
- Vaccine-associated polio after OPV
- CNS enteroviralinfxns
- hypogammaglobulinemia; Hypoplasia of lymphoid tissue
THI
- Boys & girls presenting at 4-9 mos
- Recurrent sinopulminfxns
- not life threatening
- respond approprto Abxs
- Normal lymphoid tissue
- Have Abs to shots (ie ab to diptheria and tetanus toxoids)
CVID
- Boys and girls presenting later (usu around 10yo)
- Recurrent sinopulminfxns
- EnteroviralCNS infxns rare
- Lymphoid tissue present
- Assoc: sprue, AI diseases
IgA deficiency
- Normal B cells, but no IgA
- Most Asx; recurrent respiratory, GI, GU infxns.
- Anaphylaxis to blood products
- Can evolve into CVID
- Assoc: IgG2/4 def, AI diseases
IgG2 deficiency
- Hib infxnsafter immunizations
- Assoc: IgA def XLP
HyperIgM (also listed under T-cell defects)
- Males w/recurrent sinopulminfxns in 1st-2ndyear of life
- Can’t produce IgG and A
- Lymphoid hyperplasia
- PCP infections
- Extensive verruca vulgari
Hyper IgE syndrome (Job syndrome)
- Boys and girls
- Recurrent staphabscesses
- Pruriticdermatitis
- Pneumatoceles
- Eosinophilia
CHLA Board Review 2005