Regarding agammaglobinemia… I was talking about the fact that it’s a B-cell def. So titers for tetanus and diphtheria will be low even after immunization. ABP likes for you to know that fact and can test around that information in many different ways. Here’s the updated section:
TITERS
If you suspect a B-cell (aka Humoral) deficiency, test for it by obtaining antiBody TITERS for something the child was already immunized against, such as TETANUS (testing for tetanus titers in patients with Agammaglobulinemia, a B-cell deficiency, is a an ABP favorite way of testing your knowledge). Could also test for titers against Diphtheria and Streptococcus/Pneumococcus. Do not get confused with getting SKIN TESTING for tetanus/Candida/Mumps/PPD which all test for T-cell mediated (aka cellular) immunity.
PEARLS:
* Infections related to B-cell deficiencies rarely occur before 6 months of age because of presence of maternal antibodies.
* ANTIBODY SUBCLASSES: If IgG levels are in the normal range but you still have a high suspicion for a B-cell/Humoral defect, consider checking for the presence of Ig subclasses for Tetanus, Pneumococcus, etc.