Early defects in B cell development.

Abstract

Recent clinical studies in patients with genetically proven X-linked or autosomal recessive agammaglobulinemia provide some guidelines that should influence our management of patients with suspected immunodeficiency. Males who are at a high risk of having X-linked agammaglobulinemia because they have an affected brother or uncle are often not evaluated for immunodeficiency until they are hospitalized for infection. Some of those who are evaluated are not started on gammaglobulin therapy immediately. More than 10% of patients with X-linked agammaglobulinemia are hospitalized for infection at less than 6 months of age, indicating that patients with known X-linked agammaglobulinemia should be started on therapy by 2-3 months of age. In patients with sporadic X-linked agammaglobulinemia, the incidence of chronic lung disease correlates with the age at diagnosis, highlighting the importance of early diagnosis. Although almost all patients who are diagnosed as having the condition at more than 12 months of age have a history of recurrent otitis, 93% are not evaluated for immunodeficiency until they are hospitalized for infection. Because the physical exam provides a clue to the diagnosis of the condition--unusually small or absent cervical lymph nodes and tonsils--it should be possible to make an early diagnosis in a greater percentage of patients. Patients with autosomal recessive agammaglobulinemia have an earlier onset of disease compared with patients with X-linked agammaglobulinemia and they are more likely to have severe complications of the disease. There is plenty of room for improvement in the diagnosis and management of patients with defects in early B cell development.