TOPICS: B cell disorder, T cell disorder, immunoglobulins (Ig), lymph node, germinal centers, T cell receptor excision circles (TRECs), absent T cells, fly cytometry, absent thymic shadow, IL-2R gamma chain, X-linked recessive, adenosine deaminase, autosomal recessive, thrush, recurrent infections, failure to thrive, antimicrobial prophylaxis, live vaccines, bone marrow transplant, intravenous immunoglobulins (IVIG)