[The oldest case with X-linked agammaglobulinemia in Japan lacking Bruton-type tyrosine kinase protein detected by flow cytometry].

We report a case of sporadic X-linked agammaglobulinemia previously diagnosed as variable immunodeficiency (VID). An 39-year-old male had recurrent episodes of respiratory tract infection since his early childhood. At the age of four, he developed partial paresis of the left limbs after polio immunization. After diagnosis of VID based on marked decrease of serum IgG, IgA and IgM levels and no antibody production against antigenetic stimuli at age 22 years old, he received intravenous immunoglobulin supplementation irregularly. We reexamined him and found marked decrease in B cells in the peripheral blood. In addition, we investigated the expression of Bruton-type tyrosine kinase on monocytes by flow cytometry and confirmed its deficiency. His mother was diagnosed as a carrier of XLA. The patient is probably the oldest case with XLA in Japan.