An adult diagnosed as hyper-IgM immunodeficiency syndrome.

A 27-year-old male who visited our hospital because of pneumonia was diagnosed as hyper-IgM immunodeficiency syndrome. His serum IgM level was markedly elevated, while the serum level of IgD was normal with a markedly decreased level of serum IgG and IgA. The proportion of T and B cells of peripheral blood lymphocytes was normal. However, B cells bearing surface IgG or IgA were not detectable by immunofluorescence technique. There was a consanguineous marriage in his family, suggesting that his disorder was caused by a genetic abnormality such as X-linked recessive and also autosomal recessive inheritance, although further study is necessary. CD40 ligand cDNA did not appear to contain any abnormal changes within the coding region.