Immunoglobulin deficiency with increased immunoglobulin M in three siblings: effect of long-term immunoglobulin therapy.

Diagnosis of immunoglobulin deficiency with increased IgM (hyper-IgM syndrome) was made in three siblings (two girls and a boy) on the basis of history, physical findings, and laboratory data. The prominent clinical findings were recurrent viral and bacterial infections of the respiratory tract. The most severe infections affected the male patient, who died at the age of 8 years. Family history and the lack of clinical signs in the parents and relatives indicated no immunodeficiency which, together with the occurrence of the disease in both sexes, indicated an autosomal recessive inheritance. The two female patients (18 years old and 3 years old) have been treated with intravenous acid-treated immunoglobulin for 2 years, resulting in significant clinical improvement with respect to the frequency and severity of infections.