[IgM antibody deficiency with normal serum IgM concentration in a family (author's transl)].

A 5 years old child with selective antibody deficiency having slight hypogammaglobulinaemia of the IgG-class, normal IgM and absence of IgA has been described. The patient had no isoagglutinins and no heteroagglutinins against rabbits. Antibodies of the IgG-class could be detected in a very low concentration. The child had repeated severe infections, f. e. 5 attacks of pneumonia. After diagnosis of selective antibody deficiency syndrome had been made, he has been treated with high dose gammaglobulin therapy every 4 weeks. The child did not have any severe infections since that time. Diagnostic and therapeutic possibilities in patients with selective antibody deficiency were discussed.