[Life threatening pneumocystis carinii pneumonia in a 4-month-old boy with hyper-IgM syndrome].

At the age of four months, a boy with a normal history and family history, suddenly fell ill with a life-threatening pneumocystis carinii-pneumonia. Surprisingly, this opportunistic infection was not brought about by a T-cell deficiency. However, the patient's diagnosis turned out to be the rare "Hyper-IgM-syndrome", confirmed by: serum levels of IgM always at least normal whereas IgG, IgA and IgE were markedly decreased or absent; the development of neutropenia and occasional diarrhea. Generally, infections with pneumocystis carinii are rare in isolated deficiencies of immunoglobulines, but relatively frequent in primary "Hyper-IgM-syndrome" (approx. 12% of the cases described). The boy finally recovered after receiving Cotrimoxacol (20 mg/kg bw/d) in an intensive care unit. Now, at the age of nearly two his condition is almost good under regular substitution of IgG. Cotrimoxacol (4 mg/kg bw/d) is recommended to prevent further pneumocystis carinii infections and most of the pathogenes which frequently appear in neutropenias.