Lethal pneumococcal infection in an 18-month-old girl with splenic hypoplasia and dysgammaglobulinemia

Abstract.

We report the case of an 18-month-old girl who died of overwhelming pneumococcal sepsis. Autopsy revealed a small spleen with unusual architecture. There was a marked rarefaction of the white pulp with only very few but florid germinal centers. Immunohistochemical staining showed a low number of T and B lymphocytes in the spleen, whereas normal numbers and distribution of lymphocytes were found in all other primary and secondary lymphatic organs. Whereas levels of IgM were normal, IgA and IgG levels were significantly lower than in age-matched controls. Consistent with serological data, B cells mainly expressed IgM and IgD, whereas IgG expression was lower than expected. Additionally, intestinal immunoglobulin distribution in B-cell areas of lymphofollicular hyperplasia showed normal expression of IgM, but almost no expression of IgA. A review of the literature failed to disclose a similar case of dysgammaglobulinemia associated with isolated structural spleen anomalies. We propose that the patient suffered from a defect of the B-cell differentiation pathway.