Immune competence in patients with Klinefelter syndrome.

We studied cellular and humoral immunity on ten patients with documented Klinefelter syndrome. Cellular immunity as measured by in vivo skin tests and in vitro lymphocyte transformation tests appeared intact. However, the mean values of T cells and EAC rosette-forming cells were significantly decreased as compared with controls. All patients had normal isoagglutinin titer. One patient failed to produce febrile agglutinin even after immunization. Some patients showed elevated levels of Immunoglobulin G (IgG) or Immunoglobulin M (IgM), probably due to the underlying diseases. Three patients had serum and secretory Immunoglobulin A (IgA) levels below normal. Classification of IgA deficiency and its associated diseases were discussed. These three patients are 38, 44, and 60 years old respectively. Long-term follow-up of these three patients can determine whether or not they will develop malignancy and autoimmune diseases. One patient with bronchogenic carcinoma and the other with autoimmune disease had normal serum and secretory IgA levels. It is possible that they had low IgA initially, but their underlying diseases brought up their IgA levels to the normal range.