Lymphocyte subset distribution and natural killer cell activity in men with idiopathic hypogonadotropic hypogonadism.

Sex-related differences in immune responsiveness are mediated at least in part by sex steroid hormones. Lymphocyte subset distribution in peripheral blood and natural killer cell function both have been reported to be under hormonal control. In order to gain more insight into sex steroid hormone action on the immune system, we have measured the lymphocyte subset distribution and natural killer cell activity in 18 men with idiopathic hypogonadotropic hypogonadism before treatment, and after hormonal treatment had normalized plasma testosterone levels. In untreated patients, the mean plasma testosterone concentrations were significantly lower than those in the treated men (3.0 +/- 0.5 nmol/l vs 16 +/- 1.7 nmol/l, p less than 0.001). The percentage of peripheral CD3+ lymphocytes, CD8+ cells, the CD4+/CD8+ ratio, and the natural killer cell activity of peripheral mononuclear cells measured in a 51Cr release assay against target K 562 cells did not differ between patients with idiopathic hypogonadotropic hypogonadism and healthy adults, and most importantly, did not change during hormonal treatment which normalized plasma testosterone levels in the patients. In contrast, the percentage of peripheral CD4+ cells was significantly higher in untreated patients compared with normal adult subjects or patients with idiopathic hypogonadotropic hypogonadism after hormonal treatment that resulted in normal plasma testosterone levels (53 +/- 2 vs 47 +/ 2, p less than 0.05). It should be noted that the percentage of peripheral CD16+ cells was significantly lower in untreated men with low plasma testosterone levels than in normal controls.(ABSTRACT TRUNCATED AT 250 WORDS)