Raised serum levels of CD8, CD25 and beta 2-microglobulin in common variable immunodeficiency.

Soluble CD8, soluble CD4, soluble CD25 (IL-2 receptor), beta 2-microglobulin and the cytokine tumour necrosis factor-alpha (TNF-alpha) were measured in sera from patients with common variable immunodeficiency (CVI). Levels of soluble CD8, soluble CD25 and beta 2-microglobulin but not of soluble CD4 and TNF-alpha were raised significantly above levels in normal sera. Sera from patients with X-linked agammaglobulinaemia, who are also antibody deficient, did not show this marked elevation. The raised levels of soluble CD8, soluble CD25 and beta 2-microglobulin in CVI, correlated with the extent of the defects in the B lymphocytes assessed in vitro, as well as with the clinical severity of the disease. The selective release of these molecules into sera may indicate that abnormal cellular activation occurs in most CVI patients. It is also possible that the raised levels of these soluble molecules play a part in the immunodeficiency.