Raised serum neopterin levels and imbalances of T-lymphocyte subsets in viral diseases, acquired immune deficiency and related lymphadenopathy syndromes.

D-erythro-neopterin, a biochemical marker of cell-mediated immune response, was found to be significantly (p less than 0.001) elevated in the serum of homosexual patients with acquired immunodeficiency syndrome and related lymphadenopathy syndrome. The most pronounced rise was observed in viral diseases causing a numerically measurable activation of the immune system such as EBV or CMV infections. In the latter patient groups, the increase in T8+, HLA-DR+ and monocytic antigen+ lymphocyte subsets correlated with the raised neopterin level. Thus, neopterin seems to be released under various conditions in viral diseases and may reflect a functional state of T-lymphocytes irrespective of the actual number expressing differentiation antigens on the cell surface.