A relationship of the levels of thymic peptide antibodies to those of the population and subpopulations of T lymphocytes was studied in patients with pulmonary tuberculosis, lung or breast cancer. Indirect immunofluorescence was used to determine the count of CD3-, CD4-, CD80, CD38-, CD25-, CD71-, and CD95-lymphocytes. The levels of thymic peptide antibodies were estimated by enzyme immunoassay. Unlike cancer diseases, pulmonary tuberculosis was characterized by the combination of a significantly inverse correlation between the relative count of CD3-, CD4-, CD8-lymphocytes the levels of thymogen antibodies with a significantly direct correlation between the absolute count of CD25- and CD38-lymphocytes. The studies may recommend that the levels of thymic peptide antigens should be determined to select persons with immunodeficiency particularly those with inflammatory diseases.