Relationship of leukocyte numbers, immunoregulatory cell function, and phytohemagglutinin responsiveness in cancer patients.

Leukocytes were quantitated in peripheral blood from 35 solid-tumor cancer patients and related to levels of phytohemagglutinin (PHA)-induced DNA synthesis. Levels of glass-adherent, indomethacin-sensitive, or 24-hour preculture-sensitive immunoregulatory activity were evaluated in PHA-stimulated peripheral blood mononuclear cells (PBMC). Cancer patients and patients with depressed PHA responses had significantly greater monocyte percentages in their PBMC than did healthy subjects; patients with normal PHA responses did not. Patients with disseminated disease had significantly greater monocyte percentages and depressed T-cell percentages than did controls; patients with at most minimum residual disease did not. When monocyte and lymphocyte percentages were correlated by linear regression analysis to PHA responsiveness, no significant correlation was found. A highly significant negative correlation was noted between PHA responsiveness and levels of immunoregulatory cell function. Abnormal immunoregulatory function, apart from alterations in peripheral blood leukocyte percentages and numbers contributes to impaired T-cell function in cancer patients.