Serum levels of interleukin-1β, luteinizing hormone, and prolactin correlate with the expression of CD45 isoforms on CD4+ peripheral blood T lymphocytes in healthy women

 The expected association between age and the CD45 isoforms expression on CD4+ T-PBL is much more obvious in men than in women. We investigated whether or not circulating factors influence the differentiation of CD4+ T-PBL. Peripheral blood samples were obtained from 56 healthy age-matched subjects (28 men and 28 women, 21–55 years old). Mononuclear leukocytes were analyzed by three-color flow cytometry. The serum concentrations of interleukin-1β (IL-1β), interleukin-6, tumor necrosis factor-α (TNF-α), GM colony-stimulating factor, prolactin (Prl), and luteinizing hormone (LH) were determined by ELISA. The expected age-related decrease of naive (CD45RA+,RO–) cells and increase of memory (CD45RA–,RO+) cells among CD4+ T-PBL were observed in men only (p<0.001 and 0.005). In women, these correlations were not significant. On the other hand, in women only, elevated IL-1β was associated with fewer naive and more memory cells among CD4+ T-PBL (p<0.001). In both sexes, IL-1β correlated with the expression of CD25 on CD4+ T-PBL (on either naive or memory cells, p<0.001). Other cytokines or the CD8+ T-PBL showed no significant correlation. In women, the elevation of LH at mid-cycle inversely correlated with the proportion of naive CD4+ T-PBL (p<0.01). Elevated LH was associated with more CD25 on memory CD4+ T-PBL (p<0.01). A significant correlation exists between IL-1β and LH (p<0.001). Furthermore, in both sexes, Prl correlated with the proportion of CD4+ cells among T-PBL. In men, elevated Prl was associated with more naive CD4+ T-PBL (p<0.005), while in women, Prl correlated with more transient CD45RA+, RO+ cells among CD4+ T-PBL and increased TNF-α (p<0.05 for both). Thus, circulating IL-1β could be involved in the expression of CD25 on CD4+ T-PBL and favors the generation of memory CD4+ T-PBL. In women, the IL-1β- and/or mid-cycle-dependent processes seem to overwhelm the age-related changes. Elevated Prl might exert a dual influence: it favors the development of naive CD4+ T lymphocytes and possibly acts in, synergy with other cytokines during immune stimulation. Received: 20 June 1997 / Accepted: 1 August 1997