HUMAN RESIDENT PERITONEAL-MACROPHAGES - PHENOTYPE AND BIOLOGY

Macrophages represent the primary line of host defences in the periton eal cavity. In order to study the metabolic activity and maturation st age of human resident peritoneal macrophages (PM phi), peritoneal flui d (PF) was taken by Douglas puncture from healthy hyperstimulated infe rtile women undergoing oocyte retrieval for in vitro fertilization. Pe ritoneal fluid and macrophage culture fluids were studied for differen t inflammatory mediators such as interleukin-1 (IL-1), tumour necrosis factor (TNF) and interleukin-6 (IL-6). The level of macrophage colony -stimulating factor (M-CSF), which represents a macrophage proliferati on and differentiation factor, was determined in the PF and in the ser um. Furthermore, the macrophage phenotypic profile was analysed, in pa rticular the expression of sex steroid hormone receptors. IL-1, IL-6 a nd TNF were detectable in the PF and in the culture supernatants of PM phi whether stimulated or not by IFN-gamma and LPS. The mean level of M-CSF in the PF was 6.37 +/- 2.02 ng/ml as measured by RIA; this leve l did not correlate with the concentration of PM phi. The mean PF-M-CS F level was 1.4-fold higher than in the sera as measured by a EIA. Oes trogen and progesterone receptors could not be demonstrated on the PM phi analysed, so that a direct relationship between the ovarian steroi d concentration in these women and the function of PM phi was unlikely . As compared to peripheral blood monocytes (Mo), PM phi showed a phen otypic profile, with some more mature features, e.g. increased express ion of CD14, CD68, FcRII, FcRIII, CR3, CR4 and MHC class II determinan ts. These results indicate that resident PM phi have acquired in vivo a certain differentiation and/or activation state under microenvironme ntal factors where cytokines secreted by the M phi themselves or by ot her cells such as the mesothelium may play important roles.