CONICET | Buscador de Institutos y Recursos Humanos

Macroprolactin (MPRL) is a prolactin (PRL)-IgG complex, frequently found in hyperprolactinemic individuals and usually showing minimun clinical symptoms. On the other hand, PRL induces immunoglobulin production in vitro. It is known that asymmetrically glycosilated IgG molecules (AAb), which posses an oligosaccharide group in one of the Fab fragments, cannot bind large ligands and are unable to activate effector mechanisms. The AAb synthesis can be modulated by IL-6, estrogen, progesterone and glucocorticoids. We investigated the asymmetric/symmetric IgG ratio (ELISA test before and after Concanavalin A-Sepharose affinity chromatography) as well as the levels of IgG, IgA, IgM (IDR) and IL-6 (ELISA) in MPRL serum samples in comparison with hyperprolactinemic and normal sera as control. The results demonstrated: 1) The percentage of AAb was not modified in MPRL serum (control:26.8±2.4, n=10, MPRL:32.1±2.7, n=9). Similar results were obtained with high levels of PRL (PRL>50 ng/ml, 28.9±2.4, n=11). In contrast, this proportion increased when PRL was slightly elevated (PRL 24-50ng/ml:42.4±2.5, n=14, p<0.05 vs control). 2) Total IgG was significantly increased in MPRL and hyperprolactinemia (control:1106±91mg/dl, n=10; MPRL:1527.7±102.4, n=9, p<0.05; PRL>50 ng/ml:1488.9±104.2, n=9, p<0.05 vs control; PRL 24-50ng/m:1511.0±101.8, n=12, p<0.05 vs control). 3) No differences were observed in IgA, IgM and IL-6 serum levels between groups. These data suggest that in correlation with the absence of clinical endocrine sympthomatology the macroprolactinemia would not modify the quality of the immune response (AAb) in contrast to which observed when PRL is elevated, however, total IgG was increased as well as in hyperprolactinemia.