The production of pregnancy associated alpha glycoprotein (PAG) from human peripheral blood mononuclear cells.

A sensitive enzyme-linked immuno-assay has been developed which can measure the amounts of pregnancy-associated alpha 2 glycoprotein (PAG) produced by human peripheral blood mononuclear cells (MNC) in culture. Ethinyl oestradiol, indomethacin and pokeweed mitogen (PWM) stimulated PAG production directly while indomethacin produced an additional increase in PAG production by PWM-stimulated MNC probably by inhibiting the production of prostaglandins with down-regulatory effects on the MNC. Oestrogen stimulation of MNC produced significant increases in PAG levels only by the MNC of women on oral contraceptives but not from the cells of males or of females of reproductive age not on oral contraceptives. Since PAG has immunosuppressive properties these observations may be of relevance in understanding the mechanisms involved in the significant decrease in the incidence of rheumatoid arthritis in women taking oral contraceptives.