The existence of insoluble-rheumatoid factor based immune complexes in menstrual fluid

The aim of this study was to examine the existence of insoluble immune complexes, composed of monoclonal rheumatoid factor (human decidua-associated protein-hDP 200) in the precipitate of menstrual fluid. The identification of precipitable immune aggregates was based on immunofluorescent staining and ELISA. Both assays demonstrated the existence of rheumatoid factor, as well as immunoglobulins IgG, IgM, IgA and IgE. The quantification of immunoglobulins by ELISA demonstrated the predominance of IgG and rheumatoid factor. Furthermore, ELISA was performed to demonstrate the rheumatoid factor activity in the precipitate obtained from menstrual fluid. Thus, the rheumatoid factor, identified by monoclonal antibody DEC 21, was demonstrated to form precipitable immune complexes, which might provide a physiological mechanism to remove the unnecessary antibodies formed due to fetal allograft or intra-uterine infection.