CD40LG and polycystic ovary syndrome: Hence, the variations of observed IgM titers in PCOS women may be due to different B-1a cells frequencies, responsible for spontaneous testosterone-independent secretion of natural IgM antibodies (NAbs), which represent a large extent of circulating serum IgM (Boes, 2000) that act with homeostatic housekeeping functions to multiple inflammatory reactions (Lutz et al., 2009).