Immunological Evaluation of Male Infertility

There is considerable support from clinical studies that sperm antibodies impair fertility (1-5) and are detectable in either the male or female partner in a significant proportion of couples presenting with infertility problems (6,7). Sperm antibodies may impair human fertility principally by blocking spermatozoan cervical mucus (CM) penetration, although inhibition of fertilization may also occur. The extent to which these effects are differentially expressed is related to the antibody level, immunoglobulin (Ig) class, and regional specificity of the antibodies concerned. For example, tail-tip antibodies do not significantly affect CM penetration (8) or fertilization (9) and often occur in fertile individuals (10-12). In addition, there is evidence that sperm-bound antibodies of the IgA class are more effective at blocking CM penetration than those of the IgG class (9). Other research has indicated that antibody titer is correlated directly with the severity of sperm functional impairment (13) and inversely with fecundability (1).