Do antisperm antibodies cause functional impairment of the sperm membrane as manifested by a low hypoosmotic swelling...

Low hypoosmotic swelling (HOS) test scores were found to be associated with lower pregnancy rates. The mechanism seems to be related not so much to impaired fertilization but to inhibition of implantation. The defect may be present in males with normal or subnormal semen specimens. However, anecdotal experience suggested that the subset of males with antisperm antibodies (ASAs) have a higher frequency of low HOS scores. The possibility exists that ASAs may impair the functional integrity of the sperm membrane. The study presented herein, artificially added ASAs to sperm to see if this could lower the HOS score. The study would also determine if chymotrypsin, a protein digestive enzyme, could improve HOS scores, if, in fact, they were lowered by the addition of ASAs. The results did not show a reduction in the HOS scores following the addition of ASAs. Thus, it would appear that there is no cause and effect with the simultaneous presence of low HOS scores and ASAs. Possibly, however, longer exposure or a higher concentration of antibodies is needed to lower HOS scores.