Quantitative determination of IgG and IgA on sperm from infertile patients with and without antisperm antibodies.

Immunoglobulins on patients sperm were determined by an ELISA technique, modified from the RIA described by Haas and D'Cruz (Am J Reprod Immunol, 1989; 20:37-43), i.e., suspensions of washed sperm (40, 20, 10, and 5 mill/ml) were added to a dilution of peroxydase-labelled anti-IgG or anti IgA, and after incubation the supernatants were transferred to cups in microtrays, coated with IgG or IgA, respectively. After incubation and washing ELISA reaction was carried out. Known amounts of IgG and IgA were processed in the same way to obtain a standard curve, allowing the Ig on the sperm to be expressed in ng/mill sperm. Ejaculates with increased viscosity revealed high values, irrespective of MAR-results and in some cases the same was true for samples with large numbers of non-spermatozoal cells (NSC). However, among 48 samples from men from infertile couples with negative MAR, > 20 mill sperm/ml, normal viscosity, and a ratio between sperm and NSC > 5, the median for IgG was 0.2 ng/mill sperm, 90% had < or = 0.8 ng/mill sperm, and the highest value recorded was 1.9 ng/mill sperm. For IgA the median was 0.5 ng, 90% of the 47 samples contained < or = 1.9 ng, and the highest value was 3.1 ng/mill sperm. The values for sperm from patients with a positive MAR, but without free antibodies in seminal plasma, were generally within the normal range. In contrast, increased values were recorded for most of the patients with free antibodies in seminal plasma, up to 4.2 ng/mill sperm for IgG and up to 12.5 ng/mill sperm for IgA.