Secretory IgA and other proteins in semen from healthy Nigerian men.

The secretory IgA (SIgA) levels in semen and immunoglobulin A, G, M and D concentrations in semen and serum from 30 apparently healthy Nigerian men with various sperm counts were studied. Albumin levels in the samples were also measured to determine the contribution of serum transudation to the semen concentration. Nine of the participants (30%) had no detectable SIgA in their semen, while IgM and IgD were undetectable in all the semen samples. Analysis of proteins in the semen revealed an increase in the IgA:albumin ratio as compared to serum, while the IgG:albumin ratio was the same. The relative semen concentrations for IgA were generally slightly higher than and for IgG were lower than for albumin. Those levels did not correlate for IgA and albumin, while the IgG and albumin levels correlated with each other. A mathematical estimate of the amount of IgA produced locally showed no statistically significant difference between azoospermic and normospermic men. The data indicate that some men are capable of local IgG production.