CD40LG and Infertility: Although type II-like hypersensitivity reactions to spermatozoa are quite well known to the reproductive specialists and specific IgG and IgM class antibodies to the surface of spermatozoa may be detected as a part of routine examination for infertile couples, awareness of HSP allergy is still lacking among obstetricians-gynecologists, therefore, due to insufficient differential diagnosis, this allergy is diagnosed relatively rarely (11, 12, 18).