CD40LG and cytomegalovirus infection: On the other hand, CMV infection was detected in all autistic children with 44 (97.8%) testing positive by ELISA [24 (53.3%) IgG + /IgM − , 18 (40%) IgG + /IgM + and 2 (4.4%) IgG − /IgM +] and 25 (55.6%) testing positive by RT-PCR assay.