CD40LG and sexually transmitted disease: ACE: angiotensin-converting enzyme; Ab: antibody; AG/AB: antigen/antibody; CSF: cerebrospinal fluid; DNA: deoxyribonucleic acid; HLA-B27: human leukocyte antigen B27; IgG: immunoglobulin G; IgM: immunoglobulin M; PCR: polymerase chain reaction; RBC: red blood cell count; RPR: rapid plasma reagin; VDRL: Venereal Disease Research Laboratory; WBC: white blood cell