HIV, hepatitis B/C, syphilis, Legionella, cytomegalovirus, Epstein–Barr virus, IgM, Brucella, Coxiella, Methicillin-Resistant Staphylococcus aureus, carbapenemase-producing organism, antistreptolysin O, malaria. The gene discussed is CD40LG; the disease is syphilis.