CD40LG and sexually transmitted disease: European CDC guidelines state that titers of nontreponemal and specific antitreponemal IgM are correlated with disease activity in carriers of active infectious syphilis.[11] However, the European CDC also states that a titer of <1:32 or a negative Venereal Disease Research Laboratory test/RPR test is not sufficient to exclude an active syphilis infection, although the presence of an active treponemal disease in such a patient would be unusual.