Syphilis serology in human immunodeficiency virus infection: evidence for false-negative fluorescent treponemal testing.
Injection drug users were assessed serologically for human immunodeficiency virus infection and syphilis every 6 months. Treatment histories were reviewed for any high-titer biologic false-positive (BFP) reactors, that is, persons with rapid plasma reagin (RPR) titers > or = 1:4 and negative results for fluorescent treponemal antibody absorption (FTA-ABS) tests. Selected sera were analyzed further by immunoblotting for the presence of antibodies reactive with specific Treponema pallidum antigens. Of 112 BFP reactors, 35 (31%) had at least one RPR test reactive at a dilution >1:8 while the FTA-ABS test remained nonreactive. Five reactors (4.5%) converted from nonreactive to reactive by FTA-ABS test; 4 (3.6%) were reactive by FTA-ABS tests but later became nonreactive. Antibodies to T. pallidum membrane antigens were detected in some samples that were persistently nonreactive by FTA-ABS test. Serologic patterns over time, along with very high-titer BFP reactions and reactivity with T. pallidum-specific antigens, suggest that some BFP reactions may represent FTA-negative syphilis.
Erbelding
E J
EJ
Department of Medicine, Johns Hopkins University School of Medicine and School of Hygiene and Public Health, Baltimore, Maryland 21205, USA.
Vlahov
D
D
Nelson
K E
KE
Rompalo
A M
AM
Cohn
S
S
Sanchez
P
P
Quinn
T C
TC
Brathwaite
W
W
Thomas
D L
DL
D000907:Antibodies, Bacterial / Q000097:blood*; D003951:Diagnostic Errors; D005260:Female; D005453:Fluorescence; D015658:HIV Infections / Q000276:immunology*; D006801:Humans; D015151:Immunoblotting; D008137:Longitudinal Studies; D008297:Male; D015819:Substance Abuse, Intravenous / Q000150:complications*; D013587:Syphilis / Q000175:diagnosis*; D014210:Treponema pallidum / Q000276:immunology*
D000907:Antibodies, Bacterial