Syphilis increases HIV viral load and decreases CD4 cell counts in HIV-infected patients with new syphilis infections.
BACKGROUND
Syphilitic ulcers are known to facilitate the transmission of HIV infection, but the effect of syphilis infection on HIV viral loads and CD4 cell counts is poorly understood.


METHODS
We abstracted medical records for HIV-infected male syphilis patients seen at three clinics in San Francisco and Los Angeles from January 2001 to April 2003. We compared plasma HIV-RNA levels and CD4 cell counts during syphilis infection with those before syphilis infection and after syphilis treatment, using the Wilcoxon signed rank test.


RESULTS
Fifty-two HIV-infected men with primary or secondary syphilis had HIV viral load and CD4 cell count data available for analysis; 30 (58%) were receiving antiretroviral therapy. Viral loads were higher during syphilis compared with pre-syphilis levels by a mean of 0.22 RNA log10 copies/ml (P = 0.02) and were lower by a mean of -0.10 RNA log10 copies/ml (P = 0.52) after syphilis treatment. CD4 cell counts were lower during syphilis infection than before by a mean of -62 cells/mm3 (P = 0.04), and were higher by a mean of 33 cells/mm3 (P = 0.23) after syphilis treatment. Increases in the HIV viral load and reductions in the CD4 cell count were most substantial in men with secondary syphilis and those not receiving antiretroviral therapy.


CONCLUSIONS
Syphilis infection was associated with significant increases in the HIV viral load and significant decreases in the CD4 cell count. The findings underscore the importance of preventing and promptly treating syphilis in HIV-infected individuals.
Buchacz
Kate
K
Epidemic Intelligence Service, Division of Applied Public Health Training, Epidemiology Program Office, National Center for HIV, STD and TB Prevention, Centers for Disease Control and Prevention, Atlanta, GA, USA.
Patel
Pragna
P
Taylor
Melanie
M
Kerndt
Peter R
PR
Byers
Robert H
RH
Holmberg
Scott D
SD
Klausner
Jeffrey D
JD
D000328:Adult; D023241:Antiretroviral Therapy, Highly Active; D018791:CD4 Lymphocyte Count; D016022:Case-Control Studies; D015658:HIV Infections / Q000150:complications / Q000188:drug therapy / Q000276:immunology*; D006801:Humans; D008231:Lymphopenia / Q000276:immunology / Q000382:microbiology*; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D013587:Syphilis / Q000150:complications* / Q000276:immunology; D019562:Viral Load