Secondary syphilis in HIV positive individuals: correlation with histopathologic findings, CD4 counts, and quantity of treponemes in microscopic sections.
BACKGROUND
Although syphilis is uncommon, infection rates are much higher in HIV-infected individuals than the general population. A proposed explanation is impaired cellular immunity with HIV infection.


METHODS
A search of one institution yielded 10 patients with a diagnosis of secondary syphilis on skin biopsy, positive syphilis serology and available CD4 counts. We evaluated 11 biopsies from the 10 patients. We correlated the patients' CD4 counts with the histologic findings and with the number of treponemes on skin biopsies, highlighted by immunohistochemistry (IHC). We also compared the detection of spirochetes in silver stained sections (e.g. Warthin-Starry) with T. pallidum IHC. All biopsies were assessed for various histologic features.


RESULTS
The sensitivity of IHC to detect treponemes was 64% and of silver stain was 9% (p-value 0.04). The number of treponemes on the biopsies was determined by IHC. High numbers of spirochetes (i.e. >100 per 10 hpf) were only seen in patients with CD4 counts less than 250 cells/ml.


CONCLUSIONS
The most consistent histologic finding was a moderate to severe lymphoplasmacytic infiltrate. Although the study is small, it appears that a higher number of spirochetes is associated with CD4 counts less than 250 cell/ml. The T. pallidum IHC stain was vastly superior to the Warthin-Starry stain.
Department of Pathology and Laboratory Medicine Institute, The Cleveland Clinic, Cleveland, OH, USA.
Gabriela
G
Rosa
Department of Pathology and Laboratory Medicine Institute, The Cleveland Clinic, Cleveland, OH, USA.
Gary W
GW
Procop
Department of Quantitative Health Sciences, The Cleveland Clinic, Cleveland, OH, USA.
Jesse D
JD
Schold
Sections of the Departments of Dermatology and Anatomic Pathology, The Cleveland Clinic, Cleveland, OH, USA. pilianm@ccf.org.
Melissa P
MP
Piliang
D000328:Adult; D001706:Biopsy; D018791:CD4 Lymphocyte Count; D005260:Female; D006679:HIV Seropositivity / Q000097:blood / Q000150:complications / Q000382:microbiology / Q000473:pathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D016622:Silver Staining; D012867:Skin / Q000382:microbiology / Q000473:pathology; D013587:Syphilis / Q000097:blood / Q000150:complications / Q000382:microbiology / Q000473:pathology; D014210:Treponema pallidum
HIV; Syphilis; Warthin-Starry stain; immunohistochemistry; infectious agents