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Secondary syphilis in HIV positive individuals: correlation with histopathologic findings, CD4 counts, and quantity
Gabriela Rosa1, Gary W Procop1, Jesse D Schold2
1Department of Pathology and Laboratory Medicine Institute, The Cleveland Clinic, Cleveland, OH, USA.
Insights
Syphilis infection is more common in individuals with HIV due to impaired immunity. High numbers of spirochetes in skin biopsies correlate with lower CD4 counts, indicating increased infection severity in these patients.
Area of Science:
- Infectious Diseases
- Immunology
- Dermatopathology
Background:
- Syphilis (Treponema pallidum infection) is more prevalent in HIV-infected individuals compared to the general population.
- Impaired cellular immunity associated with HIV infection is a proposed factor contributing to higher syphilis rates.
Purpose of the Study:
- To investigate the correlation between CD4 counts and the number of treponemes in skin biopsies of patients with secondary syphilis and HIV.
- To compare the efficacy of immunohistochemistry (IHC) versus silver stain for detecting T. pallidum in skin biopsies.
Main Methods:
- Retrospective analysis of 11 skin biopsies from 10 patients diagnosed with secondary syphilis and HIV.
- Correlation of patient CD4 counts with histological findings and treponeme load determined by IHC.
- Comparison of T. pallidum IHC sensitivity with Warthin-Starry silver stain.
Main Results:
- Immunohistochemistry (IHC) demonstrated a 64% sensitivity for detecting treponemes, significantly higher than silver stain (9%).
- High spirochete loads (>100 per 10 high-power fields) were exclusively observed in patients with CD4 counts below 250 cells/mL.
- A moderate to severe lymphoplasmacytic infiltrate was the most consistent histological finding.
Conclusions:
- Elevated spirochete numbers in secondary syphilis skin biopsies are associated with CD4 counts below 250 cells/mL, suggesting a link to compromised cellular immunity in HIV-infected individuals.
- T. pallidum IHC is a superior diagnostic tool compared to Warthin-Starry staining for detecting spirochetes in syphilis biopsies.
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.
Conclusion:
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.
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