26 Ago CD8+CD28-CD127loCD39+ Treg Expansion: a New Possible Pathogenic Mechanism for HIV Infection?

Background: CD8+CD28-CD127lowCD39+ T cells (CD8+Treg) are regulatory T lymphocytes, highly concentrated within tumor microenvironment, never analyzed in the circulation of HIV infected patients.
Objectives: To analyze the frequency of CD8+ Treg in the circulation of HIV infected patients.
Methods: The frequency of CD8+ Treg was analyzed and correlated with viral load and CD4+ T cells count/percentage in HIV-1 infected patients subdivided in naïve (at baseline and after 3,6,12 months of therapy), elite controllers, long-term non-progressors and affected by tumor. Same analyses were performed in HIV negative cancer patients, HCV infected patients and healthy donors.
Results: CD8+Treg frequency was analyzed in 63 ART-naive patients in comparison with that of 173 healthy subjects. The majority 125/173 (72%) of controls had no detectable CD8+ Treg. In contrast, 100% of naive patients showed CD8+ Treg in their circulation. A progressive significant reduction of circulating CD8+ Treg frequency was observed after the beginning of the treatment, as a dynamic biomarker to monitor the course of the disease. The frequency of CD8+ Treg in the EC, but not in LTNP, was significantly lower than that of naive patients.
Conclusion: The results show that: a) functional CD8+ Treg are increased in the circulation of HIV infected patients; b) monitoring their frequency in the peripheral blood of HIV infected patients may represent a clinical biomarker.