Regulatory T-Cell Dynamics in Cutaneous and Mucocutaneous Leishmaniasis due to Leishmania braziliensis

Abstract

To evaluate the dynamics of regulatory T cells (Tregs) during tegumentary leishmaniasis, we assessed peripheral blood and biopsies from 54 patients. Patients with cutaneous leishmaniasis (CL) had a decreased proportion of Tregs in the peripheral blood, but the proportion was higher in the biopsies of lesions. During treatment of CL, circulating Tregs increased reaching normal proportions, whereas antigen-specific interferon-γ responses diminished. By contrast, circulating Tregs from mucosal leishmaniasis patients failed to normalize during treatment. C-C chemokine receptor type 5 was expressed on a large proportion of Tregs at the site of infection. These results demonstrate increased Tregs at the site of infection, possibly homing from the peripheral circulation.

Chemokine receptors on human regulatory T cells during cutaneous leishmaniasis

“…Also, other research showed that Tregs were significantly higher in biopsies than in peripheral blood, corroborating our hypothesis 22 . The migration and homing of Tregs to the infection site are thought to be the result of the expression of several chemokines 21 . CCR5 plays a crucial role in the homing of Tregs at infection sites 19 .…”

“…It is important to consider that Tregs are potentially migrating to the lesion site rather than circulating in the blood. 21 Moreover, Treg migration and homing to the infection site is driven by chemokines (CCs) and their detection through receptors (CCRs) is a way to evaluate it. 21 Also, other research showed that Tregs were significantly higher in biopsies than in peripheral blood, corroborating our hypothesis.…”

“…21 Moreover, Treg migration and homing to the infection site is driven by chemokines (CCs) and their detection through receptors (CCRs) is a way to evaluate it. 21 Also, other research showed that Tregs were significantly higher in biopsies than in peripheral blood, corroborating our hypothesis. 22 The migration and homing of Tregs to the infection site are thought to be the result of the expression of several chemokines.…”

“…22 The migration and homing of Tregs to the infection site are thought to be the result of the expression of several chemokines. 21 CCR5 plays a crucial role in the homing of Tregs at infection sites. 19 Although, in our study we did not observe differentiated expression of CCR5 by Tregs between the studied groups, only a trend of non-significant increase in AD patients.…”

“…This higher percentage of Treg CD25+ and CTLA‐4+ cells in AD patients may also indicate a greater migration of these cells to the skin, since the disease is restricted to the skin in patients and the regulatory mechanisms would be based on this. It is important to consider that Tregs are potentially migrating to the lesion site rather than circulating in the blood 21 . Moreover, Treg migration and homing to the infection site is driven by chemokines (CCs) and their detection through receptors (CCRs) is a way to evaluate it 21 .…”