Elevated levels of soluble non‐classical major histocompatibility class I molecule human leucocyte antigen (HLA)‐G in the blood of HIV‐infected patients with or without visceral leishmaniasis

Summary The non‐classical class I major histocompatibility complex molecules human leucocyte antigen (HLA)‐G have been shown to play a role in HIV persistence, but no data are available on the expression of the soluble forms HLA‐G5 and sHLA‐G1 in HIV‐infected patients with and without opportunistic infections. The soluble HLA‐G isoform was measured with an enzyme‐linked immunosorbent assay (ELISA) method in plasma from 94 subjects: 31 HIV‐1‐seropositive, 17 with visceral leishmaniasis (VL), seven with both VL and HIV‐1 infection and 39 healthy HIV‐seronegative subjects. Between groups, the frequency of sHLA‐G positivity was statistically different: 81% of HIV‐infected patients were positive, as were 57% of HIV– Leishmania infantum co‐infected patients, 35% of HIV‐seronegative patients with VL and 3% of healthy controls. Levels of the soluble forms of the immunomodulatory molecules HLA‐G are elevated during HIV infection. In HIV– Leishmania co‐infected patients, sHLA‐G secretion could contribute to the tolerogenic environment and to Leishmania immune evasion.