In-vitro exposure to mercury chloride, with and without n-3 long chain polyunsaturated fatty acids, on the Th17-associated immune response in peripheral blood mononuclear cells from systemic lupus erythematosus patients

TH17 cytokines are implicated in systemic lupus erythematosus (SLE) pathogenesis. Mercury is an environmental factor associated with the exacerbation of SLE pathology, potentially by regulating the ThH17 pathway. Humans are primarily exposed to mercury from dental amalgams and fish consumption. Fish are also a rich source of the n-3 long chain polyunsaturated fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), and have been shown to reduce SLE disease symptoms. This pilot in-vitro investigation isolated peripheral blood mononuclear cells (PBMC) from SLE patients (N = 15) and healthy controls (HC, N = 15). The cells were stimulated with lipopolysaccharide (LPS) and exposed to 200 nM of mercury (II) chloride (HgCl) for 24 hr, with or without pre-exposure (24 hr) to either EPA or DHA at 100 μM each. The TH17-associated cytokines were quantified in the PBMC supernatants. Pre-exposure to EPA resulted in significantly lower concentrations of IL-27 in supernatants of LPS-HgCl treated PBMC from SLE patients (29.58 [± 22.62] pg/mL) compared to HCs (51.63 [± 42.96] pg/mL) (p = 0.04). While DHA-LPS-HgCl had significantly lower IL-27 concentrations compared in LPS-HgCl in PBMC from SLE patients and HCs, there was no significant difference between groups. IL-27 exhibits pro/anti-inflammatory effects on the immune system. We suggest that the observed reductions in IL-27 concentrations following EPA-LPS-HgCl treatment support the protective role of n-3 PUFA in autoimmune responses.