Antigens from Leishmania amastigotes inducing clinical remission of psoriatic arthritis

A first generation vaccine (AS100-1) was manufactured with protein from four cultured Leishmania species, which proved to be effective in the treatment of psoriasis. A single blind trial on 3,132 psoriasis patients revealed 508 (16.2%) subjects with psoriatic arthritis (PsA) that received AS100-1 antigens. The study group was distributed according to percent psoriasis area and severity index (PASI) reduction from PASI 10 to PASI 100. All groups decreased in arthritis score (AS), tender joints counts and nail changes after treatment; the highest decreased in the PASI 100 group. Relapses of psoriasis and PsA had PASI and AS lower than initial values before treatment. Clinical remissions were at lower doses and less time, after the second course of treatment. Peripheral blood mononuclear cells (PBMC) lymphocyte subsets (LS) varied with PASI range (1–10, 11–20 and 21–72). Pre-treatment, absolute values of gated LS: CD4+, CD8+HLA−, CD8+HLA+, CD8+CD3−, CD8+CD3+ decreased in PBMC as PASI increased, suggesting migration from the blood to the skin. In contrary to the previous finding, the following LS: CD8+CD4−, CD3+CD8−, HLA+CD8−, CD19, CD8+CD4+ and membrane surface immunoglobulin IgA+, IgD+, IgM+, IgE+, and IgG+ increased in PBMC as PASI increased suggesting activation and proliferation by unknown antigens creating a homeostatic cycle between skin/joints and peripheral blood. After nine doses of AS100-1, the following LS: CD8+CD3+, CD8+HLA+, CD3+CD8−, CD4+CD8−, CD8+HLA−, HLA+CD8−, CD8+CD3−, CD19+, CD8+CD4−, CD8+CD4+, IgA+, IgD+, IgM+, IgE+, and IgG+ decreased significantly as compared with values before treatment. The LS decreased stops the vicious cycle between skin/joints and blood explaining clinical remission of lesions.