The sera from adult patients with suggestive signs of autoimmune diseases present antinuclear autoantibodies that cross-react with Leishmania infantum conserved proteins: crude Leishmania histone and Soluble Leishmania antigens [corrected].

Visceral leishmaniasis has been associated with hyper-gammaglobulinemia and antinuclear antibodies and may simulate systemic lupus erythematosus. Sera from patients with visceral leishmaniasis have been shown to strongly react against conserved proteins from the parasite, such as ribosomal and histones. Some of these proteins have also been described as immunogenic in several auto-immune syndromes, and the detection of antibodies against them is considered to be indicative of disorder in the immune system. This study aimed to assess by enzyme-linked immunosorbent assay, test routinely employed in visceral leishmaniasis diagnosis, the recognition of Crude Leishmania histone and Soluble Leishmania antigens proteins from Leishmania infantum by adult patients with suggestive signs of autoimmune diseases. Our results show that the humoral response generated during autoimmune diseases cross-reacts with the parasitic Crude Leishmania histone and Soluble Leishmania antigens. In these cases, higher precautions must be taken to confirm the presence of visceral leishmaniasis in front of positive serology in antinuclear antibodies positive sera, in order to avoid wrong diagnosis.