An auto-immune panel (antinuclear antibody, anti-DNA, C3, C4, c-antineutrophil cytoplasmic antibody, p-antineutrophil cytoplasmic antibody, antiphospholipid antibodies, lupus anticoagulant, and anti-cardiolipin antibodies) was done to rule out macrophage activation syndrome (MAS). This evidence concerns the gene C3 and macrophage activation syndrome.