CALR and systemic lupus erythematosus: The exact etiology of SLE is still unknown, but the pathogenesis of SLE includes the loss of tolerance to self-antigens and the formation of pathogenic antibodies directed against nuclear constituents (antinuclear antibodies (ANA), anti-double stranded DNA (dsDNA), anti-smith, ribonucleoprotein (RNP), SSA (anti-Ro), SSB (anti-La) and anti-histone) as well as complement mediated tissue destruction.