HNRNPA2B1 and mixed connective tissue disease: Although initially described to occur mainly in patients with rheumatoid arthritis (RA), autoAbs to hnRNP-A2 (originally termed anti-RA33) were later detected also in 20% to 30% of patients with SLE as well as in 40% of patients with mixed connective tissue disease, usually in association with other anti-spliceosomal autoAbs [8,9].