Anti-PM/Scl-100 and anti-RNA-polymerase III antibodies in scleroderma

• Published in: Clinica chimica acta Vol. 411; no. 13; pp. 965 - 971
• Main Authors: Maes, L., Blockmans, D., Verschueren, P., Westhovens, R., Op De Beéck, K., Vermeersch, P., Van den Bergh, K., Burlingame, R.W., Mahler, M., Bossuyt, X.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 04-07-2010
• Subjects: Aged; Aged, 80 and over; Antibodies - blood; Antibodies - immunology; Autoantibodies; Autoimmune Diseases - blood; Autoimmune Diseases - immunology; Enzyme-Linked Immunosorbent Assay - methods; Exoribonucleases - immunology; Exosome Multienzyme Ribonuclease Complex; Female; Humans; Male; Middle Aged; Nuclear Proteins - immunology; PM/scl; RNA Polymerase III; RNA Polymerase III - immunology; Scleroderma, Systemic - blood; Scleroderma, Systemic - immunology; Systemic sclerosis; Autoantibodies; PM/scl; Systemic sclerosis; RNA Polymerase III
• ISSN: 0009-8981; 1873-3492
• DOI: 10.1016/j.cca.2010.03.018

Systemic sclerosis (SSc) is a rare autoimmune disease characterized by the presence of various autoantibodies, including anti-centromere, anti-topoisomerase (Scl-70), anti-PM/Scl-100, and anti-RNA-polymerase III (RNA Pol-III) antibodies. Recently, new ELISA based immunoassays have become available for the detection of anti-PM/Scl and anti-RNA Pol-lII antibodies.
We studied the prevalence and clinical association of anti-PM/Scl-100 (PM1-Alpha) and anti-RNA Pol-III antibodies.
Antibodies to PM1-Alpha and RNA Pol-III were measured by ELISA (DR. Fooke Laboratories and Inova Diagnostics, respectively) in 242 patients with various connective tissue diseases (CTD) (including 70 SSc patients) and in 36 non-CTD controls.
Low levels of PM1-Alpha antibodies were found in various CTDs, whereas high levels were exclusively found in SSc, dermatomyositis and polymyositis, albeit at low frequency (4.7%). Anti-RNA Pol-III antibodies were found in 7% of SSc and in 1% of non-CTD and CTD controls. Anti-centromere and anti-Scl-70 antibodies were found in 37% and 21% of SSc patients, respectively. Anti-centromere antibodies were associated with limited cutaneous SSc and anti-Scl-70 antibodies with diffuse cutaneous SSc and interstitial lung disease. Because of the low number of samples positive for anti-PM/Scl-100 or RNA Pol-III antibodies, no clinical feature was statistically correlated with the presence of either reactivity, but taken together the presence of either antibody was correlated with interstitial lung disease. Anti-PM1-Alpha and anti-RNA Pol-III antibodies were mutually exclusive with anti-Scl-70 antibodies.
At high levels, anti-PM/Scl-100 antibodies were associated with SSc, PM, and DM, albeit at low frequency. Anti-RNA Pol-III antibodies were associated with SSc (in 7%) with high specificity.