Cross-sectional study on association of autoantibodies and organ involvement in systemic sclerosis patients

Systemic sclerosis (SSc) is a connective tissue disease characterised by inflammation, fibrosis, and vascular abnormalities affecting multiple organs, including the skin, lungs, heart and kidneys. Between 75% and 95% of SSc patients have positive SSc-associated autoantibodies. The 2013 European League Against Rheumatism/American College of Rheumatology classification criteria for SSc includes autoantibodies as an important domain, highlighting their importance when clinical manifestations are subtle. However, the association of autoantibodies and specific clinical manifestations vary across different geographical regions and ethnicities, warranting further study across diverse populations. Hence, the objective of this study is to evaluate the association between autoantibodies and organ involvement in SSc patients at a tertiary centre in Malaysia.

This cross-sectional study included 48 SSc patients who received follow-up care at a tertiary centre in Malaysia from July 2013 to June 2023 (a ten-year period). Demographic, clinical, laboratory and radiological information were extracted from patient records.

A total of 48 patients were enrolled in our study. Forty-five (93.8%) patients were female and 3 (6.2%) patients were male. Regarding ethnicity, 26 (54.2%) patients were Malay, 17 (35.4%) patients were Chinese and 5 (10.4%) patients were Indian. Mean age at diagnosis was 52.96 years (SD ± 13.99). Thirty-nine (81.2%) patients had limited subtype and 9 (18.8%) patients had diffuse subtype. The most common clinical manifestations were sclerodactyly (97.9%) and Raynaud's phenomenon (79.2%). The most commonly found autoantibodies were anti-Ro-60 (37.5%) and anti-Scl- 70 (33.3%) while anti-Jo-1 (2.1%) was the least detected. Antinuclear antibody (ANA) was detected in 87.5% of our cohort. Anti-Scl-70 was significantly associated with interstitial lung disease (ILD) and ILD progression. Anti- Centromere was significantly associated with telangiectasia and gastroesophageal reflux disease (GERD). Meanwhile, anti-La was associated with synovitis and anti- Ribonucleoprotein (RNP) was associated with microstomia. Twenty-nine (60.4%) patients had evidence of ILD and 11 (22.9%) patients had progressive ILD. Additionally, pulmonary hypertension of varying severity was observed in 14 (29.2%) patients.

This study supports the well-established association of anti-Scl-70 with ILD and ILD progression. Other unique associations observed in this study could be due to the distinct ethnic and genetic background in the Malaysian population. To gain a more comprehensive understanding of these unique autoantibody-clinical manifestation patterns in Malaysian SSc patients, larger multicentre studies are recommended.