Ethnic influence on disease manifestations and autoantibodies in Chinese-descent patients with systemic sclerosis.

OBJECTIVE: To investigate ethnic influence on disease manifestations and autoantibody profile in patients of Chinese descent with systemic sclerosis (SSc).
METHODS: In a retrospective study of a multiethnic SSc cohort followed over a 17-year period, disease manifestations and autoantibody profile of patients of European and Chinese descent were compared.
RESULTS: There were 300 patients of European descent and 36 of Chinese descent, with similar proportions of women (81% and 72%, respectively) and patients with diffuse SSc (50% and 56%). Patients of Chinese descent [mean age+/-standard deviation (SD) 52+/-16 yrs; p=0.05] were diagnosed at an older age compared to patients of European descent (mean+/-SD 46+/-12 yrs). Patients of Chinese descent compared to those of European descent had less frequent joint (69% vs 86%; p=0.01) and gastrointestinal involvement (78% vs 94%; p=0.004), but increased prevalence of myositis (17% vs 5%; p=0.01). Patients of Chinese descent had less frequent digital ulceration (36% vs 55%; p=0.04), and an absence of renal crisis. The frequency of cardiac and pulmonary involvement was similar in both groups. More patients of Chinese than of European descent were positive for anti-topoisomerase-I (47% vs 27%; p=0.02), anti-Ro (36% vs 10%; p=0.001), and anti-U1RNP (17% vs 5%; p=0.03) antibodies. The observed differences for anti-topoisomerase-I, anti-Ro, and joint and gastrointestinal manifestations persisted in the subgroup analysis of patients matched for sex, disease subtype, and age at diagnosis.
CONCLUSION: Patients of Chinese descent have milder SSc disease with less frequent joint and gastrointestinal manifestations, less severe vasculopathy, but increased prevalence of myositis and certain autoantibodies. Research is needed to identify determinants (genetic, environmental, and cultural factors) of the relationship between ethnicity and disease.