Prognostic values of anti-Ro52 antibodies in anti-MDA5-positive clinically amyopathic dermatomyositis associated with interstitial lung disease
Antao Xu, Yan Ye, Qiong Fu, Xinyue Lian, Sheng Chen, Qiang Guo, Liangjing Lu, Min Dai, Xia Lv, Chunde Bao
Abstract
OBJECTIVE: Anti-Ro52 antibody often co-occurs with anti-Jo1 antibody in antisynthetase syndrome and their co-occurrence correlates with a more aggressive clinical phenotype and poorer prognosis. The strong association of anti-Ro52 antibody with anti-melanoma differentiation-associated protein-5 (anti-MDA5) antibody has been indicated in juvenile myositis. The aim of this study was to assess the clinical significance of anti-Ro52 antibody in a cohort of adult patients with anti-MDA5-positive clinically amyopathic dermatomyositis with interstitial lung disease (CADM-ILD). METHODS: We assessed a cohort of 83 consecutive patients with anti-MDA5-positive CADM-ILD. Anti-MDA5 antibodies and anti-Ro52 antibodies were detected in immunoblotting and semi-quantitatively analysed by densitometry. Clinical features and the 24 month survival were compared between anti-MDA5-positive patients with and without anti-Ro52 antibodies. RESULTS: Anti-Ro52 antibodies were found in 74.7% of anti-MDA5-positive CADM-ILD patients and were associated with an increased frequency of rapidly progressive interstitial lung disease (RP-ILD; 54.8% vs 23.8%; P = 0.014) and cutaneous ulcerations (27.4% vs 4.8%; P = 0.033). The cumulative 24 month survival rate tended to be lower in patients with anti-Ro52 antibodies than patients without (59.9% vs 85.7%; P = 0.051). The combination of anti-Ro52 antibody status and anti-MDA5 antibody levels further stratified patients' survival rates, showing that the survival rate of patients who were dual positive for anti-MDA5 antibody and anti-Ro52 antibody was significantly lower than patients with mild positive anti-MDA5 antibody alone (59.9% vs 100%; P = 0.019). CONCLUSION: Anti-Ro52 antibody is highly prevalent in anti-MDA5-positive CADM-ILD patients and their coexistence correlates with a subgroup of patients with more aggressive phenotypes. The combination of anti-MDA5 antibody levels and anti-Ro52 antibody status could help to predict patients' prognosis and guide risk-based therapy.