Analysis of the correlation between anti-MDA5 antibody and the severity of COVID-19: a retrospective study

OBJECTIVE To identify the anti-melanoma differentiation-associated gene 5 (MDA5) antibody (Ab) in coronavirus disease 2019 (COVID-19) and its relationship with the severity and clinical outcomes of COVID-19. DESIGN Retrospective cohort study. SETTING Three hospitals in China. PARTICIPANTS 274 adult inpatients diagnosed with COVID-19 according to the Protocol for Prevention and Control of COVID-19 (Edition 7) of China and confirmed by severe acute respiratory syndrome coronavirus 2 (SARS-CoV2) RNA testing, were included from three hospitals from Wuhan, Harbin and Beijing, China from 1 December 2019 to 19 April 2020. The Biobank of Myositis Registry Department of Rheumatology, Peking Union Medical College Hospital, provided the plasma of five patients with anti-MDA5 Ab-related dermatomyositis as positive control group. Demographic, clinical and laboratory data were collected from medical records. The anti-MDA5 Ab was determined by an ELISA assay and was verified by immunoblotting analysis. MAIN OUTCOME MEASURES In hospital death of all cause. RESULTS The positive rate of anti-MDA5 Ab in patients with COVID-19 was 48.2% (132/274) and the anti-MDA5 Ab positive patients tended to represent with severe disease (88.6% vs 66.9%, P<0.0001). The titer of anti-MDA5 Ab was significantly elevated in the non-survivals (5.95±5.16 vs 8.22±6.64, P=0.030) and the positive rate was also higher than that in the survivals (23.5% vs 12.0%, P=0.012). Regarding to severe COVID-19 patients, we found that high titer of anti-MDA5 Ab (≥10.0 U/mL) was more prevalent in the non-survivals (31.2% vs 14.0%, P=0.006). Moreover, early profiling of anti-MDA5 Ab could distinguish severe patients from those with non-severe ones. CONCLUSION Anti-MDA5 Ab was prevalent in the COVID-19 patients and high titer of this antibody is correlated with severe disease and unfavorable outcomes. Early screening and serially monitoring of anti-MDA5 Ab titer have the potential to predict the disease progression of COVID-19.