Conclusion
We describe IgM autoantibodies against CD209 and CD209L amongst patients hospitalised with COVID-19. These were not associated with disease severity. Conversely, patients with either anti-ACE2 IgM or anti-IFNα IgG antibodies had worse outcomes. Due to the small size of the study cohort, conclusions drawn should be considered cautiously.
Methods
Using banked samples (n = 118) from Johns Hopkins patients hospitalised with COVID-19, we defined autoantibodies against CD209 and CD209L by enzyme-linked immunosorbent assay (ELISA). Clinical associations of these antibodies were compared with those of patients with anti-interferon (IFN) and anti-angiotensin-converting enzyme-2 (ACE2) autoantibodies.
Results
Amongst patients hospitalised with COVID-19, 19.5% (23/118) had IgM autoantibodies against CD209L and were more likely to have coronary artery disease (44% vs 19%, P = 0.03). Antibodies against CD209 were present in 5.9% (7/118); interestingly, all 7 were male (P = 0.02). In our study, the presence of either antibody was positively associated with disease severity [OR 95% confidence interval (95% CI): 1.80 (0.69-5.03)], but the association did not reach statistical significance. In contrast, 10/118 (8.5%) had IgG autoantibodies against IFNα, and 21 (17.8%) had IgM antibodies against ACE2. These patients had significantly worse prognosis (intubation or death) and prolonged hospital stays. However, when adjusting for patient characteristics on admission, only the presence of anti-ACE2 IgM remained significant [pooled common OR (95% CI), 4.14 (1.37, 12.54)].