Correspondence on 'Clinical course of coronavirus disease 2019 (COVID-19) in a series of 17 patients with systemic lupus erythematosus under long-term treatment with hydroxychloroquine'.

Mathian et al described the clinical course and heterogeneity of COVID-19 in 17 systemic lupus erythematosus (SLE) patients.1 SLE subjects could be at higher risk of developing COVID-19, with more severe symptomatology and need for hospitalisation due to multiple underlying risk factors.1 2 Type-I interferons (IFN), including IFNα, play fundamental roles in immunity and are crucial in antiviral responses.3 Defects in IFN signalling pathways, secondary to monogenic inborn errors or to blocking autoantibodies, promote immunodeficiency and recurrent infections.4 5 Dysregulation in type-I IFN pathway also plays key pathogenic roles in SLE.6 A recent report showed association between anti-type-I IFN autoantibodies in 10% of subjects with life-threatening COVID-19 in the general population.7 A comprehensive evaluation of multiple anticytokine autoantibodies showed the presence of anti-type-I IFN autoantibodies in 11% of SLE subjects in the pre-COVID-19 era.8 We hypothesised that SLE patients having anti-IFNα autoantibodies at baseline (prior to 2020) may be at higher risk of developing COVID-19, and that the presence of these autoantibodies may help in guiding management and preventive strategies. Ten SLE females who developed COVID-19 between 1 April and 1 October 2020 were identified among lupus subjects followed at the National Institutes of Health, Bethesda, MD, USA under IRB-approved SLE natural history protocol 94-AR-0066 (online supplemental methods, table 1). Seven patients had mild to moderate COVID-19 symptoms that were managed at home with supportive care. Three patients had severe symptoms requiring hospitalisation, supplemental …