Antinuclear antibodies in COVID 19

We appreciated very much the interesting study by Chang et al. on the presence of antinuclear antibodies (ANAs) in patients with moderate/critical coronavirus disease 2019 (COVID 19). Both we and Chang and collaborators described the presence and significance of ANAs in patients with COVID‐19. The two experiences can be compared because Chang et al. studied a number of cases only slightly larger than us. In our opinion, the most important finding is represented by the presence of the nucleolar ANA reactivity, which, in the study by Chang et al., as in ours, is the most frequently detected among the different ANA patterns. In this regard, it is worth mentioning that the nucleolar ANA pattern is one of the several ANA pattern detectable by Indirect immunofluorescence, together with other patterns, such as speckled, homogenous, multiple nuclear dots, and rim like membranous; this pattern can be the serological marker of systemic sclerosis and its antigenic target is the topoisomerase I protein (or scl70). Interestingly, it is of major relevance to note that among the clinical manifestations of systemic sclerosis, it includes pulmonary involvement in the form of a restrictive syndrome secondary to interstitial pneumopathy resembling COVID‐19 interstitial pneumonia.