PRTN3 and COVID-19: 1) Different autoantibodies have been detected in many COVID-19 patients with no previous autoimmune rheumatic disease, including antinuclear antibodies, p-ANCA, c-ANCA, anti-CCP, anti-RNP, anti-centromere, Rheumatoid Factors, anti-topoisomerase I and anti-prothrombin, with no, so far, clear clinical significance.