CD40LG and Arthritis: Their COVID infection was diagnosed by nasopharyngeal RT‐PCR,16, 17, 18, 19, 20, 21, 22, 23, 30, 41, 51, 53, 54 positive antigen test,43 or positive IgM against SARS‐CoV‐2 by ELISA,55 and the arthritis diagnosis was based on clinical findings in all cases.