It is also used as an immunomodulatorfor rheumatological conditions such as systemic lupus erythematosusand rheumatoid arthritis (RA).[14] CQ has good in vitro activity againstSARS-CoV-2.[15] The postulated mechanisms of action in COVID-19infection are threefold:[16] increasing endosomal pH that inhibits theSARS-CoV-2 spike protein cleavage required for viral/endosomalfusion after entry; interference with the glycosylation of cellularreceptors (possibly through modification of angiotensin-convertingenzyme 2 (ACE2), purported to be involved with viral entry);[11,17]and immunomodulation. This evidence concerns the gene ACE2 and rheumatoid arthritis.