Although second- and third-generation oral BTK inhibitors, such as acalabrutinib (30) and zanubrutinib (31), do not inhibit ITK and might have less ocular toxicity (32), we selected ibrutinib for this study due to the relatively extensive information available on its use in autoimmune inflammatory diseases such as RA and SLE. The gene discussed is ITK; the disease is rheumatoid arthritis.