A higher level of IgG antibody was also recognized in female collagen-induced arthritis model of rheumatoid arthritis compared to male animal model of the disease by Dimitrijevice et al. Accordingly, a higher frequency of CD40L+ T cells and CD40+ B cells were identified in female lymph nodes of the animals compared to male counterparts (Dimitrijević 2020). This evidence concerns the gene CD40 and rheumatoid arthritis.