Importantly, TBX21 mRNA was not upregulated by any cytokine combinations used either in RA or in PsA T cells, while the IL1β + IL23 and IL1β + IL6 + IL23 treatments increased its expression of the healthy donor-derived T cells (p < 0.01 and p < 0.01). This evidence concerns the gene IL1B and rheumatoid arthritis.