TGFB1 and systemic sclerosis: In contrast, TGF-β promoted a significant increase in IL-13 mRNA levels and IL-13 synthesis by CD4+ and CD8+ T-cell subtypes from patients with SSc, with respective increases of 2.4 ± 0.3-fold, 1.6 ± 0.05-fold and 2.7 ± 0.02-fold.