TGFB1 and systemic sclerosis: IHC using anti-phospho-Smad2 antibody revealed enhanced Smad2 phosphorylation, a marker for TGFβ signaling, in SSc tissue, relative to normal skin specimens (87% ± 11% versus 23% ± 15%, p < 0.01), when both pre- and post-transplant tissues were analyzed together, whereas the level of total Smad2 remained comparable between normal versus SSc skin tissue.