TGFB1 and systemic sclerosis: Cross-sectional studies have shown high levels of LTB4 and LTE4 in bronchoalveolar lavage fluid of patients with scleroderma lung disease [20,29]; high amounts of CysLT in exhaled breath condensate in SSc patients [30]; in SSc skin overexpression of 5-LO, critical in LTs synthesis; an increase in SSc fibroblast LTB4 production after stimulation with an ionophore [28]; and greater expression of 5-LO in fibroblasts, which lowers collagen production and TGF-β1 when the enzyme is inhibited [31].