Table 5 Summary of key concepts

Increased PAH (2–4:1 women to men)

PAH lower in men

PAH peaks pre-menopause when estrogen highest

Increased HIV-associated PAH in men with myocarditis, which is also higher in men

Estrogen increases DCs, T cells, Th2 response, Treg, TGFβ:Th2, and TGFβ promote fibrosis

Testosterone increases mast cell and macrophage inflammation

Estrogen increases B cells, autoantibodies, and ICs

Testosterone increases TLR4 signaling, which promotes inflammation and fibrosis

Estrogen decreases BMPR2 expression on immune cells resulting in increased TGFβ and lung fibrosis

Testosterone increases profibrotic IL-1β

Increased CTD-associated PAH (9:1 women to men), especially SSc-associated PAH

More men have dcSSc form of SSc (organ involvement)

Estrogen increases SSc/lcSSc (skin involvement): pre-menopause SSc 15:1 women to men

SSc in men associated with decreased survival

SSc in women associated with increased survival

SSc in men associated with increased lung fibrosis

Estrogen decreases lung fibrosis in women with SSc

Estrogen increases Raynaud’s syndrome