IL1B and pulmonary arterial hypertension: Indeed, an elevated level of circulating pro-inflammatory cytokines, such as interleukin IL-1β, IL-2, IL-4, IL-5, IL-6, IL-8, IL-10, or tumor necrosis factor-α, are present in the PAH animal model or patients and could contribute to contractile dysfunctions in diaphragm or limb muscles [49,50,51].