Interleukin-17A is a potential therapeutic target predicted by proteomics for systemic sclerosis patients at high risk of pulmonary arterial hypertension.

We explored effective therapeutic targets for systemic sclerosis (SSc) patients with high risk for pulmonary arterial hypertension (PAH) by plasma proteomics analysis. A total of fifty-seven patients with SSc were enrolled in the study and the prevalence of PAH was 19.3%. On the other hand, 75.4% of SSc patients showed the ratio of forced vital capacity percentage/diffusing capacity of the lungs for carbon monoxide percentage> 1.6 and met criteria for high risk of PAH. Identification of elevated plasma proteins in SSc patients with high risk of PAH, followed by upstream regulator analysis, predicted interleukin (IL)-17A as a major upstream molecule. Furthermore, we performed in vitro neutralization study using MT-6194, a bispecific antibody targeting both IL-17A and IL-6 receptor. We found that MT-6194 broadly suppressed the increased expression of downstream molecules of IL-17A including IL-17A-related cytokines/chemokines, IL-17A-driven NFκB pathway and IL-6-driven JAK/STAT pathway which were shown to be increased in SSc patients with high risk of PAH by the proteomics. Consequently, it is revealed that IL-17A is a promising target for early intervention in SSc patients with high risk for PAH.