PDZK1IP1 and systemic sclerosis: Notably, circulating values of soluble suppression of tumorigenicity 2 (ST2), a member of the IL1R/Toll-like receptor family that IL33 binds to, were also found to be higher in SSc patients and to correlate with diastolic dysfunction, sPAP, DUs, and NVC abnormalities [140,141].