Pro-inflammatory cytokines such as interleukin (IL)-1β, IL-2, IL-6, and tumor necrosis factor-α (TNF-α), as well as neuropeptides like calcitonin gene-related peptide (CGRP), bradykinin, and substance P, contribute to the intense inflammatory response following trauma or injury, ultimately instigating the development of CRPS (60, 61). Here, IL1B is linked to complex regional pain syndrome.