IL1A and Feingold syndrome: Patients with FS exhibit notable increases in the expression levels of IL-1α, IL-1β, COX-1, COX-2, and TNF-α within the joint capsule and subacromial bursa.[8] In a prospective case-control study, Kabbabe et al[9] found increased mRNA expression levels of inflammatory and fibroblast cytokines, such as IL-6 and IL-8, in the synovium of patients with FS.