Increased Level of Caspase-1 in the Serum of Relapsing-remitting Multiple Sclerosis (RRMS) Patients

Abstract

Multiple sclerosis (MS) is an inflammatory autoimmune disease of the central nervous system, in which proinflammatory cytokines play a critical role in the pathogenic formation of lesions. Caspase-1 is a cysteine protease that proteolytically cleaves precursors of interleukin (IL)-18 and IL-1β and turns them into their active forms. These inflammatory cytokines play an important role in the development of MS. The aim of the present study was the investigation of caspase-1 and its downstream products, IL-18 and IL-1β, in relapsing-remitting MS (RRMS) patients. In this study, we used an ELISA assay to measure serum and cellular caspase-1 and serum levels of IL-18 and IL-1β in RRMS patients in the relapse phase (n=23) and healthy age-and gender-matched controls (n=19). We observed that the caspase-1 level was significantly increased in the serum of MS patients compared to the healthy controls (p=0.03). Although caspase-1 concentration in the lysate of peripheral blood mononuclear cells (PBMCs) was higher than serum among patients and controls (p<0.001), no significant difference was found in cellular levels of caspase-1 between the two groups. There was no significant difference in serum levels of  IL-18 and IL-1β between patients and controls. In this study, we found an elevation of extracellular caspase-1, as a reflection of its intracellular level, in the serum of RRMS patients during the relapse phase. Therefore, it suggests being a suitable peripheral biomarker of disease activity in multiple sclerosis.