A Study of Autoantibodies against Some Central Nervous System Antigens and the IL-35 Serum Level in Schizophrenia

Schizophrenia (SCZ) is a debilitating mental disorder with various causes involving complex interactions between genetic factors and environmental agents. The immune system plays a vital role in the pathology and function of the nervous system. Interleukin 35 (IL-35) is a regulatory and anti-inflammatory cytokine that can prevent autoimmune and inflammatory diseases. This study aimed to investigate the role of autoantibodies against some central nervous system (CNS) antigens and IL-35 serum levels in patients with Schizophrenia. This case-control study involved 80 participants. The serum levels of IL-35 were measured by enzyme-linked immunosorbent assay and the autoantibodies in the CNS by indirect immunofluorescence assay (IFA). The serum levels of IL-35 were decreased in patient groups compared to healthy subjects. Autoantibodies against N-methyl-D-aspartate receptor (NMDAR) and myelin-associated glycoprotein (MAG) were positive in 15% (6/40) and 7.5% (3/40), respectively; however, no antibodies against myelin, aquaporin-4 (AQP4), myelin oligodendrocyte glycoprotein (MOG), voltage-gated potassium channel (VGKC), α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPAR), γ-butyric acid receptor type B1 γ-butyric acid receptor type B1 (GABABR), antidipeptidyl peptidase-like protein-6 (DPPX), immunoglobulin-like cell adhesion molecule 5 (IgLON5), Glycine receptor (R) and acetylcholine receptor (Ach R) were detected (No statistics were computed).  We found that decreased serum IL-35 levels and the existence autoantibodies against NMDAR antigen may contribute to the pathogenesis of SCZ.