Therefore, the KIR4.1 protein expressed around the MO3.13 surface should be a better antigen to detect relevant anti-KIR4.1 antibodies. progressive.(DOCX) pone.0175538.s005.docx (5.8K) GUID:?34508EC6-A906-4F33-9F81-0FBCA12DB252 Data Availability StatementAll relevant data are within the paper and its Supporting Information Altiratinib (DCC2701) files. Abstract Introduction Antibodies targeting the inward-rectifying potassium channel KIR4.1 have been associated with multiple sclerosis (MS) but studies using diverse techniques have failed to replicate this association. The detection of these antibodies is usually challenging; KIR4.1 glycosylation patterns and the use of diverse technical approaches may account for the disparity of results. We aimed to replicate the association using three different approaches to overcome the technical limitations of a single technique. We also performed a systematic review to examine the association of anti-KIR4.1 antibodies with MS. Methods Serum samples from patients with MS (n = 108) and controls (n = 77) were tested for the presence of anti-KIR4.1 antibodies using three methods: 1) by ELISA with the low-glycosylated fraction of recombinant KIR4.1 purified from transfected HEK293 cells according to original protocols; 2) by immunocytochemistry using KIR4.1-transfected HEK293 cells; and 3) by immunocytochemistry using the KIR4.1.-transfected MO3.13 oligodendrocyte cell line. We developed a systematic review and meta-analysis of the association of anti-KIR4.1 antibodies with MS according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Results We did not detect anti-KIR4.1 antibodies in the MS patients or in controls using ELISA. Neither did we detect any significant reactivity RGS14 against the antigen around the cell surface using the KIR4.1-transfected HEK293 cells or the KIR4.1-transfected MO3.13 cells. We included 13 prospective controlled studies in the systematic review. Only three studies showed a positive association between anti-KIR4.1 and MS. Clinical and statistical heterogeneity between studies precluded meta-analysis of their results. Conclusion We found no association between anti-KIR4. 1 antibody positivity and MS. Although this lack of replication may be due to technical limitations, evidence from our study and others is usually mounting against the role of KIR4.1 as a relevant MS autoantigen. Introduction Multiple sclerosis (MS) is an autoimmune and neurodegenerative disease of the central nervous system that arises in genetically susceptible individuals exposed to environmental risk factors[1]. Clinical, genetic and experimental data in MS suggest a primary autoimmune response against oligodendrocytes is usually followed by a secondary neurodegenerative process that leads to disability[2]. Although MS is generally considered Altiratinib (DCC2701) a T-cell mediated disease, B-cells populate the demyelinating lesions and the cerebrospinal fluid (CSF) and form lymphoid follicles in the brain parenchyma and the meninges[3]. Importantly, the presence of oligoclonal bands in the CSF, the most frequently observed lab abnormality, is useful for diagnosis and MS conversion risk stratification[4,5]. Moreover, B-cell depletion has proven an effective Altiratinib (DCC2701) treatment for MS, suggesting B-cells play a central role in the pathogenesis of MS [6]. The search for the target antigen(s) of the immune response is an active field of MS research[7]. The discovery of antibodies targeting aquaporin-4 provided a biological marker to classify these patients as a specific disease subset (neuromyelitis optica) and the proof of theory that humoral factors could also mediate MS pathogenesis[8]. Despite exhaustive research using diverse approaches, the target antigen (or antigens) of the MS immune response remains largely unknown. Thus, MS lacks a disease-specific diagnostic biomarker and diagnosis relies on clinical and brain imaging criteria[9]. In 2012, Srivastava et al published a landmark article describing the presence of antibodies against the inward-rectifying potassium channel 4.1 (KIR4.1) in approximately half of the MS patients they studied [10]. A similar study in children with MS by the same group yielded comparable results[11]. Antibodies against KIR4.1 were originally described using ELISA assays.