C3, C4, and AChR were measured in the serum, whereas C5a was measured in the plasma, which was obtained using Futhan (BD FUT-175?, BD Biosciences, San Jose, CA, USA) as an inhibitor of the activity of proteases and components of the classical complement pathway in a retrospective analysis of patients with MG who had repetitive determinations of AChR-ab concentration in the follow up.22 Our results suggest that AChR-ab titers may be a useful marker of disease severity in patients with MG with generalized AChR-ab-positive MG, particularly in patients with shorter disease duration. and serological classification of patients with MG, the efficacy of AChR-abs titer as a marker of severity has been widely questioned.17C24 The objective of this study was to identify biomarkers of clinical severity in patients with generalized AChR-ab-positive MG at different clinical stages. For this purpose, the power of AChR-abs titer and concentration of complement system factors (C3, C4, and C5a) as potential prognostic markers to identify the severity of MG were evaluated. Materials and methods Patients and clinical data This cross-sectional study was approved by the Bioethics Committee of the Jos Mara Ramos Meja Hospital in Buenos Aires, Argentina. Patients aged 18?years who were diagnosed with generalized AChR-ab-positive MG and referred to the Section of Neuroimmunology and Electrophysiology of this hospital from April 2016 to June 2018 were included in this study. Patients with other associated active autoimmune diseases, infectious disease, pregnant women, patients with cognitive or psychiatric comorbidities that prevented measuring the evaluated parameters, and patients who received treatment with intravenous immunoglobulin or plasma exchange in the 4? weeks prior to consultation were excluded from the study. The study was approved by local ethical committee (Resolution number 97 485/MSG/2011). All study participants signed an informed consent form. Data regarding sex, age, age at disease onset, duration of MG, presence of thymic abnormalities, history of thymectomy, and type of pharmacological treatment received were collected. A detailed neurological examination was performed using the activities of daily living (ADL) scale and MG composite (MGC) scale. According to the clinical status at the time of examination, the patients were considered to exhibit disease exacerbation in cases where the status deteriorated along with an increase of ?3 points in ADL and/or MGC scores with regard to previous consultation. Patients not meeting these criteria were considered to have Metoclopramide HCl stable disease. The effect of immunosuppressive treatment around the prognostic value of complement system components was decided after classifying the patients with either stable or exacerbated disease status into subgroups according to the treatment received at the time of consultation. Serological assessments AChR-abs were quantified in serum samples at a clinical analysis laboratory by radio-immunoprecipitation single analysis. Values 0.1?nmol/L were CGB considered negative or normal. New blood samples were centrifuged to obtain serum and plasma. C3, C4, and AChR were measured in the serum, whereas C5a was measured Metoclopramide HCl in the plasma, Metoclopramide HCl which was obtained using Futhan (BD FUT-175?, BD Biosciences, San Jose, CA, USA) as an inhibitor of the activity of proteases and components of the classical complement pathway in a retrospective analysis of patients with MG who had repetitive determinations of AChR-ab concentration in the follow up.22 Our results suggest that AChR-ab titers may be a useful marker of disease severity in patients with MG with Metoclopramide HCl generalized AChR-ab-positive MG, particularly in patients with shorter disease duration. However, our transversal study design did not allow a statistical comparison at an intra-individual level, which could Metoclopramide HCl be relevant, as has been described previously. Experimental studies have provided evidence that variations in serum concentration of different complement system components might affect the clinical course of MG;27 complement depletion protects animals against the induction of experimental autoimmune MG (EAMG),14 antibodies that block the soluble C1q receptor protect animals against EAMG,28 and animals with reduced.