( 5 , 7 ) Part of these mechanisms, as well as some clinical features, are remarkably similar in AIH and other systemic autoimmune diseases, particularly systemic lupus erythematous (SLE). One SX-3228 of the important biomarkers in SLE associated with specific disease features is the anti-ribosomal P protein antibody (anti-P). of the latter association remains controversial. This study aimed to evaluate the frequency of SX-3228 anti-P antibodies in autoimmune hepatitis using two different immunoassays. Methods One-hundred and seventy-seven patients with autoimmune hepatitis were screened, and 142 were analyzed for anti-P antibody positivity. The samples were first analyzed using two different immunoassays: enzyme-linked immunosorbent assay (ELISA) and chemiluminescence and then compared with a group of 60 patients with systemic lupus erythematous. The positive samples were subjected to western blot analysis. Results Anti-P was found in 5/142 autoimmune hepatitis cases SX-3228 (3.5%) by chemiluminescence and in none by ELISA. Among the CSF3R five chemiluminescence-positive autoimmune hepatitis samples, on anti-P western blot analysis one was negative, two were weakly positive, and two were positive. In contrast, anti-P was detected in 10/60 patients with systemic lupus erythematosus (16.7%) and presented higher chemiluminescence units than the autoimmune hepatitis samples. Conclusion A low frequency of anti-P antibodies was observed in autoimmune hepatitis, suggesting that this test is not useful for the diagnosis or management of this disease. Visual Abstract Open in a separate window Visual Abstract INTRODUCTION Specific and nonspecific autoantibodies are hallmarks of autoimmune liver diseases. ( 1 ) Autoimmune hepatitis (AIH) is an emblematic member of this disease group and is largely distributed worldwide, with a prevalence varying from 8.0-18.3/100,000, ( 2 , 3 ) with a ratio of 3.6 females/males affected. Despite wide distribution among races, European are predominantly affected. Clinically, a spectrum of presentations can be expected, ranging from acute hepatitis to chronic and overt liver disease, and one-fourth of the patients have advanced-stage liver fibrosis at the time of diagnosis. ( 4 ) The gold standard diagnostic methods remain the histopathological findings on liver biopsy, which are characterized by interface hepatitis, lymphoplasmacytic infiltrates, and rosette formation. ( 5 ) Autoantibodies are also important in diagnosis and include anti-smooth muscle antibodies (ASM; actin-F fraction), antinuclear antibodies (ANA), anti-liver and kidney microsomal antibody type-1 (LKM1), and anti-soluble liver antigen (SLA-LP) antibodies, sometimes in association with other autoantibodies at lower frequencies. ( 1 ) Regulatory T cell imbalance leads to increased production of Th17 cells, ( 6 ) cytotoxicity, apoptosis, necroptosis, and antibody production, causing perennial stimulus of the inflammatory cascade that results in hepatic tissue lesions, consequently evolving to fibrosis and cirrhosis. ( 5 , 7 ) Part of these SX-3228 mechanisms, as well as some clinical features, are remarkably similar in AIH and other systemic autoimmune diseases, particularly systemic lupus erythematous (SLE). One of the important biomarkers in SLE associated with specific disease features is the anti-ribosomal P protein antibody (anti-P). This autoantibody is found in 6C46% of patients with SLE and is associated with specific manifestations of the disease, such as type V nephritis, hepatitis, and neuropsychiatric involvement. ( 8 ) Based on several similar features of these two autoimmune diseases, the possibility that anti-P could also be present in non-SLE associated AIH has been considered. Calich et al. ( 9 ) found anti-P in nine of 93 (9.7%) patients with non-SLE-associated AIH, and anti-P was associated with a higher frequency of cirrhosis in the long-term follow-up of these patients. However, these findings have not been confirmed in other studies. ( 10 – 12 ) OBJECTIVE To evaluate the frequency of anti-P antibodies in patients with autoimmune hepatitis. METHODS Study design This prospective study evaluated the presence of anti-P in patients with AIH. The scholarly research was executed on the Gastroenterology and Hepatology Department, , Brazil and was accepted by the Institutional Ethics Committee under CAAE: 49776615.0.0000.5505; number 1# 1.524.672. Sufferers Patients identified as SX-3228 having AIH predicated on the requirements from the International Autoimmune Hepatitis Group ( 13 ) had been consecutively recruited between 2015 and 2020. Sufferers with overlapping syndromes and various other associated factors behind liver organ disease (HBV trojan, HCV virus, alcoholic beverages, NASH) had been excluded. A cohort of sufferers with a verified medical diagnosis of SLE, accompanied by the Rheumatology Department from the same school, was included as the Control Group. Sex, age group, AIH classification, autoantibody positivity, and stage of.