The Serum Levels Of A Proliferation-inducing Ligand,b-lymphocyte Activating Factor Mrna In Patients With Autoimmune Hepatitis Type-i And Their Relations To Clinical Features

Autoimmune liver disease (AILD) is a kind of liver disease related with abnormal autoimmune, and its etiology and pathogenesis are not clear. There are three types of ALID: autoimmune hepatitis (AIH), primary sclerosing cholangitis (PSC) and primary biliary cirrhosis(PBC). Clinically, some types of AILD were founded that at the same time or subsequent to show other types of AILD's features, it is called AILD overlap syndrome. At present, because of its more higher morbidity, unknown etiology, multiplicity clinical manifestation, diagnostic criteria and the end of the treatment so it need to further explored in many aspects. Therefore, it is of great significance to strengthen the exploration of AILD. Its pathogenesis have not yet been fully clarified, the present study showed that immune- mediated by a variety of factors involved in the complex process. Through continuously research, a proliferationinducing ligand (APRIL, also called TNFSF13) and B-cell activating factor belonging to the tumor necrosis factor family (BAFF, also called BlyS/zTNF4/TALL-1) play a very important role in the etiology. And now internal and abroad scholars focus on APRIL and BAFF.AIH is a progressive inflammatory liver disease associated with high gammaglo bulinemia and liver-related autoantibodies. The predominant histological finding of mononuclear infiltrating cells in the liver of a patient with AIH is CD8~+ T cells. Therefore, the recognized AIH pathogenesis hypothesis is that environmental factors trigger the T-cell-mediated liver autoantigen water-like cascade, resulting in progres sive necrosis of the liver inflammatory and fibrosis. Serum cytokines are thought to be involved in AIH pathogenesis via immune dysregulation. BAFF is a member of the tumor necrosis factor (TNF) superfamily and is known for its role in the survival and maturation of B cells. BAFF is produced by several cells, including monocytes, macrophages, neutrophils, dendritic cells and T lymphocytes. APRIL is a newly identified member of the TNF ligand family, a typeⅡmembrane binding protein of 250 amino acids. At first, APRIL is reported to have a regulatory role in tumor growth. APRIL has a similar sequence homologue with the recently reported BAFF, also a member of the tumor necrosis factor family. APRIL binds to two of the three BAFF receptors [B cell maturation antigen (BCMA) and transmembrane activator and cyclophilin ligand interactor (TACI)] and is supposed to have a regulatory role in B cell proliferation. From the above we can see, APRIL and BAFF are newly identified members of the TNF ligand superfamily and are known for their roles in promoting B cell differentiation, proliferation, and immature subtypes of B lymphocytes.The aim of the study was to evaluate the serum levels of APRIL,BAFF mRNA in patients with a diagnosis of type-1 (Diagnosis was based on clinical, serologic, and histologic findings. All patients were classified with definite AIH on the basis of their International Autoimmune Hepatitis Group score autoimmune hepatitis), chronic B hepatitis (HBV) and healthy controls, Meanwhile to detect biochemistry and immunity parameters, inflammation and fibrosis grade of liver biopsy. To determine whether serum levels of APRIL,BAFF mRNA are raised in patients with autoimmune hepatitis type-1 correlate with pathogenesis, disease activity or prognosis .Material and Methods1. Extraction of total RNA of samples and reverse transcriptase PCR, serum samples from 37 patients with AIH-1(34 female,3 male, mean age 50.0 years old), 19 patients with HBV(17 female, 2 male, mean age 46.2 years old)and15 healthy controls (13 female, 2 male, mean age 39.5 years old)were assayed for APRIL,BAFF mRNA by semi-quantitative polymerase chain reaction. To take the GAPDH as the internal control.2. Medical charts were retrospectively reviewed for immunoglobulin G , immunoglobulin M and immunoglobulin A levels. Complement 3(C3), complement 4(C4), C reaction protein(CRP) and erythroeyte sedimentation rate (ESR) levels were also assayed in AIH-1 patients with special protein machine.3. Liver function tests [aspartate aminotransferase (ALT), alanine aminotransferase (AST)]and globulin levels were determined using the automatic analyzer.4. Antinuclear antibody and anti-smooth muscle antibody titers were detected by indirect immunofluorescence.5. Statistical analysis was performed using SPSS version13.0 for the expression differences of APRIL,BAFF in 37 patients with autoimmune hepatitis type-1,19 patients with chronic hepatitis B and 15 healthy controls . The Kruskal-Wallis test was used for the comparison of continuous data. Nominal variables were correlated by contingency tables. Correlation coefficients were calculated by Spearman's Test. Ap value<0.05 was considered statistically significant.RESULTS:1. The serum levels of APRIL and BAFF in 37patients with autoimmune hepatitis, 19 patients with HBV, and in 15 healthy controls were measured using the semi-quantitative polymerase chain reaction. The mean(SD) serum levels of APRIL and BAFF in patients with AIH-1 (APPIL:0.66±0.41, BAFF:0.76±0.35) were significantly higher than those in the healthy controls(APRIL:0.30±0.25,p=0.000,BAFF:0.23±0.19, p=0.000) and in patients with HBV(APRIL:0.33±0.26, p=0.001,BAFF:0.33±0.26,p=0.000), there have statistically significant difference between the mean level of the experimental group and the two control groups. While there was not significant difference (p=0.694. p=0.074).2. A retrospective chart reviewed the level of APRIL,BAFF mRNA of 37 patients with AIH-Ⅰ, 19 patients with HBV and 15 healthy controls showed a moderate positive correlations between BAFF (t=0.048, p=0.010; t=0.158. p=0.048; t=0.505. p=0.049) and serum APRIL levels.3. The mean (SD) serum levels of APRIL in patients with AIH-Ⅰdo not correlate with age or sex. 37 patients with AIH-Ⅰwas divided into three groups: Disease onset groups, disease recurrence groups and disease remission groups. The mean (SD) serum levels of APRIL in the three groups respective were 0.65±0.39,1.00±0.21 and 0.24±0.10. The mean (SD) serum levels of APRIL in the disease onset groups and recurrence groups were significantly higher than those in the disease remission groups (p=0.001, p=0.000). While there were not significant differences between the two former groups.4. While the mean (SD) serum levels of BAFF in disease onset groups was 0.76±0.36, in disease remission groups was 0.68±0.25 and in disease recurrence groups was 0.87±0.41. There were not significant differences among the three groups (t=-0.654,p=0.518; t= -0.807, p=0.446; t=0397,p=0.707).5. However, there were no significant correlations among BAFF, APRIL and disease activity (biochemical, immunology) . Histological staging (inflammation and fibrosis score) did not correlate with serum APRIL and BAFF levels either. But the expression level of BAFF mRNA and IgA has a moderate degree positive correlation (p<0.05)CONCLUSION:1. The mRNA expression of APRIL and BAFF in patients with AIH-1 are higher than that in healthy control.2. There is a moderate correlation between the expression of APRIL and BAFF.3. The expression of APRIL is higher in disease onset groups and disease recurrence groups; but it has a lower expression in disease remission groups.4. APRIL,BAFF contribute to liver injury and disease development in AIH-1 patients. Patients with raised serum APRIL and BAFF levels may be ideal candidates for therapeutic targeting of APRIL and BAFF.