The correlation of results of panel reactive antibody, identification, and single antigen beads in detection of anti-HLA antibodies: Istanbul Faculty of Medicine, tissue typing laboratory experience.

BACKGROUND: We have performed a retrospective analysis of anti-HLA class I MHC and class II MHC antibodies measured using a single antigen bead (SAB) assay and a panel reactive antibody (PRA) assay. MATERIAL AND METHODS: A group of 256 patients with end-stage renal disease (ESRD) was tested for anti-HLA antibodies in the tissue typing laboratory between 2017 and 2020. In the cohort, the serum samples of patients waiting for transplantation were tested. Both the PRA and SAB tests of these patients were analyzed using the Luminex (Immucor) method. The threshold of positivity was accepted as median fluorescence intensities (MFI) ≥1000 for PRA screening and MFI ≥750 for SAB screening. RESULTS: Overall, antibodies to HLA antigens were detected in 202 (78.9%) out of 256 patients in the PRA study. Antibodies against both class I/II antigens were detected only in 15.6% of these patients, whereas antibodies against only against class I HLA in 31.3% and only against class II HLA in 32.0%. By comparison, the SAB study found that 66.8% of patients were positive for HLA antigens. Furthermore, donor-specific antibodies (DSA) were detected in 52.0% of PRA-positive patients and 52.6% of SAB-positive patients. It was shown that 168 patients (83.2%) out of 202 PRA-positive patients were found to be SAB-positive. In addition, 51 patients negative in the SAB assay (94.4%) were also negative in the PRA assay. Statistical analysis established a significant correlation between the PRA and SAB positivity (p > 0.001). It was also shown that MFI ≥3000 PRA positivity for class I HLA antigens (p = 0.049) and MFI ≥5000 PRA positivity for class II antigens (p < 0.001) correlated with the SAB positivity in patients. CONCLUSION: Our results showed the importance of both PRA and SAB assays to define the status of sensitization in patients.

COSMC expression as a predictor of remission in IgA nephropathy.

PURPOSE: The impact of core 1,3-galactosyltransferase-specific molecular chaperon (COSMC) gene expression and methylation profile on clinical progression of IgA nephropathy (IgAN) is unclear. The aim of this study was to determine the clinical significance and the relation of the COSMC gene expression and methylation pattern with the progression of IgAN. METHODS: Thirty-nine biopsy-confirmed IgAN patients, 11 healthy relatives and 20 healthy controls were recruited. The COSMC mRNA levels and methylation profile of COSMC gene promoter were measured using the quantitative real-time PCR. The galactose-deficient IgA1 (Gd-IgA1) levels were measured using ELISA in serum and cell culture supernatant. The effect of IL-4 and AZA on COSMC expression and methylation and the correlation of COSMC gene expression and methylation levels with baseline kidney function tests, histology and long-term outcomes were examined. RESULTS: The mean COSMC mRNA level was significantly lower, and serum Gd-IgA1 level was higher in IgAN patients compared with the control groups (p < 0.001, and p = < 0.001, respectively). The COSMC mRNA levels were correlated with intensity of hematuria (r = - 0.41, p = 0.009), serum creatinine level (r = - 0.37, p = 0.002) and eGFR (r = 0.36, p = 0.002). The COSMC methylation levels were correlated with age (r = 0.25, p = 0.04) and baseline eGFR (r = - 0.326, p = 0.006). Twenty IgAN patients (51.3%) reached to complete (5, 12.8%) or partial remission (15, 38.5%) after a median of 34.5 months (IQR, 13.75-71). In multivariable Cox regression analysis, COSMC mRNA expression (adjusted HR (aHR) 1.871, 95% CI 1.287-2.722, p = 0.001) and Oxford T score (aHR 0.355, 95% CI 0.146-0.859, p = 0.022) predicted the remission. CONCLUSION: COSMC mRNA level is a novel biomarker candidate to predict the remission in IgAN patients.

Can Direct-Acting Antiviral Treatment Change the Immunologic Risk Profile in Patients Infected with Hepatitis C Virus Who Are on the Cadaveric Waiting List?

BACKGROUND: In patients with hepatitis C virus (HCV) infection, the activation of the immune system by the virus or viral proteins leads to the production of numerous autoantibodies and clinical manifestations. The objectives of this study were to investigate the relationship between HCV and anti-HLA antibodies, as well as the effect of viremia on the antibody response and of direct-acting antivirals (DAAs) on anti-HLA antibody persistence in patients on the waiting list for a cadaveric kidney transplant. METHODS: A total of 395 patients from the cadaveric renal transplant waiting list were included in the study. The patients were grouped according to the presence of HCV infection, and patients with HCV positivity were further divided into a spontaneous clearance group and a persistent group. Anti-HLA antibodies were examined before and after treatment of the patients in the persistent group. The One Lambda Luminex method (Thermo Fisher Scientific, Waltham, MA, United States) was used to assess both HLA class I and II alleles and the anti-HLA antibody profile. RESULTS: Anti-HLA class I and II antibodies were detected in 48.2% and 55.1%, respectively, of the patients infected with HCV and in 21.8% and 20.4%, respectively, of the patients who were not infected. The level of anti-HLA A3, A11, B72, B52, Cw6, Cw16, DR3, and DQ4 antibodies was significantly higher in the patients infected with HCV. There was no statistically significant difference in class I and II antibody titration between the HCV-infected spontaneous clearance group and the persistent group (class I mean fluorescence intensity [MFI] ± SD: 13,583 ± 6224, 13,450 ± 9540, P = .808; Class II MFI ± SD: 13,000 ± 8673, 8440 ± 8302, P = .317, respectively). There was no significant difference in the class I and class II anti-HLA antibody profile and titration in the persistent group after treatment with DAAs (P > .05). CONCLUSIONS: The results of this study demonstrated that hepatitis C DAA treatment did not change the anti-HLA antibody profile and titration.