HLA antigens and anti-sperm antibody production in Iranian vasectomized men

Dear Editor： Anti-sperm antibodies （ASAs） are composed of numerous antibodies interacting with multiple sperm antigens that play a role in fertility. In males, ASAs cause ＇immune infertility＇ by decreasing sperm counts and normal forms, as well as reducing sperm motility and viability, markedly reducing the likelihood of natural conception. The development of ASA in the male depends on the release of sequestered antigens on germ cells following the disruption of the blood-testis barrier.

HLA ANTIGENS AND VOGT-KOYANAGI- HARADA'S DISEASE

Thirty patients with Vogt-Koyanagi-Haradas disease were typed for HLA-A and HLA-B antigenic determinants by a microlymphocytotoxicity technique. HLA-B22 antigen showed an increased frequency of 43.3% in the patient group(relative risk=8.69; exact P<0.0001; corrected P<0.0025) compared with normal control group(frequency=7.69%). This association suggests that immunogenetic factor may play an important role in the pathogenesis of Vogt-Koyanagi-Harada's disease.

Immunohistochemical Study of HLA-DR Antigen in Endometrial Tis-sue of Patients with Endometriosis

In order to evaluate the expression of HLA DR antigen in glandular cells in eutopic and ectopic endometrium in patients with endometriosis, 19 infertile patients with endometriosis were analyzed immunohistochemically by labelled streptavidin biotin (LSAB) method. Nineteen infertile patients without endometriosis were studied as controls. The results showed that the expression of HLA DR antigen in the glandular cells in both eutopic and ectopic endometrium was increased significantly as compared with that in the controls ( P <0.01). It is likely that aberrant expression of HLA DR antigen in endometriotic tissue is involved in abormal immunogenesis of endometriosis.

REPORT OF HLA DISTRIBUTION IN 2315 VOLUNTEER DONORS OF CHINESE BONE MARROW BANK FROM NORTHWEST CHINA

Objective To report the HLA data of volunteer donors of Chinese bank from Northwest China and characterize the distribution of HLA genes in Northwest China. Methods HLA-A, B antigens of 2315 volunteer donors were examined by the method of microlymphocytetoxicity (MLT) test .The antigen frequencies(AF) were assessed by directly counting; and based on that gene frequencies(GF) were calculated. HLA data from other population were collected and distribution characteristics were compared. With the raw data, Hardy-Weinberg equilibrium, statistical parameters of forensic medicine interest for HLA were computed. Results A total of 18 specific antigens were detected in HLA-A and the most frequent antigen was A2 . AF and GF were 0.5136 and 0.3026, respectively. A total of 42 specific antigens were detected in HLA-B and the most frequent antigen was A13. Its' AF and GF were 0.1978 and 0.1044, respectively. The heterozygosity(H), polymorphism information content(PIC), discrimination power(DP) and probability of paternity exclusion (PPE) of HLA-A were 0.8215, 0.8212, 0.9356 and 0.7798 accordingly; while H,PIC, DP and PPE of HLA-B were 0.9322, 0.9322, 0.9878 and 0.9528. Conclusion The polymorphism of HLA-A,B genes is characteristic in Chinese. In this research, the genetic trait of HLA in 2315 volunteers is consistent with Northern Han population.

Expression of CⅡTA Gene in Five Human Malignant Hematological Cell Lines and Its Significance

The role of MHC class Ⅱ transactivator (CⅡTA) in constitutive or IFN-γ inducible expression of HLA molecules in human malignant hematological cell lines was investigated. The expression of HLA molecules and CⅡTA protein was detected by Western blot, immunohistochemistry and flow cytometry. The expression of CⅡTA gene was determined by RT-PCR. The capability of peripheral blood T cell reaction stimulated by tumor cells was monitored by mixed lymphocyte reaction. It was found that the HLAⅡ-positive tumor cells expressed the CⅡ TA quite well, and the expression of HLAⅠ+Ⅱ was increased in the tumor cells with constitutive or inducible expression of CⅡ TA after induced by IFN-γ. The tumor cells which did not express CⅡ TA after induced by IFN- γ were not response to the expression of HLAⅡ promoted by IFN- γ. It suggests a correlation between the inability of some malignant hematological cell lines in response to IFN-γ for HLA expression and the deficiency in the inducible expression of CⅡTA, indicating CⅡ TA might take part in the regulation of HLA Ⅰ+Ⅱ expression in the tumor cells, which might play an important role in tumor immunologic escape.

Polymorphism of the HLA-DQA1 and -DQB1 genes of Han population in Jiangsu Province,China

The HLA genes, located on the short arm of human chromosome 6, encode peptides involved in host immune response, are important in tissue transplantation and are associated with a variety of infectious, autoimmune, and inflammatory diseases. Moreover, the HLA loci display an unprecedented degree of diversity and the distribution of HLA alleles and haplotypes among different populations is considerably variable. The expression of particular HLA alleles may be associated with the susceptibility or resistance to some diseases. In this study, the genetic polymorphism of HLA-DQA1 and -DQB1 in Jiangsu Han population was analyzed by polymerase chain reaction-sequence-based typing （PCR-SBT）.

Expression of HLA class I and II on peripheral blood lymphocytes in HBV infection

Persistent hepatitis B virus （HBV） infection is the most important reason for chronic hepatitis B,hepatic cirrhosis, and hepatocellular carcinoma. T lymphocytes, including CD4^＋ and CD8^＋ T cells, are major composition of host cellular immunity. Furthermore, CD8^＋ cells play a primary role in host immune reaction of anti-tumor and anti-infection. It has been confirmed that HBV infection leads to disorder of cellular immune function in patients, especially disorder in regulative function of T lymphocyte subgroups and cytokine. It has been paid more attention to the expression of HLA class I on hepatocytes infected by HBV and tumor cells, but less to the expression of HLA class I on peripheral blood lymphocytes in the past. In this study, we evaluated the expression of HLA class I and II on peripheral blood lymphocytes in patients with chronic hepatitis B, hepatic cirrhosis, and hepatocellular carcinoma and tried to provide new thought for the mechanism of disorder of celluar immunity.

Genetic variants in the 6p21.3 region influence hepatitis B virus clearance and chronic hepatitis B risk in the Han Chinese population

Background and aim:A genome-wide association study has indicated the association of numerous genes in the 6p21.3 region with chronic hepatitis B virus(HBV)infection.In this study,we screened 12 representative single-nucleotide polymorphisms(SNPs)from the 6p21.3 region and investigated their association with the risk of chronic hepatitis B(CHB)to better understand the molecular etiology un-derlying CHB risk in the Han Chinese population.Methods:Between March 2021 and November 2022,we included 183 patients with CHB(case group)and 196 with natural HBV clearance(control group).Allele typing of the selected SNPs was performed using snapshot technology.The correlation between the 12 chosen SNPs and the risk of chronic HBV infection was examined using binary logistic regression analysis.Interacting genes of the variants were identified,and expression quantitative trait loci(eQTL)were analyzed using the 3DSNP database.Results:We validated 12 previously reported CHB susceptibility sites,including rs1419881 of tran-scription factor 19(TCF19),rs3130542 and rs2853953 of human leukocyte antigen(HLA)-C,rs652888 of euchromatic histone-lysine-methyltransferase 2(EHMT2),rs2856718,rs9276370,rs7756516,and rs7453920 of HLA-DQ,rs378352 of HLA-DOA,and rs3077,rs9277535,and rs9366816 of HLA-DP.Logistic regression analyses revealed that polymorphisms such as rs9276370,rs7756516,rs7453920,rs3077,rs9277535,and rs9366816 were positively correlated with natural HBV clearance in the dominant model.Conversely,rs3130542 and rs378352 were identified as risk factors for CHB.Haplotype analysis revealed that rs9276370,rs7756516,and rs7453920 in HLA-DQ were TTG and GCA haplotypes.Although the TTG haplotype was positively correlated with a higher risk of CHB,the GCA haplotype significantly influenced the natural clearance of HBV.Bioinformatics analysis demonstrated that rs378352,rs3077,and rs9366816 were located within enhancer states;rs3077 and rs9366816 overlapped with nine tran-scription factor-binding sites,whereas rs378352 altered five sequence motifs.Furthermore,eQTL analysis demonstrated the functional tendencies of eight statistically significant SNPs(rs3130542,rs9276370,rs7756516,rs7453920,rs378352,rs3077,rs9277535,and rs9366816).Conclusions:Genetic variations within the 6p21.3 region were associated with chronic HBV infection in the Han Chinese population in southern China.Furthermore,the GCA haplotype including rs9276370,rs7756516,and rs7453920 of HLA-DQ contributed significantly to natural HBV clearance,implying that multiple SNPs exert a cumulative allelic effect on HBV infection.

Impact of human leukocyte antigen matching and recipients＇ panel reactive antibodies on two-year outcome in presensitized renal allograft recipients

Background Renal transplantation in sensitized candidates remains a highly significant challenge worldwide. The production of panel reactive antibody （PRA） against human leukocyte antigen （HLA） is a major risk factor in presensitized recipients. The aim of this study was to evaluate the impact of HLA matching and recipients＇ PRA on two-year outcome in presensitized renal allograft recipients. Methods We determined the percentage of panel reactivity and specificity of anti-HLA immunoglobulin （Ig） G antibodies in 73 presensitized renal allograft recipients compared with 81 unsensitized recipients （control group）. HLA genotyping of both recipients and corresponding donors was performed by PCR with sequence-specific primers （PCR-SSP）. We analyzed the factors influencing the early graft outcome （two-year rejection rates and survival rates of the grafts）, including HLA mismatching, class and degree of panel reactivity, and target antigen of donors. Results Presensitized recipients had a worse two-year outcome than unsensitized recipients （P=0.019 for rejection rate, P=0.01 for survival rate）. The difference in number of HLA-mismatched alleles with either 6-antigen matching （Ag M） standard or amino acid residue matching （Res M） standard was not significant between the rejection and non-rejection groups of presensitized recipients or between the graft survival group and graft loss group. Compared with the control group, recipients with both PRA-I and PRA-II antibodies had a significantly worse two-year outcome （P=0.001 for rejection rate, P=0.002 for survival rate）. The two-year outcomes of the peak PRA 〉50% group and its subgroup, at-transplant PRA 〉50% group, were significantly worse compared with the control group （P=0.025 and P=0.001 for rejection rate, P=0.043 and P=0.024 for survival rate）. The rejection rates of the at-transplant target antigen positive group and its subgroup, HLA-I target antigen positive group, were significantly higher than the control group （P=0.001 and P=-0.001）, target antigen negative group （P=0.003 and P=0.001）, and peak target antigen positive with negative at-transplant target antigen group （P=0.024 and ,0=-0.002）. Two-year graft survival rates of the target antigen positive group and HLA-I target antigen positive group were significantly lower than the control group （P=0.012 and ,P=0.001）. The two-year outcome of target antigen unknown group was similar to that of the target antigen positive group. Presensitized recipients with pre-transplant plasmapheresis or immunoadsorption （PRA prepared group） had a better but non-significant two-year outcome than the control group. However, the PRA unprepared presensitized recipients were different to the control group （P=-0.004 for rejection rate and P=-0.005 for survival rate）. Hyperacute rejection （HR） occurred in three recipients with positive HLA-I target antigen and without mismatch according to Res M and in one case with positive PRA-II （for an unknown target antigen）. No HR occurred in eight cases with positive HLA-II target antigens. Conclusions Pre-transplant PRA preparations might improve the access of presensitized patients to renal donors. Avoiding antigen-positive donors remains a fundamental measure in preventing HR and early rejections.

Detecting donor-specific antibodies: the importance of sorting the wheat from the chaff

Human leukocyte antigen(HLA)compatibility is very important for successful transplantation of solid organs.In this paper,we focused on the humoral arm of immunity in the clinical setting of organ transplantation:how HLA antibodies develop,how they can be detected,and what they can do to injure organ transplants.Specifically,we explore the technical perspectives of detecting donor-specific antibodies(DSA)in HLA laboratories,and use real-life clinical cases to explain the principles.Currently there are many tools in our HLA antibody detection toolbox:conventional cytotoxicity cross match,flow cross match,and solid phase assays using beads conjugated with single or multiple HLA antigens.Single antigen bead(SAB)assay is the most sensitive tool available for detecting HLA antibodies and assessing the immunological risk for organ transplant.However,there are intrinsic limitations to solid-phase assays and they are prone to both false negativity and importantly,false positivity.Denatured antigens on single antigen beads might be the most prominent source of false positive reactivity,and may have been underestimated by many HLA experts.No single assay is perfect and therefore multiple methods,including the less sensitive assays,should be employed to determine the clinical relevance of detected HLA antibodies.Thoughtful process,including knowledge of HLA systems,cross reactivity,epitopes,and the patient's clinical history should be employed to correctly interpret data.The clinical team should work closely with HLA laboratories to ensure accurate interpretation of information and optimal management of patients before and after organ transplantation.

Molecular Advances in Severe Acute Respiratory Syndrome-associated Coronavirus (SARS-CoV)

The sudden outbreak of severe acute respiratory syndrome (SARS) in 2002 prompted the establishment of a global scientific network subsuming most of the traditional rivalries in the competitive field of virology. Within months of the SARS outbreak, collaborative work revealed the identity of the disastrous pathogen as SARS-associated coronavirus (SARS-CoV). However, although the rapid identifi-

DQB1＊060101 may contribute to susceptibility to immunoglobulin A nephropathy in southern Han Chinese

Immunoglobulin A nephropathy （IgAN） is a common form of chronic glomerulonephritis with unknown pathogenesis. Accumulating evidences have shown the ethnic-specific association between certain human leukocyte antigen （HLA） alleles and IgAN susceptibility. This study was designed to explore the relationship between HLA-DQB1 alleles and disease susceptibility and clinical manifestations of patients with IgAN in southern Han Chinese. A PCR sequence-based typing technique was used to detect HLA-DQB1 alleles in 217 IgAN patients and 229 healthy subjects. Clinical data were collected from each patient at the time of renal biopsy. Twenty HLA-DQB1 alleles were detected in IgAN patients and healthy subjects. High frequency of HLA- DQB1＊060101 and low frequency of HLA-DQB1＊030101 were observed in IgAN patients compared with healthy controls. Further stratification analysis revealed that the frequency of DQB1＊060101 was significantly higher in patients with urine protein ≥1.0 g/24 h than in patients with urine protein 〈 1.0 g/24 h. In combination with our previous DRB1 results, we also analyzed the association of DRB1-DQB1 haplotypes with IgAN. We found that the frequency of haplotype DRBI＊090102-DQB1＊060101 was significantly higher [odds ratio （OR） = 4.409, Pc = 0.016], whereas that of HLA-DRBI＊070101-DQB1＊020101 was significantly lower （OR= 0.194, Pc = 0.016） compared with healthy controls. Our study indicated that HLA-DQB ＊060101 alleles may be a potential predictor of high-risk IgAN susceptibility in Chinese Han population.

The impact of alloantibodies directed against the second donor on long-term outcomes of repeat liver transplantation

Background:Despite reports that associate donor specific antibody(DSA)with rejection after liver transplantation,grafts are still allocated according to blood group(ABO)but not human leukocyte antigen(HLA)compatibility,possibly due to the absence of an easily discernible clinical association between adverse recipient outcome and DSA.Re-transplantation provides a test environment where the presence of preformed DSA is prevalent and its effect on outcome should be apparent.Methods:All patients undergoing a second liver transplantation with available pre-operative serum were included with the exception of ABO incompatible or multiple organ transplants.Banked sera were tested for anti-HLA antibodies with Luminex-based solid phase assays.Anti-HLA antibodies to the second donor(D2SA)were determined using antibodies specificity and HLA typing of 2nd liver donor.Results:Preformed HLA antibodies directed to second liver transplantation(D2SA)were found in 31(39%)of the 79 patients that were included in the study.Primary and re-transplantation characteristics were similar in both subgroups except first graft survival which was significantly shorter in recipients who are negative for D2SA.Mean survival of the second graft was similar in D2SA+and D2SA?cohorts[8.55(range,0.01–24.74)vs.7.56(range,0–23.53)years respectively,P=0.574].Mean patient survival after 2nd liver transplantation was similar in D2SA+and D2SA?cohorts[9.11(range,0.01–24.74)vs.8.10(range,0–23.53)years respectively,P=0.504].Subgroup univariate analysis demonstrated no detrimental effect of class,locus,or strength of D2SA on survival of the second liver transplant.In multivariate cox regression model,neither class I D2DSA(HR=1.101,P=0.92)nor class II D2SA(HR=1.74,P=0.359)were significant risks of graft failure.Conclusions:Presence of D2SA was not found to be associated with inferior outcomes in this retrospective cohort study of liver re-transplantation suggesting that changes to the allocation system are not required.