The study of the HLA system was primarily initiated to understand the basis for the histocompatibility between recipients and tissue donors. HLA typing methods are being continuously improved and biochemical and molecular typing, in particular, are expected to provide precise typing of the HLA system. Conventional HLA typing methods can define antigen specificities, while biochemical and molecular methods will provide direct allele typing that is based on the actual sequence polymorphism. The precise tissue typing will definitely improve the outcome of transplantation. Structural studies have revealed the highly polymorphic nature of the HLA system and given insight to understanding the molecular basis of the HLA polymorphism. One big immunological puzzle remaining to be answered is how T-cell receptor molecules recognize peptide antigen in conjunction with the HLA molecule. The crystallization of the T-cell receptor molecule, an experiment currently underway, will eventually reveal the structural basis of the trimolecular interaction.
Animals ; Genes, MHC Class I ; Genes, MHC Class II ; Histocompatibility Antigens Class I/analysis/chemistry/*physiology ; Histocompatibility Antigens Class II/analysis/chemistry/*physiology ; Human ; Polymorphism (Genetics) ; Protein Conformation

OBJECTIVE: To detect loss of heterozygosity (LOH) at human leukocyte antigen (HLA) loci in a Chinese patient with leukemia after haploidentical hematopoietic stem cell transplantation. METHODS: HLA genotyping was carried out on peripheral blood, hair follicle and buccal swab samples derived from the patient after the transplantation as well as peripheral blood samples from his parents by using PCR-sequence specific oligonucleotide probe method and PCR-sequence based typing method. Short tandem repeat (STR) loci were detected by using a 23 site STR assay kit and a self-developed 6 STR loci assay for the HLA regions. RESULTS: After the transplantation, the HLA genotype of the peripheral blood sample of the patient was identical to his father. The patient was HLA-A*02:01,24:02, C*03:03,03:04, B*13:01,15:01, DRB1*08:03,12:02, DQB1*03:01,06:01 for his hair follicle specimen. However, homozygosity of the HLA loci was found in his buccal swab sample. Only the HLA-A*24:02-C*03:03-B*15:01-DRB1*08:03-DQB1*06:01 haplotype from his father's was present, while the HLA-A*02:01-C*03:04-B*13:01-DRB1*12:02-DQB1*03:01 haplotype from his mother was lost. After the transplantation, the alleles of the 23 STR sites in the patient's peripheral blood sample were consistent to his father, with no allelic loss detected in his buccal swab sample. However, at least 4 STR loci in the HLA region were lost in his buccal swab sample. CONCLUSION LOH at the HLA loci has been detected in the buccal swab sample of a patient with leukemia who received haploidentical hematopoietic stem cell transplantation.
HLA Antigens/genetics* ; HLA-A Antigens/genetics* ; Histocompatibility Antigens Class I/genetics* ; Humans ; Leukemia/genetics* ; Loss of Heterozygosity

Fresh rat corneas as well as corneas preserved in several different corneal preservation media were stained with Avidin-Biotin-peroxidase Complex method in order to evaluate major histocompatibility complex (MHC) antigen expression. In fresh corneas, class I antigen was identified in corneal epithelium, stroma and endothelium. Class II antigen was identified only in stroma. In corneas preserved in the media which contained chondroitin and dextran for 7 days, class I antigen was somewhat decreased but class II antigen was increased. In corneas preserved in the medium which contained insulin or epidermal growth factor for 7 days, class II antigens seemed to be increased compaired to the fresh cornea. Expression of MHC antigens of corneas in the medium with fetal bovine serum were similar to those of fresh corneas.
Animals ; Cornea/*metabolism ; Culture Media ; Histocompatibility Antigens Class I/*biosynthesis ; Histocompatibility Antigens Class II/*biosynthesis ; Immunoenzyme Techniques ; Major Histocompatibility Complex ; Organ Preservation/methods ; Rats ; Rats, Inbred Lew

PURPOSE: Stem cells are considered promising candidates for cell replacement therapy in many devastating diseases. However, it is assumed that stem cells may be rejected on transplantation. Therefore, we introduced human cytomegalovirus (hCMV) US genes, which are known to be able to reduce MHC class I expression on the cell surface after infection, into two known stem cell lines in order to test the feasibility of modifying these cells to reduced MHC class I antigens by the introduction of hCMV US genes. METHODS: The MHC class I expressions of mock-transfected or hCMV US gene-transfected human embryonic neural stem cell line (HB1.F3) and human breast epithelial stem cell line (M13SV1) were examined by FACS. RESULTS: MHC class I expressions in HB1.F3 and M13SV1 cells were dramatically induced by IFN-gamma treatment. In FACS analysis, cells transfected with the hCMV US2, 3, 6 or 11 genes exhibited a dramatic reduction (40~60%) of MHC class I expression compared with mock-transfected cells. CONCLUSION: Our results suggest that human stem cells express high levels of MHC class I antigens, and thus may be rejected on transplantation unless they are odified. In addition introduction of hCMV US genes can be exploited for stemcell transplantation.
Breast ; Cytomegalovirus ; Down-Regulation* ; Histocompatibility Antigens Class I ; Humans* ; Neural Stem Cells ; Stem Cells*

PURPOSE: Due to their unique capacity to self-renew and for multiple differentiation, stem cells are considered potent candidates for cell replacement therapy in many devastating diseases. However, studies on immune rejection, which is a major problem facing successful stem cell therapy, are rare. Thus, we examined MHC expression of human stem cells and effects of IFN-gamma on the MHC class I expression of the cells in order to determine whether human stem cells might be rejected after transplantation. METHODS: The MHC antigen expressions of human embryonic neural stem cell line (HB1.F3) and human breast epithelial stem cell line (M13SV1) were examined by RT-PCR and FACS. The effects of varying concentrations of IFN-gamma and of varying incubation times with IFN-gamma on the expression of MHC class I antigens in these stem cell lines were also examined by FACS. RESULTS: The results show low expression levels of MHC class I antigens on surfaces of these cells. A dramatic induction of MHC class I expression was observed when the cells were treated with IFN-gamma. Maximal induction of MHC class I antigen expression in HB1.F3 and M13SV1 cells was observed at above the concentrations of 20 ng/mL and 5 ng/mL of IFN-gamma 48 h after treatment, respectively. Elevated MHC class I levels in HB1.F3 and M13SV1 cells were sustained for 48 h and 72 h after withdrawing IFN-gamma, respectively. CONCLUSION: These results suggest that human stem cells express high levels of MHC class I antigens, and thus may be rejected on transplantation unless they are modified. Therefore, in addition to studies on stem cell differentiation, studies on overcoming the immunological barriers to stem cell transplantation are prerequisite for successful clinical application of stem cell therapy.
Adult* ; Breast* ; Histocompatibility Antigens Class I ; Humans* ; Neural Stem Cells* ; Stem Cell Transplantation ; Stem Cells*

OBJECTIVETo review the role of polymorphism of major histocompatibility complex class I-related chain A (MICA) gene and antibodies against MICA antigens in transplant immunology.

DATA SOURCESThe data used in this review were mainly from our own results and from the relevant English language literatures published from 1999 to 2010. Some data presented in this review are in press.

STUDY SELECTIONArticles regarding MICA gene discovery and pioneering finding of antibodies against MICA antigen and allograft rejection were selected. This review chronicles the development of our understanding of the role that MICA antigens and antibodies may play in organ transplantation.

RESULTSPolymorphic glycoprotein MICA antigens were detected on freshly isolated human umbilical cord endothelial cells, but not on peripheral lymphocytes. Antibodies were found and typing of recipients and donors by sequencing the MICA alleles has established that de novo antibodies produced in kidney transplant recipients are directed at mismatched MICA epitopes and are associated with acute rejection and chronic transplant failure. The specificity of antibodies against the epitopes of MICA antigens were well characterized by donor MICA typing, single antigen array testing with antibody absorption and elution. Acute graft-versus-host disease was observed in stem-cell recipients who were mismatched for MICA.

CONCLUSIONSImmunization against mismatched MICA epitopes encountered in donor organs after transplantation may result in antibodies against MICA alleles. Testing for MICA donor-specific antibodies (DSA) which are associated with early failure of kidney transplants may be helpful for identifying some of the targets of antibodies against antigens other than the human leukocyte antigen (HLA) and for improving transplantation outcome.

Hematopoietic Stem Cell Transplantation ; Histocompatibility Antigens Class I ; genetics ; Humans ; Polymorphism, Genetic ; Transplantation, Homologous

OBJECTIVETo investigate the genetic polymorphism of microsatellite in the exon 5 of MICA gene and the intron 1 of MICB gene in Guangdong Han population.

METHODSOne hundred and six samples of Guangdong Han population were genotyped by polymerase chain reaction and fluorescent technique (6-FAM). Gene frequency, power of discrimination, expected heterozygosity, polymorphism information content and probability of paternity exclusion were calculated.

RESULTSThe genotype distributions of MICA and MICB microsatellite met Hardy-Weinberg equilibrium. MICA A5 was the most common allele (0.2877), whereas A4 was the least popular one (0.1321). The genotype distribution frequencies of A5-5.1 (14.15%) and A5-5 (10.38%) are high. MICB CA14 was the most common allele (0.3255), and CA19,28 was the least popular one (0.0047). CA27 was not observed. The genotype distribution frequency of CA14-CA14(14.15%) is high.

CONCLUSIONThe microsatellite of the exon 5 of MICA gene and the intron 1 of MICB gene could be used as the genetic markers of Chinese population in the studies of anthropology, linkage analysis of genetic disease genes, individual identification and paternity test in forensic medicine.

Hemochromatosis/genetics* ; Histocompatibility Antigens Class I/genetics* ; Humans ; Mutation ; Receptors, Transferrin/genetics*

OBJECTIVE: To explore the relationship between the level of soluble HLA-E (sHLA-E) molecules in plasma and gene polymorphism and leukemia in Shenzhen of China. METHODS: Enzyme-linked immunosorbent assay was used to detect sHLA-E level in plasma of 103 leukemia patients and 113 healthy blood donors. PCR-SBT was used to identify the HLA-E genotype of 73 leukemia patients and 76 healthy blood donors. RESULTS: The level of plasma sHLA-E of 103 leukemia patients was significantly higher than that of 113 healthy blood donors (P<0.001); And the level of plasma sHLA-E in 77 myeloid leukemia patients was also significantly higher (P<0.001). The percentage of patients with plasma sHLA-E concentration of 0-199 ng/ml in leukemia and myeloid leukemia patients was 37.86% and 32.47%, respectively, which was significantly lower than 53.98% of healthy donors, the difference was statistically significant (P<0.05, P<0.01); While, when the plasma sHLA-E concentration was more than 400 ng/ml, the percentage was 33.01% and 36.36%, respectively, which was significantly higher than 13.28% of healthy donors, the difference was also statistically significant (P=0.001, P<0.001). There was no significant difference in the level of plasma sHLA-E among different HLA-E genotypes (P>0.05), whether healthy blood donors or leukemia patients. CONCLUSION The level of plasma sHLA-E in patients with leukemia (especially myeloid leukemia) is significantly higher than that of healthy blood donors, but different HLA-E genotypes do not affect the level of plasma sHLA-E. A cut-off value for the concentration of plasma sHLA-E (recommended risk value >400 ng/ml) can be set to assess the risk of certain pre-leukemia patients.
Genotype ; Histocompatibility Antigens Class I/genetics* ; Humans ; Leukemia/genetics* ; Polymorphism, Genetic