DNA typing revealing high HLA-Cw polymorphism completes availability of major histocompatibility complex loci in forensic medicine.

Studies of human population genetics in Hungary have revealed relevant heterogeneity in the major histocompatibility complex. In the present studies, two isolated ethnic groups were chosen: people living in the Káli Basin westward from the Danube River, and those living in Opusztaszer, a village eastward from Danube, who are known as native ancient Hungarians. Blood samples were collected from 70 people in the Káli Basin and from 45 people in Opusztaszer. The frequency of HLA-Cw alleles was determined by serology as well as by DNA typing in 46 and 32 samples of the two populations, respectively, and in 44 randomly selected subjects of Hungarian origin. Compared with a random population of cadaver donors (the deaths having resulted mostly from accidents or, in a smaller number, strokes or heart infarcts) and voluntary bone marrow donors (typed in the last 10 years) recruited from all parts of Hungary and representing the mixed Hungarian population, remarkable differences were found in haplotype and allele frequencies. HLA-A, -B, -Cw typing was performed by serology and, in the case of the HLA-Cw locus, by polymerase chain reaction (PCR)-SSP and/or PCR-SSOP techniques, as well. The PCR-SSO oligotyping procedure allowed the identification of 32 Cw alleles in contrast with the 9 serologically detectable types. Because of the combination of low antigen expression and the lack of specific serologic reagents of good quality, no HLA-Cw antigens were detectable in 41%, and only one was detected in 48%, of the investigated individuals by standard serologic typing. With PCR-SSO typing, however, 97% of the investigated individuals proved to be heterozygous for HLA-Cw alleles. The two isolated populations differed from each other, from mixed Hungarian and other Caucasian populations in HLA-Cw* allele frequencies, as well as in haplotype distribution. This newly recognized polymorphism at the HLA-Cw locus completes the availability of major histocompatibility complex typing in forensic science and practice.

Immunological importance of chimerism in transplantation: new conditioning protocol in BMT and the development of chimeric state.

Chimerism is an exceptional immunogenetic state, characterized by the survival and collaboration of cell populations originated from two different individuals. The prerequisits to induce chimerism are immuno-suppression, myeloablation, or severe immunodeficiency of the recipients on the one side and donor originated immuno-hematopoietic cells in the graft on the other. The pathologic or special immunogenetic conditions to establish chimerism are combined with bone marrow transplantation, transfusion, and various kinds of solid organ grafting. Different types of chimerism are known including complete, mixed and mosaic, or split chimerism. There are various methods used to detect the type of chimera state, depending on the immunogenetic differences between the donor and recipient. The induction of complete or mixed chimerism is first determinated by the effect of myeloablative therapy. The chimera state seems to be one of the leading factors to influence the course of the post-transplant period, the frequency and severity of GVHD, and the rate of relapse. However, the most important contribution of the chimeric state is in development of graft versus leukemia effect. A new conditioning protocol (DBM/Ara-C/Cy) for allogeneic BMT in CML patients and its consequence on chimera state and GVL effect is demonstrated.

Immunoglobulin variable regions usage by B-lymphocytes infiltrating a human breast medullary carcinoma.

Breast medullary carcinoma are heavily infiltrated by B-lymphocytes and associated with a good prognosis despite their high histological grade. We investigated the Ig repertoire of B-lymphocytes infiltrating one such tumour. A single cell suspension was obtained from a tumor specimen by enzymatic digestion. VH, Vkappa, and Vlambda regions were amplified by RT-PCR using mixtures of primers optimized to maximize the diversity of the PCR products. They were then cloned and sequenced. Analysis of 9 VH, 5 Vkappa, and 10 Vlambda sequences using the Kabat database indicated that several VH and VL region subgroups (I, II and III) are expressed by B-lymphocytes infiltrating this tumor. The analysis of CDR3 regions also showed a variability, although some VH and VL clones exhibited identical or nearly identical sequences. Thus, the B-cell infiltration observed in this breast medullary carcinoma does not reflect a monoclonal proliferation and represents an oligoclonal or a polyclonal B-cell proliferation.

Long-term related kidney graft survival in high-risk patients after monitored donor-specific transfusion protocol.

Altogether 57 patients were included in the related kidney transplantation program. Forty-four recipients were mixed lymphocyte culture (MLC) negative or slightly positive (SI < 7) against their mother/father donor, and most of them showed Fc gamma RII [erythrocyte antibody inhibition (EAI)] blocking antibody in their sera as the consequence of previous random transfusion. Thirteen patients showed significantly high MLC reactivity against their prospective parent donor (SI > 7) and had no EAI blocking antibody in their sera. The latter group was immunized either by buffy coat or purified platelets obtained from their donor in general two or three times at biweekly intervals. The indication for transplantation of donor-specific transfusion (DST)-treated patients was based on the appearance of EAI antibody and a significant reduction in the MLC reactivity (9 patients). DST patients had 100% kidney graft survival for 5 years and the DST untreated ones 75%. Suggested responsible factors for this observation are the haploidentity in HLA and the induction of suppressive immune regulation by DST.

Influence of HLA-DPB1 mismatches on MLR responses: the role of high resolution HLA class II typing and MLC in unrelated donor selection for BMT.

Twenty eight Hungarian patients lacking a compatible related donor and their 61 HLA-A,B,DR serologically identical potential unrelated donors (selected from BMDW) were investigated in this study. Out of the 61 donor-recipient pairs only 7 (11,5%) proved to be HLA-identical at DNA level. Thirty one pairs (50,8%) differed in DP alleles, 1 pair (1,6%) has a DQ mismatch only and 22 (36,1%) pairs differed in more alleles. More than one potential donor was found for 26 patients and 5 of them have several donors with DP mismatches only. Among the 31 donor-recipient pairs differing only in DP alleles, 0, 1 and 2 mismatches were observed in GvH direction in 7, 10 and 14 cases, respectively. In the MLC assay no proliferative response was observed when no DP mismatch has been found. Among the 1 and 2 DP mismatched cases 11 (35,5%) gave negative and 13 (41,9%) gave positive MLR results. We have found a large scatter in RR values. On the basis of the DNA typing and MLR results we have found that HLA-DPB1*0101-0201 stimulator-responder combination always gave negative MLR in both direction. HLA-DPB1*0201-0301 and DPB1*0301-0401 allele combinations were reactive in all cases. In conclusion MLC assay might indicate the low immunogeneicity in certain DP allele combinations as well as the avoidable positive combinations, which may help to select the best fitting donor for BMT.

Haemopoietic cell transplantation activity and results: a single institution experience.

Between February 1993 and November 1997, 62 patients with severe aplastic anaemia (SAA), acute myeloid (AML), acute lymphoid (ALL), or chronic myeloid leukaemia (CML) as well as two patients with NHL underwent allogeneic marrow transplantation (BMT) from HLA-identical or one-antigen mismatched sibling or unrelated donors. Patients received preparative regimens according to the baseline disease. Patients with SAA were conditioned with ATG/Cy (2 cases) and TAI/Cy (3 cases), AML, ALL and NHL with TBI/Cy (21 cases including two retransplantations) and CML with Mitobronitol/Ara-C/Cy except two patients conditioned traditionally with Bu/Cy. For GVHD prevention, patients received cyclosporin-A (CsA) with short course methotheraxe according to the Seattle protocol. Significantly better overall survival rates were associated with the Mitobronitol (DBM)/Ara-C/Cy conditioning regarded the patients as a whole. Autologous stem cell transplantation (bone marrow and/or peripheral blood) were performed in ten cases including 2 AML, 4 non-Hodgkin's lymphoma (NHL), 3 Hodgkin's disease (HD) and 1 patient with multiple myeloma (MM). Patients with AML and two patients with NHL were conditioned with TBI/Cy and the others with BEAM combined chemotherapy. Eight out of ten patients are leukaemia- or lymphoma-free survivors. One patient relapsed having conventional chemotherapy and interferon maintenance therapy. One patient died in a rapid relapse five months post-BMT.

Immunophenotypic characterisation of cord blood B-lymphocytes.

The phenotypic analysis of human umbilical cord blood (CB) mononuclear cells is important to study their maturity and differentiation regarding their transplantable capacity. In this work we have studied differential expression of B cell antigens on CD5-/HLA-DR+ B cells (B1b, B2) and CD5+/HLA-DR+ cells (Bla) from the CB (n=6) and adult peripheral blood (PB) (N=6). CD5-PE, HLA-DR-PerCP and FITC labelled anti-B cell MoAb panel of the 6th International Workshop on Human Differentiation Antigens were used for detection of B cell subpopulations. FacsCalibur (B-D) flow cytometer was used for evaluation of samples. CB Bla (CD5/HLA-DR++) cells proved to be positive with CD9, CD19, CD20, CD21, CD22, CD23, CD24, CD32, CD39, CD45RA, CD76, CD79, MHC-II, IgM and anti Ig light chains MoAbs. CB B1b (CD5-/HLA-DR+) cells reacted with CD9, CD19, CD20, CD21, CD22, CD23, CD24, CD32, CD39, CD45RA, CD79, MHC-II, and IgM MoAbs. PB B cells (B2) expressed CD19, CD20, CD21, CD22, CD24, CD32, CD37, CD39, MHC-II and CD79 Ags. Unlike to the PB the CB B lymphocytes proved to be predominantly B1 cells representing a new-born B cell repertoire. Besides expressing many B cell antigens both the CB Bla and B1b cells showed CD9+, CD45RA+, IgM+ immature, "naive" B cell phenotype. Functionally, B1 cells are capable producing polyreactive IgM and natural autoantibodies but not IgG. This antibody profile might be insufficient regarding the recipient humoral immune defense result in more severe immunodeficiency after CB transplantation.

Immunologic consequences of blood transfusion and their clinical manifestations.

Aspects of clinical immunology, in the context of transfusion medicine, became highlighted in the last decade as a consequence of the accelerating expansion of basic immunology, immunogenetics and molecular biology. In addition sophisticated new technologies, which were capable of producing pure and safe blood products, attracted more attention to research and monitor the consequences of transfusion. These technologies also had obvious effects on supportive hematological therapy. The transfusion of blood components follows the rules of organ transplantation: when there is a mismatch between the donor and the recipient, the transfusion has the potential to induce various kinds of immune response against alloantigens. Antigen-compatible transfusions that involve major and rare blood groups are in almost all cases mismatched with respect to various polymorphic systems expressed on the cellular blood components. These include histocompatibility leukocyte antigens (HLA), tissue-specific and differentiation alloantigens, and, in the case of plasma, immunoglobulins, complement components, heat shock proteins, and shedded soluble membrane alloantigens. Clinical manifestations of alloimmune responses are typically deleterious. For example, immediate antigen-antibody binding and its consequences as secondary activations are paralleled by the nonhaemolytic febrile reaction, HLA sensitization can lead to a state of platelet refractoriness and inconvenient clinical symptoms. In certain immunogenetic situations and in immunodeficient patients graft-versus-host disease can be induced by blood products that contain live lymphocytes. Leukocyte filtration techniques are widely used to avoid most but not all of these harmful side effects of blood component therapy. In contrast to these harmful side effects in certain immunogenetic conditions, alloantigens that are expressed on various blood products can elicit an advantageous suppression of the immune response in the recipient. In the context of kidney transplantation this is termed the 'beneficial transfusion effect', and typically results in the prolongation of the graft's survival. In cases of recurrent habitual abortion and IgG therapy associated with certain autoimmune diseases, immunization with leukocytes specifically takes advantage of this phenomenon. To date the beneficial transfusion effect is not fully understood. In certain cases of malignancies or gastrointestinal surgeries this suppression of immune regulation that is induced by transfusion can worsen the clinical state either by permitting the spread of the tumor or by allowing severe infections to proceed unchecked. In conclusion it is imperative to monitor the immunological consequences of transfusion in order to deter the disadvantageous side effects. Taking advantage of the 'beneficial transfusion effect' may also provide a new means for immune therapy using the various blood products.

Comparison of the lymphoid toxicities of mitobronitol and busulphan in mice: reduced B cell toxicity and improved thymic recovery as possible contributors to the reduced risk for complications following BMT with mitobronitol preconditioning.

It has previously been reported that the use of mitobronitol (dibromomannitol, DBM) instead of busulphan (BU) for myelosuppression is associated with significantly decreased risk for several complications of allogeneic bone marrow transplantation in accelerated chronic granulocytic leukemia. In exploring the pharmacologic basis for this observation, we have compared the acute and subacute cytotoxicities of DBM and BU on the spleen and thymus of mice. While there was comparable early (day 3) weight loss in both organs following these treatments, splenic B cells exhibited significantly less damage, and thymic regeneration (over weeks) was significantly faster following DBM treatment than with BU. These observations raise the possibility that improved post-BMT immune recovery could contribute to the clinical benefits observed with DBM-preconditioning.

Association between long-term kidney graft survival and the presence of pre-transplant cytotoxic anti-HLA and/or non-MHC 'Fc gamma RII blocking' (anti-TLX) alloantibody.

One hundred kidney graft recipients were analysed retrospectively with regard to the presence of Fc gamma RII (EAI) blocking or cytotoxic HLA antibody induced by pretransplant transfusion. Previous studies suggested that transfusion induces the production of EAI blocking antibody which may have specificity to TLX/CD46/MCP alloantigens. A superior graft survival (65%/9 yr) was found in the presence of EAI alloantibody compared to graft survival in the absence of this antibody (40%/9 yr). Further analysis showed the following survival rates in relation to the combined appearance of HLA cytotoxic and EAI antibody (EAI positive, HLA negative 67%/9 yr; EAI positive, HLA positive 60%/9 yr; EAI negative, HLA positive 0%/9 yr; EAI negative, HLA negative 40%/9 yr). There was striking low graft failure in the first 6 months in patients with EAI antibody. Taking into consideration that the HLA B/DR mismatching grade in all various groups were the same and no considerable difference was found in association to graft survival, the presence or absence of alpha EAI (anti-TLX) antibody solely seems to have superior or additional effect on graft survival as compared to HLA matching.

Production of cytokines by rat immunocytoma clonal variants: a new type of intratumor heterogeneity.

A long-term tissue culture line of highly metastatic IR202 immunocytoma of LOU rats, and five of its clones (B4, C2, C4, C5, D3) was examined for their ability to produce cytokines. A combination of cytokine detection bioassays was employed in order to compensate for differences in sensitivity and specificity, and the possibility of inhibitors masking an activity. All the IR202 variants tested were shown to secrete constitutively varying amount of interleukin (IL-6). In addition, most of the cells produce IL-10 and TGF-beta, except clones C4 and C2, respectively. Moreover, supernatants from clone B4, C2, C4, and D3 may contain low levels of soluble IL-1. Membrane-bound IL-1 was found on the surface of B4, C4, and D3 cells. None of the IR202 variants, however, produced IL-2, IL-4, tumor necrosis factor-alpha (TNF-alpha), or LT. These results are consistent with the concept of a new type of intratumor heterogeneity and the ability of immunocytoma tumors to generate different immunoregulatory molecules in tumor-bearing hosts.

Immunophenotypic and functional characteristics of haemopoietic cells from human cord blood.

Cord blood (CB) as a new source for bone marrow transplantation represents advantageous features concerning stem cell and leucocyte compartments and function. We attempted to get more information about the phenotypes and function of CB cells by investigating their cell surface markers and also the production of IL-2, IFN-gamma and IL-6 by mitogen and alloantigen stimulation. The CB cells were characterized by a low proportion of CD3+ T cells, CD4+ T subpopulation, activated T cells and CD3+CD16/CD56+ cytotoxic cells, suggesting reduced graft versus host potential. The significant increase of CD19/CD3 double positive cells and decrease of CD19/HLA-DR double positive mature B cells reflect that immature B cells exist in CB. In the functional studies, a 27- and 5-fold reduction was observed in the production of IFN-gamma by CB cells stimulated with PHA and allogeneic cells, respectively. The production of IL-2 in PHA-stimulated CB cells also showed a 50% determination. Decrease in the production of these cytokines by CB cells is supported by the decline of the proportion of CD3+ T cells. However, an increase was observed in the production of IL-6 by CB cells stimulated with allogeneic cells as compared with the controls. These results suggest a difference in the functional activity of the T helper cell subsets between the CB and peripheral blood and/or differences in the functional maturity of T helper cell subsets and B cells in these compartments.

Relationship between the reactivity to hepatitis B virus vaccination and the frequency of MHC class I, II and III alleles in haemodialysis patients.

To study the immunoreactivity genes in a heterogeneous human population needs a large number of individuals. Associations between HLA antigens and immunoresponse to viral or bacterial antigens have been studied with controversial results. As a homogeneous population, the MHC class I, II and III allele distribution was studied in 153 end-stage renal disease patients (ESRD, average duration of renal replacement: 8.2 + 5.1 years) immunized with a recombinant hepatitis B vaccine in accordance to the standard vaccination schedule. Thirty-four patients with an antibody titre of less than 10 U/l following the last booster injection were considered as non-responders while 119 patients with antibody titre equal to or more than 10 U/l were considered as responders. The responder group was divided into two subgroups: low responders (antibody titre: < or = 1000 U/l) and high responders (antibody titre: > 1000 U/1). Marked differences were observed between responders and non-responders in the occurrence of carriers of different MHC class I, II and III alleles. Homozygotes for HLA-A1, HLA-B8, HLA-DR3 and HLA-DQ2 were found almost exclusively in the non-responder group and significantly more heterozygotes for these alleles were found in the non-responder group compared to the responders. Similar albeit less marked differences were found in the frequency of some MHC class III alleles (C4A*6, C4A*QO, Bf*F, Bf*S0.7). Within the responder group, carriers of HLA-A2, HLA-B7 and HLA-DR4 were found to be clustered in the low responder sub-group whereas carriers of HLA-A1, HLA-B27, HLA-Cw2, C4A*6 and Bf*F were observed more frequently in the group of high responders. Similar differences were found with extended haplotypes as well. For example, the extended haplotypes HLA-A1, B8, BfS, C4AQO, C4B1, DR3, DQ2 and HLA-A1, B8, BfF, C4A6, C4B2, DR3, DQ2 were present in nine of 34 cases of non-responders but only in one of 119 case of responders (P < 0.000001). These observations indicate that the presence or absence of certain MHC alleles even in heterozygous form determine the responsiveness to hepatitis B vaccination in end-stage renal disease patients, and among responders, the intensity of antibody response is also markedly influence by immunogenetic factors.

The regulation of expression of histocompatibility antigens on the cell surface; molecular genetic basis.

Histocompatibility antigens play a fundamental role in the immune functions by their polymorphic capture structure for binding exogenous and endogenous peptides and presenting them to the appropriate T and B cell receptors. The genetic background of the control of synthesis of the histocompatibility antigens is very complex including several loci controlling the wide polymorphic variation of class I and class II histocompatibility molecules and their regulation of expression. Most significant variability in the presence or absence of histocompatibility antigens could be observed during development, differentiation, and activation. The tissue-specific expression is influenced by pathological events such as malignant transformation, viral infection and genetic defectiveness as well. The research in the field of molecular genetics of the MHC in the last decade revealed, upstream of the coding genes of class I and class II molecules, a very complex regulatory machinery including a series of genes termed enhancer and promoter region. At the DNA level, various gene boxes and regulatory elements were discovered, which are activated by the binding of the appropriate histone proteins, cytokines or hormones responsible for the upregulation and downregulation of histocompatibility antigen expression. Regulation is mainly functioning at the transcriptional level, but other factors such as viral proteins, oncogenes, biomolecules, and physical effects take part, either indirectly or directly affecting the regulatory genes and DNA binding proteins. The increasing knowledge about the regulatory machinery may lead to the introduction of genetic manipulation, either experimental or clinical, with the aim of changing the expression of histocompatibility molecules on the cell surface in order to achieve normal or demanded immune functions.

Graft-versus-host disease in bone marrow transplantation: experimental, laboratory, and clinical contributions of the last few years.

Graft-versus-host disease (GVHD) is a major and often lethal complication of bone marrow transplantation. Research of the past few years has greatly expanded our understanding of the disease and enriched the arsenal of preventive and therapeutic procedures. The present review attempts to give a survey of experimental and clinical GVHD, updating essential knowledge with the latest information until July 1993. The covered topics include the complex immune pathomechanism of acute and chronic GVHD in murine models, the pathogenic role of major, minor, and other antigenic disparities, laboratory markers predicting GVHD, factors influencing appearance and course of the disease, the relationship between GVHD and the graft-versus-leukemia effect, and novel experimental and clinically tested preventive and therapeutic modalities. Finally, the authors set forth their perspective on the most relevant questions in GVHD-related research.

Susceptibility to autoimmune disease: a multigenic viewpoint.

In Hungary, analysis of genetic predisposition to disease has generally been studied from a multigenic point of view. Alongside markers of the HLA system, other blood groups and allotypes of immunoglobulins and complement components have been studied. These have been correlated with functional parameters in different autoimmune conditions.

Cellular and humoral suppression in transplantation.

Transplantation immunity and tolerance induction are two sides of the same coin. This article describes a couple of very different approaches, one experimental and one clinical, that may improve the understanding of transplantation immunology through analysis of tolerance induction.

TCR gamma/delta bearing lymphocytes in peripheral blood of allogenic bone marrow transplanted patients.

The presence of two distinct T-cell receptors (TCR) alpha/beta and gamma/delta dimers as well as of the activated T cells was analysed in peripheral blood mononuclear cells from seventeen recipients of allogeneic bone marrow transplants for leukemia and for severe aplastic anemia. Nine of seventeen recipients expressed an elevated percentage of T cells bearing TCR gamma/delta receptors in their peripheral blood. Seven out of nine cases having elevated gamma/delta positive cells showed chronic graft-versus-host (GVH) disease; one patient was treated with Cyclosporin A, and one patient was asymptomatic. In the twelve patients with GVH or other clinical symptoms, activated T cells (CD3+/HLA-DR+) were elevated indicating an autoreactive or alloreactive cell population. Our results confirmed earlier in vitro data showing that TCR-gamma/delta-bearing lymphocytes may be an activated T-cell population, and this T cell subset might be involved in mediating GVH disease, or in prolonging immunodeficiency after transplantation.