Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0018133 (graft-versus-host disease)
 18,032 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Immune-mediated elimination of tumor cells by donor T cells recognizing recipient minor H antigens contributes to the curative potential of allogeneic HCT. The importance of the allogeneic response to a successful outcome is clearly illustrated by the results of stem cell transplant for malignancy after nonmyeloablative conditioning. Remarkably little is understood about the molecular nature of minor H antigens and this has impeded efforts to determine the role of specific disparities in graft versus tumor reactions or to manipulate T cell responses to augment antitumor activity without exacerbating GVHD. The isolation of minor H antigen-specific CD8+ and CD4+ T cell clones from recipients of allogeneic HCT has provided the reagents to characterize their expression on leukemic progenitors and to identify the genes encoding these antigens. Using cDNA expression cloning, genetic polymorphisms in the human IFI-75, Uty, KIAA0020, and UGT2B17 genes have been identified to encode new minor H antigens presented by HLA A3, B8, A2, and A29 respectively. Two of these genes are preferentially expressed in hematopoietic cells including leukemic progenitors suggesting it may be possible to augment T cell responses to promote a selective graft versus leukemia effect. A third gene, UGT2B17 is highly expressed in liver and GI tract and may be a target for GVHD in these organs. The studies to identify the molecular nature of minor H antigens have provided insights into the complexities of the graft versus host response associated with allogeneic HCT, but the challenge for the future will be to develop strategies that can selectively induce durable graft versus tumor effects without GVHD. A critical issue in developing specific immunotherapy to augment GVL responses is to determine which minor H antigens are expressed on leukemic stem cells. Studies using transplantation of human AML into SCID mice have identified a putative leukemic stem cell which is contained in the CD34+ CD38- subset of the blast population and is present in very low frequency (<1/200,000) in blood or bone marrow from AML patents. We have examined the ability of minor H antigen-specific CTL to prevent engraftment of human AML in NOD/SCID mice. These studies show that engraftment of leukemias derived from individuals encoding the minor H antigen can be specifically prevented demonstrating that AML stem cells express minor H antigens and are targets for CTL. One approach to determine directly which minor H antigens can be selectively targeted to induce a GVL effect without GVHD is to adoptively transfer T cell clones of defined specificity and function to patients who relapse after HCT. Studies of this approach are now in progress in acute leukemia and have provided important insights into potential obstacles of T cell therapy for relapsed leukemia after HCT.
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PMID:Minor histocompatibility antigens--targets of graft versus leukemia responses. 1243 Sep 18

The fetal semi-allograft can induce expansion and tolerance of antigen-specific maternal T and B cells through paternally inherited major histocompatibility complex and minor histocompatibility antigens (mHAgs). The effects of these antigens have important consequences on the maternal immune system both during and long after pregnancy. Herein, we investigate the possibility that the placental syncytiotrophoblast and deported trophoblastic debris serve as sources of fetal mHAgs. We mapped the expression of four mHAgs (human mHAg 1, pumilio domain-containing protein KIAA0020, B-cell lymphoma 2-related protein A1, and ribosomal protein S4, Y linked) in the placenta. Each of these proteins was expressed in several placental cell types, including the syncytiotrophoblast. These antigens and two additional Y chromosome-encoded antigens [DEAD box polypeptide 3, Y linked (DDX3Y), and lysine demethylase5D] were also identified by RT-PCR in the placenta, purified trophoblast cells, and cord blood cells. Finally, we used a proteomic approach to investigate the presence of mHAgs in the syncytiotrophoblast and trophoblast debris shed from first-trimester placenta. By this method, four antigens (DDX3Y; ribosomal protein S4, Y linked; solute carrier 1A5; and signal sequence receptor 1) were found in the syncytiotrophoblast, and one antigen (DDX3Y) was found in shed trophoblast debris. The finding of mHAgs in the placenta and in trophoblast debris provides the first direct evidence that fetal antigens are present in debris shed from the human placenta. The data, thus, suggest a mechanism by which the maternal immune system is exposed to fetal alloantigens, possibly explaining the relationship between parity and graft-versus-host disease.
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PMID:Minor histocompatibility antigens are expressed in syncytiotrophoblast and trophoblast debris: implications for maternal alloreactivity to the fetus. 2207 31