[Truncated abstract] Natural killer (NK) cell alloreactivity can be exploited in haploidentical haematopoietic stem cell transplantation (HSCT) to improve graft survival, reduce graft versus host disease and decrease leukaemic relapse. NK cells lyse cells that have reduced expression of class I HLA molecules. In an allogeneic setting, donor NK cells may be activated by the absence of donor (self) class I HLA molecules on recipient cells; the absence of self-epitopes being detected by inhibitory KIR receptors on donor NK cells. The way in which genetic polymorphism of the receptors and ligands affects NK allorecognition of missing self, has not been fully elucidated. HLA-C molecules are divided into two groups, C1 and C2, with KIR2DL1 recognising cells expressing C2 and KIR2DL2 and KIR2DL3 recognising cells expressing C1. Donor NK cells expressing KIR2DL2 or KIR2DL3 can be alloreactive towards a recipient if they lack the C1 epitope and donor NK cells expressing KIR2DL1 can be alloreactive towards a recipient if they lack the C2 epitope. KIR3DL1 recognises the Bw4 epitope present on one-third of HLA-B alleles and certain HLA-A alleles. NK cells from donors expressing KIR3DL1 can be alloreactive towards recipients whose cells lack Bw4. Mismatches of KIR related HLA epitopes does not always results in NK alloreactivity. Therefore it is not possible to reliably predict NK alloreactivity based solely on the donor's HLA type and KIR repertoire and the recipient's HLA type. ... All Bw4-positive HLA-B alleles, with the exception of HLA-B*1301 and B*1302, protected targets from lysis. HLA-A*2402 and HLA-A*3201 unequivocally protected target cells from lysis whereas HLA-A*2501 and HLA-A*2301 provided only weak protection from lysis. KIR3DL1-dependent alloreactive NK clones were identified in donors whose only Bw4 positive allele was HLA-A*2402 but not in donors whose only Bw4 positive HLA allele was HLA-B*1301 or B*1302. Finally this thesis demonstrated that an activating KIR can control NK cell alloreactivity. Donors who are C2 negative and KIR2DS1 positive had NK cells that expressed the activating receptor KIR2DS1 and were capable of lysing cells expressing the C2 epitope. More so, KIR2DS1 dependent NK clones were shown to override inhibitory signals generated by NKG2A interacting with its ligand, HLA-E. The identification of these NK clones has important implications for haploidentical HSCT in that recipient expressing all three NK epitopes, C1, C2 and Bw4 were previously thought to be resistant to alloreactive NK cells controlled by inhibitory receptors. Such patients may be amenable to haploidentical HSCT from C2 negative, KIR2DS1 positive donors. These results will improve the ability to predict NK cell alloreactivity based on a donor's HLA type and KIR repertoire and the recipient?s HLA type.

Diss. (sammanfattning) Stockholm : Karolinska institutet, 2010.

Orientadores: Cármino Antonio de Souza, Jeane Eliete Laguila Visentainer / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas / Made available in DSpace on 2018-08-22T17:20:39Z (GMT). No. of bitstreams: 1 Cardozo_DanielaMaira_D.pdf: 3033896 bytes, checksum: b4696b2dc5fc0ec422091c74289aed9f (MD5) Previous issue date: 2013 / Resumo: No organismo humano, as moléculas HLA (Human Leukocyte Antigens) são proteínas expressas na superfície da maioria das células nucleadas e são codificadas por genes localizados no braço curto do cromossomo 6 na região do Complexo Principal de Histocompatibilidade (CPH). Essas proteínas são caracterizadas pelo alto grau de polimorfismo, e também faz a ligação com receptores KIR (Immunoglobulin-like Receptors), expressos nas células Natural Killer. Os receptores KIR, que reconhecem moléculas do complexo HLA de classe I, estão entre os principais receptores inibidores dos linfócitos NK. Células infectadas por vírus e células tumorais perdem ou têm diminuída a expressão de moléculas HLA de classe I e, por isso, são eliminadas pela ausência de ligação entre moléculas HLA e receptores KIR inibitórios. Atualmente, muitos estudos têm destacado a importância dos genes KIR e HLA no Transplante de Células Progenitoras Hematopoiéticas (TCPH). O TCPH é o tratamento de escolha para muitas doenças hematológicas e dependem de vários fatores incluindo o estágio da doença, o regime de condicionamento, a fonte de células, o grau de identidade HLA entre doador e receptor e o desenvolvimento da doença do enxerto contra o hospedeiro (DECH). Estudos recentes indicam que a presença de células NK alorreativas no enxerto representa um fator favorável à recuperação de pacientes, uma vez que essas células têm a capacidade de eliminar células tumorais residuais pela ausência ou diminuição da expressão de moléculas HLA e sem a indução da DECH. Também outros fatores podem estar envolvidos na resposta pós-transplante, como a presença e ausência de determinados alelos HLA e genes KIR, os quais podem estar ligados à melhor ou pior resposta pós-transplante. O primeiro ensaio investigou a associação entre HLA e a ocorrência da DECH aguda e crônica em pacientes que receberam transplante de células progenitoras hematopoiéticas HLA-idêntico, aparentados. No total, foram 176 pacientes que receberam o primeiro transplante entre 1997 e 2009. DECH aguda foi positivamente associada ao HLA-A10 (P = 0.0007), HLA-A26 (P = 0.002), B55 (P = 0.001), DRB1*15 (P = 0.0211) e DQB1*05 (P = 0.038), enquanto que HLA-B16 (P = 0.0333) foi mais frequente em pacientes sem DECH aguda. DECH crônica foi positivamente associada com HLA-A9 (P = 0.01) e A23 (P = 0.0292) e negativamente associada com HLA-A2 (P = 0.0031) e B53 (P = 0.0116). HLA-B35 (P = 0.0373), B49 (P = 0.0155) e B55 (P = 0.0024) foi alta em pacientes com DECH aguda grau 3 ou mais, do que os outros pacientes. Nos pacientes com DECH crônica extensa, HLA-A9 (P = 0.0004), A24 (P = 0.0059) e A26 (P = 0.0411) foi maior do que nos outros pacientes, enquanto HLA-A2 foi baixo (P = 0.0097). O objetivo do segundo ensaio foi avaliar as possíveis interações dos genes KIR e HLA com o curso clínico do transplante HLA compatível, aparentado e não depletado de linfócitos T, particularmente na doença do enxerto contra o hospedeiro (DECH) aguda e crônica, recaída, sobrevida global e sobrevida livre de evento. A maioria dos doadores (78%) apresentaram o haplótipo B do KIR enquanto que 22% apresentaram o haplótipo A. Dos pacientes que receberam o haplótipo A do doador, 90% tiveram DECH, aguda ou crônica, comparados com os que receberam o haplótipo B (58%) (dados não estatisticamente significantes). Não houve diferença significativa para recaída entre pacientes que receberam os haplótipo A ou B (27% vs 23%). Não houve diferença no desenvolvimento da DECH e recaída para os pacientes homozigotos (C1C1 ou C2C2) e heterozigotos (C1C2) e nem para aqueles com HLA-Bw4 presente e ausente. Também, a sobrevida global não foi diferente para os grupos de pacientes analisados. No entanto, houve forte correlação entre o grupo de pacientes heterozigotos para HLA-C (C1C2) e a incidência de DECH aguda e recaída. A SLE foi maior nos pacientes heterozigotos que não desenvolveram DECHa (p<0,0001). Resultados mostraram que as variantes de HLA podem influenciar na ocorrência de DECH em transplante alogênico, com doadores relacionados, HLA-idênticos, tanto como fatores de proteção, quanto como fatores de susceptibilidade. Ainda, a interação KIR/HLA tem impacto significante no resultado dos transplantes relacionados, HLA compatível, sem depleção de linfócitos T, influenciando na incidência de recaída e na ocorrência da DECH. Resultados mostraram que para o grupo heterozigoto (C1C2) a maioria dos pacientes não desenvolveu DECH aguda e apresentou maior SLE, sugerindo um possível efeito protetor para esse grupo / Abstract: In the human organism, the HLA (human leukocyte antigens) are proteins expressed on the surface of most nucleated cells and are encoded by genes located on the short arm of chromosome 6 in the region of the Major Histocompatibility Complex (MHC). These proteins are characterized by a high degree of polymorphism, and also make the connection with KIR (Immunoglobulin-like Receptors), expressed in Natural Killer cells. KIR receptors that recognize HLA molecules of class I are among the major inhibitory receptors of NK-cells. Virus infected cells and tumor cells have lost or diminished expression of HLA class I molecules and therefore are eliminated by the absence of binding between HLA molecules and inhibitory KIR receptors. Currently, many studies have highlighted the importance of KIR and HLA genes in Hematopoietic Stem Cell Transplantation (HSCT). HPCT is the treatment of choice for many hematological malignancies and depends on various factors including stage of disease, the conditioning regimen, the source of cells, the degree of identity between donor and recipient HLA and development of chronic graft-versus-host (GVHD). Recent studies indicate that the presence of alloreactive NK cells in the graft is a factor aiding the recovery of patients, since these cells have the ability to eliminate residual tumor cells by the absence or diminution of expression of HLA molecules and without inducing GVHD. Also other factors may be involved in response post-transplant, as the presence or absence of certain HLA genes and KIR, which can be connected to a better or worse response after transplantation. The first trial investigated the association between HLA and the occurrence of acute and chronic GVHD in patients receiving hematopoietic stem cell transplant HLA-identical related. In total, 176 patients who received a first transplant between 1997 and 2009. GVHD was positively associated with HLA-A10 (P = 0.0007), HLA-A26 (P = 0.002), B55 (P = 0.001), DRB1 * 15 (P = 0.0211) and DQB1 * 05 (P = 0.038), while that HLA-B16 (P = 0.0333) was more frequent in patients without acute GVHD. Chronic GVHD was positively associated with HLA-A9 (P = 0.01) and A23 (P = 0.0292) and negatively associated with HLA-A2 (P = 0.0031) and B53 (P = 0.0116). HLA-B35 (P = 0.0373), B49 (P = 0.0155) and B55 (P = 0.0024) was high in patients with acute GVHD grade 3 or more, than the other patients. In patients with extensive chronic GvHD, HLA-A9 (P = 0.0004), A24 (P = 0.0059) and A26 (P = 0.0411) was greater than in the other patients, whereas HLA-A2 was low (P = 0.0097). The objective of the second test was to evaluate the possible interactions of KIR and HLA genes with the clinical course of the transplant HLA compatible related and not depleted of T lymphocytes, particularly in chronic graft versus host disease (GVHD) acute and chronic relapse, survival overall and event-free survival. Most donors (78%) presented the KIR B haplotype while 22% were haplotype A. Of the patients who received the donor haplotype A, 90% had GvHD, acute or chronic, compared with those who received the haplotype B (58%) (data not statistically significant). There was no significant difference in relapse between patients who received the haplotype A or B (27% vs 23%). There was no difference in the development of GVHD and relapse for patients homozygous (C1C1 or C2C2) and heterozygous (C1C2) and not for those with HLA-Bw4 present and absent. Also, the overall survival was not different for the groups of patients studied. However, there was strong correlation between the group of patients heterozygous for HLA-C (C1C2) and the incidence of acute GVHD and relapse. The SLE was higher in patients who did not develop GVHD heterozygotes (p <0.0001). Results showed that the HLA variants may influence the occurrence of GVHD in allogeneic transplantation with related donors, HLA-identical, both as protective factors, such as susceptibility factors. Furthermore, the interaction KIR / HLA has a significant impact on the outcome of transplantation related HLA-compatible, without depletion of T cells, influencing the incidence of relapse and the occurrence of GVHD. Results showed that for the heterozygous group (C1C2) most patients did not develop acute GVHD and showed higher SLE, suggesting a possible protective effect for this group / Doutorado / Clinica Medica / Doutora em Clínica Médica

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