NKG2D Polymorphism in Melanoma Patients from Southeastern Spain.

BACKGROUND: Natural killer (NK) and CD8+ T cells are involved in the immune response against melanoma. C-Type lectin-like NK cell receptors are located in the Natural Killer Complex (NKC) region 12p13.2-p12.3 and play a critical role in regulating the activity of NK and CD8+ T cells. An association between polymorphisms in the NKC region, including the NKG2D gene and NKG2A promoter, and the risk of cancer has been previously described. The aim of this study was to analyze the association of polymorphisms in the NKC region with cutaneous melanoma in patients from southeastern Spain. METHODS: Seven single-nucleotide polymorphisms (SNPs) in the NKG2D gene (NKC3,4,7,9,10,11,12), and one SNP in the NKG2A promoter (NKC17) were genotyped by a TaqMan 5' Nuclease Assay in 233 melanoma patients and 200 matched healthy controls. RESULTS: A linkage disequilibrium analysis of the SNPs performed in the NKC region revealed two blocks of haplotypes (Hb-1 and Hb-2) with 14 and seven different haplotype subtypes, respectively. The third most frequent haplotype from the block Hb-2-NK3 (CAT haplotype)-was significantly more frequent on melanoma patients than on healthy controls (p = 0.00009, Pc = 0.0006). No further associations were found when NKC SNPs were considered independently. CONCLUSIONS: Our results suggest an association between NKG2D polymorphisms and the risk of cutaneous malignant melanoma.

Natural killer receptors on CD8 T cells and natural killer cells from different HLA-C phenotypes in melanoma patients.

PURPOSE: Because immune mechanisms involved in cutaneous melanoma have not been fully elucidated, efforts have been made to achieve prognosis markers and potential targets for immune therapies, but they have not been entirely fruitful thus far. Therefore, the goal of this study was to investigate the involvement of early changes in CD8 T cells and CD56 natural killer (NK) cells expressing NK receptors in different HLA-C dimorphism groups of melanoma patients. EXPERIMENTAL DESIGN: CD8 T cells and CD56 NK cells were analyzed in 41 patients and 39 sex- and age-matched controls with different HLA-C genotypes by flow cytometry. HLA-C dimorphism at position 80 was tested by PCR sequence-specific primers and PCR sequence-specific oligonucleotide to examine whether it could mediate in the emergence of cells expressing killer cell immunoglobulin-like receptors. RESULTS: Thirty-five of 41 patients had benign sentinel node, and showed an imbalance in the absolute number of CD8(+)DR(+) or CD8(+)CD161(+) peripheral blood T cells according to the CD28 coexpression compared with controls. CD8(+)CD28(-)CD158a(+) T and CD56(+)CD158a(+) NK cells were significantly increased in HLA-C(Lys80) homozygous nonmetastatic patients, whereas only CD56(+)CD158a(+) NK cells increased in heterozygous ones. An up-regulation of the CD158a KIR receptor was also seen on NK cells but not in T cells of patients at advanced disease stages. CONCLUSIONS: This work provides, for the first time, evidence of immune activation in early stages of cutaneous melanoma, together with an increase of cells expressing CD158a in patients bearing the corresponding HLA-C ligand, which may be important to evaluate the disease progression and to use individualized immune therapeutic approaches.

TGF-beta1 gene polymorphism in liver graft recipients.

Cytokines are known to be important mediators during liver graft outcome and their gene polymorphism could affect the overall expression and secretion of cytokines. In this retrospective study, we analyzed the effect of TGF-beta1 polymorphism in 150 liver allograft recipients. Genotyping PCR-SSP were performed for TGF-beta1 gene (codon 10T/C and 25C/G). TGF-beta1 polymorphism at codon 10 and 25 correlate borderline with liver graft acceptance and when the combination between codon 10 and 25 was analyzed, it revealed that T/T G/C genotype and the TC haplotype were significantly associated with graft acceptance (p<0.05). TGF-beta1 high secretor phenotype was also increased in the acute rejection group close to significance (p=0.06). In conclusion, these findings show a correlation between TGF-beta1 gene polymorphism and liver graft acceptance.

Human leucocyte antigen-C in B chronic lymphocytic leukaemia.

This study aimed at characterising the distribution of human leucocyte antigen (HLA)-C alleles in a large group of patients with B chronic lymphocytic leukaemia from Southeastern Spain. Ninety-eight adult patients and 194 geographically and ethnically matched controls were studied. HLA-C was determined by polymerase chain reaction sequence-specific primers (PCR-SSP) and PCR-sequence-specific oligonucleotides (SSO) methods. The HLA-Cw*16 allele frequency was found to be significantly increased amongst patients compared with controls in our population (27.6% vs. 12.4%, P = 0.0012, Pc = 0.016). HLA-C dimorphism was also analysed but no association was found.

The promyelocytic leukemia zinc finger protein down-regulates apoptosis and expression of the proapoptotic BID protein in lymphocytes.

The promyelocytic leukemia zinc finger (PLZF) gene, involved in rare cases of acute promyelocytic leukemia, encodes a Krüppel-type zinc finger transcription factor. It has been reported that PLZF affects myeloid cell growth, differentiation, and apoptosis. However, the function of PLZF in the lymphoid compartment, where PLZF is also expressed, remains largely unknown. To investigate a potential relationship between PLZF expression in lymphocytes and programmed cell death, an inducible model of stable clones of the lymphoid Jurkat cell line was created by using the tet-off system. Although induction of PLZF expression by itself did not produce changes in the basal levels of apoptosis, PLZF had a significant anti-apoptotic effect in Jurkat cells cultured in conditions of serum starvation, as measured by annexin V staining and terminal deoxynucleotidyltransferase-mediated dUTP nick end labeling. In addition, retarded loss of mitochondrial transmembrane potential was observed in the PLZF-expressing clones, suggesting that PLZF protects from cell death through a mitochondrial-dependent mechanism. To identify apoptosis-related targets of PLZF, a screen for differential expression identified BID, a proapoptotic member of the Bcl2 family, as significantly down-regulated by PLZF. Furthermore, a high-affinity PLZF-binding site element was identified upstream of the BID transcriptional start site, as assessed by electrophoretic mobility-shift assays. These results suggest that BID is a target of PLZF repression and a candidate gene to mediate the PLZF-induced resistance to apoptosis.