KIR gene variability in cutaneous malignant melanoma: influence of KIR2D/HLA-C pairings on disease susceptibility and prognosis.

Natural killer and CD8(+) T cells are believed to be involved in the immune protection against melanoma. Their function may be regulated by a group of receptors defined as killer immunoglobulin-like receptors (KIRs) and their cognate HLA class I ligands. In this study, we analyzed the influence of KIR genes and KIR/HLA-I combinations on melanoma susceptibility and/or prognosis in a Spanish Caucasian population. For this purpose, KIR genotyping by PCR-SSP and HLA-C genotyping by reverse PCR-SSO were performed in 187 melanoma patients and 200 matched controls. We found a significantly low frequency of KIR2DL3 in nodular melanoma (NM) patients (P = 0.001) and in ulcerated melanoma patients (P < 0.0001). Similarly, the KIR2DL3/C1 combination was significantly decreased in melanoma patients (Pc = 0.008) and in patients with sentinel lymph node (SLN) melanoma metastasis (Pc = 0.002). Multivariate logistic regression models showed that KIR2DL3 behaves as a protective marker for NM and ulcerated melanoma (P = 0.02, odds ratio (OR) = 0.14 and P = 0.04, OR = 0.28, respectively), whereas the KIR2DL3/C1 pair acts as a protective marker for melanoma (P = 0.017, OR = 0.54), particularly superficial spreading melanoma (P = 0.02, OR = 0.52), and SLN metastasis (P = 0.0004, OR = 0.14). In contrast, the KIR2DL3(-)/C1C2 genotype seems to be correlated with NM and ulceration. We also report that the KIR2DL1(+)/S1(-)/C2C2 genotype is associated with susceptibility to melanoma and SLN metastasis. Altogether, the study of KIR2D genes and HLA-C ligands may help in assessing cutaneous melanoma risk and prognosis.

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.

Post-transplant soluble MICA and MICA antibodies predict subsequent heart graft outcome.

The objective of this retrospective study was to evaluate the role of MICA in heart graft acceptance. Pre- and post-transplant sera from 31 patients were evaluated for MICA antibodies by cytotoxicity on recombinant cell lines and soluble MICA (sMICA) concentrations by ELISA. The results demonstrated that the patients with post-transplant anti-MICA antibodies were at a high risk for the development of severe acute rejection (AR) (p<0.03; OR=8.5). However, the presence of post-transplant sMICA was found to be associated with functioning grafts without AR episodes (p<0.03, OR=7.9). In this preliminary survey, the negative association of sMICA with AR was found to be in the absence of MICA antibodies. Further research is needed to clarify the role of sMICA in allograft acceptance. Post-transplant evaluation of humoral immune response to MICA and the measure of sMICA in patient's sera may provide a good predictor of AR.

Changes in the number of CD80(+), CD86(+), and CD28(+) peripheral blood lymphocytes have prognostic value in melanoma patients.

Our aim was to evaluate whether the number of circulating lymphocytes expressing costimulatory molecules can be associated with melanoma prognosis. We determined the concentration of peripheral blood lymphocytes, which expressed the CD80/CD86 or CD28/CTLA-4 molecules, in 38 patients with cutaneous melanoma and 27 controls. The number of each cell subset was compared between patients and controls, as well as between groups of patients stratified according to Breslow thickness of the primary tumor (< or = 2 mm vs > 2 mm) or to survival after 3 years. The concentration of circulating lymphocytes expressing the CD80/CD86 molecules was not significantly different between patients and controls. There was a lower number of CD3(+)CD8(+)CD28(+) cells, as well as a higher CD3(+)CD8(+)/CD3(+)CD8(+)CD28(+) cell ratio, in melanoma patients than in controls. Melanoma patients with thinner tumors and those surviving revealed an increase of CD19(+)CD80(+) and CD19(+)CD80(+)CD86(+) cells, as well as a higher concentration of CD3(+)CD4(+)CD28(+) cells. CD80(+) B cells and a low CD8 suppressor/cytolytic cell ratio correlate with a good prognosis in melanoma. Our findings support our conclusion that CD80(+) B cells may be important antigen presenting cells that can contribute to an antimelanoma immune response and are candidates to be monitored in melanoma patients.

HLA class I and class II frequencies in patients with cutaneous malignant melanoma from southeastern Spain: the role of HLA-C in disease prognosis.

Available data have led to a controversy on the relationship between human leukocyte antigen (HLA) and cutaneous malignant melanoma susceptibility or prognosis. Moreover, the influence of HLA-C on melanoma has not yet been well established. Therefore, the aim of the current study was to analyze the possible influence of the HLA system on melanoma susceptibility and prognosis in the Spanish population. For this purpose, HLA-A and HLA-B serotyping and HLA-C, HLA-DRB1, and HLA-DQB1 genotyping by polymerase chain reactions using sequence-specific oligonucleotide (PCR-SSO) and sequence-specific primer (PCR-SSP) were performed in 174 melanoma patients and 227 ethnically matched controls. The number of controls was increased up to 356 for HLA-C typing. Patients were stratified according to the histological subtypes of melanoma, sentinel lymph node status, tumor thickness, and ulceration of primary lesion. No HLA-A, HLA-B, HLA-DRB1, or HLA-DQB1 relationship with melanoma was observed for susceptibility or disease prognosis. However, the analysis of HLA-C locus showed that individuals homozygous for HLA-C(Lys80) were significantly more frequent within the patient than the control group. Remarkably, individuals homozygous for group 2 HLA-C alleles (HLA-C(Lys80)) seem to be associated with metastatic progression of melanoma. In contrast, we found a negative association between group 1 HLA-C alleles (HLA-C(Asn80)) and disease susceptibility or metastasis development. In conclusion, although an association with HLA-A, HLA-B, HLA-DRB1, or HLA-DQB1 was not demonstrated, the study of the HLA-C locus revealed that the analysis of the dimorphism at position 80 in the alpha1 helix may help to evaluate the risk and prognosis of melanoma in our population.

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.