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Biomedical subjects

Denis Reviron

Publications and source records attributed to Denis Reviron.

14 recordsLinked to original sources
PubMed2006

Human NK cell education by inhibitory receptors for MHC class I.

Natural killer (NK) cells recognize the absence of self MHC class I as a way to discriminate normal cells from cells in distress. In humans, this "missing self" recognition is ensured by inhibitory receptors such as KIR, which dampen NK cell activation upon interaction with their MHC class I ligands. We show here that NK cells lacking inhibitory KIR for self MHC class I molecules are present in human peripheral blood. These cells harbor a mature NK cell phenotype but are hyporesponsive to various stimuli, including MHC class I-deficient target cells. This response is in contrast to NK cells that express a single inhibitory KIR specific for self MHC class I, which are functionally competent when exposed to the same stimuli. These results show the involvement of KIR-MHC class I interactions in the calibration of NK cell effector capacities, suggesting its role in the subsequent "missing self" recognition.

Animals↗
PubMed2006

HLA-DRB1 polymorphism is associated with Kell immunisation.

K immunisation is observed in some polytransfused patients and pregnant women but does not occur in all cases of K incompatibility. This study analysed the role of genetic background in this selective response to K antigen by investigating HLA-DRB1 alleles associated with K immunisation in a southern European population. HLA-DRB1 genotyping was performed by polymerase chain reaction sequence-specific oligonucleotide/sequence-specific primer procedures in 54 K immunised patients and 200 healthy controls. The frequency of HLA-DRB1*11 was significantly higher in K immunised patients than healthy controls: 31 of 54 (57%) vs. 56 of 200 (28%) (P(c) < 0.001). In the remaining K immunised HLA-DRB1*11-negative patients, the frequency of HLA-DRB1*13 was increased: 14 of 23 (61%) vs. 49 of 144 in healthy controls (34%) (P < 0.02). The combined frequency of the two HLA-DRB1 alleles (HLA-DRB1*11 and HLA-DRB1*13) was 83% in K immunised patients when compared with 52% in healthy controls (P(c) < 0.001). K and k differ by a single amino acid T193 (M). The DRB1*11 and DRB1*13 alleles share a HLA-DRB1 gene sequence containing S in position 13, D in 70 and A in 74, and coding for the P4 pocket within the HLA-DR binding groove. This feature of the HLA-DRB1 gene could be involved in the K peptide presentation through a polymorphism ligand specific for the T193 (M) of K. In conclusion, this study demonstrated a high frequency of HLA-DRB1*11 or HLA-DRB1*13 alleles in K immunised patients, which could be due to specific K peptide presentation by HLA-DR molecules.

Alleles↗
PubMed2005

HLA-DRB1 alleles and Jk(a) immunization.

BACKGROUND: In transfusion medicine, anti-Jk(a) has been implicated in hemolytic transfusion reactions. Development of anti-Jk(a) after transfusion does not always occur after Jk(a-) patients receive at least 1 unit of Jk(a+) blood unit. This study was designed to identify HLA-DRB1 alleles associated with predisposition to Jk(a) immunization after blood transfusion or pregnancy. STUDY DESIGN AND METHODS: Genotyping by polymerase chain reaction and sequence-specific oligonucleotide probe nonradioactive hybridization/sequence-specific primers was performed in 20 Jk(a)-immunized patients and 200 controls from the same southern European population. RESULTS: Genotyping showed that HLA-DRB1*01 was significantly more frequent in Jk(a)-immunized patients than controls: 55 percent versus 17 percent (odds ratio [OR], 5.9; confidence interval [CI], 2.3-15.5; corrected p value<0.05). Because HLA-DRB1*0101, DRB1*0102, and DRB1*1001 share a common sequence in their B1 chain, that is, F in 13, R in 71, and A in 74, HLA genetic predisposition was analyzed by comparing patients and controls with respect to the distribution of F13/R71/A74-positive and -negative alleles. Results demonstrated greater positivity of the F13/R71/A74 sequence (DRB1*0101, *0102, or *1001) in patients than in controls: 65 percent versus 19.5 percent (OR, 7.7; CI, 2.9-20.5; p<0.001). CONCLUSION: In conclusion, HLA-DRB1*0101, DRB1*0102, and DRB1*1001, which share a common DRB1 sequence, appeared to be overrepresented in Jk(a)-immunized patients.

Alleles↗
PubMed2004

Comparative analysis of NK cell subset distribution in normal and lymphoproliferative disease of granular lymphocyte conditions.

We have characterized the heterogeneity of human blood NK cell subsets defined by expression of KIR, lectin like receptors and NK cell differentiation markers within a cohort of 51 healthy Caucasian individuals. High inter-individual variability in cell surface expression of most NK cell markers is observed. Range values defining NK cell subsets in healthy donors were further used as references to characterize 14 patients with NK-type lymphoproliferative disease of granular lymphocytes (NK-LDGL). Alterations of the KIR repertoire were noted in all NK-LDGL patients. NK cell expansions were classified as oligoclonal KIR(+) or as non-detectable KIR ((nd)KIR) using anti-KIR2DL1/2DS1, anti-KIR2DL2/2DL3/2DS2, anti-KIR3DL1 and anti-KIR2DS4 monoclonal antibodies. A major reduction in the size of the CD56(bright) NK cell subset was a constant feature of NK-LDGL. Altered distribution of CD94(+), CD161(+), and CD162R(+) NK cell subsets was also observed in NK-LDGL patients. Considering the potential role of NK cells in eliminating tumors or virus-infected cells, the reference values defined in this study should be valuable to characterize both quantitative and qualitative alterations of the NK cell repertoire in pathological conditions and to monitor NK cell reconstitution following hematopoietic transplantation.

Adolescent↗
PubMed2004

Genetic characterization of the population of Grande Comore Island (Njazidja) according to major blood groups.

The Comorian population is historically considered a blend of influences from African Bantus, Arabs, and possibly Austronesians. In this study we present the first genetic data on the current Comorian population. Serologic analysis of the six major blood group systems (ABO, RH, KEL, FY, JK, and MNS) was performed on 164 individuals from Grande Comore Island (Njazidja). In addition, Duffy genotypes were determined by polymerase chain reaction using allele-specific primers. Our findings establish a high frequency of the Fy(a- b-) phenotype (86%), presenting the same genetic background as in sub-Saharan Africa. Analysis of genetic frequencies, distances, and admixture with other populations indicates that African Bantus made the main contribution to the gene pool (73.2%+/-15.5%). The Arab contribution from the Arabian peninsula was smaller (24.2%+/-7%) and the Indonesian contribution was minor (2.6%+/-9%). The major Bantu contribution was commensurate with the Bantu cultural influence. The contribution from the Arabian peninsula seemed in relation to its permeating religious and linguistic influence. As with the language, the Indonesian contribution to the Comorian gene pool was small. These results are in agreement with historical, sociological, and linguistic data.

Alleles↗
PubMed2003

Epstein-Barr virus load in the peripheral blood of patients with rheumatoid arthritis: accurate quantification using real-time polymerase chain reaction.

OBJECTIVE: To determine whether patients with rheumatoid arthritis (RA) have elevated Epstein-Barr virus (EBV) load in their peripheral blood mononuclear cells (PBMCs) and whether it is correlated with the HLA-DR genes they express, we developed an accurate EBV DNA quantitative assay using real-time polymerase chain reaction (PCR) with fluorescent probes. METHODS: We studied the EBV DNA load in the PBMCs of 84 patients with RA, 69 normal controls, and 22 patients with rheumatic conditions other than RA. A 214-bp segment from the long internal repeat of EBV was amplified from 500 ng of PBMC DNA (150,000 cells) and quantified by real-time PCR with fluorescent probes. RESULTS: We demonstrated that in patients with RA, the EBV DNA load in PBMCs is increased almost 10-fold compared with that in normal controls. The EBV load is stable over time and is not obviously influenced by disease-modifying antirheumatic drugs or HLA-DR. CONCLUSION: Patients with RA have elevated EBV load in their peripheral blood.

Arthritis, Rheumatoid↗
PubMed2003

Polymorphism at position -308 of the tumor necrosis factor alpha gene influences outcome of infliximab therapy in rheumatoid arthritis.

OBJECTIVE: To test whether the G-to-A polymorphism at position -308 in the promoter of the tumor necrosis factor alpha (TNFalpha) gene influences response to infliximab therapy in patients with rheumatoid arthritis (RA). METHODS: We genotyped 59 RA patients by polymerase chain reaction and subdivided them into two groups: those with the A/A or A/G genotype and those with the G/G genotype. We compared the groups' clinical responses to infliximab treatment after 22 weeks, using the Disease Activity Score in 28 joints (DAS28). RESULTS: We found that 42% of patients in the A/A and A/G group and 81% of patients in the G/G group had improvement of at least 1.2 in the DAS28 score (P = 0.0086). The average improvement in the DAS28 score was 1.24 in the A/A and A/G patients and 2.29 in the G/G patients (P = 0.029). CONCLUSION: These data suggest that patients with a TNFalpha -308G/G genotype are better infliximab responders than are patients with A/A or A/G genotypes. TNFalpha -308 genotyping may be a useful tool for predicting response to infliximab treatment.

Adult↗
PubMed2003

Functional categorization of HLA-DRB1 alleles in rheumatoid arthritis: the protective effect.

Because of past recombination event, human leukocyte antigen (HLA) alleles that are not closely related in overall sequence may come to resemble each other in areas coding for peptide binding regions (PBR) of HLA molecules. Peptide binding is likely to be important for the role of HLA molecules in autoimmune disease. As a result, it has been suggested that a strategy of searching for HLA disease associations that groups alleles in functional categories based on PBR motifs may be more successful than conventional strategies based on studying different alleles. Using such functional categorization, we examined the possibility of discriminating subcategories of HLA-DRB1 alleles associated with rheumatoid arthritis (RA) in a Southern French population. HLA-DRB1 genotyping was performed by polymerase chain reaction with sequence-specific oligonucleotide hybridization or sequence-specific primers. HLA-DRB1 alleles were classified according to a functional categorization that defined seven similar subregion structures or restrictive supertype patterns (RSPs) within pocket 4 of HLA-DR peptide binding groove as the molecular basis for grouping these alleles. HLA-DRB1* RSPs "A," "De," "Q," "Dr," "E," " R," and "a" association with susceptibility or resistance to disease was then studied in 200 RA patients versus 200 controls. DRB1* RSP "A" containing the shared epitope alleles (DRB1*0101, *0102, *0401, *0404, *0405, *0408, *1001, *1402; odds ratio [OR] = 4.35; pc < 0.001) had a predisposing effect, with double-dose effect as expected, OR 6.68 (pc < 0.001). Among the six remaining RSPs, two had significantly protective effect: DRB1* RSP "De" (DRB1*0103, *0402, *1102, *1103, *1301, *1302, *1304; OR = 0.33; p(c) < 0.001), and DRB1* RSP "Q" (DRB1*0701; OR = 0.40; pc < 0.001). One had non-significantly protective effect: DRB1* RSP "Dr" (DRB1*08, *1101, *1104, *1106, *12, *1303, *16; OR = 0.68; p < 0.05, pc = not significant [NS]). Three had neutral effect: HLA-DRB1* RSPs "E" (DRB1*0403, *0407, *0901, *1401; OR = 0.71; p = NS), " R" (DRB1*0301, *0302; OR = 0.76; p = NS), and "a" (DRB1*1501, *1502; OR = 0.94; p = NS). The functional categorization allowed us to discriminate among the HLA-DRB1 alleles those that confer a predisposing effect, a neutral effect, and a protective effect in RA.

Alleles↗
PubMed2003

Bone marrow as stem cell source for allogeneic HLA-identical sibling transplantation following reduced-intensity preparative regimen.

OBJECTIVE: Reduced-intensity conditioning regimens (RIC) and peripheral blood stem cells (PBSC) are increasingly used for allogeneic stem cell transplantation (allo-BMT). RIC has been shown to allow engraftment with minimal early transplant-related mortality (TRM). However, in the context of RIC, the use of bone marrow (BM) as stem cell source is still little evaluated. PATIENTS AND METHODS: In this report, we analyzed the outcome of 32 high-risk patients with hematological malignancies who received an HLA-identical sibling allo-BMT after RIC including fludarabine, busulfan, and anti-thymocyte globulin (ATG). RESULTS: Sustained neutrophil and platelet recovery occurred at a median of 13 days (range, 10-19) and 17 days (range, 0-45) respectively. Early and durable full donor chimerism could be established as soon as the first month after allo-BMT. Also, a sustained and early CD8(+) T-cell recovery was observed, but the CD4(+) T-cell compartment remained profoundly low. The cumulative incidences of grade II-IV acute GVHD and chronic GVHD were 26% (95% CI, 11-41%) and 31% (95% CI, 15-47%) respectively. The overall cumulative incidence of TRM was 28% (95% CI, 12-44%) occurring mainly in patients aged over 50. In this setting, GVHD showed a protective effect on disease progression or relapse with better progression-free survival for patients with GVHD as compared to patients without GVHD (p=0.03). CONCLUSIONS: Collectively, these results confirm that the use of BM grafts for RIC is feasible with durable donor engraftment and no detrimental GVHD.

Adult↗
PubMed2002

Defective expression and function of natural killer cell-triggering receptors in patients with acute myeloid leukemia.

The cytolytic function of natural killer (NK) cells is induced by the engagement of a series of activating receptors and coreceptors some of which have recently been identified and collectively termed natural cytotoxicity receptors (NCRs). Here, we analyzed the cytolytic function of NK cells obtained from patients with acute myeloid leukemia (AML). In sharp contrast with healthy donors, in most (16 of 18) patients with AML the majority of NK cells displayed low NCR surface density (NCR(dull)). This phenotype correlated with a weak cytolytic activity against autologous leukemic cells that could not be reversed by the monoclonal antibody-mediated disruption of HLA class I/killer immunoglobulinlike receptor interaction. The remaining 2 patients were characterized by NK cells having an NCR(bright) phenotype. Surprisingly, although displaying NCR-mediated cytolytic activity, these NCR(bright) NK cells were unable to kill autologous leukemic blasts. Importantly, the leukemic blasts from these 2 patients were also resistant to lysis mediated by normal NCR(bright) allogeneic NK cells. Our study suggests that in most instances the inability of NK cells to kill autologous leukemic blasts is consequent to low NCR surface expression. In few cases, however, this failure appears to involve a mechanism of tumor escape based on down-regulation of ligands relevant for NCR-mediated target cell recognition.

Acute Disease↗
PubMed2002

No association between lck gene polymorphisms and protein level in type 1 diabetes.

We previously described a reduced expression of the protein tyrosine kinase Lck in T-cells from type 1 diabetic patients, the origin of which is still unknown. The human lck gene, located on chromosome 1p35-34.3, was evaluated as a candidate susceptibility gene for type 1 diabetes. A molecular scan of the sequence variations in the coding, the relevant promoter, and most of the intronic sequences of the lck gene (representing a total of 10.5 kb fragment) was performed in 187 Caucasian subjects including 91 type 1 diabetic patients and 96 normoglycemic control subjects. We identified 35 sequence variations, including one deletion and 34 single nucleotide polymorphisms (SNPs), 33 of them being new. Four variants were frequent but not significantly associated with diabetes or Lck protein level. Of the SNP variants, 11 were only found within the diabetic population and some were associated with low Lck protein levels. The low frequency of these polymorphisms did not permit any statistically significant correlations with the disease status, suggesting that the lck gene probably does not contribute to genetic susceptibility to type 1 diabetes.

3' Untranslated Regions↗