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C Raffoux

Publications and source records attributed to C Raffoux.

At least 37 records · Page 2Linked to original sources
PubMed1998

Influence of CD34 cell selection on the incidence of mixed chimaerism and minimal residual disease after allogeneic unrelated donor transplantation.

Marrow transplantation from unrelated donors has been linked with an increased risk of graft-versus-host disease (GVHD). In an attempt to lower the risk of acute GVHD we used CD34 marrow cell selection for T cell depletion. Since T cell depletion has been linked to an increased risk of relapse and an increased risk of marrow failure, we used PCR amplification of minisatellite sequences to investigate donor cell engraftment and RT-PCR amplification of recurrent chromosomal translocations to investigate the residual disease post-transplant. Twenty-three patients who underwent BMT after positive selection of the CD34-positive cell population were studied. Results were then compared with those of 37 patients who underwent transplantation with unmanipulated marrow graft. Among the 23 patients who received CD34+ selected cell grafts, seven (30%) had evidence of full donor engraftment, 14 had evidence of residual recipient cells (61%), one had a non-take, and one autologous bone marrow recovery. Analysis of the chimaerism status post-transplant in 36 patients who received unmanipulated marrow grafts showed that 31 patients (86%) had evidence of full donor engraftment. The difference in the incidence of mixed chimaerism profile between patients who received unmanipulated marrow graft and those receiving CD34+ selected cell grafts was statistically significant (P< 0.01). Nine patients who received CD34+ selected cell grafts could be analysed for the presence of minimal residual disease post-transplant (one with t(9;22) acute lymphoblastic leukaemia and eight with CML). In the patient transplanted for a Ph-positive acute leukaemia, and in two out of the eight patients with CML, the search fora fusion transcript was consistently negative after transplantation. Among the six patients with evidence of residual disease, three patients also had a mixed chimaerism profile and were given donor lymphocyte infusions. Minimal residual disease study was performed post-transplant in 16 patients who received unmanipulated marrow grafts. In 10 of 14 patients with CML, and in two patients with acute leukaemia the search for a fusion transcript was consistently negative after transplantation. The difference in the incidence of minimal residual disease between patients who received an unmanipulated marrow graft and those receiving CD34+ selected cell grafts was not statistically significantly significant, but numbers of patients included in this analysis are still few. In conclusion, our study highlights the strong influence of graft manipulation on the incidence of mixed chimaerism after transplantation from an unrelated donor.

Adolescent↗
PubMed1997

[Which cross-match before organ transplantation in 1997?].

GOALS: The objective of pre-transplantation cross-matching is to detect in the recipient's serum solely those anti-donor antibodies which could have a deleterious effect on the grafted organ. It is important to avoid refusing organs on the basis of recipient antibodies which do not imply a risk of rejection. SEVERAL METHODS: In most laboratories cross-matching or compatibility tests made before organ transplantation are based on a complement-dependent microlymphocytotoxicity technique, sometimes sensitized with anti-human globulin serum, reactive against target T-cells. A positive results is reported if the reactions are week, but other methods are available. CHOICE OF SERA FOR CMX: This is essential. Several sera must be used: the most positive sera, the last serum and the current sera if the patient has been transfused between the date of the last serum harvested and the CMX. IMMUNOLOGICAL STATUS: There is wide agreement on the requirement for quality surveillance of the recipient's immunological status. This policy is the only way to effectively select sera to cross-match before transplantation, whatever the technique used, and thus improve transplantation outcome and reduce the number of rejections. CASE BY CASE: These prerequisites hold for all organs, but especially so for renal (and/or pancreas) grafts. For heart or heart-lung transplantations, emergency procedures may be needed.

Graft Rejection↗
PubMed1997

Donor work-up and transport of bone marrow--recommendations and requirements for a standardized practice throughout the world from the Donor Registries and Quality Assurance Working Groups of the World Marrow Donor Association (WMDA).

In October 1995 the World Marrow Donor Association (WMDA) was restructured in order to facilitate its primary function of establishing guidelines in relation to international bone marrow and blood stem cell transplants -- transplants in which the donor is in one country and the patient is in another country. Five new working groups were established -- Donor Registries, Ethics, Quality Assurance, Finances, and Stem Cells. This paper, prepared by members of the Donor Registries Working Group, in consultation with the Quality Assurance Working Group, provides recommendations for the 'donor work-up'. This term covers events that start when the definitive donor has been identified, includes the harvesting (collection) and transportation of the stem cell product and ends when the product reaches the transplant centre. The paper includes examples of the documentation intended to ensure compliance with the recommendations at all key points in the sequence.

Bone Marrow Transplantation↗
PubMed1996

High prevalence of diabetes mellitus in patients with chronic hepatitis C. A case-control study.

OBJECTIVES AND METHODS: Extrahepatic manifestations have been reported in hepatitis C virus infection. To assess the relationship between diabetes mellitus and hepatitis C virus, we studied 152 patients with chronic hepatitis C and 152 controls hospitalized during the same period with hepatitis B virus (n = 51) or alcohol-induced (n = 101) liver diseases matched for age, sex, and the presence of cirrhosis (prevalence: 58%). Patients with jaundice, ascites, encephalopathy, prothrombin activity < 65%, or serum albumin < 35 g/L were excluded. RESULTS: Diabetes, defined by fasting serum glycemia > 1.4 g/L on at least two separate occasions or previously treated overt diabetes, was present in 38 patients with chronic hepatitis C (24%) and in 13 patients in the control group (9%, P < 0.002). In the 51 diabetic patients, irrespective of serum anti-hepatitis C virus status, 41 (81%) had non insulin dependent diabetes and 45 (88%) had cirrhosis. Family history of diabetes or obesity was observed in 2 (5%) of the diabetic patients with chronic hepatitis C and in 6 (46%) of the diabetic controls (P = 0.002). Plasma C-peptide (855 +/- 448 pmol/L versus 1,152 +/- 491 pmol/L, NS) and insulin levels (83 +/- 40 pmol/L versus 184 +/- 86 pmol/L, NS), assayed in 17 diabetic patients with chronic hepatitis C and in 9 diabetic controls, were lower in the former. The prevalence of HLA B8, DR3 or DR4 antigens, which was searched for in 77 patients with chronic hepatitis C, was not different in diabetic and non diabetic patients, and, was similar to the reference population. Serum islet-cell antibodies were found in 5 patients with chronic hepatitis C (3 with diabetes) and in 2 controls. CONCLUSION: Diabetes mellitus is more prevalent in patients with chronic hepatitis C than in patients with other liver diseases, and usually occurs in the absence of predisposing factors. These results suggest a role of hepatitis C virus infection in the pathogenesis of diabetes.

Adult↗
PubMed1995

HLA-Cw allele analysis by PCR-restriction fragment length polymorphism: study of known and additional alleles.

We describe a technique for HLA-Cw genotyping by digestion of PCR-amplified genes with restriction endonucleases. Locus-specific primers selectively amplified HLA-Cw sequences from exon 2 in a single PCR that avoided coamplification of other classical and nonclassical class I genes. Amplified DNAs were digested with selected enzymes. Sixty-three homozygous cell lines from International Histocompatibility Workshop X and 113 unrelated individual cells were genotypes for HLA-Cw and compared with serology. The present protocol can distinguish 23 alleles corresponding to the known HLA-Cw sequences. Genotyping of serologically undetectable alleles (HLA-Cw Blank) and of heterozygous cells was made possible by using this method. Six additional HLA-Cw alleles were identified by unusual restriction patterns and confirmed by sequencing; this observation suggests the presence of another family of allele-sharing clusters in the HLA-B locus. This PCR-restriction endonuclease method provides a simple and convenient approach for HLA-Cw DNA typing, allowing the definition of serologically undetectable alleles, and will contribute to the evaluation of the biological role of the HLA-C locus.

Alleles↗
PubMed1995

HLA -A, -B, -DR haplotype frequencies in France--implications for recruitment of potential bone marrow donors.

We have undertaken a study of the haplotypes among French potential bone marrow donors in order to define the geographical regions of France with the maximum of polymorphism and also to develop a strategy for optimal donor recruitment. A maximum likelihood estimator was used to calculate haplotype frequencies and their support limits for each region and for the whole of France. The observed differences between the regions were statistically significant. For each region, the minimum number of haplotypes necessary to explain 50% of the total frequency was calculated and compared with the equivalent values, and confidence intervals, obtained by repeated random samplings from the overall file. This approach shows that some regions (e.g., Provence) appear to be richer in terms of the numbers of haplotypes observed, and others (e.g., Bretagne) poorer. In the latter case, however, the frequencies of the most common haplotypes are greater. The haplotype frequencies of the whole sample were used to calculate the probability of finding a match for the next potential recipient for given sizes of the donor file, assuming random selection of donors. They were also used to calculate expected numbers of the major phenotypes, assuming Hardy-Weinberg equilibrium, and these were compared with those observed in the real data file. In this way, a large number of under-represented and nonrepresented phenotypes were identified. For each of these phenotypes, the most probable haplotypes and the regions in which these have the greatest frequencies have been identified. A search for donors with such particular phenotypes would be much more fruitful if directed towards these regions.

Alleles↗
PubMed1995

Relevance of 10 Caucasian HLA haplotypes in searches for unrelated bone marrow donors for 100 patients from a single center.

Unrelated donor searches for 100 Caucasian patients were referred to France Greffe de Moëlle Registry (FGM) from September 1987 (24,600 donors) to December 1993 (71,500 donors, 61% DR typed). After DR typing of HLA-A,B matched donors, unsuccessful searches were extended to other European Registries for 36 patients. Twenty two patients had a donor (FGM: 19, other Registries: 3) selected on: (1) HLA-A,B and DRB,DQB1 split identity; and (2) unidirectional relative response < 5% in MLR performed twice. Estimated probability of finding a compatible donor at 9 months in FGM was 12% (s.e. +/- 4%) and 25% at 2 years (s.e. +/- 6%). This probability was stringently dependent on a phenoidentity to one very common HLA-A,B,DR or B,DR haplotype (25% at 9 months when present, representing 19 of 19 patients with a compatible donor). Without this phenoidentity, the probability was zero per cent (P = 0.0001) in FGM searches and < 4% (n = 1) in extended searches. The MLR test was shown to be insensitive for screening for DPB1 mismatches. Clinical status influenced the probability of finding a compatible donor at one year ranging from 9% +/- 9% for ALL to 23% +/- 8% for CML (NS). Disregarding DPB1 mismatches is the most efficient way of increasing search efficiency.

Bone Marrow Transplantation↗
PubMed1994

EMDIS: European Marrow Donor Information System.

EMDIS is an open network between different bone marrow Donor Registries for patients awaiting a transplant and lacking compatible family donors. The network is composed of an identical system in all countries. The architecture makes clear definition between the user system (US) and the EMDIS core system (CS). E-mail approach is used as communication method. A logical model including the EMDIS CS and the US, as well as the list of messages exchanged between US/CS and CS/CS, has been defined. An actually functioning pilot system between three European countries could be used as a trial basis by other research projects.

Bone Marrow Transplantation↗
PubMed1994

Influence of human leukocyte antigen genes on TCR V gene segment frequencies.

Human leukocyte antigen (HLA)-dependent selection mechanisms exerted during thymic maturation are supposed to be main contributing factors to the genetic predetermination of the TCR repertoire and may have a detectable effect on adult peripheral blood lymphocyte V segment frequencies. Here, we analyzed whether polymorphic or non-polymorphic HLA determinants are associated with selected expression of some V gene segment specificities. We first examined the reactivity of 17 V segment specific mAb on purified CD4+ and CD8+ cell fractions in 10 unrelated people. We found a significant overexpression of only three V segment products (V beta 2, V beta 5.1 and V beta 6.7) in CD4+ and none in CD8+ cell fractions in most individuals. Skewing of certain V beta segments by non-polymorphic HLA determinants (i.e. class II for CD4+ and class I for CD8+ cells) is therefore more limited (3/17) than previously thought. Considering the effects of polymorphic HLA determinants, we compared TCR V segment frequencies in HLA-identical siblings to sibling pairs who differ at one or both HLA haplotypes, using 13 V beta specific mAb. In pairwise comparisons, we found that the HLA complex had no detectable effect on TCR repertoire in five large families with multiple siblings. Together, these observations suggest that HLA-predicted selection mechanisms exerted during thymic maturation might not have a predominant influence shaping the TCR repertoire of normal adults.

Antibodies, Monoclonal↗
PubMed1994

[Prevalence and characteristics of anti-tissue antibodies in chronic hepatitis caused by hepatitis C virus].

OBJECTIVES: The prevalence and significance of antiorganelle antibodies in the serum of patients with chronic hepatitis C is a subject of controversy. We studied prospectively these characteristics in patients with chronic hepatitis C. METHODS AND RESULTS: Among 156 patients (age: 55 +/- 14 years; 83 females), 30 (19%) had significant titers of antiorganelle antibodies: anti-nuclear antibodies in 18, anti-smooth muscle antibodies in 8 (no anti-actin or anti-vimentine subtypes), anti-LKM1 in 2, type 2 anti-mitochondrial antibodies in 2 patients. Anti-organelle antibodies were not detected in 126 patients. Patients with anti-organelle antibodies were significantly older but no difference was found between the two groups for sex ratio, serum amino-transferases or gammaglobulins, histopathological liver activity or prevalence of lymphocytic sialadenitis. The presence of anti-organelle antibodies was not related to HLA phenotype, especially B8 DR3, or DR4. Response to alpha interferon, estimated by serum aminotransferase levels after six months of treatment, was the same in both groups. CONCLUSIONS: These results suggest that serum anti-organelle antibodies are prevalent in during chronic hepatitis C but do not indicate a distinct autoimmune mechanism. Furthermore, the typing of anti-smooth muscle antibodies might help distinguish chronic hepatitis C from type 1 autoimmune chronic hepatitis.

Adult↗