IL2 and TNFA gene polymorphisms and the risk of graft-versus-host disease after allogeneic haematopoietic stem cell transplantation.

This study aimed to analyse the association of gene polymorphisms with the outcome of allogeneic haematopoietic stem cell transplantation. We studied 122 donor/recipient pairs who received HLA-identical transplants from siblings at the Universidade Estadual de Campinas, Brazil, between June 1996 and June 2006. Donor/recipient alleles for TNFA-238 and IL2-330/+166 single-nucleotide polymorphisms (SNP) were analysed by PCR-SSP. No association was observed between the risk of acute graft-versus-host disease (GVHD) and these SNP. However, our findings suggest that the polymorphism of promoter gene TNFA-238GA is associated with the occurrence and severity of chronic GVHD. The probability of chronic GVHD in patients with GA genotype at position -238 of TNFA gene is 91.7% in contrast to 59.4% in patients with GG genotype (P = 0.038). In patients with donor GA genotype the probability of chronic GVHD is 90.8%, and 57.9% in patients with donor GG genotype (P = 0.038). The probability of extensive chronic GVHD in patients with TNFA-238GA is 91.7% compared with 46.3% in patients with TNFA-238GG (P = 0.0046). In patients with donor GA genotype at position -238 of the TNFA gene, it is 81.7%, compared with 44.5% in patients with donor GG genotype (P = 0.016). However, further studies with more patients are required to identify cytokine gene polymorphisms and their association with transplant-related complication in Brazil, particularly due to ethnic background, the relatively low power of detection of genetic markers of this study, and the complexity of the MHC region.

Effect of panel-reactive antibody in predicting crossmatch selection of cadaveric kidney recipients.

AIM: The influence of panel-reactive antibody level (%PRA) on crossmatch results was evaluated among 866 patients on the waiting list for cadaveric renal allografting from January 2001 to August 2005. We evaluated the results for 124 potential donors for a kidney, including 2008 crossmatches. Four hundred eighteen patients were tested against only 1 donor. METHODS: Serum samples were screened for anti-HLA antibodies using immunoglobulin (Ig)G enzyme-linked immunosorbent assay (ELISA) PRA kit and the %PRA of the most reactive sample (peak) was used for patient stratification, according to sensitization level. Crossmatches were performed on fresh donor T lymphocytes from peripheral lymph nodes, using classical and anti-human-globulin enhanced complement-dependent cytotoxicity (CDC-T) methods. The tests were performed using peak and current patient sera before and after dithiothreitol treatment. The crossmatch was assumed to be negative when no reactivity was observed in all tests. RESULTS: The incidences of positive crossmatch were as follows: 72.3%, 14.6%, and 7.2%, among patients with PRA >50%, PRA

Correlation of mixed lymphocyte culture with chronic graft-versus-host disease following allogeneic stem cell transplantation.

The purpose of the present study was to evaluate the mixed lymphocyte culture as a predictive assay of acute and chronic graft-versus-host disease (GVHD). We studied 153 patients who received a first bone marrow transplantation from human leukocyte antigen-identical siblings. Acute GVHD was observed in 26 of 128 (20.3%) patients evaluated and chronic GVHD occurred in 60 of 114 (52.6%). One-way mixed lymphocyte culture (MLC) assays were performed by the standard method. MLC results are reported as the relative response (RR) from donor against patient cells. The responses ranged from -47.0 to 40.7%, with a median of 0.5%. The Kaplan-Meier probability of developing GVHD was determined for patients with positive and negative MLC. There was no significant difference in incidence of acute GVHD between the groups studied. However, the incidence of chronic GVHD was higher in recipients with RR >4.5% than in those with RR < or =4.5%. The Cox Proportional Hazards model was used to examine the effect of MLC levels on incidence of chronic GVHD, while adjusting for the potential confounding effect of others suspected or observed risk factors. The relative risk of chronic GVHD was 2.5 for patients with positive MLC (RR >4.5%), 2.9 for those who received peripheral blood progenitor cells as a graft, and 2.2 for patients who developed previous acute GVHD. MLC was not useful for predicting acute GVHD, but MLC with RR >4.5% associated with other risk factors could predict the development of chronic GVHD, being of help for the prevention and/or treatment of this late complication.

Correlation of mixed lymphocyte culture with chronic graft-versus-host disease following allogeneic stem cell transplantation

The purpose of the present study was to evaluate the mixed lymphocyte culture as a predictive assay of acute and chronic graft-versus-host disease (GVHD). We studied 153 patients who received a first bone marrow transplantation from human leukocyte antigen-identical siblings. Acute GVHD was observed in 26 of 128 (20.3 percent) patients evaluated and chronic GVHD occurred in 60 of 114 (52.6 percent). One-way mixed lymphocyte culture (MLC) assays were performed by the standard method. MLC results are reported as the relative response (RR) from donor against patient cells. The responses ranged from -47.0 to 40.7 percent, with a median of 0.5 percent. The Kaplan-Meier probability of developing GVHD was determined for patients with positive and negative MLC. There was no significant difference in incidence of acute GVHD between the groups studied. However, the incidence of chronic GVHD was higher in recipients with RR >4.5 percent than in those with RR <=4.5 percent. The Cox Proportional Hazards model was used to examine the effect of MLC levels on incidence of chronic GVHD, while adjusting for the potential confounding effect of others suspected or observed risk factors. The relative risk of chronic GVHD was 2.5 for patients with positive MLC (RR >4.5 percent), 2.9 for those who received peripheral blood progenitor cells as a graft, and 2.2 for patients who developed previous acute GVHD. MLC was not useful for predicting acute GVHD, but MLC with RR >4.5 percent associated with other risk factors could predict the development of chronic GVHD, being of help for the prevention and/or treatment of this late complication

Distribution of HLA-DRB1 alleles in a mixed population with insulin-dependent diabetes mellitus from the southeast of Brazil.

HLA class II genes are strongly associated with susceptibility and resistance to insulin-dependent diabetes mellitus (IDDM). The present study reports the HLA-DRB1 genotyping of 41 IDDM patients and 99 healthy subjects from the Southeast of Brazil (Campinas region). Both groups consisted of an ethnic mixture of Caucasian, African Negro and Amerindian origin. HLA-DRB1*03 and *04 alleles were found at significantly higher frequencies among IDDM patients compared to the controls (DRB1*03: 48.8% vs 18.2%, P < 0.005, RR = 4.27; DRB1*04: 43.9% vs 15.1%, P < 0.008, RR = 4.37) and were associated with a susceptibility to the disease. DRB1*03/*04 heterozygosity conferred a strong IDDM risk (RR = 5.44). In contrast, the HLA-DRB1*11 allele frequency was lower among IDDM patients (7.3% vs 26.3% in controls), but the difference was not significant. These data agree with those described for other populations and allow genetic characterization of IDDM in Brazil.

Distribution of HLA-DRB1 alleles in a mixed population with insulin-dependent diabetes mellitus from the Southeast of Brazil

HLA class II genes are strongly associated with susceptibility and resistance to insulin-dependent diabetes mellitus (IDDM). The present study reports the HLA-DRB1 genotyping of 41 IDDM patients and 99 healthy subjects from the Southeast of Brazil (Campinas region). Both groups consisted of an ethnic mixture of Caucasian, African Negro and Amerindian origin. HLA-DRB1*03 and *04 alleles were found at significantly higher frequencies among IDDM patients compared to the controls (DRB1*03: 48.8 percent vs 18.2 percent, P<0.005, RR= 4.27); DRB1*04:43.9 percent vs 15.1 percent, P<0.008, RR=4.37) and were associated with a susceptibility to the disease. DRB1*03/*04 heterozygosity conferred a strong IDDM risk (RR=5.44). In contrast, the HLA-DRB1*11 allele frequency was lower among IDDM patients (7.3 percent vs 26.3 percent in controls), but the difference was not significant. These data agree with those described for other populations and allow genetic characterization of IDDM in Brazil.

Micronucleus monitoring to assess human occupational exposure to organochlorides.

Health surveillance for hazardous situations due to chemical exposure, in particular those which are carcinogenic, requires sensitive monitoring tests. Although experimental studies have shown the genotoxic and carcinogenic effect of several organochlorides, the lack of epidemiologic studies prevents their classification as carcinogenic to human beings. In this context, genotoxicity tests of short duration in human cells gain importance. The relation between the clastogenic effects (chromosome breaks) and cancer induction is already known to the scientific literature. The micronucleus test has been proposed as a good indicator of clastogenesis. In the present study, we evaluated, by means of the micronucleus test, 41 workers of a chemical industry in the state of São Paulo, southeast region of Brazil, who had been exposed to a mixture of chlorinated solvents (carbon tetrachloride, perchloroethylene, and hexachlorobenzene) and 28 workers who had not been exposed. Peripheral lymphocytes stimulated by phytohemagglutinin and with cytokinesis blocked by cytochalasin B were used. The results showed that the exposed workers presented a statistically significant higher frequency of micronuclei than the group which had not been exposed.