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 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.