Paradoxical functions of B7: CD28 costimulation in a MHC class II-mismatched cardiac transplant model

Blockade of the B7: CD28 costimulatory pathway has emerged as a promising therapy to prevent allograft rejection. However, this pathway has also been demonstrated to be important for the generation and maintenance of regulatory T cells. In this study, we investigated the role of the B7: CD28 pathway in the 'bm12 into B6' MHC class II-mismatched vascularized cardiac transplant model of chronic rejection. Allograft rejection was remarkably accelerated in B6 background B7DKO and CD28KO recipients compared with B6 wild-type (WT) recipients. Allograft rejection was associated with a significantly enhanced Th1/Th2 alloreactivity and marked reduction in the ratio of regulatory T cells to CD4(+) effector/memory cells. We noted that administration of anti-B7-1 and anti-B7-2 mAb prior to transplantation also accelerated allograft rejection. Furthermore, depleting CD25(+) cells in B6 WT recipients of bm12 hearts prior to transplant also precipitated rejection at a similar rate. Neither B7/CD28 deficiency nor CD25 depletion affected graft survival in single MHC class I-mismatched (bm1 into B6) recipients. This study highlights the paradoxical functions of B7: CD28 costimulation in a MHC class II-mismatched model, in which the B7: CD28 pathway is demonstrated to be important in preventing rejection through the generation and maintenance of Tregs.

Assessment of quality of life in a single centre dialysis population using the KDQOL-SF questionnaire

Health-related quality of life (HRQOL) is a valid marker of outcome for chronic dialysis therapy. A wide range of questionnaires are now available which assess different aspects of an individual's health. Appreciation of those factors that contribute to explaining HRQOL items remains poorly defined. The development of disease-specific questionnaires such as KDQOL-SF, should allow for such questions to be better answered. A cross-sectional analysis of our chronic dialysis population was made using the KDQOL-SF questionnaire. By multiple linear regression analysis demographic, clinical and dialysis-related factors were assessed for their contribution to the HRQOL in this population. The HRQOL of these patients was also compared against a general population sample. From a total of 190 chronic dialysis patients, 146 completed the KDQOL-SF questionnaire. The haemodialysis (HD) and peritoneal dialysis (PD) patients were similar with respect to most demographic, clinical and dialysis variables except for haemoglobin and albumin which were significantly (p < 0.05) greater in the peritoneal and haemodialysis populations respectively. Compared to the general population, the HRQOL of dialysis patients was impaired for all SF-36 subscales. Use of the disease-specific components of KDQOL-SF discriminated between dialysis modality for our dialysis population. Multiple linear regression analysis demonstrated that 27.5 to 42.7% of the variance in the SF-36 subscales could be explained. Satisfactory sleep, dialysis related symptoms, effect of kidney disease on lifestyle and burden of kidney disease were found to be the most important determinants of HRQOL for this population.