Organ transplantation in Bulgaria.

The transplantation program in Bulgaria started in 1968 with renal transplantations to a child and adult woman. In 1986 the first heart transplantation was performed. To date a total of 10 heart transplants have been performed, including one combined heart/lung. A liver transplantation program was launched in 2005 with a total number of 16 transplantations-7 from living donors and 9 from deceased donors. The highest transplantation activity is registered in the field of renal transplantation. During the period 1980-2006, 462 Bulgarian recipients of kidney were transplanted in Bulgaria. The ratio between transplantations from deceased and living related donors is approximately 1:0.9. Annual transplantation activity varies among the years from 1 to 12 renal transplantations p.m.p./per year. The 1- (80.7% vs. 63.1%), 5- (57.86% vs. 39.0%) and 10-year (42.65% vs. 23.62%) graft survival rates are higher for recipients of living donor kidneys compared to those of deceased donor. In 1983 a National kidney waiting list was established. Currently the number of the registered patients eligible for renal transplantation is 885. The proportion of sensitized patients in the waiting list is 20.45% and 4.34% of them are hyperimmunized. Recently HLAMatchmaker program has been implemented not only for sensitized patients but also for those with rare alleles and haplotypes. Post-transplant immunological monitoring showed a strong association between alloantibody presence and delayed graft function (Chi-square=10.73, P<0.001), acute rejection (Chi-square=14.504, P<0.001), chronic rejection (Chi-square=12.84, P<0.001) and graft loss (Chi-square=20.283, P<0.001). Based on the experience in our transplant center a strategy for improvement of long-term renal graft survival was developed and implemented.

Clinical relevance of anti-HLA antibodies detected by flow-cytometry bead-based assays--single-center experience.

The purpose of this study was to define the incidence, dynamics, and profiles of anti-human leukocyte antigen antibodies (HLA-Abs) produced after kidney transplantation and their impact on graft outcome. A total of 72 first cadaver donor kidney recipients were prospectively monitored for the development of HLA-Abs using bead-based flow-cytometry assays (One Lambda FlowPRA tests). Sixteen recipients (22.2%) developed HLA-Abs after transplantation (class I, n = 7; class I+II, n = 6; class II, n = 3), in most cases (81.25%) within the first 2 weeks posttransplantation. A strong association between alloantibody presence and delayed graft function (Chi-square = 7.659, p < 0.01), acute rejection (Chi-square = 14.504, p < 0.001), chronic rejection (Chi-square = 12.84, p < 0.001), and graft loss (Chi-square = 20.283, p < 0.001) was found. Patients with higher alloantibody titers experienced acute rejections and even early graft loss, compared with those with lower titers for whom chronic rejections were more common. Immunologic complications occurred in recipients with both donor-specific and cross-reacting groups or non-donor-specific antibodies alone. A positive correlation (Pearson correlation, 0.245; p < 0.05) between HLA class I amino acid triplet incompatibility and alloantibody production was observed, mainly resulting from immunogenic triplotypes. Given the results obtained in this study, an alloantibody testing algorithm has been designed and implemented for routine monitoring and to define optimally the alloantibody reactivity in kidney transplant recipients.