Renal transplantation. Strategies to prevent organ rejection--the role of an inter-regional reference center.

This paper summarizes the role of the Inter-Regional Reference Center (RC) of the North Italy Transplant program (NITp), in coordinating a donor procurement and organ transplantation network, with a special focus on the strategies to minimize immunological risk and complications after transplantation. In the NITp, patients enrolled on the renal transplantation (RT) waiting list are typed for HLA-A,B,DRB1 antigens with a genomic method. They are periodically screened for the presence of lymphocytotoxic antibodies in their serum by the RC and their suitability to receive the transplant is checked periodically. Cadaver kidney allocation is ruled by a computerized algorithm, named NITK3, established in 1997, which aims at ensuring quality, equity, transparency and traceability during all the phases of the allocation decision-making process. NITK3 has been set up by the NITp Working Group on the basis of biological, medical and administrative criteria and it is periodically reviewed after the analysis of transplant results. In this paper, we show the results of a preliminary analysis of RTs performed from 1998 to 2002 in nine out of sixteen centers of the NITp area, which demonstrates the general quality of the NITp program in terms of patients and graft survival and the special attention to the patients at higher immunological risk.

A prospective survey on incidence and outcome of Broviac/Hickman catheter-related complications in pediatric patients affected by hematological and oncological diseases.

A prospective pediatric survey on the incidence of central venous catheter (CVC) complications was performed aimed at identifying risk factors of premature CVC removal. The study comprised 129 Broviac-Hickman CVCs inserted during a 13-month period in 112 children. The total number of CVC days was 19,328 (median: 122 days, range: 1-385). The overall rate of complications was 6.2/1000 CVC days, i.e., 4.5/1000 and 1.7/1000 CVC days for mechanical and infectious complications, respectively. Interestingly, only two CVC-related cases of septicemia and no thrombotic events were documented. At the end of the study period, 38 of 129 CVC (29.5%) had been removed: 20 due to CVC-related complications (dislocation18, rupture 2), 10 due to the patient's death, and 8 due to completion of therapy. Age at CVC insertion <4.9 years was a significant predictor of premature CVC removal ( p=0.01). Mechanical complications, especially in younger children, are the main cause of premature loss of CVC. These data underline the importance of more effectively securing the CVC to subcutaneous tissue in pediatric patients to reduce accidental dislocations.

Thrombotic microangiopathy associated with parvovirus B 19 infection after renal transplantation.

Human parvovirus B19 is considered an etiologic agent of aplastic anemia in immunosuppressed patients. Microscopic vasculitis, with or without renal involvement, has recently been attributed to this viral infection in immunocompetent patients. This study describes four cases of thrombotic renal graft microangiopathy presumably secondary to B19 infection. Twelve to 50 days after transplantation, four patients presented a renal graft dysfunction with creatinine rising to 360 to 1088 micromol/L and requiring hemodialysis in three cases. Renal involvement appeared after a systemic illness characterized by fever, fatigue and arthralgia, aplastic anemia (hemoglobin ranged from 5.3 to 7.8 g/dl), and thrombocytopenia. A thrombotic microangiopathy was observed in the renal biopsies, and the parvovirus B19 genome was isolated by PCR from the specimens. All four patients also became IgM-positive for parvovirus. Three of the four renal biopsies taken at the time of transplantation (T0) from the same patients were found positive for the B19 genome. Graft function recovered, with resolution of the aplastic anemia, within 22 to 110 d. Twenty biopsies performed as routine controls or for suspected acute rejection and nine T0 biopsies of patients with no signs of B19 infection were used. The B19 genome was found in two of 20 posttransplant biopsies and in one of nine T0 biopsies. The temporal association between aplastic anemia and the onset of thrombotic graft microangiopathy, isolation of the viral genome in renal specimens, seroconversion, and endothelial tropism of the virus suggests that B19 could be the etiologic agent of thrombotic microangiopathy in these cases. The development of the disease after infection could depend on other detrimental cofactors, which make the patient more susceptible to microthrombi formation in the renal microvasculature. The renal graft could represent the route of B19 transmission.