Acute Rejection Features in Dual Kidney Transplant Recipients from Elderly Donors: Comparison of Calcineurin Inhibitor-Based and Calcineurin Inhibitor-Free Immunosuppressive Protocols

Features of acute rejection in dual kidney transplant have not been studied. The aim of this study is to compare acute rejections in dual kidney transplant recipients from elderly donors on different immunosuppressive protocols. Sixty-nine patients were evaluated: 28 received calcineurin inhibitor-based (group 1) and 41 received calcineurin inhibitor-free immunosuppression (group 2). Histology of all donor kidneys was evaluated before implantation. All rejections showed tubulitis in both groups, and were classified as T cell-mediated acute rejections. Incidence and Banff grade of rejections in the two groups were not significantly different. Late rejections however, were observed in group 1 ( P < 0.01) whereas steroid-resistant rejections occurred in group 2 ( P < 0.03). C4d deposition was only observed in group 2. Occurrence of acute rejection was significantly associated with graft loss due to interstitial fibrosis/tubular atrophy in both groups. In group 1 mean serum creatinine levels of patients with rejections at six months and one year were higher than those of patients without rejections ( P < 0.03 and P < 0.009, respectively). In group 2 they were higher at six months ( P < 0.01) but not at one year. In addition, graft loss due to interstitial fibrosis/tubular atrophy occurred in 3/28 patients in group 1 (10.7%, OR= 1.95, 95%CI 1.02–3.71), and in 1/41 patients in group 2 (2.4%, OR= 0.41, 95%CI 0.07–2.24). Taken together these results suggest better renal function in patients on calcineurin inhibitor-free immunosuppression. In conclusion, acute rejections were detrimental irrespective of the type of immunosuppression, but different features were observed with each therapy. A tailored approach should be advantageous for prevention and treatment of acute rejections.

Histological Markers of Humoral Rejection in Renal Transplant Patients

Diagnosis of "suspicious humoral rejection" can be formulated in the presence of peritubular capillary (PTC) C4d deposition and one of the following tissue changes: (1) acute tubular necrosis, (2) glomerulitis or presence of polymophonuclear leukocytes or monocytes in PTC, or (3) arteritis. From January 2004 to October 2006, we performed immunohistochemical staining with anti-C4d antibody on 54 renal biopsies from 39 renal transplant patients. In 25 biopsies we observed diffuse (n = 13) or focal (n = 12) C4d deposition. Based on C4d-positivity, patients were divided into three groups: group 1 included 19 C4d-negative patients; group 2, 10 patients with diffuse C4d-positivity; and group 3, 10 patients with focal C4d-positivity. Panel-reaction antibody-positive tests were associated with diffuse C4d-positivity: 50% of group 2 patients showed a positive test, while no group 1 or 3 patients had a positive test (P < .001). Glomerulitis was observed in six biopsies and associated with diffuse C4d staining. Graft loss occurred in 3/10 group 2 patients (30%); 2/19 group 1 patients (10.5%), and 1/10 group 3 patients (10%). Viral infections were experienced in the year of the biopsy by 50% of group 1 patients 80% of group 2 patients, and 100% of group 3 patients (P < .025), indicating a significantly greater number of infections among patients with C4d-positive biopsies. In eight cases, anti-thymocyte globulin was administered less than 21 days before the biopsy: four had diffuse and four had focal C4d positivity.

Prospective study on the behaviour of the metalloprotease ADAMTS13 and of von Willebrand factor after bone marrow transplantation

Thrombotic microangiopathies (TMAs) are rare but serious complications of bone marrow transplantation (BMT). Clinical manifestations are similar to those of thrombotic thrombocytopenic purpura (TTP), but prognosis is generally poorer despite plasma exchange. The enzymatic activity of the plasma metalloprotease ADAMTS13, which cleaves ultralarge thrombogenic multimers of von Willebrand factor (VWF) derived from activated endothelial cells, is very low or undetectable in patients with classic TTP, and protease deficiency is thought to play a mechanistic role in the formation of platelet thrombi in the microcirculation. This is the first prospective study to evaluate the incidence of TMA in 46 consecutively recruited patients undergoing autologous or allogeneic BMT and explore in parallel the behaviour of ADAMTS13, VWF antigen and VWF multimer size. The incidence of post-BMT TMA was 6% (three of 46); all cases occurred after allogeneic BMT. Compared with baseline values plasma ADAMTS13 activity was significantly reduced in patients undergoing BMT, particularly after the conditioning regimen (mean values: 50 +/- 22 vs. 77 +/- 32%; P < 0.0001). In the three patients who developed TMA, ADAMTS13 decreased after conditioning, but was very low in one case only (8%). VWF antigen levels progressively increased after the conditioning regimen (228 +/- 75 vs. 178 +/- 76% at baseline, P = 0.002). The mean proportion of high-molecular weight VWF multimers did not change in the various stages of BMT, even though ultralarge multimers were transiently found in same cases with and without TMA. Hence, the measurements evaluated in this study are not clinically useful to predict the occurrence of post-BMT TMA.

[Renal transplantation in the North Italy Transplant program (NITp): Organ allocation and results]

Renal transplantation is an effective therapeutic tool for patients with end-stage renal diseases (ESRDs). Data reported in this article summarize the results obtained from 30 years' activity in the North Italy Transplant program (NITp), the first transplant organization in Italy that implemented a donor procurement and organ transplantation network. In the NITp kidney allocation is governed by a computerized algorithm, NITK3, put in place in 1997, aimed at ensuring equity, transparency and traceability during the stages of the allocation decision-making process. The NITp working group has recognized the NITK3 criteria and they are periodically reviewed following the results of the analysis of patients' transplantation odds. The results obtained with the use of the NITK3 algorithm have been very satisfactory: after 6 yrs, a significantly higher percentage of patients at immunological risk (sensitized or waiting for re-transplant), of patients waiting for >3 yrs and of patients with 0-1 HLA A,B,DR mismatches have been transplanted. Moreover, a higher percentage of kidneys were used locally (in a hospital within the procurement area), and this is known to stimulate donor procurement. Finally, we performed a preliminary statistical analysis of transplants carried out from 1998-2002 in 5/16 centers of the NITp area, demonstrating the quality of the NITp program in terms of patient and graft survival, and that donor and recipient age are the variables significantly impacting on transplant results.