Immunological factors and renal allograft survival for more than fifteen years: a single center study from Tunisia.
Late loss of kidney allograft, caused by immunological and non-immunological factors, remains a major problem in the field of transplantation. The aim of this study was to analyze the risk factors affecting long-term kidney graft survival more than 15 years. In a retro-spective analysis, clinical and laboratory variables and outcome of 330 patients who received a kidney transplant from living or cadaveric ABO-compatible donors at the Charles Nicolle Hospital, Tunis between 1986 and 2005 were recorded. A total of 58 patients who had follow-up data longer than 15 years constituted the subjects of this study. Patients were classified into two groups: Group I (Gp I), those who had kidney graft survival more than 15 years and Group II (Gp II), those who had kidney graft survival less than 15 years. There were 27 patients in Gp I (46.5%) and 31 in Gp II (53.5%). Graft loss in Gp II patients occurred in the first year in 15.1%, at three years in 35.5 %, at five years in 71 % and at 10 years in 83.9 %. The cause of graft loss was chronic graft dysfunction in 24 cases (77.4%), recurrence of the original kidney disease in three and graft versus host disease, urinary fistula, vascular rejection and graft rupture in one case each. There was no statistically significant difference between recipient and donor age or sex, duration on dialysis, number of acute rejections and infections between the two groups. Eleven of 27 patients (40.7 %) in Gp I and eight of 31 patients (25.8 %) in Gp II received total mismatched kidneys while the others received kidneys with varying degrees of match. The HLA DR2 matching was higher in Gp I (44.4 %) than in Gp II (29 %), whereas DR3 matching was higher in Gp II (45.2 %) in comparison with Gp I (11.1 %). Cross-match was negative in all our patients. Thirteen patients (48.1%) in Gp I and 17 (54.8 %) in Gp II.had a history of having episode(s) of acute rejection The number of acute rejection episodes did not contribute significantly to long-term graft survival in our series. Delayed graft function significantly lowered long-term graft survival; it was seen in seven cases in Gp I (25.9 %) versus 23 cases in Gp II (74.2 %) (X2=13.46). In our study, the long-term graft survival was similar to what is reported from developed countries. The main risk factors were HLA DR matching and delayed graft function.