A Single-Centre Experience of Clinico-Pathological Features, Risk Factors and Treatment Outcome of Posttransplant Lymphoproliferative Disorders (PTLD) after Renal Transplantation.

Background: PTLD is a lymphoid proliferation that develops as a consequence of immunosuppression and represents monoclonal B-cell, or rarely T-cell proliferations, occurring in a setting of decreased T-cell immune surveillance. PTLD is a major complication after solid organ transplantation. The disease is often unpredictable and devastating of nature resulting in a high rate of morbidity and patient mortality.

Methods: Between 1990 and 2005 872 renal transplantations in 793 patients were performed at Skejby University Hospital in Aarhus and 11 cases of PTLD were identified retrospectively. PTLD Patients were investigated according to transplantation procedure, patient characteristics, type of lymphoma, treatment and outcome.

Results: 11 of 793 renal transplant recipients (1,4%) developed PTLD. Patients (7 male, 4 female) ranged from 19 to 73 years of age at the time of diagnosis (mean age: 42 years). 8 had a cadaveric renal transplant while 3 received a transplant from related donor. Lymphomas were classified as diffuse large B-cell lymphoma in 10 cases and as Burkitt lymphoma in 1 case. No cases were of T-cell origin or Hodgkins lymphomas. Six cases were EBV positive (54%). Out of 11 cases, 5 were diagnosed within 1 year after transplantation, among which 4 were EBV positive, whereas 6 had a latency period of more than 1 year, among which only 2 were EBV positive. The mean latency time between grafting and diagnosis of PTLD among the early lesions was 7 months and among late lesions 6 years and 2 months (ranging from 1 month to 10 years and 8 months). Sites involved in PTLD were renal graft in 2 cases (both early lesions), lungs in 1 case, bowel system in 4 cases, CNS in 1 case, isolated lymph nodes in 1 case, widespread disease in 1 case and uncertain location in 1 case. All patients were treated by tapering of the immunosuppressive regimen. Two were treated with additional surgery and 3 with chemotherapy - all 5 of them are alive and in complete remission. Among those 5 patients 3 have preserved graft function (60%) and 2 returned to dialysis. One patient was treated with anti-CD20 monoclonal antibody, 3 had both conventional chemotherapy and anti-CD20 immunotherapy and 2 did not receive additional treatment. All 6 were dead at the end of the study period. With a median follow-up period of 5 years and 2 months (ranging from 6 months to 11½ years) 5 patients of 11 PTLD cases (45%) were alive with no sign of lymphoma relapse.

Conclusions: PTLD is a severe complication, usually running an aggressive course and the outcome remains poor. The incidence in our population-based regional study material is 1,4%. Overall survival after a median follow-up of 62 months was 45%, with 60% of survivors maintaining graft function.