Epstein-Barr virus primary mismatching and HLA matching: key risk factors for post lung transplant lymphoproliferative disease.

Background: Posttransplant lymphoproliferative disease (PTLD) in lung transplant recipients (LTRs) is potentially lethal with considerable morbidity. The role of donor (D)/recipient (R) HLA matching is unknown.

Method: We reviewed our LTRs from January 1994, when routine D/R Epstein-Barr virus (EBV) serologic screening was begun, through to January 2000. We examined whether D/R HLA match status influenced the risk of PTLD in EBV D+/R- mismatched LTRs.

Results: There were 16 D+/R- EBV-mismatched LTRs, 5 (31%) of whom developed PTLD (from a total of 237 LTRs; 218 survived >30 days). There were only two other cases of PTLD among the non-EBV primary mismatched patients. All patients received baseline immunosuppression of cyclosporine, azathioprine, and prednisolone without cytolytics and ganciclovir prophylaxis if "at risk" from cytomegalovirus. The five PTLD cases were diagnosed 81 to 734 (median 116) days from transplantation; three involved the lung allograft and two others involved lymph nodes. All PTLD patients seroconverted for EBV, whereas 7 of the 11 remaining EBV-mismatched patients who did not develop PTLD did not seroconvert. In the 16 EBV primary mismatched patients, there were 4 of 66 HLA allele matches in the 11 PTLD-free patients versus 15 of 30 matches in the 5 PTLD patients (P<0.001). This resulted in 2 or more HLA (A/B/DR) matches in 4 of 5 patients with PTLD versus 0 of 11 in the PTLD-free group (P=0.003). All PTLD patients were treated with reduced immunosuppression and antiviral therapy. Only two of the five LTRs who developed PTLD died, one with progressive disease despite chemotherapy and the other from chronic allograft rejection.

Conclusion: A high degree of HLA matching in D/R EBV-mismatched LTRs significantly increases the risk of PTLD.