Post-transplant lymphoproliferative disease in pediatric lung transplant recipients: Recent advances in monitoring

To investigate the clinical validity of newer diagnostic tests such as monitoring of EBVqPCR and lymphocyte function assay ImmuKnow in helping to diagnose PTLD in pediatric lung transplant recipients. Single-center, retrospective case-control study. CsA trough levels, EBVqPCR and ImmuKnow (Cyclex Inc., Columbia, MD, USA) levels were measured serially as part of routine care. Re-transplant patients and patients who did not reach 12 months post-transplant at the time of analysis were excluded. Twenty-seven patients met the inclusion criteria. The study group consisted of seven patients who developed PTLD, five of which were EBV- recipients who received EBV+ lungs. The rest of the eligible patients served as controls. Median time to develop PTLD was 273 days (range: 166-343). One, two, three, six, and nine months after transplant, mean (±s.d.) CsA trough whole blood levels (ng/mL) were not different between the two groups: 378 ± 38, 390 ± 52, 402 ± 89, 359 ± 42, and 342 ± 115, vs. 416 ± 105, 347 ± 64, 337 ± 78, 333 ± 86, and 281 ± 54 [PTLD vs. no-PTLD, respectively (p > 0.05 for all time points)]. Mean (±s.d.) EBVqPCR levels (copies/mL) measured at three, six, and nine months post-transplant were significantly elevated in PTLD group compared to no-PTLD group: 84 ± 99, 3384 ± 7428 and 839 ± 1444 vs. 9 ± 26, 8 ± 36 and 32 ± 136, respectively (p < 0.05 for all time points). Mean (±s.d.) ImmuKnow levels (ATP ng/mL) at three, six, and nine months post-transplant were significantly lower in the PTLD group when compared with no-PTLD group: 144 ± 67, 137 ± 110, and 120 ± 153 vs. 290 ± 161, 300 ± 162, and 293 ± 190, respectively (p < 0.05 for all time points). Close monitoring of EBV viral load by qPCR and the degree of immunosuppression via ImmuKnow may guide physicians to reach the diagnosis of PTLD early.