Therapeutic drug monitoring of prednisolone after lung transplantation.

BACKGROUND: Despite well-known and serious potential side-effects of corticosteroid therapy, therapeutic drug monitoring (TDM) of prednisolone is rarely performed after lung transplantation (LTx). METHODS: We measured prednisolone exposure using a 6-hour area-under-the-curve (AUC) analysis in 52 LTx recipients (41 bilateral, 9 single and 2 heart-lung), who were 99 +/- 13 (mean +/- SEM) weeks (range 4 to 380) post-LTx. Fourteen of 52 had cystic fibrosis (CF), and 36 of 52 were on cyclosporine and 16 of 52 on tacrolimus. Prednisolone dose was 9.8 +/- 0.7 mg/day (range 1 to 20). RESULTS: Only 9 of 52 LTx patients had a prednisolone AUC within the previously reported reference range for healthy adult control subjects (170 to 260 nmol x hr/liter/milligram prednisolone). Six patients had values below and 37 above this range. Prednisolone AUC was higher in patients with CF compared with non-CF patients (511 +/- 82 vs 349 +/- 27 nmol x hr/liter/milligram, p < 0.02) and 70% of LTx recipients had measurable prednisolone levels at baseline (26.5 +/- 4.5 nmol/liter), unlike normal controls. CONCLUSIONS: LTx recipients show a wide inter-individual variation in prednisolone pharmacokinetics; therefore, many are overdosed on conventional protocols. Side-effects of corticosteroid therapy remain a major clinical problem after transplantation, justifying the use of prednisolone TDM to optimize dosing and minimize morbidity.

Determining virological, serological and immunological parameters of EBV infection in the development of PTLD.

Post-transplant lymphoproliferative disease (PTLD) in Epstein-Barr virus (EBV) seronegative solid organ transplant recipients remains a significant problem, particularly in the first year post-transplant. Immune monitoring of a cohort of high-risk patients indicated that four EBV seronegative transplant recipients developed early-onset PTLD prior to evidence of an EBV humoral response. EBV status has been classically defined serologically, however these patients demonstrated multiple parameters of EBV infection, including the generation of EBV-specific CTL, outgrowth of spontaneous lymphoblastoid cell lines, and elevated EBV DNA levels, despite the absence of a classic EBV antibody response. As EBV serology is influenced by both immunosuppression and cytomegalovirus immunoglobulin treatment, both the EBV-specific CTL response and elevated EBV levels are more reliable indicators of EBV infection post-transplant.

Reconstitution of the latent T-lymphocyte response to Epstein-Barr virus is coincident with long-term recovery from posttransplant lymphoma after adoptive immunotherapy.

BACKGROUND: Adoptive transfer of Epstein-Barr virus (EBV)-specific cytotoxic T lymphocytes (CTLs) has been used to treat EBV-induced posttransplant lymphoproliferative disease (PTLD) in solid-organ recipients. This study defines, in detail, the temporal relationship between adoptive transfer and the clinical response, EBV DNA load, and CTL response to EBV latent and lytic antigens in a patient with a subcutaneous PTLD presentation treated with adoptive transfer of autologous CTL. METHODS: A heart transplant patient developed multiple subcutaneous PTLD deposits and was treated with a total of six doses (20 x 106 CTL per dose) of cultured autologous polyclonal EBV-specific CTL by adoptive transfer. RESULTS: Complete regression occurred after the sixth CTL dose, and the patient has remained disease-free from 47 weeks to the present (136 weeks). Real-time polymerase chain reaction analysis showed a reduction in viral load after therapy. Enzyme-linked immunospot analysis using defined EBV CTL epitopes showed that the CTL precursor frequency (pCTL) toward a lytic antigen epitope was elevated early in the course of disease but tended to decrease to lower levels after long-term regression of PTLD. The most dramatic result was seen in relation to three latent CTL epitopes studied. Long-term regression of PTLD was characterized by high pCTL toward the latent antigens. CONCLUSIONS: Increased pCTL reactivity to latent EBV CTL epitopes is coincident with recovery from disease after adoptive transfer of autologous CTL. Furthermore, the results are compatible with the belief that activation of a sustained CTL response to EBV latent epitopes is protective and may be a characteristic of patients in long-term remission from PTLD.