Recurrent lupus nephritis after kidney transplantation: a surveillance biopsy study.

OBJECTIVES: To determine the incidence of recurrent lupus nephritis (LN) in renal transplant recipients with systemic lupus erythematosus (SLE). METHODS: All patients with SLE that had undergone transplant with a functioning graft were asked in 2008 to participate in a cross-sectional study. The study included a standardised clinical examination, laboratory tests and a biopsy of the transplanted kidney. RESULTS: A total of 41 (93%) of a cohort of 44 patients with SLE with renal transplants participated. Of the biopsies, 3 were indication biopsies and 38 were surveillance biopsies. In all, 22 patients (54%) had biopsy-proven recurrence of LN. The majority of the cases were subclinical and characterised as class I/class II LN. Proteinuria (mg protein/mmol creatinine) was significantly increased in patients with recurrence, 70.6 (104.9) mg/mmol versus 11.9 (6.7) mg/mmol in patients without recurrence (p=0.038). Lupus anticoagulant was found more frequently in the patients with recurrence, nine versus two patients (p=0.033). Recurrence of LN was associated with receiving a kidney from a living donor (p=0.049). In all, 83% (34 of 41) had chronic allograft nephropathy in the transplanted kidneys with no difference between patients with recurrence or without. CONCLUSIONS: Subclinical recurrence of LN is common in patients with renal transplants with SLE. The majority of the patients have chronic allograft nephropathy.

Mycophenolate pharmacokinetics and pharmacodynamics in belatacept treated renal allograft recipients - a pilot study.

BACKGROUND: Mycophenolic acid (MPA) is widely used as part of immunosuppressive regimens following allograft transplantation. The large pharmacokinetic (PK) and pharmacodynamic (PD) variability and narrow therapeutic range of MPA provide a potential for therapeutic drug monitoring. The objective of this pilot study was to investigate the MPA PK and PD relation in combination with belatacept (2nd generation CTLA4-Ig) or cyclosporine (CsA). METHODS: Seven renal allograft recipients were randomized to either belatacept (n = 4) or cyclosporine (n = 3) based immunosuppression. Samples for MPA PK and PD evaluations were collected predose and at 1, 2 and 13 weeks posttransplant. Plasma concentrations of MPA were determined by HPLC-UV. Activity of inosine monophosphate dehydrogenase (IMPDH) and the expressions of two IMPDH isoforms were measured in CD4+ cells by HPLC-UV and real-time reverse-transcription PCR, respectively. Subsets of T cells were characterized by flow cytometry. RESULTS: The MPA exposure tended to be higher among belatacept patients than in CsA patients at week 1 (P = 0.057). Further, MPA concentrations (AUC0-9 h and C0) increased with time in both groups and were higher at week 13 than at week 2 (P = 0.031, n = 6). In contrast to the postdose reductions of IMPDH activity observed early posttransplant, IMPDH activity within both treatment groups was elevated throughout the dosing interval at week 13. Transient postdose increments were also observed for IMPDH1 expression, starting at week 1. Higher MPA exposure was associated with larger elevations of IMPDH1 (r = 0.81, P = 0.023, n = 7 for MPA and IMPDH1 AUC0-9 h at week 1). The maximum IMPDH1 expression was 52 (13-177)% higher at week 13 compared to week 1 (P = 0.031, n = 6). One patient showed lower MPA exposure with time and did neither display elevations of IMPDH activity nor IMPDH1 expression. No difference was observed in T cell subsets between treatment groups. CONCLUSION: The significant influence of MPA on IMPDH1 expression, possibly mediated through reduced guanine nucleotide levels, could explain the elevations of IMPDH activity within dosing intervals at week 13. The present regulation of IMPDH in CD4+ cells should be considered when interpreting measurements of IMPDH inhibition.