Faculty Bibliography

BACKGROUND: Kidney transplantation (KT) is the treatment for end-stage renal disease in appropriate HIV-positive individuals. However, acute rejection (AR) rates are over twice those of HIV-negative recipients. METHODS: To better understand optimal immunosuppression for HIV-positive KT recipients, we studied associations between immunosuppression regimen, AR at 1 year, and survival in 516 HIV-positive and 93,027 HIV-negative adult kidney-only recipients using Scientific Registry of Transplant Recipients data from 2003 to 2011. RESULTS: Consistent with previous reports, HIV-positive patients had twofold higher risk of AR (adjusted relative risk [aRR], 1.77; 95% confidence interval [CI], 1.45-2.2; P<0.001) than their HIV-negative counterparts as well as a higher risk of graft loss (adjusted hazard ratio, 1.51; 95% CI, 1.18-1.94; P=0.001), but these differences were not seen among patients receiving antithymocyte globulin (ATG) induction (aRR for AR, 1.16; 95% CI, 0.41-3.35, P=0.77; adjusted hazard ratio for graft loss, 1.54; 95% CI, 0.73-3.25; P=0.26). Furthermore, HIV-positive patients receiving ATG induction had a 2.6-fold lower risk of AR (aRR, 0.39; 95% CI, 0.18-0.87; P=0.02) than those receiving no antibody induction. Conversely, HIV-positive patients receiving sirolimus-based therapy had a 2.2-fold higher risk of AR (aRR, 2.15; 95% CI, 1.20-3.86; P=0.01) than those receiving calcineurin inhibitor-based regimens. CONCLUSION: These findings support a role for ATG induction, and caution against the use of sirolimus-based maintenance therapy, in HIV-positive individuals undergoing KT.

IMPORTANCE: Risk of end-stage renal disease (ESRD) in kidney donors has been compared with risk faced by the general population, but the general population represents an unscreened, high-risk comparator. A comparison to similarly screened healthy nondonors would more properly estimate the sequelae of kidney donation. OBJECTIVES: To compare the risk of ESRD in kidney donors with that of a healthy cohort of nondonors who are at equally low risk of renal disease and free of contraindications to live donation and to stratify these comparisons by patient demographics. DESIGN, SETTINGS, AND PARTICIPANTS: A cohort of 96,217 kidney donors in the United States between April 1994 and November 2011 and a cohort of 20,024 participants of the Third National Health and Nutrition Examination Survey (NHANES III) were linked to Centers for Medicare & Medicaid Services data to ascertain development of ESRD, which was defined as the initiation of maintenance dialysis, placement on the waiting list, or receipt of a living or deceased donor kidney transplant, whichever was identified first. Maximum follow-up was 15.0 years; median follow-up was 7.6 years (interquartile range [IQR], 3.9-11.5 years) for kidney donors and 15.0 years (IQR, 13.7-15.0 years) for matched healthy nondonors. MAIN OUTCOMES AND MEASURES: Cumulative incidence and lifetime risk of ESRD. RESULTS: Among live donors, with median follow-up of 7.6 years (maximum, 15.0), ESRD developed in 99 individuals in a mean (SD) of 8.6 (3.6) years after donation. Among matched healthy nondonors, with median follow-up of 15.0 years (maximum, 15.0), ESRD developed in 36 nondonors in 10.7 (3.2) years, drawn from 17 ESRD events in the unmatched healthy nondonor pool of 9364. Estimated risk of ESRD at 15 years after donation was 30.8 per 10,000 (95% CI, 24.3-38.5) in kidney donors and 3.9 per 10,000 (95% CI, 0.8-8.9) in their matched healthy nondonor counterparts (P < .001). This difference was observed in both black and white individuals, with an estimated risk of 74.7 per 10,000 black donors (95% CI, 47.8-105.8) vs 23.9 per 10,000 black nondonors (95% CI, 1.6-62.4; P < .001) and an estimated risk of 22.7 per 10,000 white donors (95% CI, 15.6-30.1) vs 0.0 white nondonors (P < .001). Estimated lifetime risk of ESRD was 90 per 10,000 donors, 326 per 10,000 unscreened nondonors (general population), and 14 per 10,000 healthy nondonors. CONCLUSIONS AND RELEVANCE: Compared with matched healthy nondonors, kidney donors had an increased risk of ESRD over a median of 7.6 years; however, the magnitude of the absolute risk increase was small. These findings may help inform discussions with persons considering live kidney donation.

Renal transplantation in patients with antiphospholipid antibodies has historically proven challenging due to increased risk for thrombosis and allograft failure. This is especially true for patients with antiphospholipid antibody syndrome (APS) and its rare subtype, the catastrophic antiphospholipid antibody syndrome (CAPS). Since a critical mechanism of thrombosis in APS/CAPS is one mediated by complement activation, we hypothesized that preemptive treatment with the terminal complement inhibitor, eculizumab, would reduce the extent of vascular injury and thrombosis, enabling renal transplantation for patients in whom it would otherwise be contraindicated. Three patients with APS, two with a history of CAPS, were treated with continuous systemic anticoagulation together with eculizumab prior to and following live donor renal transplantation. Two patients were also sensitized to human leukocyte antigens (HLA) and required plasmapheresis for reduction of donor-specific antibodies. After follow-up ranging from 4 months to 4 years, all patients have functioning renal allografts. No systemic thrombotic events or early graft losses were observed. While the appropriate duration of treatment remains to be determined, this case series suggests that complement inhibitors such as eculizumab may prove to be effective in preventing the recurrence of APS after renal transplantation.

BACKGROUND AND AIM: Green fluorescent protein (GFP) is a widely used molecular tag to trace transplanted cells in rodent liver injury models. The differing results from various previously reported studies using GFP could be attributed to the immunogenicity of GFP. METHODS: Hepatocytes were obtained from GFP-expressing transgenic (Tg) Lewis rats and were transplanted into the livers of wild-type Lewis rats after they had undergone a partial hepatectomy. The proliferation of endogenous hepatocytes in recipient rats was inhibited by pretreatment with retrorsine to enhance the proliferation of the transplanted hepatocytes. Transplantation of wild-type hepatocytes into GFP-Tg rat liver was also performed for comparison. RESULTS: All biopsy specimens taken seven days after transplantation showed engraftment of transplanted hepatocytes, with the numbers of transplanted hepatocytes increasing until day 14. GFP-positive hepatocytes in wild-type rat livers were decreased by day 28 and could not be detected on day 42, whereas the number of wild-type hepatocytes steadily increased in GFP-Tg rat liver. Histological examination showed degenerative change of GFP-positive hepatocytes and the accumulation of infiltrating cells on day 28. PCR analysis for the GFP transgene suggested that transplanted hepatocytes were eliminated rather than being retained along with the loss of GFP expression. Both modification of the immunological response using tacrolimus and bone marrow transplantation prolonged the survival of GFP-positive hepatocytes. In contrast, host immunization with GFP-positive hepatocytes led to complete loss of GFP-positive hepatocytes by day 14. CONCLUSION: GFP-positive hepatocytes isolated from GFP-Tg Lewis rats did not survive long term in the livers of retrorsine-pretreated wild-type Lewis rats. The mechanism underlying this phenomenon most likely involves an immunological reaction against GFP. The influence of GFP immunogenicity on cell transplantation models should be considered in planning in vivo experiments using GFP and in interpreting their results.

Renal involvement by sarcoidosis in native and transplanted kidneys classically presents as non caseating granulomatous interstitial nephritis. However, the incidence of sarcoidosis in native and transplant kidney biopsies, its frequency as a cause of end stage renal disease and its recurrence in renal allograft are not well defined, which prompted this study. The electronic medical records and the pathology findings in native and transplant kidney biopsies reviewed at the Johns Hopkins Hospital from 1/1/2000 to 6/30/2011 were searched. A total of 51 patients with a diagnosis of sarcoidosis and renal abnormalities requiring a native kidney biopsy were identified. Granulomatous interstitial nephritis, consistent with renal sarcoidosis was identified in kidney biopsies from 19 of these subjects (37%). This is equivalent to a frequency of 0.18% of this diagnosis in a total of 10,023 biopsies from native kidney reviewed at our institution. Follow-up information was available in 10 patients with biopsy-proven renal sarcoidosis: 6 responded to treatment with prednisone, one progressed to end stage renal disease. Renal sarcoidosis was the primary cause of end stage renal disease in only 2 out of 2,331 transplants performed. Only one biopsy-proven recurrence of sarcoidosis granulomatous interstitial nephritis was identified. CONCLUSIONS: Renal involvement by sarcoidosis in the form of granulomatous interstitial nephritis was a rare finding in biopsies from native kidneys reviewed at our center, and was found to be a rare cause of end stage renal disease. However, our observations indicate that recurrence of sarcoid granulomatous inflammation may occur in the transplanted kidney of patients with sarcoidosis as the original kidney disease.