Basit Javaid

Treatment of renal allograft polyoma BK virus infection with leflunomide.

Background. Polyoma BK virus produces an aggressively destructive nephropathy in approximately 3% to 8% of renal allografts, is associated with graft loss within one year in 35% to 67% of those infected and there is no therapy of proven efficacy. Leflunomide is an immune suppressive drug with anti viral activity in vitro and in animals. Methods. We treated twenty-six patients with biopsy proven NK virus nephropathy (BKN) with either leflunomide alone (n=17) or leflunomide plus a course of cidofovir (n=9) and followed them for six to forty months. Leflunomide was dosed to a targeted blood level of active metabolite, A77 1726, of 50 &mgr;g/ml to 100 &mgr;g/ml (150 &mgr;M to 300 &mgr;M). Response to treatment was gauged by serial determinations of viral load in blood and urine (PCR), serum creatinine, and repeat allograft biopsy. Results. In the 22 patients consistently sustaining the targeted blood levels of active drug, blood and urine viral load levels uniformly decreased over time (P<.001). Mean serum creatinine levels stabilized over the first six months of treatment, and with 12 months or more of follow-up in 16 patients the mean serum creatinine has not changed significantly from base line. Four patients who did not consistently have blood levels of active drug (A77 1726) above 40 &mgr;g/ml did not clear the virus until these levels were attained or cidofovir was added. Conclusions. Leflunomide inhibits Polyoma virus replication in vitro and closely monitored leflunomide therapy with specifically targeted blood levels appears to be a safe and effective treatment for Polyoma BK nephropathy.

Implications of Immunohistochemical Detection of C4d along Peritubular Capillaries in Late Acute Renal Allograft Rejection

Background. Immunohistochemical detection of the C4d complement product along peritubular capillaries (PC) may indicate humoral rejection of renal allografts. We examined the frequency of PC C4d expression in renal-allograft biopsies with acute rejection (AR) arising more than 6 months after transplantation and the impact of this finding. Methods. C4d was detected by immunoperoxidase in 2-micron paraffin sections of consecutive biopsies obtained over a 3-year period. The extent was classified as diffuse (≥50% PC C4d+), focal (<50% C4d+), and negative (C4d−). Clinical data were obtained by retrospective chart review. Fifty-five AR episodes with Banff 97 types 1A (n=13), 1B (n=26), 2A (n=11), 2B (n=3), and 3 (n=2) met inclusion criteria. Results. PC C4d expression was diffuse in 23 (42%), focal in 9 (16%), and negative in 23 (42%) biopsies. AR episodes with focal and diffuse C4d expression had higher proportionate elevation of serum creatinine at biopsy and 4 weeks after diagnosis (P≤0.05). Biopsies with diffuse PC C4d had interstitial hemorrhage (56.5%) and plasmacytic infiltrates (52%) more frequently than C4d− biopsies (22% and 16%), P=0.02, but had no other distinctive histologic features. Graft loss was greater in diffuse (65%) compared with focal C4d+ (33%) and C4d− (33%) groups 1 year after diagnosis, P=0.03. Other clinical and pathologic parameters did not differ significantly, including treatment received for AR. Conclusion. Evidence of acute cellular with occult humoral rejection is identified in more than 40% of late AR episodes. Late acute humoral rejection may be associated with interstitial hemorrhage and plasma cells and contributes significantly to graft loss.

Treatment of de novo and recurrent membranous nephropathy in renal transplant patients

Membranous nephropathy (MN) is one of the common glomerular diseases diagnosed in transplanted kidneys. The exact impact of posttransplantation MN on the risk for graft loss and long-term graft outcome is not defined clearly. In recent reports, it has emerged as the third most frequent glomerulonephritis (de novo or recurrent) associated with renal allograft loss. Most cases of posttransplantation MN are thought to be idiopathic but cases associated with established secondary causes also have been reported. Patients can present with varying degrees of proteinuria and graft dysfunction. Risk factors that predict a poor outcome are not well established and unlike MN in the native kidneys, spontaneous remission is rare. Patients should be evaluated carefully for complications associated with nephrotic syndrome or graft dysfunction and managed accordingly. The beneficial effects of steroids, cyclosporine, mycophenolate mofetil, cyclophosphamide, chlorambucil, or other agents have not been validated. The role of specific treatments in cases of secondary MN is uncertain. Retransplantation is a reasonable option for patients who develop graft failure secondary to MN.

Kidney Transplant Chains Amplify Benefit of Nondirected Donors

IMPORTANCE Despite the potential for altruistic nondirected donors (NDDs) to trigger multiple transplants through nonsimultaneous transplant chains, concerns exist that these chains siphon NDDs from the deceased donor wait list and that donors within chains might not donate after their partner receives a transplant. OBJECTIVE To determine the number of transplantations NDDs trigger through chains. DESIGN Retrospective review of large, multicenter living donor-recipient database. SETTING Fifty-seven US transplant centers contributing donor-recipient pairs to the database. PARTICIPANTS The NDDs initiating chain transplantation. MAIN OUTCOMES MEASURE Number of transplants per NDD. RESULTS Seventy-seven NDDs enabled 373 transplantations during 46 months starting February 2008. Mean chain length initiated by NDDs was 4.8 transplants (median, 3; range, 1-30). The 40 blood type O NDDs triggered a mean chain length of 6.0 (median, 4; range, 2-30). During the interval, 66 of 77 chains were closed to the wait list, 4 of 77 were ongoing, and 7 of 77 were broken because bridge donors became unavailable. No chains were broken in the last 15 months, and every recipient whose incompatible donor donated received a kidney. One hundred thirty-three blood type O recipients were transplanted. CONCLUSION AND RELEVANCE This large series demonstrates that NDDs trigger almost 5 transplants on average, more if the NDD is blood type O. There were more blood type O recipients than blood type O NDDs participating. The benefits of transplanting 373 patients and enabling others without living donors to advance outweigh the risk of broken chains that is decreasing with experience. Even 66 patients on the wait list without living donors underwent transplantation with living-donor grafts at the end of these chains.

Pauci-immune and Immune Glomerular Lesions in Kidney Transplants for Systemic Lupus Erythematosus

BACKGROUND AND OBJECTIVES Glomerular lesions in allografts in recipients with end-stage nephritis resulting from systemic lupus erythematosus (SLE) were examined to determine the spectrum of glomerular pathology in recurrent glomerulonephritis (GN). DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS A total of 156 biopsy samples, from 49 serial allografts in 43 recipients with end-stage lupus nephritis, were examined by light microscopy, and by immunofluorescence and electron microscopy in selected cases. These were compared with control allografts (n = 35). RESULTS Glomerular lesions best explained by recurrent lupus nephritis were observed in 19 of 49 allografts (38.8%) in lupus recipients. Three categories of glomerulopathies were identified: 1) immune complex glomerulopathies, including mesangial GN (28%) and membranous GN (4%); 2) atypical glomerulopathies, including acute proliferative GN (32%) and focal segmental glomerulosclerosis (12%), with scant immune deposits in glomerular capillaries, frequent endothelial tubuloreticular inclusions, and thrombotic microangiopathy; and 3) transplant-associated glomerulopathies (24%). CONCLUSIONS Allografts from recipients with SLE had typical immune complex-mediated GN and atypical pauci-immune, proliferative GN and segmental glomerular sclerosis. Atypical glomerulopathies like these suggest a role for nonimmune complex-mediated glomerular injury in recurrent lupus GN.

BK Polyomavirus Infection in the Renal Transplant Recipient

Renal transplant recipients continue to have progressive kidney dysfunction and renal graft loss has been attributed to emerging opportunistic infections, specifically BK virus (BKV). BKV is postulated to be selected by the new potent immunosuppressive medications and to be an important factor in graft failure. The prevalence of BKV nephropathy (BKVN) is estimated to be 1% to 10% and renal allograft loss from BKVN has been estimated to occur in up to 50% of affected recipients. With the increasing recognition of BKV infection using PCR assays coupled with the immediate reduction in immunosuppression for BKVN, the incidence of graft failure secondary to BKVN may be decreasing.

Leflunomide in solid organ transplantation and polyoma virus infection.

Leflunomide, trade name Arava® (Aventis Pharmaceuticals Incorporation, Bridgewater, New Jersey, U.S.A.), belongs to a family of drugs called the malonitrilamides. Some, like leflunomide, have substantial immune suppressive activity in experimental allograft models. In addition to experimental data suggesting leflunomide’s value in preventing1, 2, 3, 4, 5 and reversing acute1,5 and chronic rejection,6,7 it has been shown to inhibit human cytomegalovirus (CMV) and herpes simplex virus (HSV) in vitro.8, 9, 10 Because it is a drug with a variety of biologic activities, it has been investigated for diseases as disparate as cancer and autoimmunity. Leflunomide was approved for the treatment of rheumatoid arthritis and has been used in more than 300,000 patients worldwide with efficacy and a favorable side effect profile. In this chapter, we will discuss the immunemodulatory effects of leflunomide and its metabolite A77 1726 that prevent organ rejection. We will also share our experience in the treatment of polyomavirus infections.

Variability in assessing for BK viremia: whole blood is not reliable and plasma is not above reproach – a retrospective analysis

Polyomavirus nephropathy (PVN) is a major complication of kidney transplantation. Most reports describe polyomavirus viremia either precedes or is detectable at the time of diagnosis of PVN. This association is the basis of current screening recommendations. We retrospectively reviewed the PCR results of blood and urine samples from 29 kidney transplant recipients with biopsy‐proven PVN. Biopsies were performed for a rise in serum creatinine or persistent high‐level BK viruria. All biopsies showed polyoma virus large T‐antigen expression in tubular epithelium using immunohistochemistry. All had viruria preceding or at the time of biopsy (range, 5.2 × 104 to >25 × 106 BKV DNA copies/ml). Twenty (69%) had viremia ranging from 2.5 × 103 to 4.3 × 106 copies/ml at the time of the biopsy. Via blood BK PCR assay, nine (31%) had no BK viremia detected either preceding or at the time of the biopsy. In five recipients where sufficient specimen permitted, additional plasma BK assessment revealed positive detection of viremia. A comparative analysis of assays from two centres was performed with spiked samples. BK DNA may not be detected in the blood of some kidney transplant recipients with histologically confirmed PVN. This may reflect limitation of whole blood as opposed to plasma‐based BK DNA assessment.