Sameh R. Abul-Ezz

Drug Interaction between St. John's Wort and Cyclosporine

OBJECTIVE: To report a probable drug interaction between the herbal dietary supplement St. Johns wort and cyclosporine. CASE REPORT: A 29-year-old white woman who received a cadaveric kidney and pancreas transplant, with stable organ function and stable cyclosporine concentrations began self-medicating with St. Johns wort. After taking St. Johns wort supplements for four to eight weeks, her cyclosporine concentrations became subtherapeutic; this was associated with organ rejection. Four weeks after stopping St. Johns wort, her cyclosporine concentrations again became therapeutic. Subsequent to this rejection episode, she has developed chronic rejection and now has returned to dialysis. DISCUSSION: St. Johns wort is suspected to be a significant inducer of CYP3A4 isoenzyme activity and of P-glycoprotein (P-gp) expression, both of which are important in the metabolism and absorption of cyclosporine. Cyclosporine exhibits a relatively small therapeutic window and is sensitive to medications that can modulate the CYP3A4 isoenzyme and P-gp in both the liver and small intestines. CONCLUSIONS: Patients taking St. Johns wort concomitant with other prescription medications whose absorption and metabolism are mediated by the CYP3A4 isoenzyme and P-gp require close monitoring. Patient medication histories should include inquiries into the use of herbal dietary supplements.

Herbal supplements: a potential for drug interactions in transplant recipients.

Background. Herbal dietary supplements represent a potential and possibly an overlooked cause for drug interactions in transplant recipients. Methods. Two patients are reported which suggest that St. John’s Wort (SJW) may induce cytochrome P-450 3A4 activity and/or P-glycoprotein expression. Both of these mechanisms are significantly involved in the metabolism and absorption of cyclosporine (CSA) and other immunosuppressants. Results. After two renal transplant recipients started self-medicating with SJW, their CSA concentrations were consistently documented to be subtherapeutic. While on SJW, one patient developed acute graft rejection due to low CSA concentrations. In both patients, termination of SJW returned their CSA concentrations to therapeutic values. Conclusions. Patients taking SJW concomitantly with CSA or other medications whose absorption and metabolism are mediated by cytochrome P-450 and/or P-glycoprotein should require close monitoring. Potential herb-prescription drug interactions are not just limited to SJW. Inquiries regarding the usage of herbal supplements should be an integral component of a transplant recipient’s medication history.

Polyoma viral infection in renal transplantation: the role of immunosuppressive therapy

Background: Polyoma virus infection in renal transplant recipients has been observed with increasing frequency in recent years. Renal allograft involvement in this condition may occur as a result of primary infection or secondary to reactivation of the latent virus. Interstitial nephritis, ureteric stenosis, rise in serum creatinine and allograft function loss have been attributed to this viral infection. 
Methods: In this study we reviewed our experience with 8 patients who developed polyoma viral infection confirmed by allograft biopsy. All patients were receiving mycophenolate mofetil as part of the immunosuppression and 7 of the 8 patients were on tacrolimus. All patients have biopsy proven polyoma viral infection. The following therapeutic maneuvers were carried out following the diagnosis of polyoma viral infection: 1) stopping mycophenolate and 2) switching tacrolimus to cyclosporine or reducing the tacrolimus dose to adjust it at a lower therapeutic trough level. The clinical course and outcome of our patients were reviewed in relation to manipulation of immunosuppressive medications. 
Results: The incidence of this infection in our transplant program in the last 3 yr was 5.3%. Seventy‐five percent of the patients had at least one rejection episode and 63% had more than one rejection episode. The main risk factor for the development of polyoma viral infection was related to the intensity of immunosuppression. The use of antirejection therapy after histological diagnosis of polyoma virus infection was not associated with improvement of renal function despite the histological appearance of acute rejection. Thus, the interstitial nephritis associated with polyoma viral infection appears to be an inflammatory response to the virus rather than acute rejection. Six out of the 8 patients stabilized renal function with reduction in immunosuppression. 
Conclusions: Reduction in immunosuppression was associated with the stabilization of renal function when instituted early. However, these patients were left with a degree of allograft dysfunction and their outcome may be significantly compromised. The lack of effective antiviral therapy for polyoma virus may limit the use of newer and more potent immunosuppressive medications.

Sirolimus-induced thrombotic microangiopathy in a renal transplant recipient

A rare but well-documented serious adverse reaction to the administration of the calcineurin inhibitors tacrolimus and cyclosporine in renal transplant recipients is the development of medication-induced thrombotic microangiopathy. The recently introduced immunosuppressive medication sirolimus has a very similar molecular structure to tacrolimus and also binds to the same intracellular proteins. Despite these similarities with tacrolimus, sirolimus has a different side-effect profile and reportedly lacks documented specific renal toxicity. This is a case report of the isolated administration of sirolimus without a concomitant calcineurin inhibitor being associated with the development of renal transplant biopsy-proven thrombotic microangiopathy. The patient is a 47-year-old African-American woman whose primary cause of renal failure was not thrombotic micrangiopathy, and she received a 5-antigen mismatched cadaveric renal transplant. Because of preexisting nephrosclerosis in the renal transplant, this patient was never administered a calcineurin inhibitor but was always maintained on sirolimus. With recent animal data showing that sirolmus can be nephrotoxic in a renal ischemic-reperfusion model (similar to what happens with a renal transplant), the authors speculate on a mechanism for this adverse reaction.

Long‐term remission of recurrent parvovirus‐B associated anemia in a renal transplant recipient induced by treatment with immunoglobulin and positive seroconversion

Abstract: Parvovirus B‐19 (PVB)‐related recurrent anemia is reported in a renal transplant recipient with long‐term remission induced by intravenous immunoglobulin and decreasing immunosuppression. Positive plasma polymerase chain reaction (PCR) and intense bone marrow infection were present at diagnosis, despite the absence of serum immunoglobulin IgG and IgM antibodies to the virus. Seroconversion against the virus was followed by long‐term remission while the plasma PCR for PVB remained positive. This case illustrates the absence of serum antibodies in an immunosuppressed host despite florid infection with the virus. Positive seroconversion in a naïve subject is associated with long‐term remission even in the presence of detectable viral DNA copies in the plasma.

Renal allograft dysfunction associated with cytomegalovirus infection

Renal transplant recipients are at an increased risk for cytomegalovirus (CMV) infection, which occurs as a primary infection or as a result of reactivation of a latent virus. The main risk factors for symptomatic CMV disease include a CMV-negative recipient of a kidney from a CMV-positive donor (primary infection) and treatment of rejection with monoclonal or polyclonal antibodies. In this study, we report a renal transplant recipient with multiple risk factors for the development of CMV infection. He developed three episodes of CMV disease; the first was associated with gastrointestinal tract involvement, and the second episode was diagnosed according to surveillance laboratory test results in the absence of symptoms. The third episode was associated with acute allograft dysfunction. The renal transplant biopsy specimen showed viral inclusions without acute rejection or glomerular abnormality. Despite the absence of morphological injury on biopsy, treatment of CMV with ganciclovir was accompanied by an improvement in renal function. Further studies are needed to establish the mechanism of allograft dysfunction in the absence of inflammatory changes.

The tolerability of newer immunosuppressive medications in a patient with acute intermittent porphyria

Acute intermittent porphyria results from a deficiency of the porphobilinogen deaminase enzyme of heme biosynthesis and is commonly exacerbated by a wide variety of medications. When referred a patient with acute intermittent porphyria for a renal transplant, only steroids and azathioprine were discovered as safe in patients with acute intermittent porphyria. The administration of many newer immunosuppressive medications, including calcineurin inhibitors, has not been documented in acute intermittent porphyria. Actually, cyclosporine is presently considered contraindicated in acute intermittent porphyria. To determine if calcineurin inhibitors would be tolerated in acute intermittent porphyria, cyclosporine and tacrolimus were administered pretransplant and were documented not to exacerbate acute intermittent porphyria. A successful renal transplant was then performed using tacrolimus. This is the first reported patient with documented acute intermittent porphyria to tolerate safely several of the newer immunosuppressive medications, including tacrolimus, mycophenolate, and rabbit antithymocytic globulin following renal transplantation. This patients pretransplant evaluation also suggested that cyclosporine may be safe for some patients with acute intermittent porphyria.

Religious reasons for discontinuation of immunosuppressive medications after renal transplant.

It is commonly believed that religion has no influence on medication compliance. We present a case in which belief in faith healing led to discontinuation of immunosuppressive medications after renal transplantation. Conflict occurs when patients believe they are healed but experience continued illness. Religious and spiritual beliefs should be assessed pre- and post-transplant, and efforts made to encourage medication compliance.

Subclinical Celiac Disease and Crystal-Induced Kidney Disease Following Kidney Transplant

Decreased kidney function from kidney deposition of calcium oxalate has been described previously in inflammatory bowel disease and after jejuno-ileal and Roux-en-Y gastric bypass surgeries. Although celiac disease is the most prevalent bowel abnormality associated with intestinal malabsorption, its relationship to high kidney oxalate burden and decreased kidney function has not been established. We report a case of subclinical celiac disease and hyperoxaluria that presented with loss of kidney function as a result of high oxalate load in the absence of overt diarrhea, documented intestinal fat malabsorption, and nephrolithiasis. Subclinical celiac disease is commonly overlooked and hyperoxaluria is not usually investigated in kidney patients. We propose that this entity should be suspected in patients with chronic kidney disease in which the cause of kidney damage has not been clearly established.

KIM-1 expression in kidney allograft biopsies: Improving the gold standard

Long-term outcomes of kidney allografts have shown only marginal improvement over the last three decades, despite the remarkable improvement in acute rejection and one-year graft survival. Novel biomarkers of tubular injury may prevent irreversible damage to the tubulointerstitial compartment and improve allograft survival.