Gilbert Thiel

Polyomavirus disease under new immunosuppressive drugs : A cause of renal graft dysfunction and graft loss

BACKGROUND Manifest polyomavirus (PV) renal graft infection is a rare complication. We diagnosed 5 cases among 70 kidney recipients undergoing transplants since December 1995; however, there were no cases at our institution before December 1995. METHOD To identify risk factors promoting manifest PV graft infection, we compared those 5 patients with kidney recipients who had signs of PV replication but no manifest graft infection (n=23, control group). PV replication was judged by the presence of intranuclear inclusion cells in the urine. RESULTS Before the infection, five of five patients had recurrent rejection episodes. All were switched from cyclosporine A to high dose tacrolimus as rescue therapy. Infection was diagnosed histologically 9+/-2 months posttransplantation; it persisted and led to graft loss in four of five patients. In control patients, graft function was stable, 1 of 23 patients were switched to tacrolimus as rescue therapy, and graft loss occurred in 4 of 23 patients. CONCLUSION Recurrent rejection episodes and high dose immunosuppressive therapy, including tacrolimus, are risk factors for manifest PV kidney graft infection, which has an ominous prognosis.

Transmission of Human Herpesvirus 8 Infection from Renal-Transplant Donors to Recipients

BACKGROUND Human herpesvirus 8 (HHV-8) has been detected in all forms of Kaposis sarcoma, including transplantation-associated Kaposis sarcoma. To investigate the possibility of transmission of HHV-8 through allografts, we measured the seroprevalence of HHV-8 before and after renal transplantation. METHODS Using an enzyme-linked immunosorbent assay with the recombinant HHV-8 protein orf 65.2, we analyzed serum samples from 220 renal-transplant recipients for the presence of antibodies to HHV-8 on the day of transplantation and one year later. Positive results were confirmed by an indirect immunofluorescence assay that detects antibodies to latent antigen and by Western blotting. Follow-up lasted at least four years. RESULTS The seroprevalence of HHV-8 in graft recipients increased from 6.4 percent on the day of transplantation to 17.7 percent one year after transplantation. Seroconversion occurred within the first year after transplantation in 25 patients, and Kaposis sarcoma developed in 2 of them within 26 months after transplantation. Sequential serum samples were obtained from 10 of the patients with seroconversion, and in 8 of these patients, IgM antibodies to HHV-8 appeared within three months after transplantation. In the case of six patients who seroconverted, serum samples from the donors were available, and five (83 percent) tested positive for HHV-8. In a control group of eight patients who were seronegative at the time of transplantation and who received allografts from HHV-8-negative donors, none seroconverted within the year after transplantation. CONCLUSIONS HHV-8 is transmitted through renal allografts and is a risk factor for transplantation-associated Kaposis sarcoma.

Cytomegalovirus (CMV)—Specific T Cell Immunity after Renal Transplantation Mediates Protection from CMV Disease by Limiting the Systemic Virus Load

The role of cytomegalovirus (CMV)-specific cytotoxic T lymphocytes (CTLs) and T helper cells (Th) in controlling CMV infection, as detected by antigenemia assay and polymerase chain reaction (PCR) in blood leukocytes, and CMV disease was investigated in 20 renal transplant recipients. Within 3 months after transplant, CMV-specific CTL and Th responses were demonstrable in 11 (55%) and 15 (75%) patients, respectively; CMV infection was detected by antigenemia and PCR in 19 (95%) patients each. During the month of first CMV detection, there was an inverse correlation between CTL response and antigenemia at >/=20 positive cells/105 leukocytes (P=.007) but no association with lower antigenemia levels or PCR positivity. CMV disease developed in 7 (35%) patients and was associated with high-level antigenemia but was inversely correlated with detection of CTLs (P=.04). After renal transplantation, CMV-specific CTLs limit the systemic virus load as reflected by antigenemia levels and thereby mediate protection from CMV disease.

Cytomegalovirus infection and graft rejection in renal transplantation.

Background. Cytomegalovirus (CMV) infection and CMV disease have been associated with acute and chronic graft rejection. The introduction of the sensitive CMV antigenemia pp65 assay for detection of CMV infection allowed us to study the time course of CMV infection and acute rejection and the long-term outcome in renal transplant recipients with and without a CMV risk constellation. Methods. Prospective single center study including 48 renal transplant recipients at risk for CMV infection (donor and/or recipient CMV seropositive) and a control group of 36 CMV seronegative recipients of CMV seronegative kidney donors. Evidence of CMV infection was monitored by the CMV antigenemia pp65 assay every 1 to 2 weeks and compared with the occurrence of acute rejection in the posttransplant period and graft function at 5 years. Results. CMV infection developed in 83% (40/48) of patients of the CMV risk group within 4 months posttransplant. A total of 18 of patients experienced an acute rejection episode (control group 16/36;P =0.65). In 12/18 CMV infection followed rejection and in three patients antigenemia preceded the diagnosis of rejection. In three patients CMV antigenemia remained negative. Five-year follow up: Patient survival (44/48 vs. 31/36;P =0.48), graft survival (38/48 vs. 27/36;P =0.79), number of patients with at least one acute rejection episode: CMV risk group: 42.1%, control group 51% (P =0.46), serum creatinine: CMV risk group:130±66 &mgr;mol/liter, control group: 126±37 &mgr;mol/liter (P =0.56), proteinuria: CMV risk group: 0.02±0.02 g/mmol creatinine, control group: 0.02±0.02 g/mmol creatinine (P =1.0). Conclusion. CMV infection within 4 months posttransplant, as defined by a positive antigenemia assay was not found to be a risk factor for acute graft rejection or chronic graft dysfunction at 5 years.

Intravenous cyclosporine kinetics in renal failure

Kinetics of the novel immunosuppressive cyclosporine were determined in four patients with terminal renal failure. After a short intravenous infusion (2.05 to 3.5 mg/kg in 4 hr), blood and plasma concentrations were measured (HPLC and radioimmunoassay [RIA]) up to 36 hr. After infusion, concentration curves of the drug were characterized by a rapid initial fall (t½α 0.10 ± 0.03 hr), followed by a biphasic elimination phase with corresponding t½s of 1.08 ± 0.25 hr (t½β) and 15.8 ± 8.4 hr (t½γ). The volumes of distribution, calculated from whole blood concentrations (HPLC), were 0.140 ± 0.48 l/kg (volume of the central compartment) and 3.49 ± 2.65 l/kg (volume of distribution at steady state), whereas systemic clearances were 0.369 ± 0.08 l/hr/kg. Blood levels measured by RIA exceeded the HPLC values after the fourth hour by up to 100%, indicating the production of cross‐reacting cyclosporine metabolites. Plasma concentrations were considerably lower than in whole blood. Elimination of unchanged cyclosporine in patients with renal failure appears to be of the same order as in those with normal kidney function. Modification of the initial dosage regimens is therefore probably not required.

Prevention of cancellous bone loss but persistence of renal bone disease despite normal 1,25 vitamin D levels two years after kidney transplantation.

Osteopenia has been observed to occur frequently after renal transplantation. The present study was undertaken to assess whether an immunosuppressive regimen combining cyclosporine with no or the lowest possible maintenance doses of glucocorticoid may prevent osteopenia after kidney transplantation. Thirty-four patients were prospectively followed for two years. Serial blood drawings were done for determination of serum indices of calcium and bone metabolism and an iliac crest bone biopsy was performed at time of transplantation. A second bone biopsy was done in 20 patients during the second year of observation. Creatinine clearance was 56 +/- 6 ml/min one year and 46 +/- 6 ml/min two years after transplantation. Serum parathyroid hormone levels were elevated in 24 patients at time of grafting, decreased significantly thereafter, but remained above the normal range. Ten patients had low or normal serum parathyroid hormone levels at time of transplantation and showed a significant increase after grafting. Two years after transplantation, the mean cumulative dose of prednisone was 5.9 +/- 0.5 g. After the first six months, 30-40% of the patients were not on maintenance doses of steroids. None of the patients experienced fractures, and cancellous bone volume was within or above the normal range in all repeat bone biopsies. It is of note that metabolic bone abnormalities did not resolve 1-2 years after transplantation despite normalization of serum 1,25 vitamin D levels. The histologic abnormalities at the time were consistent with the bone findings in renal failure suggesting resistance of bone to normal circulating levels of 1,25 vitamin D.

Blood group A and B antigen expression in human kidneys correlated to A1/A2/B, Lewis, and secretor status.

Background. In the revived interest in crossing ABO barriers in organ transplantation renal A/B antigen expression has been correlated with donor ABO, Lewis, and secretor subtype to predict antigen expression. Methods. A/B antigen expression was explored by immunohistochemistry in LD renal biopsies. Donor A1/A2/B, Lewis, and secretor status were determined by serology and polymerase chain reaction. Results. In the renal vascular bed, three distinct A antigen expression patterns with a major, minor, and minimal staining distribution, and intensity (designated as types 3+, 1+ and (+) respectively) were identified. Type 3+ had a strong A antigen expression in the endothelium of arteries, glomerular/peritubular capillaries and veins. The type 1+ showed an overall weaker antigen expression, whereas type (+) had faint staining of peritubular capillaries only. In all cases, distal tubular epithelium was focally stained, whereas proximal tubules were negative. Type 3+ were all from blood group A1 subtype individuals while A2 cases expressed either a 1+ or (+) pattern. The secretor gene did not appear to influence renal A antigen expression. All B kidneys examined showed a B antigen pattern slightly weaker but otherwise similar to A type 3+. Conclusion. Renal vascular A antigen expression correlates to donor A1/A2 subtypes, whereas B individuals show one singular antigen pattern. From antigen perspective, A1 and B donors are a “major” and A2 individuals a “minor” antigen challenge in ABO-incompatible renal transplantation.

Transplantation-associated Malignancies: Restriction of Human Herpes Virus 8 to Kaposi's Sarcoma

BACKGROUND The human herpes virus 8 (HHV8) has been detected in all forms of Kaposis sarcoma. HHV8 was also reported to be present in epithelial skin tumors of patients after renal transplantation, raising the question of the clinical relevance of HHV8 in transplant-related tumors. METHODS Using a highly sensitive nested polymerase chain reaction assay, we analyzed for the presence of HHV8-DNA in the tumor tissue of renal transplant recipients with Kaposis sarcoma (n=2) and non-Hodgkins lymphomas (n=6), and in 32 tumors from 10 patients with multiple epithelial skin tumors. RESULTS HHV8-DNA was detected in both cases of Kaposis sarcoma but not in either the non-Hodgkins lymphomas or the epithelial skin tumors. CONCLUSIONS Our data confirm the association of HHV8 with Kaposis sarcoma but not with other transplant-related tumors. Further studies are needed to analyze the risk for transmission of HHV8 by the donor and the possible exclusion of HHV8-positive patients as organ donors.

Karyomegalic interstitial nephritis: Further support for a distinct entity and evidence for a genetic defect

Karyomegalic interstitial nephritis was first described in 1979 by Mihatsch, who was reporting three such cases. We report here four additional cases as well as two family investigations. Our findings support the association of karyomegaly and interstitial nephritis as a distinct entity. Typical clinical features are asymptomatic progressive renal failure in the third decade of life and recurrent infections, mostly of the upper respiratory tract. Histologic alterations consist of markedly enlarged and hyperchromic nuclei in many tubular epithelial cells throughout the nephron accompanied by interstitial fibrosis in the surrounding atrophic tubules. Karyomegaly is not limited to the kidneys. In one case, autopsy revealed karyomegaly in epithelial and mesenchymal cells of many other organs. However, no association of karyomegaly with further histologic damage is evident except in the kidneys. Because of the familial clustering, karyomegalic interstitial nephritis seems to be an inherited disease. Examination of the nuclear proliferation-associated structures proliferating cell nuclear antigen/cyclin, Ki 67, and p53 suggests an inhibition of mitosis in karyomegalic cells. The finding of the same HLA haplotype, A9/B35, in four of six HLA-typed cases suggests the possibility of a genetic defect on chromosome 6, which is inherited and linked to the HLA locus.

Gentamicin-Induced Acute Renal Failure in the Rat

Acute renal failure was induced in rats by subcutaneous injection of 200 mg/kg body weight gentamicin on 3 consecutive days. Following the last gentamicin injection, the animals began to produce increased amounts of dilute urine and usually remained polyuric throughout the experimental period which lasted up to 2 weeks. Plasma concentrations of creatinine rose to values between 2 and 10 mg%, of urea to values between 100 and 1,000 mg% 5-7 days after the last gentamicin injection and returned to levels slightly above control after 14 days. Average proximal tubular pressure was slightly elevated to 13.7 +/- 0.5 mm Hg on the 2nd day after the last gentamicin dose, decreased to 6.1 +/- 0.4 mm Hg after 1 week, and returned to 11.8 +/- 0.2 mm Hg after 2 weeks (control proximal tubular pressure 11.6 +/- 0.2 mm Hg). These average values hide the fact that early in this model of gentamicin-induced acute renal failure many tubules had proximal tubular pressures increased to values between 18 and 25 mm Hg, suggesting tubular obstruction. Decreased proximal tubular pressures and the histological finding of wide-spread necrosis of proximal convolutions is suggestive of tubular leakage. Dehydration, similarly to other models of acute renal failure, markedly potentiated gentamicin-induced acute renal failure. Salt diuresis induced either by DOCA-saline or by furosemide failed to afford functional protection and increased the degree of morphological damage. No relation was found between the concentration of gentamicin in renal tissue and the degree of functional or morphological impairment.