Incidence of polyomavirus-nephropathy in renal allografts: influence of modern immunosuppressive drugs.

BACKGROUND: In recent years an increasing number of cases with polyomavirus (PV)-nephropathy after renal transplantation were reported from several transplant centres. New, highly potent immunosuppressive drugs like tacrolimus or mycophenolate mofetil were accused as risk factors for this increase. However, data about the incidence of PV-nephropathy in correlation to different immunosuppressive therapy concepts are lacking. METHODS: All renal transplant biopsies performed at Hannover Medical School between 1999 and 2001 (n=1276) were immunohistochemically screened for the presence of PV-specific proteins. The results were correlated to the different immunosuppressive therapy protocols and patients with PV-nephropathy were compared with a matched control group. RESULTS: PV-nephropathy was found in <1% of all investigated allograft biopsies (11/1276) and in approximately 1% of all patients (7/638), respectively. All patients being immunohistochemically positive for PV-specific proteins also showed the typical morphological changes of PV-nephropathy. Four out of seven patients with PV-nephropathy were under triple immunosuppression comprising tacrolimus and mycophenolate mofetil. Under this immunosuppressive therapy protocol an eight times higher incidence and a 13 times higher risk (multivariate odds ratio 12.7) of PV-nephropathy was observed in our patients compared with the control group. CONCLUSIONS: PV-nephropathy is a rare but serious complication after renal transplantation. A small group of patients under intensive immunosuppression comprising tacrolimus in combination with mycophenolate mofetil has a significantly increased risk of acquiring this deleterious complication.     

Comparison of the effects of various immunosuppressive drugs on subrenal capsule assay (SRC assay)

We evaluated the effect of various immunosuppressive drugs in the SRC assay. We chose the most appropriate day to obtain the results of the SRC assay using the MBT-2 tumor. MBT-2 tumor-bearing mice of homogenic and heterogenic strains were separately given one of the three: cyclophosphamide, azathioprine or mizoribine. These drugs were evaluated on the 6th and the 11th day for the immunosuppressive effects expected from a host versus graft reaction. Concerning the homogenic mice that were injected with drugs, on the 11th day, the growth of the tumor was favorably suppressed in comparison with the growth of the control group (A-1) due to the anti-tumor effect of immunosuppressive drugs. We concluded that the 6th day was the most, appropriate day to obtain the results of this assay. Concerning the heterogenic mice, similar results were observed. In the mizoribine-group, we subcutaneously injected 200 mg/kg on alternate days. Yet the implanted tumor grew almost at the same rate as that of the A-1 group. In this group, a histological study showed reduction of the tumor cells and few inflammatory cells. We concluded that this drug was more useful than the others in the SRC assay and the suitable day for judgement was the 6th day.     

Synergistic effects of combined immunosuppressive modulation. I. Unresponsiveness to dendritic cell-depleted renal allografts in dogs exposed to total-lymphoid irradiation

Attenuation of the allogeneic stimulus provided by dendritic cells (DC) was achieved by irradiation of the donors, followed by their reconstitution with bone marrow from the prospective DLA-identical recipient. Following long-term (131-187 days) recovery free of graft-versus-host (GVH) disease, the chimeric kidneys were placed into the corresponding recipients; such allografts were rejected at 55, 55, and 60 days, respectively. Four other recipients were conditioned with 1750-1790 cgy of total lymphoid irradiation (TLI) and were then given a similar chimeric kidney from the corresponding partner. These allografts currently survive for 296, 295, 290, and 252 days, respectively. A third group of four dogs was exposed to TLI prior to transplantation of a normal DLA-identical kidney. These grafts were rejected at 20, 42, 46, and 242 days, respectively. Thirteen DLA-identical renal allografts transplanted into normal dogs survived for 13-38 days (mean survival time = 28.6 days). Depletion of allogeneic DC alone, or TLI alone, produced relative prolongations in allograft survival in canine recipients. Combined use of these two modalities, however, resulted in long-term allogeneic unresponsiveness in the recipients.     

Abrogation of the immunosuppressive effect of donor spleen cells on renal allografts in the rat by irradiation or heat treatment

In the donor-recipient strain combination Lewis (RT1l) to Dark Agouti (RT1a), indefinite renal allograft survival (MST greater than 100 days) was induced by pretreating recipient animals i.v. with 10(6) to 10(8) viable spleen lymphocytes, seven days before transplantation. Pretreatment with 10(4) or 10(5) cells was ineffective (MST 10 days). However when 10(7) live, but heat-treated (55 degrees C for 10 min) or irradiated (1000 rads) cells were used, all the animals rejected the allograft in a normal fashion (MST 10 and 11 days, respectively). Median survival time of third-party controls was 10 days. The relative amount of cell surface major histocompatibility antigens (class I and class II) expressed by the three spleen cell preparations was investigated using monoclonal antibodies and fluorescence activated cell sorter analysis and found to be similar. After 24 hr in culture, only 1% of heat-treated and 10% of irradiated cells were viable, in contrast to 75% of untreated splenocytes. Trafficking of these lymphocytes in recipient animals was investigated by 51chromium labeling of the cells: 30% of lymphocytes had localized in the liver within 3 hr with little difference in localization among the different cell preparations. But, although 20% of normal and irradiated cells localized in the spleen within 3 hr, at no stage were more than 5% of the heat-treated cells found in the spleen. It is suggested that the length of time viable donor lymphocytes remain in the recipient circulation is important in the induction of specific immunosuppression by spleen lymphocytes.     

Post-transplant diabetes: incidence, relationship to choice of immunosuppressive drugs, and treatment protocol

Post-transplant diabetes mellitus (PTDM) is one of the feared complications of immunosuppressive therapy. Despite advances, including the introduction of the steroid-sparing calcineurin inhibitors, cyclosporine and tacrolimus, the incidence rate remains greater than 10% to 30%, especially in minority populations. PTDM increases the subsequent risk of both graft loss and patient death, and predisposes patients to all complications of diabetes, including retinopathy and neuropathy. Patients should be monitored closely, especially during the first 3 months post-transplant, and treated aggressively, should glucose intolerance be detected. Minimization of immunosuppression dose, diet, oral hypoglycemic agents, and insulin have all been used in the treatment of PTDM, however, the insulin-sensitizing agents have not been studied. It is hoped that newer immunosuppressive regimens and, ultimately, the ability to achieve tolerance will eventually solve the problem of PTDM.     

A simple way of administering oxygen to the pediatric patient with upper airway obstruction.

An open-top oxygen tent has been developed for supplying humidified oxygen to the pediatric patient while allowing easy access to the child's head, neck, and upper thoracic region with limited impairment of either observations or movement of the child. This tent is easily and economically fabricated from 0.002-in clear plastic sheeting and 3/4-in polyvinyl chloride pipe available from a local hardware store.     

Comparison of osteopenia after gastrectomy, ovariectomy and prednisolone treatment in the young female rat.

Rat models of osteopenia include ovariectomy and long-term glucocorticoid treatment. Although ovariectomy produces significant trabecular bone loss after 2 weeks, long-term glucocorticoid treatment has been reported to cause osteopenia in some studies but not in others. In the present 8-week-study, we compared the osteopenia associated with gastrectomy (GX) to that induced by ovariectomy (OVX) or prednisolone (PRE) treatment. Female Sprague-Dawley rats (10 weeks old) were subjected to GX, OVX, PRE treatment or SHAM operation. At the end of the study, calvariae, femurs and fifth lumbar vertebrae (L5) were collected and subjected to bone density measurement (femur and L5), transillumination (calvaria) and histomorphometry (calvaria and femur). Bone density was reduced in L5 and the distal femur in the OVX and GX groups, but not in the PRE group. Transillumination of the calvaria showed marked bone loss in the GX rats, but not in the other groups. Morphometric analysis of the femur revealed reduced trabecular bone volume, trabecular thickness, trabecular number and osteoclast number, but increased osteoclast surface (expressed as per cent of the trabecular bone surface covered by osteoclasts) in the GX and OVX rats. The PRE rats seemed unaffected. Cortical thickness was reduced in the GX rats, but not in the other groups. The findings indicate that GX induces osteopenia in, e.g., femur and vertebra of a magnitude similar to or greater than that induced by OVX, while at the same time inducing osteopenia in the calvaria. Although osteoclast activation seems to contribute, the precise mechanism underlying the GX-evoked osteopenia remains obscure.     

Enhancement of cardiac allografts in rats. Comparison of host responses to different treatment protocols.

Immunological responses to heterotopic (L X BN)F1 cardiac allografts placed in untreated L rats were compared with those grafts enhanced by different treatment regimens. Host pretreatment by antigen and antibody (Ag-Ab) 11 and 10 days before transplantation, respectively, was the most effective treatment regimen for prolongation of graft function; active or passive immunization alone increased survival only modestly. A late dose of antiserum administered to Ag-Ab-pretreated animals significantly shortened graft survival. Patterns of cellular responsiveness were measured serially by lymphocyte-mediated cytotoxicity; humoral immunity by Ab-lymphocyte-mediated cytotoxicity, capillary hemagglutination, and complement-dependent cytotoxicity. Allograft rejection in animals of all groups was heralded in vitro by increasing immunological activity. All cellular and humoral responses were depressed consistently in Ag-Ab-pretreated recipients. Cellular but not humoral responses were decreased in Ag-pretreated hosts, while humoral but not cellular responses were decreased in Ab-treated animals. The results suggest that the in vitro determinants of immunological activity used in this study generally followed clinical patterns of rejection or enhancement of cardiac allografts in the rat. Recipient pretreatment with Ag and Ab is more effective in graft prolongation than treatment with Ag or Ab alone, and in vitro data suggest an additive effect of these two regiments.     

A novel immunosuppressive agent, sirolimus, in the treatment of Kaposi's sarcoma in a renal transplant recipient

Renal transplant recipients are susceptible to Kaposi's sarcoma (KS) because of treatment with immunosuppressive drugs. Sirolimus, a new immunosuppressive agent, has been successfully used for immune-suppression in kidney transplant recipients. Several studies have shown the potential role of sirolimus to inhibit progression of KS in kidney-transplant recipients. This report details a kidney-transplant recipient with cutaneous KS who had a complete remission in response to sirolimus therapy.     

Comparison of the cost-effectiveness of administering heparin subcutaneously or intravenously for the treatment of deep vein thrombosis.

The cost-effectiveness of subcutaneous heparin (20,000 iu, twice daily, prefilled syringes), a continuous intravenous infusion of 24,000 iu heparin in 24 h, and the intravenous infusion of 48,000 iu heparin as two consecutive 12-h infusions of 24,000 iu, were compared. The costs were calculated by timing and observing staff in three hospitals, and by noting the costs of what they used. Cannulation of a vein by a doctor took a mean of 4 min 16 s and cost 2.61 pounds. To prepare and administer the 24,000 iu of heparin in a 24-h infusion took a mean of 22 min 42 s/day and cost 9.52 pounds. If a 48,000 iu in 24-h infusion was used it took a mean of 36 min 3 s/day and cost 16.81 pounds. The use of heparin syringes, 20,000 iu subcutaneously twice daily, took 2 min 53 s/day and cost 4.80 pounds. A generic cost formula was calculated to allow for variation in staff or drug costs. The subcutaneous and intravenous routes were assumed to be equally effective on the basis of the medical literature. This study shows that subcutaneous heparin therapy is significantly more cost-effective than intravenous heparin therapy. The reduction in cost and liberation of nursing time mean that the subcutaneous route should be preferred.     

Comparison of osteopenia after gastrectomy, ovariectomy and prednisolone treatment in the young female rat

Rat models of osteopenia include ovariectomy and long-term glucocorticoid treatment. Although ovariectomy produces significant trabecular bone loss after 2 weeks, long-term glucocorticoid treatment has been reported to cause osteopenia in some studies but not in others. In the present 8-week-study, we compared the osteopenia associated with gastrectomy (GX) to that induced by ovariectomy (OVX) or prednisolone (PRE) treatment. Female Sprague-Dawley rats (10 weeks old) were subjected to GX, OVX, PRE treatment or SHAM operation. At the end of the study, calvariae, femurs and fifth lumbar vertebrae (L5) were collected and subjected to bone density measurement (femur and L5), transillumination (calvaria) and histomorphometry (calvaria and femur). Bone density was reduced in L5 and the distal femur in the OVX and GX groups, but not in the PRE group. Transillumination of the calvaria showed marked bone loss in the GX rats, but not in the other groups. Morphometric analysis of the femur revealed reduced trabecular bone volume, trabecular thickness, trabecular number and osteoclast number, but increased osteoclast surface (expressed as per cent of the trabecular bone surface covered by osteoclasts) in the GX and OVX rats. The PRE rats seemed unaffected. Cortical thickness was reduced in the GX rats, but not in the other groups. The findings indicate that GX induces osteopenia in, e.g., femur and vertebra of a magnitude similar to or greater than that induced by OVX, while at the same time inducing osteopenia in the calvaria. Although osteoclast activation seems to contribute, the precise mechanism underlying the GX-evoked osteopenia remains obscure.