Complicated diverticulitis following renal transplantation.

PURPOSE: Colonic perforations in renal transplant recipients have historically been associated with mortality rates as high as 50 to 100 percent. However, these previous series generally predate the use of cyclosporine-based immunosuppressive protocols. METHODS: We retrospectively reviewed all patients who had undergone renal transplant from our institution and who developed complicated diverticulitis. Complicated diverticulitis was defined as diverticulitis involving free perforation, abscess, phlegmon, or fistula. Factors analyzed included the time interval since transplantation, use of cyclosporine, living-related vs. cadaveric donor, cause of renal failure, and presenting signs and symptoms. RESULTS: Between August 1969 and September 1996, 1,211 kidney transplants were performed in 1,137 patients. The first 388 patients (1969-1984) received prednisone and azathioprine, with cyclosporine added to the immunosuppressive regimen for the subsequent 823 recipients (1984-1996). Thirteen (1.1 percent) patients had episodes of complicated diverticulitis, occurring from 25 days to 14 years after transplant; all required surgical therapy. Clinical presentation was highly variable, ranging from asymptomatic pneumoperitoneum (2 patients) to generalized peritonitis. There was one perioperative mortality (7.7 percent). Patients with polycystic kidney disease as the cause of renal failure had a significantly higher rate of complicated diverticulitis. Specifically, patients with polycystic kidney disease (9 percent of the total transplant population) accounted for 46 percent of the cases of diverticulitis (P < 0.001, Fisher's exact probability test). Neither treatment with cyclosporine nor donor source had a significant effect on the rate of diverticular complications (P = 0.36 and P = 0.99, respectively, Fisher's exact probability test). CONCLUSION: Complicated diverticulitis following renal transplantation is rare, and the clinical presentation may be atypical in the immunosuppressed transplant recipient. Patients with polycystic kidney disease experience a significantly higher rate of complicated diverticulitis than do other transplant patients and, therefore, warrant aggressive diagnostic evaluation of even vague abdominal symptoms. In addition, pretransplant screening and prophylactic sigmoid resection in this high-risk population deserve consideration and further study.

Comparative pharmacokinetics and renal effects of cyclosporin A and cyclosporin G in renal allograft recipients.

Cyclosporin G (CSG) has produced less nephrotoxicity than cyclosporin A (CSA) at equivalent doses in animal models. Conflicting results have been reported concerning differences in the pharmacokinetics of CSA and CSG in preclinical studies, and no data exist regarding the effect of steady-state oral administration of CSG on renal function in transplant patients or CSG-induced release of endothelin and nitric oxide (NO) in vivo. The objective of the study was to examine steady-state pharmacokinetic profiles of adult renal allograft recipients receiving CSA and CSG in relation to concentrations of endothelin-1 and NO2/NO3 in urine and plasma, creatinine clearance (Clcr), and urinary excretion of N-acetyl-beta-D-glucosaminidase (NAG) 9 months after transplantation. Concentrations of CSA and CSG were measured in whole blood over a 12-hour dose interval by both a monoclonal and polyclonal fluorescence polarization radioimmunoassay for CSA. A metabolite fraction was defined as the numerical difference between the levels obtained at each time point by both assays. Patient groups were defined as follows: group 1: initial CSA (n = 6); group 2: initial CSG (n = 7); group 3: five of the seven patients in group 2 taking CSG subsequently undergoing conversion to CSA; group 4: the same five patients in group 3 restudied 1 month after 1:1 dosage conversion to CSA; and group 5: CSA groups 1 and 4 combined (n = 11). In group 1, the metabolite fraction accounted for 32% to 54% of the total measurable drug concentration at each time point, whereas in group 2, the metabolite fraction accounted for at most 10% to 15% of the total drug levels measurable by polyclonal fluorescence polarization radioimmunoassay. Although there were no significant differences in any of the mean pharmacokinetic parameters between groups using monoclonal fluorescence polarization radioimmunoassay, the normalized area under the concentration-time curve (NAUC) value was less in four of five patients after conversion from CSG to CSA, with a more variable and delayed time to reach peak concentration (tmax) but equivalent apparent oral clearance (Clpa) values. Clcr was found to change significantly with time in groups 1 and 5 but not in group 2, with CSA producing a more profound and sustained decrease than CSG. Endothelin-1 and NO2/NO3 levels in plasma and urine remained relatively constant after administration of both CSA and CSG, and there were no significant differences between groups 3 and 4 regarding mean endothelin-1 and NO2/NO3 concentrations in plasma, urinary release of endothelin-1 and NO2/NO3, and mean AUC of endothelin-1 and AUC of NO2/NO3. However, monoclonal NAUC correlated significantly with total urinary endothelin-1 within CSA groups 1 and 5 but not within CSG group 2. Metabolite NAUC correlated significantly with total urinary NAG within CSA group 1. Although limited by the small number of patients, this study suggests that 1) CSG may produce less of a reduction in Clcr over time after oral administration at steady state than does CSA, and 2) this beneficial effect of CSG may be in part due to decreased intrarenal release of endothelin-1, as urinary excretion of endothelin-1 seemed to correlate better with CSA than with CSG exposure.

Preemptive ganciclovir therapy in cytomegalovirus-seropositive renal transplants recipients.

OBJECTIVE: To evaluate the efficacy, safety, and cost of preemptive ganciclovir therapy in cytomegalovirus (CMV)-seropositive renal transplant recipients treated with antilymphocyte antibody (ALA) preparations. DESIGN AND SETTING: A prospective, randomized trial at a 650-bed tertiary medical center hospital. PATIENTS: Forty consecutive CMV-seropositive renal allograft recipients who underwent transplantation between January 1992 and January 1994 and were treated with ALA for induction immunosuppression or acute rejection therapy. MAIN OUTCOME MEASURES: The incidence and severity of CMV disease, length of hospitalization, and patient and allograft survival. INTERVENTION: Cytomegalovirus infection prophylaxis by use of intravenous ganciclovir during ALA therapy was administered to 22 patients (group 1) and the results were compared with those obtained in 18 control patients who did not receive prophylaxis for CMV disease (group 2). RESULTS: Preemptive ganciclovir therapy significantly reduced the incidence of CMV disease (P < .05) in CMV-seropositive renal transplant patients who were treated with ALA and was well tolerated. In addition, the cost of prophylactic therapy was offset by the decreased length of hospitalization observed in patients in group 1. CONCLUSION: Preemptive ganciclovir therapy provides a cost-effective approach toward significantly improving the outcome of renal transplantation in CMV-seropositive patients treated with ALA.

Prophylaxis of primary cytomegalovirus disease in renal transplant recipients. A trial of ganciclovir vs immunoglobulin.

OBJECTIVE: To compare the efficacy, safety, and cost of prophylactic low-dose ganciclovir with that of immunoglobulin in renal transplant recipients at risk for primary cytomegalovirus (CMV) disease. DESIGN AND SETTING: A prospective, randomized trial at a 650-bed tertiary medical center hospital. PATIENTS: Fifty-one consecutive CMV-seronegative patients who received renal allografts from seropositive donors between March 1990 and April 1992. MAIN OUTCOME MEASURES: Patient and allograft survival, and the incidence and severity of CMV disease. INTERVENTION: Cytomegalovirus prophylaxis with seven doses of intravenous immunoglobulin for 6-week periods (group 1, n = 27) or low-dose intravenous ganciclovir for 3 weeks (group 2, n = 24). Results were compared with those obtained in 23 CMV-seronegative historical controls who received renal allografts from CMV-seropositive donors between 1987 and 1989, and who did not receive prophylaxis for CMV (group 3). RESULTS: Both prophylactic regimens significantly reduced the incidence of invasive CMV infection (P < .05) and were well tolerated. However, the cost of ganciclovir ($350 per patient) was substantially less than that of immunoglobulin ($4000 per patient). CONCLUSIONS: These data suggest that prophylactic ganciclovir therapy provides a cost-effective approach toward significantly improving the outcome of renal transplantation in recipients at risk for primary CMV disease.

Placement of a double lumen silastic catheter for hemodialysis access through the cephalic vein.

The cephalic vein within the deltopectoral groove provides adequate access to the central venous system for the PermCath hemodialysis catheter. Unlike EJV techniques, which are successful in few instances, the cephalic vein approach was successful in approximately 75 percent of instances. In addition, the rate of complications secondary to bleeding or catheter kinking are decreased with the cephalic vein technique as compared with insertion through the EJV or IJV. We conclude that the cephalic vein is a dependable and functional approach to the central venous system for the PermCath hemodialysis catheter.

Assessment of the in vivo immunosuppressive activity of the major cyclosporine metabolite by leukemia allograft rejection.

AM1 (M17) is the major metabolite of cyclosporine found in the blood of human transplant recipients, and trough levels of this derivative exceed those of the parent compound approximately two-fold. Studies performed in vitro indicate that AM1 retains only 10-20% of the biological activity of the parent compound, but very little is known about its in vivo immunosuppressive effects. We therefore developed a rapid and sensitive method, based on the rejection of allogeneic L1210 (H-2d) leukemia cells by C57BL/6 (H-2b) mice, to assess the immunosuppressive activity of AM1 in vivo. Rejection of the leukemia allograft was determined by analyzing the spleens from mice injected intravenously with 10(5) L1210 cells for the presence of H-2Kd-positive cells by flow cytometry using an FITC-conjugated monoclonal anti-H-2Kd antibody. Nonimmunosuppressed mice rejected the allogeneic cells and survived indefinitely. Spleens from these mice were virtually free of H-2Kd-positive cells (0.51 +/- 0.21%) by day 7. In contrast, C57BL/6 mice treated with 10 mg/kg/day s.c. of CsA all died from the L1210 challenge (mean survival time of 9 +/- 1 days). Spleens from mice treated in this manner contained 11.02 +/- 3.31% H-2Kd-positive cells on day 7. There was a direct correlation between the dose of CsA administered (7.5-50 mg/kg/day) and the percentage of H-2Kd-positive cells in the spleen. We then compared the immunosuppressive activity of AM1 and CsA in this model. AM1 was purified from the urine of CsA-treated renal allograft recipients by a combination of preparative adsorption-desorption chromatography and preparative elution high-performance liquid chromatography. AM1 at a dose of 10 mg/kg/day exhibited no demonstrable immunosuppressive effect, and trough levels of AM1 on day 7 were only 36 +/- 4 ng/ml. Increasing the dose of AM1 to 50 mg/kg/day resulted in only 1.05 +/- 0.16% H-2Kd-positive cells in the spleens (P = NS) and a mean trough level of 221 +/- 27 ng/ml. In contrast, mice treated with 50 mg/kg/day of CsA exhibited 17.7 +/- 2.9% H-2Kd-positive cells in their spleens and a mean trough CsA level of 3036 +/- 277 ng/ml. The half-life of a single subcutaneous dose of 10 mg/kg of AM1 (4.6 hr) was significantly shorter than that of CsA (9.7 hr) in mice. Compared with CsA, the lack of immunosuppressive effect of AM1 in vivo therefore appears to be due to a combination of decreased immunosuppressive activity and increased rate of clearance in mice.

The effects of immunosuppressive agents on in vitro production of human immunoglobulins.

We have evaluated the effects of CsA, methylprednisolone (MP), 6-mercaptopurine (6-MP), and FK506 on T cell-dependent and T cell-independent immunoglobulin production. FK506 and 6-MP were potent inhibitors of IgG and IgM production by PWM-stimulated peripheral blood mononuclear cells, which depend on the presence of T cells. CsA was less effective in this system and MP actually enhanced IgG and IgM production. In order to assess the direct effects of these various immunosuppressive agents on B cells, we utilized human B cell lines representing different stages of B cell differentiation. The B cell lines CESS and SKW6.4 exhibit increased production of IgG and IgM, respectively, in response to interleukin-6. These cells represent activated, but not fully differentiated, B cells. CsA inhibited IL-6-induced IgG production by CESS cells by 64% at 100 ng/ml and 6-MP inhibited this response by 82% at 250 ng/ml. Neither CsA nor 6-MP effectively inhibited IL-6-induced IgM production by SKW6.4 cells. MP at 250 ng/ml inhibited IL-6-induced IgG production by 89%, but enhanced IL-6-induced IgM production more than two-fold. FK506 did not inhibit IL-6-induced IgG or IgM production, suggesting that it has no direct effect on the ability of B cells to respond to this differentiation factor. These experiments clearly demonstrate that CsA, MP and 6-MP have direct inhibitory effects on the response of human B cells to IL-6. In contrast, FK506 has no direct effect on these B cells lines, but is more potent than the other agents at inhibiting T cell-dependent immunoglobulin production.

Inhibition of interleukin-2 production in the human T cell line JURKAT by nonpolar maleimides.

The immunosuppressive properties of polar and nonpolar maleimides were studied by measuring their ability to inhibit mitogen-induced interleukin-2 (IL-2) production by JURKAT T cells. The nonpolar maleimides N-ethylmaleimide (NEM) and N-phenylmaleimide (NPM) inhibited IL-2 production by 85-99%, but only when added to JURKAT cells prior to the mitogen. The polar maleimides N-hydroxymaleimide (NHM) and 4-maleimidosalicylic acid (M84) did not suppress IL-2 production significantly, even though NHM reacted with more cellular thiols (12%) than did NPM (8%). Both NEM and NPM suppressed IL-2 production at doses that did not affect proliferation. NEM inhibited IL-2 production induced by PHA, anti-CD3 (alpha CD3) monoclonal antibodies or PMA, and A23187, but did not interfere with the binding of alpha CD3 to the cells. NEM inhibited IL-2 production at concentrations that did not interfere with the PHA-induced increase in intracellular free calcium [( Ca]i). Neither NPM nor NHM inhibited the rise in [Ca]i, even at the highest concentrations tested. Although JURKAT T cells require both PMA and A23187 to induce IL-2 production, we found that cells pretreated with PMA could respond to A23187 added 18 hr later. PMA-treated cells were not resistant to the immunosuppressive effects of NEM or NPM. However, PMA-pretreated cells became resistant to the inhibitory effects of NEM upon the addition of A23187, suggesting that nonpolar maleimides inhibit activation events induced by the rise in [Ca]i.

The inhibitory effects of N-ethylmaleimide, colchicine and cytochalasins on human T-cell functions.

The thiol-alkylating agent, N-ethylmaleimide (NEM), was found to inhibit the response of human peripheral blood mononuclear cells to the T-cell mitogen, concanavalin A (Con A). NEM (10 microM) blocked Con A-induced agglutination, production of interleukin-2 (IL-2) and expression of the IL-2 receptors (Tac) without toxicity. In order to determine whether the effects of NEM on lymphokine production were related to inhibition of agglutination, we compared the immunosuppressive effects of NEM with those of cytochalasin A, cytochalasin B and colchicine. NEM did not inhibit E-rosette (ER) formation, suggesting that it does not interfere with actin filaments. Low concentrations of NEM (4 microM) inhibited IL-2 production and Tac expression without inhibiting agglutination, while 6-10 microM NEM blocked agglutination and DNA synthesis as well. In contrast, 5-10 microM cytochalasin B (CB) inhibited ER formation, agglutination, Tac expression and DNA synthesis, but augmented IL-2 production by three- to ten-fold. Colchicine (0.1-10 microM) had no effect on ER formation or agglutination and augmented IL-2 production by as much as 18-fold. However, colchicine blocked Tac expression by greater than 40% and DNA synthesis by greater than 80%. Cytochalasin A (CA), which has the thiol-reactive properties of NEM, the actin filament-disrupting properties of CB, and the microtubule-disrupting properties of colchicine, exhibited the immunosuppressive effects of all three compounds. These studies suggest that the inhibitory effects of NEM on IL-2 production do not appear to be due to reactivity with the cytoskeleton, but are probably due to effects on signal transduction pathways leading to IL-2 production and expression of IL-2 receptors.