Dinesh Ranjan

Impact of acute rejection episodes on long-term graft survival following simultaneous kidney-pancreas transplantation.

Although it is well established that acute rejection is one of the major risk factors for chronic graft loss following kidney transplantation, its effect on long‐term graft survival following simultaneous kidney‐pancreas transplants (SKPTs) is less well known. We analyzed a large cohort of SKPTs and cadaver kidney transplants reported to the United Network for Organ Sharing database during 1988–97, to determine the impact of acute rejection episodes on long‐term kidney and pancreas graft survival. Only patients whose kidney and pancreas grafts had survived for at least 1u2003year were included. Other potential risk factors influencing long‐term graft survival were included in the analysis. Of the 4251 SKPTs, 45% had no acute rejection, 36% had kidney only rejection, 3% had pancreas only rejection, and 16% had both kidney and pancreas rejection within the 1st year post transplant. The 5‐year kidney and pancreas graft survival rates adjusted for other risk factors were 91% and 85%, respectively; for those with no acute rejection episodes, 88% and 84%, respectively; for those with kidney only rejection, 94% and 83%, respectively; for those with pancreas only rejection; and 86% and 78%, respectively, for those with both kidney and pancreas rejection. The relative risk (RR) of kidney graft failure was 1.32 when acute rejection involved the kidney graft only, while the RR was 1.53 when the rejection involved both organs. We conclude that acute rejection episodes have a negative impact on the long‐term kidney graft survival in the SKPT population similar to that in the cadaver kidney transplant population. Patients who had acute rejection episodes of both kidney and pancreas have the worst long‐term graft survival.

Gastric intramural pH as indicator of early allograft viability in orthotopic liver transplantation.

The determination of the viability of OLT grafts has relied upon metabolic tests of the liver, which take several hours to evaluate and therefore are only conclusive in most patients well into the postoperative period. Earlier diagnosis of graft failure or nonfunction would allow intraoperative reassessment of surgical technique and, in the case of graft failure, earlier planning for retransplantation. Since gastrointestinal mucosal ischemia is one of the earliest manifestations of impaired core tissue in the critically ill, a tonometric nasogastric tube (Tonomitor) was used in our patients to measure intramucosal gastric pH (pHi) during the preanhepatic (stage I), anhepatic (stage II), and neohepatic (stage III) phases of OLT in 35 patients as an indicator of graft liver function and viability. Based on the results of the pHi measurement 30 min after reperfusion during stage III, patients were divided into 2 groups using a pHi of 7.30 as the dividing point. Patients with a pHi equal or higher than 7.30 were assigned to group 1 (n = 24) and patients with a pHi lower than 7.30 were assigned to group 2 (n = 11). The pHi in group 1 patients averaged 7.37 +/- 0.5 30 min after reperfusion and throughout surgery. The pHi in group 2 patients was lower than that of the group 1 patients 30 min after reperfusion, 7.23 +/- 0.04 (P < 0.001). The pHi in 10 group 2 patients returned to normal within 3 hr after reperfusion and the pHi values for these patients were not significantly different from those of group 1 at 3 hr after reperfusion. The pHi in 1 group 2 patient remained lower than 7.30 and never returned to normal; this patient underwent retransplantation the following day. Utilizing the tonometric nasogastric tube to sample intramucosal pH allowed early detection of graft function and intermittent trending of pHi in patients with questionable graft function during the operative period. It also provided a means of assessing graft function independent of enzymatic criteria, which provide little information in the early phase of transplantation.

Curcumin has potent liver preservation properties in an isolated perfusion model.

Background. Curcumin has profound antioxidant and anti-inflammatory properties. This research assessed the effect of curcumin on liver preservation. Methods. Sprague-Dawley rat livers were flushed with different preservation solutions [Euro-Collins solution (EC), phosphate buffer saline (PBS), University of Wisconsin solution (UW)] with or without curcumin (25–200 &mgr;M) and stored at 4°C for 24–48 hours. Livers were then perfused for 120 minutes via the portal vein with oxygenated Krebs-Henseleit bicarbonate buffer solution at a pressure of 18 cm H2O in a perfusion apparatus. The livers in the normal (NL) group were flushed with EC, PBS, or UW, then immediately perfused (zero preservation time). Results. We found that curcumin at 100 &mgr;M concentration had the optimal preservation characteristics. Portal flow rates and bile production were significantly higher and liver enzymes (alanine aminotransferase, aspartate aminotransferase, and lactate dehydrogenase) were significantly lower in the EC+C livers and PBS+C livers than in the EC or PBS with optimum concentration of 100 &mgr;M of curcumin. Comparing UW+C vs. UW livers, at 24 hours there was no difference in these parameters; however, at 36 hours and 48 hours, portal flow rates and bile production were significantly higher in UW+C livers. Conclusions. We found that curcumin has inherent organ preservation quality as it enhanced liver preservation in PBS. In addition, curcumin enhanced the preservation quality of EC and UW solutions, thereby extending the preservation time while maintaining the organ quality.

The effect of acute hypocapnia on middle cerebral artery transcranial Doppler velocity during orthotopic liver transplantation: changes at reperfusion.

This study examines the effects of acute hypocapnia, instituted prior to reperfusion of the graft liver, on the middle cerebral artery (MCA) Doppler blood flow velocity response to reperfusion during orthotopic liver transplantation in humans.Seventeen patients with chronic liver disease underwent continuous, noninvasive Doppler imaging of the MCA. Hyperventilation to an end-tidal PCO2 of 25 +/- 1 mm Hg was associated with a decrease in mean MCA flow velocity (FVm) from 51.6 +/- 5.7 to 37.0 +/- 3.3 cm/s (P < 0.05). After reperfusion, the PaCO2 increased from 32 +/- 1 to 40 +/- 1 mm Hg (P < 0.05), mean arterial pressure (MAP) decreased from 76 +/- 3 to 60 +/- 2 mm Hg, and the FVm increased from 37.0 +/- 3.3 to 54.0 +/- 4.7 cm/s (P < 0.05). FVm increased postreperfusion despite prior hyperventilation, decreased MAP, and abrupt increases in central venous and pulmonary artery pressures, but FVm did not exceed the prereperfusion level. In 10 of the 17 patients, the baseline FVm versus PaCO2 response slopes and PaCO2 measured postreperfusion were used to predict the FVm response to PaCO2 after reperfusion. The slopes were similar to those reported for anesthetized patients without liver disease. Predicted FVm exceeded measured FVm in 9 of the 10 patients. We conclude that mild hyperventilation prior to reperfusion of the graft liver prevents FVm increases above prereperfusion baseline level. (Anesth Analg 1995;80:1194-8)

Factors affecting the ten-year outcome of human renal allografts. The effect of viral infections.

Long-term (10-year) results of kidney transplantation have been analyzed from this center with respect to several variables. In this report the influence of viral disease was added in studying the effect of cadaver versus living-related donor, recipient race, and compliance. Over all, 10-year actuarial patient and graft survival were 68% and 48%, respectively. Cytomegalovirus, hepatitis B and C, and HIV-1 were studied for their effects, and survival curves analyzed statistically. Although cadaver and living-related donor, recipient race, and compliance were 3 main variables influencing graft survival, these 4 viruses were not selective in their effects on any of them. Hepatitis B surface antigen positivity and hepatitis C antibody positivity did not influence overall mortality or graft survival. Only cytomegalovirus seronegative status was important (as opposed to seropositive status, which was not). Of seronegative patients only those receiving a kidney from a seropositive donor were adversely affected. The presence of HIV-1 antibody had an adverse effect on graft survival, but the question remains as to whether overall mortality in HIV seropositive patients is any worse than those receiving dialysis therapy.

The effects of tissue-associated and MHC class II antigen presentation on in vitro lymphoproliferative responses against canine liver and kidney cell subpopulations

Purified hepatocytes (LH), Kupffer cells (LKu), and intrahepatic biliary duct cells (LD) were isolated from canine livers, as well as tubular cells from canine kidneys, by enzymatic digestion, gradient centrifugation, and tissue culture techniques. Incubation of LH, LKu, and LD for 48 hr in a two-compartment diffusion chamber opposite two-way mixed lymphocyte cultures, or with canine gamma interferon purified and standardized in our laboratory, resulted in a significant increase in class II expression. This was detected in the cell analyzer with directly fluoresceinated B1F6, a monoclonal antibody (mab) generated in our laboratory vs. a canine class II monomorphic epitope. An amplification of the allogeneic mixed lymphocyte liver cell cultures (MLLC) of at least 2-fold was observed by preinduction of canine class II expression with IFN-gamma on LKu and LD cells, but an autologous reaction could not be elicited. However, an autologous as well as allogeneic lymphoproliferation against kidney tubular cells (MLKC) could be easily observed without IFN-gamma and amplified with IFN-gamma to stimulation indices of at least 3 times that of noninduced cultures. Dependence of the allogeneic MLLC and allogeneic and autologous MLKC on class II gene expression was also evidenced by blocking of 3H-thymidine uptake seen by incubation with 5 micrograms of B1F6. Another mab, I1F6, generated against tubular cells and inhibiting the autologous and allogeneic MLKC, had no blocking effect on lymphoproliferation with any of the liver cell preparations. No such tissue-specific mab (analogous to I1F6) has thus far been found in response to mouse immunization with LH, LKu, or LD. In the absence of accepted defined molecular probes in the dog as yet, we conclude that, in contrast to kidney tubular cells, cells of the normal canine liver do not readily stimulate a primary lymphoproliferative autoimmune reaction in vitro despite class II amplification. Thus autoreactivity (as opposed to alloreactivity) is much less prominent in immune recognition of purified cellular components of nondiseased liver tissue than of kidney tissue in which tissue-associated epitopes are more operative.

OKT3 induction via idiotypic networks of mirror-image immunosuppressive antiimmunoglobulins in renal transplant recipients

Four of 21 renal transplant recipients treated with OKT3 for rejection episodes developed a second sustained (approximately 2 weeks) depression in CD3 peripheral blood lymphocyte cell-surface-marker expression. This occurred after OKT3 therapy had ceased, subsequent to a return toward baseline CD3 levels seen before OKT3 therapy was instituted. The second decrease in CD3 T cell counts was dissociated from CD2 marker T cell counts using flow cytometry and coincided with transient cytomegaloviral infections. Three phases of immunosuppression were defined in these 4 patients: phase I (during OKT3 treatment); phase II (after treatment when CD3 counts were reconstituted); and phase III (when CD3 counts again were depressed). During phase III, serum of the 4 affected patients could transfer a blocking effect on the expression of the CD3 marker of peripheral blood T cells of normal laboratory volunteers. Contained in these sera were human IgG antibodies that bound on Western blot analysis and by radioautography after immunoprecipitation to a protein band of a T cell membrane lysate with an m.w. of 23 kD. The reaction was identical to that seen with OKT3 (immunoprecipitation). Moreover, this Western blot binding could be virtually (but not completely) eliminated by multiple absorptions of the T cell membrane lysate with OKT3. By using an affinity-purified human anti-OKT3 IgG from one of the 4 patients, it was possible to immunoabsorb from phase III sera the CD3 blocking activity as well as the binding to the 23 KD protein band. A reverse immune absorption by the phase III sera with the anti-OKT3 IgG after ultracentrifugation prevented the anti-OKT3 IgG from binding to OKT3 coated plates in solid-phase radioimmunoassay. These data support the notion that autoimmune human anti-anti-id (Ab2) antibodies can occasionally be generated by treatment with OKT3, which are directed against CD3 complex epitopes similar to the ligand of OKT3.

Evidence that antibodies to cytomegalovirus and the T cell receptor (TCR)/CD3 complex may have common ligands

Immunoglobulins derived from sera containing anti-antiidiotypic antibodies (Ab2) generated in renal transplant recipients after OKT3 monoclonal antibody therapy, as reported in our previous study (1), have now been proved to bind to several bands of T cell membrane lysates (TCML) in immunoblotting analyses ranging in molecular weight from 40 to 55 KD. These sera also blocked the expression of the ligand binding to WT31 in flow cytometry. WT31 is a MAb that recognizes a common determinant on the T cell receptor (TCR). Immunoglobulins from these sera suppressed the activation of normal peripheral blood T lymphocytes (PBT) induced by OKT3. All patients (7/32) who developed this Ab2 had distinct culture-proved cytomegaloviral infections. In further immunoblotting studies, alpha F1, another MAb recognizing the framework of the TCR alpha chain, more deeply inserted in the T cell membrane, also showed binding to protein bands of cytomegalovirus pellet lysates derived from virus-infected embryonic fibroblasts. In addition, alpha F1 showed positive binding to several ligands in the membrane lysate of CMV-infected, but not noninfected MRC-5 cells. An anti-CMV MAb recognizing late nuclear antigen (LAb), also strongly bound to a approximately 50 KD band of TCML and several bands (approximately 34, approximately 40, and approximately 50 KD) of H33HJAJ1 (human T leukemia) cell lysate. Furthermore, alpha F1 immunoprecipitated a approximately 96 KD ligand of CMV-infected MRC5 lysate that had the same electrophoretic mobility as one of the proteins precipitable with LAb. Both LAb and alpha F1 also showed positive binding to paraformaldehyde-fixed and Triton X-100-permeabilized PBT in flow cytometry. Sera containing Ab2 blocked alpha F1 binding to acetone-fixed cytofuged PBT preparations on slides. Moreover, both alpha F1 and LAb inhibited mitogen-stimulated lymphocyte activation in vitro. These data support the notion that T cell functional abnormalities associated with CMV infection observed after treatment of transplant recipients with anti-T cell monoclonals might be caused by binding to T cell ligands by a variety of crossreacting human Igs operative in a regulatory network. Confirmatory evidence is the effect of MAbs generated against CMV virion epitopes crossreacting with T cell ligands, and vice versa.