A randomized, placebo-controlled trial with anti-interleukin-2 receptor antibody for immunosuppressive induction therapy after liver transplantation

The introduction of quadruple induction therapy after liver transplantation with the murine anti-interleukin-2 receptor (IL-2R) antibody (BT563) has decreased the incidence of serious side effects, such as tachycardia, hypertension, rash, fever and nausea since it does not lyse its target cell. To investigate the immunosuppressive efficacy of BT563, a placebo-controlled trial was performed and BT563 was added to the standard triple induction after liver transplantation. Forty consecutive recipients of primary orthotopic liver transplants (OLT) (median age 47 yr [range 18-65]) were randomized. All patients received triple immunosuppression with cyclosporine A (CyA), prednisolone (PRED) and azathioprine (AZA). In addition, 19 patients received BT563 (Biotest, Dreieich, Germany) at a dose of 10 mg/d from day 0 until day 12. The remaining 21 patients received a placebo infusion at the same days after transplantation. Minimal follow-up for all patients was 3 yr. Patient survival at 3 yr was 74% in the BT563 group and 90% in placebo group. Similar results were observed for graft survival. Two acute rejection episodes were detected in the BT563 group and 9 acute rejections (5 steroid-resistant) were observed in the placebo group (p < 0.034). The incidences of sepsis, pneumonia, cholangitis, urinary tract infections as well as cytomegalo-virus (CMV) infections were similar in both groups. Side effects of the BT563 therapy and/or post-transplant lymphoproliferative disease (PTLD) were not detected. Quadruple induction therapy with BT563 significantly reduces the incidence of rejection episodes after liver transplantation, while infectious complications and/or PTLD is not increased. Therefore, the anti-IL2 receptor antibody BT563 constitutes a safe and efficient addition to the immunosuppressive induction regimen following OLT.

[Fatal course of measles infection in a patient with a low-grade malignant non-Hodgkin lymphoma]

HISTORY AND CLINICAL FINDINGS

A 35-year-old man, for 6 years known to have non-Hodgkin lymphoma (NHL) was admitted because of deteriorating general condition, drowsiness and 11 days of flu-like symptoms. A generalized rash had been noted 5 days after onset of symptoms. His 2-year-old son had fallen ill with measles a few days earlier. The patient had reportedly had measles as a child. On admission a generalized rash was found, he had a fever of 40.5 degrees C, tachypnoea, conjunctivitis and possible meningismus.

INVESTIGATIONS

Lactate dehydrogenase activity was raised to 458 U/ml, and C-reactive protein to 240 mg/ml. Cerebrospinal fluid contained 8/3 cells and protein of 269 mg/l. The chest radiogram revealed opacification in the left upper lobe. Computed tomography of the skull demonstrated a pansinusitis.

DIAGNOSIS, TREATMENT AND COURSE

As measles encephalitis seemed unlikely he was treated for the measles superinfection of bacterial pneumonitis (measles RNA in the bronchoalveolar lavage) and the sinusitis with broad-spectrum antibiotics. After initial improvement artificial ventilation had to be be gun on day 3 because of an acute respiratory distress syndrome, diagnosed both clinically and radiologically. Despite additional antiviral and intensive medical treatment he died on day 11.

CONCLUSION

Patients with impaired immunocompetence due to NHL may lose their immunological "memory" for a previous measles infection. Prevention of exposure may therefore be necessary, in addition to early hyperimmunoglobulin administration.

Combined liver-kidney transplantation: long-term follow up in 18 patients

Since August 1992, 18 patients underwent combined liver and kidney transplantation. Eight patients had lymphocytotoxic antibodies pretransplant and 5 of these patients (27.7%) had a positive crossmatch. Fifteen patients received cyclosporine-based immunosuppression and 3 patients were treated with a tacrolimus-based immunosuppressive protocol. One patient died in the postoperative course due to intractable bleeding episodes after 96 days and one kidney graft was lost due to technical complications. The 1 year survival rate of patients with combined transplantation was 95% vs 87% in patients with liver transplantation alone. None of the patients with a positive crossmatch experienced a hyperacute rejection of the kidney. The long-term patient and graft survival was not impaired in patients with a positive crossmatch. These results suggest that combined liver-kidney transplantation is a safe treatment for end-stage liver and renal disease. A positive crossmatch or positive lymphocytotoxic antibodies are not contraindications for a combined transplantation.

Studies on 2-benzyloxy-4H-3,1-benzoxazin-4-ones as serine protease inhibitors

The class of 3,1-benzoxazin-4-ones includes potent inhibitors of various serine proteases. Structural investigation on three 2-benzyloxy-4H-3,1-benzoxazin-4-ones (1-3) are described with respect to their reactivity to alkaline hydrolysis. The 13C NMR data of 2-benzyloxy-5-methyl-4H-3,1-benzoxazin-4-one 3 are discussed. This peri substituted compound was subjected to a crystal structure analysis. The heterocyclic skeleton together with the carbonyl oxygen and the methyl carbon is planar, and only small angle distortions occurred. The inhibition of neutrophil serine proteases by 1-3 is reported. The different reactivity of the 5-methyl derivative 3 towards serine proteases is mainly influenced by specific interactions within the active sites. Thus, 3 was found to rapidly acylate human leukocyte proteinase 3 and exhibited a Ki value of 1.8 nM.

A single amino acid substitution changes ribonuclease 4 from a uridine-specific to a cytidine-specific enzyme

The structural features underlying the strong uridine specificity of ribonuclease 4 (RNase 4) are largely unknown. It has been hypothesized that the negatively charged alpha-carboxylate is close to the pyrimidine binding pocket, due to a unique C-terminal deletion. This would suppress the cleavage of cytidine-containing substrates [Zhou, H.-M., and Strydom, D. J. (1993) Eur. J. Biochem. 217, 401-410]. Replacement of the alpha-carboxylate by an alpha-carboxamide in a fragment complementation system decreased both (kcat/Km)CpA and (kcat/Km)UpA , thus refuting the hypothesis. However, model building showed that the deletion allowed the side chain of Arg-101 to reach the pyrimidine binding pocket. From the 386-fold reduction in (kcat/Km)UpA in RNase 4;R101N, it is concluded that this residue functions in uridine binding, analogous to Ser-123 in RNase A. In addition, it may have an effect on Asp-80. The 2-fold increase in (kcat/Km)CpA in the mutant R101N and the close proximity of the side chains of Arg-101 and Asp-80 suggested that the latter could be involved in suppressing CpA catalysis. The substrate specificity of RNase 4;D80A was completely reversed: (kcat/Km)UpA decreased 159-fold, whereas (kcat/Km)CpA increased 233-fold. The effect on CpA was unexpected, because the corresponding residue in bovine pancreatic RNase A (Asp-83) hardly affects cytidine-containing substrates. Furthermore, the residue is conserved in nearly all sequences of mammalian RNase 1. Thus, an evolutionary highly conserved residue does not necessarily function in the same way in homologous enzymes. A model, which proposes that the structure of RNase 4 has been optimized to permanently fix the position of Asp-80 and impede its movement away from the pyrimidine binding pocket, is presented.

Novel thieno[2,3-d][1,3]oxazin-4-ones as inhibitors of human leukocyte elastase

A series of thieno[2,3-d][1,3]oxazin-4-ones was synthesized and evaluated in vitro for inhibitory activity toward human leukocyte elastase. New synthetic routes to 2-alkoxy-, 2-alkylthio-, and 2-sec-amino-substituted derivatives are reported. This study demonstrates the versatility of 2-aminothiophenes prepared by Gewald reaction as a synthetic entry to serine protease-inhibiting, fused 1,3-oxazin-4-ones. Introduction of ethoxy, n-propoxy, and ethylthio groups at C-2 delivered the most potent inhibitors of this series with Ki values lower than 11 nM. Kinetic studies and product analyses revealed the formation of acyl-enzymes as a result of the attack of the active site serine at the carbon C-4 and subsequent deacylation. This mode of action is similar to the inhibition of serine proteases by 4H-3,1-benzoxazin-4-ones. Replacement of the benzene ring in benzoxazinones by a (substituted) thiophene led to improved hydrolytic stability and retained inhibitory potency.

The impact of donor organ quality on postoperative liver function after orthotopic rat liver transplantation

The impact of donor factors for posttransplant liver function was evaluated in the model of orthotopic rearterialized liver transplantation in the rat. The effect of donor fasting, parenteral hyperalimentation, hypotension, warm ischemia and endotoxins on histology, clinical chemistry and MEGX test was analyzed in syngeneic and allogeneic recipients of livers stored for 4 hrs on ice. In syngeneic animals, 20 min of warm ischemia led to significantly elevated serum transaminase levels and degree 2 histological damage on POD 2. Endotoxins produced a grade 1 histological damage. All groups had a lower MEGX formation rate compared to controls. In allogeneic animals, warm ischemia was the single most detrimental parameter. The strength of the rejection response on POD 8 did not depend on the type of donor pretreatment. The major finding of this non-survival study is the deleterious effect of warm ischemia and endotoxin on the functional and structural integrity of liver grafts after 4 hrs of cold ischemia.

Glycosphingolipids of skeletal muscle: I. Subcellular distribution of neutral glycosphingolipids and gangliosides in rabbit skeletal muscle

Membrane vesicles were prepared from rabbit skeletal muscle, separated by sucrose density gradient centrifugation and characterized by their specific marker enzymes, ligand binding, and ion flux activities. The fractions obtained (in the order of increasing density) were sarcolemma (SL), T-tubules (TT), sarcoplasmic reticulum (SR1 and SR2) and triads/mitochondria (Tr/M). Their glycosphingolipid compositions were analyzed by biochemical and immunochemical methods with specific antibodies (TLC immunostaining) and characteristic patterns were obtained from respective membrane fractions, expressed on a protein basis. Glucosylceramide, the main neutral glycosphingolipid of rabbit muscle, was found in SL and TT fractions, whereas SR and Tr/M vesicles lack this compound. Lactosylceramide was selectively recovered in the SR1 fraction. GM3(Neu5Ac), the main ganglioside in rabbit muscle, was found to account for 64% in the SL, 13% in the TT, 7% in the SR1, 3% in the SR2 and 13% in the Tr/M fractions. IV3Neu5Ac-nLcOse4Cer was mostly abundant in SL and decreased in the order SL > TT, Tr/M > SR1, SR2. IV6Neu5Ac-nLcOse4Cer was only detected in the SL and Tr/M fractions in noteworthy quantities. Ganglioseries gangliosides GM1, GD1a, GD1b and GT1b displayed homogeneous distribution patterns in each membrane preparation. They were expressed only in small amounts but mainly in SL, TT and Tr/M vesicles and to less extent in SR1 and SR2 fractions. The presence of GM3(Neu5Ac) in the SL as well as on subcellular level was confirmed in transverse muscle cryosections by means of indirect immunofluorescence microscopy. The SL was brightly stained, but considerable intracellular fluorescence was observed as expected from the biochemical analyses. Thus, the neutral GSL and ganglioside expression of the SL and the intracellular membraneous network is different in skeletal muscle both in terms of quantitative and qualitative GSL composition as demonstrated in details by means of biochemical and immunochemical techniques. The modulatory functions of GM3 and gangliosides of the neolacto- and ganglio-series towards the voltage dependent Ca(2+)-channel, largely preponderant in the triads-containing Tr/M fraction, is the subject of the accompanying paper (J. Müthing, U. Maurer, and S. Weber-Schürholz, Carbohydr. Res., 307 (1998) 147-157).

Prophylactic use of low-dose urodilatin for prevention of renal impairment following liver transplantation: a randomized placebo-controlled study

Many therapeutic measures have been employed to prevent or at least ameliorate postoperative renal impairment following liver transplantation. Recent clinical phase II studies have demonstrated that the new natriuretic peptide urodilatin has beneficial effects on renal function following heart and liver transplantation. The present study reports the first prospective randomized placebo-controlled trial of prophylactic urodilatin administration following liver transplantation. Seventy consecutive recipients of primary liver transplants were included in the study following randomization, and 33 patients continuously received urodilatin at a dose of 20 ng/kg/min for 7 d. The remaining 37 patients received a placebo infusion for the same time period. The course of serum creatinine and urea did not differ between the two groups nor did the daily urine production. However, the urodilatin group showed a higher preoperative median serum creatinine and a significant reduction on days 1 and 2, whereas this observation was not made in the placebo group. Furthermore, less furosemide was administered to the patients in the urodilatin group during the first 2 d. The incidence of postoperative hemodialysis and the number of treatments did not differ between the groups either (urodilatin group 4, vs. placebo group 6 and 22 for both groups, respectively). Side effects of the urodilatin therapy were not detected. The prophylactic low-dose urodilatin administration resulted in a trend towards amelioration of the renal function, but did not result in significant differences between the two experimental groups. Further studies, using higher doses, will be required to define the value of urodilatin for prevention of renal impairment after liver transplantation.

De novo malignancies after liver transplantation using tacrolimus-based protocols or cyclosporine-based quadruple immunosuppression with an interleukin-2 receptor antibody or antithymocyte globulin

BACKGROUND

Although conventional immunosuppression after liver transplantation consists of cyclosporine A (CsA), steroids, and azathioprine, recently introduced protocols entail CsA-based quadruple induction protocols or tacrolimus-based combinations. These protocols aim to reduce the rejection rate and the considerable morbidity related to the side effects of additional immunosuppressive treatment, but have not yet been analyzed regarding their long term de novo neoplastic risk.

METHODS

From September 1988 to May 1994, 500 liver transplantations were performed in 458 patients. The median follow-up was 50 months (range, 0.3-97 months) for all patients. Conventional triple therapy was implemented in 25 patients, CsA-based quadruple induction therapy using an antilymphocyte globulin preparation (ATG) in 190 patients, an interleukin-2 receptor antibody (BT563) in 141 patients, and tacrolimus-based dual or triple immunosuppression in 102 patients. The different protocols were evaluated in four randomized and two nonrandomized prospective trials.

RESULTS

De novo neoplasias were detected in 33 patients (7.2%) and were comprised of lymphomas (n = 7), skin malignancies (n = 8 lesions in 7 patients), intraepithelial neoplasias of the cervix uteri (n = 7), breast carcinoma (n = 3), lung carcinoma (n = 3), and other malignancies (n = 6). The incidence of de novo neoplasias did not differ in the different trial arms. Only a positive T-crossmatch and a low CD4+/CD8+ ratio in patients receiving CsA-based immunosuppression demonstrated a significant correlation with the development of a de novo tumor in a multivariant logistic regression analysis.

CONCLUSIONS

The development of de novo neoplastic diseases after liver transplantation with the use of CsA-based quadruple induction protocols or tacrolimus-based regimens for immunosuppresion was assessed over the long term. Recently introduced immunosuppressive protocols did not alter the posttransplant de novo tumor rate. Patients with a low CD4+/CD8+ ratio during CsA-based therapy or a positive T-crossmatch were identified to be at an increased risk for the development of a de novo malignancy.

De novo malignancies after liver transplantation using tacrolimus-based protocols or cyclosporine-based quadruple immunosuppression with an interleukin-2 receptor antibody or antithymocyte globulin

BACKGROUND

Although conventional immunosuppression after liver transplantation consists of cyclosporine A (CsA), steroids, and azathioprine, recently introduced protocols entail CsA-based quadruple induction protocols or tacrolimus-based combinations. These protocols aim to reduce the rejection rate and the considerable morbidity related to the side effects of additional immunosuppressive treatment, but have not yet been analyzed regarding their long term de novo neoplastic risk.

METHODS

From September 1988 to May 1994, 500 liver transplantations were performed in 458 patients. The median follow-up was 50 months (range, 0.3-97 months) for all patients. Conventional triple therapy was implemented in 25 patients, CsA-based quadruple induction therapy using an antilymphocyte globulin preparation (ATG) in 190 patients, an interleukin-2 receptor antibody (BT563) in 141 patients, and tacrolimus-based dual or triple immunosuppression in 102 patients. The different protocols were evaluated in four randomized and two nonrandomized prospective trials.

RESULTS

De novo neoplasias were detected in 33 patients (7.2%) and were comprised of lymphomas (n = 7), skin malignancies (n = 8 lesions in 7 patients), intraepithelial neoplasias of the cervix uteri (n = 7), breast carcinoma (n = 3), lung carcinoma (n = 3), and other malignancies (n = 6). The incidence of de novo neoplasias did not differ in the different trial arms. Only a positive T-crossmatch and a low CD4+/CD8+ ratio in patients receiving CsA-based immunosuppression demonstrated a significant correlation with the development of a de novo tumor in a multivariant logistic regression analysis.

CONCLUSIONS

The development of de novo neoplastic diseases after liver transplantation with the use of CsA-based quadruple induction protocols or tacrolimus-based regimens for immunosuppresion was assessed over the long term. Recently introduced immunosuppressive protocols did not alter the posttransplant de novo tumor rate. Patients with a low CD4+/CD8+ ratio during CsA-based therapy or a positive T-crossmatch were identified to be at an increased risk for the development of a de novo malignancy.

Inhibition of cathepsin G by 4H-3,1-benzoxazin-4-ones

A series of 4H-3,1-benzoxazin-4-ones is reported that inhibit the serine proteases human cathepsin G and bovine chymotrypsin. The synthesis and kinetic parameters of the alkaline hydrolysis is described. These compounds act as acyl-enzyme inhibitors of both enzymes. The reaction of cathepsin G with 2-benzylamino-4H-3,1-benzoxazin-4-one (20) was studied in detail. A partition in deacylation of the initially formed acyl-enzyme was observed, leading to the formation of 2-(3-benzylureido)benzoic acid (26) and 3-benzylquinazoline-2,4-(1H,3H)-dione (27). A 6-methyl substitution strongly increased the acylation rate of both proteases. Introduction of an aryl moiety into the 2-substituent led to compounds with Ki values towards cathepsin G in the nanomolar range. Their inhibitory potency is stronger than that of other synthetic inhibitors of cathepsin G.

De novo malignancies after liver transplantation using tacrolimus-based protocols or cyclosporine-based quadruple immunosuppression with an interleukin-2 receptor antibody or antithymocyte globulin

BACKGROUND

Although conventional immunosuppression after liver transplantation consists of cyclosporine A (CsA), steroids, and azathioprine, recently introduced protocols entail CsA-based quadruple induction protocols or tacrolimus-based combinations. These protocols aim to reduce the rejection rate and the considerable morbidity related to the side effects of additional immunosuppressive treatment, but have not yet been analyzed regarding their long term de novo neoplastic risk.

METHODS

From September 1988 to May 1994, 500 liver transplantations were performed in 458 patients. The median follow-up was 50 months (range, 0.3-97 months) for all patients. Conventional triple therapy was implemented in 25 patients, CsA-based quadruple induction therapy using an antilymphocyte globulin preparation (ATG) in 190 patients, an interleukin-2 receptor antibody (BT563) in 141 patients, and tacrolimus-based dual or triple immunosuppression in 102 patients. The different protocols were evaluated in four randomized and two nonrandomized prospective trials.

RESULTS

De novo neoplasias were detected in 33 patients (7.2%) and were comprised of lymphomas (n = 7), skin malignancies (n = 8 lesions in 7 patients), intraepithelial neoplasias of the cervix uteri (n = 7), breast carcinoma (n = 3), lung carcinoma (n = 3), and other malignancies (n = 6). The incidence of de novo neoplasias did not differ in the different trial arms. Only a positive T-crossmatch and a low CD4+/CD8+ ratio in patients receiving CsA-based immunosuppression demonstrated a significant correlation with the development of a de novo tumor in a multivariant logistic regression analysis.

CONCLUSIONS

The development of de novo neoplastic diseases after liver transplantation with the use of CsA-based quadruple induction protocols or tacrolimus-based regimens for immunosuppresion was assessed over the long term. Recently introduced immunosuppressive protocols did not alter the posttransplant de novo tumor rate. Patients with a low CD4+/CD8+ ratio during CsA-based therapy or a positive T-crossmatch were identified to be at an increased risk for the development of a de novo malignancy.

Characterization of porin from Roseobacter denitrificans

Porin from Roseobacter denitrificans was isolated and purified to homogeneity. The pore characteristics from this marine bacterium were compared to those of its phylogenetically closely related freshwater bacteria Rhodobacter capsulatus, Rhodobacter sphaeroides and Rhodopseudomonas blastica. The porin formed weakly cation-selective, general diffusion pores in lipid bilayer membranes. High transmembrane potentials caused channel closing in steps that were of one or two thirds of the initial on-steps indicating that the porin of R. denitrificans comprised three more or less independent channels similar to PhoE and OmpC of Escherichia coli and the porin of Rhodobacter capsulatus. 37b4 Prediction of the secondary structure of the 36 N-terminal amino acid residues indicated two transmembrane beta-strands similar to those of the porins of Rhodobacter capsulatus 37b4 and Rhodopseudomonas blastica. Differences of the single channel conductivities between the porin of R. denitrificans and those of the related freshwater bacteria show that R. denitrificans evolved porin channels that are well adapted to the marine habitat.

[Pilot study on the prevalence of Ornithobacterium rhinotracheale infections in food chickens in northwest Germany]

Samples of sera from broiler chicken and broiler chicken breeder flocks of North Western Germany were examined for presence of antibodies against Ornithobacterium (O.) rhinotracheale with a self-developed ELISA system. A total of 3600 samples of sera from 190 broiler flocks in 70 different farms were tested. In 332 samples of sera (9.4%) from 25 flocks (13.2%) in 22 farms specific antibodies were detected. Additionally, serum samples from the breeder hens, taken between the 9, and 61, weeks of age were tested. In 28 from 29 flocks (96.6%) specific antibodies were detected using this ELISA-system. First detectable antibodies were found between the 14, and 36, week of age in the parent breeder flocks. These results show that infections with O. rhinotracheale are widely distributed in the parent-breeder chicken broiler flocks. The significance of this bacterium as the cause of respiratory diseases in chickens are discussed.

A prospective randomized trial comparing interleukin-2 receptor antibody versus antithymocyte globulin as part of a quadruple immunosuppressive induction therapy following orthotopic liver transplantation

BACKGROUND

Quadruple immunosuppressive induction therapy has been shown to markedly reduce the incidence of acute rejection episodes without increasing the incidence of infectious complications after liver transplantation. However, the use of polyclonal antibody preparations (e.g. antithymocyte globulin [ATG]) is associated with side effects such as fever and tachycardia. To evaluate the efficacy and the safety of a monoclonal antibody directed against the interleukin-2 receptor (BT563) in comparison with ATG as part of a quadruple induction regimen, a prospective, randomized study was conducted.

METHODS

Eighty consecutive adult recipients of primary orthotopic liver transplants were randomized to receive either BT563 (10 mg/day; days 0-12; n=39) or ATG (5 mg/kg/day; days 0-6; n=41) in addition to the standard immunosuppressive protocol consisting of cyclosporine, and prednisolone, and azathioprine.

RESULTS

Patients treated with BT563 had a significantly lower incidence of steroid-sensitive rejection episodes (3 vs. 11; P<0.025) and also significantly fewer drug-related side effects (4 vs. 18, P<0.038) when compared with patients treated with ATG. The incidence of infectious complications was not different between the two groups. Patient survival did not differ significantly between the two groups (84.6% at 1, 2, and 3 years in the BT563 group and 90.2% at 1 year and 87.8% at 2 and 3 years for the ATG group). Analysis of graft function showed an advantage for the BT563 group in terms of postoperative bilirubin levels. However, no differences were observed in long-term follow-up between the two groups.

CONCLUSIONS

Our results indicate that treatment with anti-interleukin-2 receptor antibody as part of quadruple induction therapy after orthotopic liver transplantation is safe and effective and shows fewer steroid-sensitive rejection episodes as well as fewer side effects when compared with quadruple induction therapy including ATG.