SIRPγ-CD47 Interaction Positively Regulates the Activation of Human T Cells in Situation of Chronic Stimulation.

A numerous number of positive and negative signals via various molecules modulate T-cell activation. Within the various transmembrane proteins, SIRPγ is of interest since it is not expressed in rodents. SIRPγ interaction with CD47 is reevaluated in this study. Indeed, we show that the anti-SIRPγ mAb clone LSB2.20 previously used by others has not been appropriately characterized. We reveal that the anti-SIRPα clone KWAR23 is a Pan anti-SIRP mAb which efficiently blocks SIRPα and SIRPγ interactions with CD47. We show that SIRPγ expression on T cells varies with their differentiation and while being expressed on Tregs, is not implicated in their suppressive functions. SIRPγ spatial reorganization at the immune synapse is independent of its interaction with CD47. In vitro SIRPα-γ/CD47 blockade with KWAR23 impairs IFN-γ secretion by chronically activated T cells. In vivo in a xeno-GvHD model in NSG mice, the SIRPγ/CD47 blockade with the KWAR23 significantly delays the onset of the xeno-GvHD and deeply impairs human chimerism. In conclusion, we have shown that T-cell interaction with CD47 is of importance notably in chronic stimulation.

γδ T Cell-Secreted XCL1 Mediates Anti-CD3-Induced Oral Tolerance.

Oral tolerance is defined as the specific suppression of cellular and/or humoral immune responses to an Ag by prior administration of the Ag through the oral route. Although the investigation of oral tolerance has classically involved Ag feeding, we have found that oral administration of anti-CD3 mAb induced tolerance through regulatory T (Treg) cell generation. However, the mechanisms underlying this effect remain unknown. In this study, we show that conventional but not plasmacytoid dendritic cells (DCs) are required for anti-CD3-induced oral tolerance. Moreover, oral anti-CD3 promotes XCL1 secretion by small intestine lamina propria γδ T cells that, in turn, induces tolerogenic XCR1+ DC migration to the mesenteric lymph node, where Treg cells are induced and oral tolerance is established. Consistent with this, TCRδ-/- mice did not develop oral tolerance upon oral administration of anti-CD3. However, XCL1 was not required for oral tolerance induced by fed Ags, indicating that a different mechanism underlies this effect. Accordingly, oral administration of anti-CD3 enhanced oral tolerance induced by fed MOG35-55 peptide, resulting in less severe experimental autoimmune encephalomyelitis, which was associated with decreased inflammatory immune cell infiltration in the CNS and increased Treg cells in the spleen. Thus, Treg cell induction by oral anti-CD3 is a consequence of the cross-talk between γδ T cells and tolerogenic DCs in the gut. Furthermore, anti-CD3 may serve as an adjuvant to enhance oral tolerance to fed Ags.

Development and Evaluation of Tri-Functional Immunoliposomes for the Treatment of HER2 Positive Breast Cancer.

PURPOSE: Trastuzumab combined with Doxorubicin (DOX) demonstrates significant clinical activity in human epidermal growth factor receptor-2 (HER2)-positive breast cancer (BC). However, emergence of treatment resistance and trastuzumab associated cardiotoxicity remain clinical challenges. In an effort to improve patient outcome, we have developed and evaluated novel tri-functional immunoliposomes (TFIL) that target HER2-receptors on BC cells and CD3-receptors on T-lymphocytes, and deliver DOX. METHODS: Trastuzumab (anti-HER2) and OKT-3 (anti-CD3) antibodies were conjugated to liposomes using a micelle-transfer method. Cytotoxicity of targeted immunoliposomes loaded with DOX was examined in vitro on HER2-positive BC cells (BT474), with peripheral blood monocytic cells (PBMC) as immune effector cells. RESULTS: TFIL demonstrated high antibody-liposome conjugation ratios (100-130 µg protein/µmol phospholipid) and cargo capacity (0.21 mol:mol drug:lipid), highly efficient DOX loading (>90%), a particle size favorable for extended circulation (~150 nm), and good stability (up to 3 months at 4°C). In the presence of PBMCs, TFIL showed complete killing of BT474 cells, and were superior to mono-targeted trastuzumab-bearing liposomes, non-targeted liposomes, and free Trastuzumab and DOX. CONCLUSIONS: Novel anti-HER2xCD3 + DOX TFIL show promise as a means to both engage immune cells against HER2 positive breast cancer cells and deliver chemotherapy, and have the potential to improve clinical outcomes.

IL-10-dependent Tr1 cells attenuate astrocyte activation and ameliorate chronic central nervous system inflammation.

SEE WINGER AND ZAMVIL DOI101093/BRAIN/AWW121 FOR A SCIENTIFIC COMMENTARY ON THIS ARTICLE: The innate immune system plays a central role in the chronic central nervous system inflammation that drives neurological disability in progressive forms of multiple sclerosis, for which there are no effective treatments. The mucosal immune system is a unique tolerogenic organ that provides a physiological approach for the induction of regulatory T cells. Here we report that nasal administration of CD3-specific antibody ameliorates disease in a progressive animal model of multiple sclerosis. This effect is IL-10-dependent and is mediated by the induction of regulatory T cells that share a similar transcriptional profile to Tr1 regulatory cells and that suppress the astrocyte inflammatory transcriptional program. Treatment results in an attenuated inflammatory milieu in the central nervous system, decreased microglia activation, reduced recruitment of peripheral monocytes, stabilization of the blood-brain barrier and less neurodegeneration. These findings suggest a new therapeutic approach for the treatment of progressive forms of multiple sclerosis and potentially other types of chronic central nervous system inflammation.

Oral Administration of OKT3 MAb to Patients with NASH, Promotes Regulatory T-cell Induction, and Alleviates Insulin Resistance: Results of a Phase IIa Blinded Placebo-Controlled Trial.

UNLABELLED: Oral administration of anti-CD3 antibodies induced regulatory T cells (Tregs) alleviating the insulin resistance and liver damage in animal models. OBJECTIVE: To determine the safety and biological effects of oral OKT3 monoclonal antibody (Balashov et al. Neurology 55:192-8, 2000) in patients with NASH. DESIGN: In this Phase-IIa trial, four groups of patients with biopsy-proven NASH (n = 9/group) received placebo (group A) or oral OKT3 (group B: 0.2; C: 1.0; D: 5.0 mg/day) for 30 days. Patients were followed for safety, liver enzymes, glucose, lipid profile, oral glucose tolerance test (OGTT), serum cytokines and Tregs. RESULTS: Oral OKT3 was well tolerated without treatment-related adverse events. OKT3 induced Tregs: with significant increases of CD4(+)LAP(+) (Latency associated peptide) and CD4(+)CD25(+)LAP(+) cells in Group D, and a significant increase in TGF-ß in Groups C and D. AST decreased significantly in group D and a trend in Groups B and C. Fasting plasma glucose decreased significantly in all treatment groups compared with placebo. OGTT decreased significantly in Group D. Correlations were observed between the changes in several immune-modulatory effects and clinical biomarkers. While serum anti-CD3 levels where undetectable increases in human anti-mouse antibody levels were observed in Groups C and D. CONCLUSION: Oral administration of anti-CD3 MAb to patients with NASH was safe and well tolerated. Positive biological effects were noted in several hepatic, metabolic and immunologic parameters. These findings provide the basis for future trials to investigate the effect of oral anti-CD3 MAb immunotherapy in patients with NASH.

Long-term stability of T-cell activation and transduction components critical to the processing of clinical batches of gene-engineered T cells.

BACKGROUND AIMS: The generation of gene-modified T cells for clinical adoptive T-cell therapy is challenged by the potential instability and concomitant high financial costs of critical T-cell activation and transduction components. As part of a clinical trial to treat patients with metastatic renal cell cancer with autologous T cells engineered with a chimeric antigen receptor (CAR) recognizing carboxy-anhydrase-IX (CAIX), we evaluated functional stability of the retroviral vector, T-cell activation agent Orthoclone OKT3 (Janssen-Cilag, Beerse, Belgium) monoclonal antibody (mAb) and the transduction promoting agent RetroNectin (Takara, Otsu, Japan). METHODS: Carboxy-anhydrase-IX chimeric antigen receptor retrovirus-containing culture supernatants (RTVsups) were generated from two packaging cell lines, Phoenix-Ampho (BioReliance, Sterling, UK) and PG13, and stored at -80°C over 10 years and 14 years. For Orthoclone OKT3 and RetroNectin, aliquots for single use were prepared and stored at -80°C. Transduction efficiencies of both batches of RTVsups were analyzed using the same lots of cryopreserved donor peripheral blood mononuclear cells, Orthoclone OKT3 and RetroNectin over time. RESULTS: We revisit here an earlier report on the long-term functional stability of the RTVsup, observed to be 9 years, and demonstrate that this stability is at least 14 years. Also, we now demonstrate that Orthoclone OKT3 and RetroNectin are functionally stable for periods of at least 6 years and 10 years. CONCLUSIONS: High-cost critical components for adoptive T-cell therapy can be preserved for ≥10 years when prepared in aliquots for single use and stored at -80°C. These findings may significantly facilitate, and decrease the financial risks of, clinical application of gene-modified T cells in multicenter studies.

Newly defined clinical features and treatment experience of seventh day syndrome following living donor liver transplantation.

AIM: The aim of this study was to describe a unique Seventh-Day Syndrome (7DS) in our liver transplantation center. METHODS: We performed a retrospective analysis of 244 cases of adult living donor liver transplantations (LDLT) performed in our liver transplantation center from January 1995 to January 2009. RESULTS: Since 2005, we identified 8 cases of 7DS. Previously reported features for 7DS include a rapid deterioration of liver function followed by renal failure and a sudden peak in liver enzyme levels around day 7. In addition, the following attributes have been observed in our patients: (1) all recipients were males while the donors included both genders; (2) most patients showed increased levels of irritability; (3) color Doppler revealed reduced blood flow or bidirectional blood flow in the portal vein; (4) coagulation necrosis was observed with disruption of lobular architecture and increased expression of death receptor Fas in all examined patients; (5) after onset, a steroid pulse with or without OKT3 therapy showed minimal effect; (6) a abrupt increase in liver enzymes was noted 1-2 days after intravenous (IV) methylprednisolone was switched to oral immunosuppressants; and (7) extension of IV methylprednisolone treatment delayed the occurrence from 8 to 11 days postoperatively. CONCLUSIONS: 7DS is a distinct entity associated with early graft dysfunction, which is associated with a high rate of mortality and need for retransplantation. Coagulation necrosis and Fas receptor activation may be implicated in the occurrence of 7DS. Our study supported the hypothesis that 7DS may be associated with an undefined immune response. Our experience extending IV methylprednisolone treatment seeking to delay occurrence and reduce mortality provided a possible therapeutic approach for 7DS.

Teplizumab for treatment of type 1 diabetes (Protégé study): 1-year results from a randomised, placebo-controlled trial.

BACKGROUND: Findings of small studies have suggested that short treatments with anti-CD3 monoclonal antibodies that are mutated to reduce Fc receptor binding preserve ß-cell function and decrease insulin needs in patients with recent-onset type 1 diabetes. In this phase 3 trial, we assessed the safety and efficacy of one such antibody, teplizumab. METHODS: In this 2-year trial, patients aged 8-35 years who had been diagnosed with type 1 diabetes for 12 weeks or fewer were enrolled and treated at 83 clinical centres in North America, Europe, Israel, and India. Participants were allocated (2:1:1:1 ratio) by an interactive telephone system, according to computer-generated block randomisation, to receive one of three regimens of teplizumab infusions (14-day full dose, 14-day low dose, or 6-day full dose) or placebo at baseline and at 26 weeks. The Protégé study is still underway, and patients and study staff remain masked through to study closure. The primary composite outcome was the percentage of patients with insulin use of less than 0·5 U/kg per day and glycated haemoglobin A(1c) (HbA(1C)) of less than 6·5% at 1 year. Analyses included all patients who received at least one dose of study drug. This trial is registered with ClinicalTrials.gov, number NCT00385697. FINDINGS: 763 patients were screened, of whom 516 were randomised to receive 14-day full-dose teplizumab (n=209), 14-day low-dose teplizumab (n=102), 6-day full-dose teplizumab (n=106), or placebo (n=99). Two patients in the 14-day full-dose group and one patient in the placebo group did not start treatment, so 513 patients were eligible for efficacy analyses. The primary outcome did not differ between groups at 1 year: 19·8% (41/207) in the 14-day full-dose group; 13·7% (14/102) in the 14-day low-dose group; 20·8% (22/106) in the 6-day full-dose group; and 20·4% (20/98) in the placebo group. 5% (19/415) of patients in the teplizumab groups were not taking insulin at 1 year, compared with no patients in the placebo group at 1 year (p=0·03). Across the four study groups, similar proportions of patients had adverse events (414/417 [99%] in the teplizumab groups vs 98/99 [99%] in the placebo group) and serious adverse events (42/417 [10%] vs 9/99 [9%]). The most common clinical adverse event in the teplizumab groups was rash (220/417 [53%] vs 20/99 [20%] in the placebo group). INTERPRETATION: Findings of exploratory analyses suggest that future studies of immunotherapeutic intervention with teplizumab might have increased success in prevention of a decline in ß-cell function (measured by C-peptide) and provision of glycaemic control at reduced doses of insulin if they target patients early after diagnosis of diabetes and children. FUNDING: MacroGenics, the Juvenile Diabetes Research Foundation, and Eli Lilly.

[Clinical study of single-dose of recombinant humanized anti-CD3 monoclonal antibody injection in kidney transplant recipients].

OBJECTIVE: To evaluate short-term and long-term safety of using single-dose escalation of recombinant humanized anti-CD3 monoclonal antibody (OKT3) in kidney transplantation recipients. METHODS: A total of 29 recipients of cadaveric kidney transplant from June 2008 to December 2008 were sequently assigned to receive single-dose intravenous injection of OKT3 with different doses of 2.5 mg (n = 9), 5.0 mg (n = 10) and 10.0 mg (n = 10) at Days 7 - 14 post-operation. Meanwhile, a control group was established by selecting kidney transplant recipients, who did not participate in the trial in the same period. All patients were followed up for at least 2 years. During this period, liver function, kidney function, hemoglobin and other biochemical indicators were monitored and adverse events recorded over time. RESULTS: No obvious first dose effect was observed, except low heat (7/29), chills (4/29), mild liver damage (2/29), upper respiratory tract infection and headache (1/29) across all doses. Other adverse reactions were mild, unrelated with doses. The 2-year patients/grafts survival rates of treatment group and control group were 100%/100%, and 100%/97%, respectively. The incidence of acute rejection confirmed by renal biopsy was 6.9% (2/29) and 10.0% (3/30) in treatment group and control group, respectively. The incidence of lung infection was 10.3% (3/29) and 13.3% (4/30), respectively. The values of serum creatinine at 1 week and 3, 6, 12, 24 months showed no statistically significance in two groups (all P > 0.05). CONCLUSION: It is safe to use single-shot OKT3 intravenously in kidney transplant recipients. The recombinant humanized OKT3 may be an effective immunosuppressive agent with milder toxicity for solid organ transplantation.

Induction treatment with monoclonal antibodies for heart transplantation.

Individualization of induction therapy for heart transplantation (HT) is needed, given that only patients at significant risk for fatal rejection seem to present a favorable risk-benefit ratio. The question whether monoclonal interleukin 2 antagonists or antilymphocyte antibodies should be recommended remains unanswered. As most studies suggest that they have similar efficacy in preventing acute rejection, other variables related to safety or management costs should be taken into account. The cytokine release syndrome, associated with the use of OKT3, complicates management of HT patient. The experience in our center with 2 consecutive cohorts, treated with basiliximab (BAS) and OKT3, respectively, suggests that the use of BAS is associated, in addition to similar immunosuppressive efficacy and better safety profile than OKT3, with simpler patient management during the initial hospital stay, which could be associated with a reduction in posttransplant costs. Because few centers continue to use OKT3 as induction therapy in HT, more studies comparing cost-effectiveness of BAS vs polyclonal antilymphocyte antibodies (ATG) are needed.

Muromonab-CD3 therapy for refractory rejections after liver transplantation: a single-center experience during two decades in Japan.

BACKGROUND/PURPOSE: Refractory rejections still occur in the liver transplantation (LT) field. The aim of this study was to investigate significant factors for the introduction of therapy with muromonab-CD3 (MCD3) after LT. METHODS: A total of 1415 LT patients were retrospectively evaluated, and 11 of the recipients received MCD3 therapy because of steroid-resistant rejections. The clinical factors before LT and before MCD3 therapy were investigated. RESULTS: The recipients were retrospectively divided into two groups based on responses to MCD3 therapy, including their clinical courses after MCD3 therapy and their outcomes. The MCD3 therapy had positive effects in LT recipients with the following four factors: low score of model for end-stage liver disease or pediatric end-stage liver disease; earlier time point of the first incidence of rejection; more frequent steroid pulse therapy (SPT) within 2 weeks after LT; and the expression of CD3 in the peripheral blood before MCD3 introduction. CONCLUSION: Optimal induction of MCD3 triggered recovery from refractory rejections, especially in LT recipients in a stable condition, but not in those in a critical or compromised condition.

Oral administration of OKT3 monoclonal antibody to human subjects induces a dose-dependent immunologic effect in T cells and dendritic cells.

INTRODUCTION: Parenteral OKT3 is used to treat transplant rejection and a humanized anti-CD3 Mab has shown positive clinical effects in new onset diabetes. Oral administration of anti-CD3 has not been tested in humans, but suppresses autoimmunity in animal models. Beta-glucosylceramide enhances NKT cell and regulatory T cell activity and enhances the effects of oral anti-CD3 in animals. MATERIALS AND METHODS: Fifteen healthy volunteers (three per group) received orally administered OKT3 over a dose range of 0.2 to 5.0 mg daily with or without beta-glucosylceramide 7.5 mg for 5 days. Safety and immune parameters were measured on days 5, 10, and 30. RESULTS AND DISCUSSION: Oral OKT3 enhanced T cell proliferation, suppressed Th1 and Th17 responses by 43% and 41%, respectively, increased TGF-beta/IL-10 expression and decreased IL-23/IL-6 expression by dendritic cells, and affected the IgG repertoire as measured by antigen arrays. Co-administration of oral beta-glucosylceramide induced similar effects. No side effects were observed and no subjects developed human anti-mouse antibodies. CONCLUSION: These findings demonstrate that oral anti-CD3 monoclonal antibody is safe and biologically active in humans and presents a new avenue for the treatment of autoimmune diseases.

Usefulness of immunosuppression for giant cell myocarditis.

Giant cell myocarditis (GCM) is a rare and highly lethal disorder. The only multicenter case series with treatment data lacked cardiac function assessments and had a retrospective design. We conducted a prospective, multicenter study of immunosuppression including cyclosporine and steroids for acute, microscopically-confirmed GCM. From June 1999 to June 2005 in a standard protocol, 11 subjects received high dose steroids and cyclosporine, and 9 subjects received muromonab-CD3. In these, 7 of 11 were women, the mean age was 60 +/- 15 years, and the mean time from symptom onset to presentation was 27 +/- 33 days. During 1 year of treatment, 1 subject died of respiratory complications on day 178, and 2 subjects received heart transplantations on days 2 and 27, respectively. Serial endomyocardial biopsies revealed that after 4 weeks of treatment the degree of necrosis, cellular inflammation, and giant cells decreased (p = 0.001). One patient who completed the trial subsequently died of a fatal GCM recurrence after withdrawal of immunosuppression. Her case demonstrates for the first time that there is a risk of recurrent, sometimes fatal, GCM after cessation of immunosuppression. In conclusion, this prospective study of immunosuppression for GCM confirms retrospective case reports that such therapy improves long-term survival. Additionally, withdrawal of immunosuppression can be associated with fatal GCM recurrence.

Delayed onset of cardiac allograft vasculopathy by induction therapy using anti-thymocyte globulin.

BACKGROUND: In this study we sought to compare the long-term effects of anti-thymocyte globulin (ATG) and muromonab-CD3 (OKT3) as induction therapy after heart transplantation, with special regard to cardiac allograft vasculopathy (CAV), post-transplant infections, post-transplant non-skin cancers and patient survival. METHODS: From 1988 to 1991, 25 heart transplant patients received OKT3 as induction treatment. Accordingly, 25 consecutive patients who received ATG and 25 consecutive patients without induction therapy were enrolled. RESULTS: At a follow-up period of 13.4 +/- 4.6 years, time to onset of non-significant and significant CAV was 8.77 +/- 3.38 and 11.60 +/- 4.28 years, respectively, in the ATG group, which was significantly delayed compared with 5.71 +/- 3.08 and 7.44 +/- 2.74 years, respectively, in the non-induction group. In the OKT3 group, time to onset of non-significant and significant CAV (6.10 +/- 2.73 and 7.86 +/- 3.19 years, respectively) did not differ significantly from the non-induction group. Ten- and 15-year actuarial survival rates of ATG- and OKT3-treated patients were not significantly different from those of patients without induction treatment. CONCLUSIONS: Our study suggests the long-term advantage of ATG in prevention of cardiac allograft vasculopathy. In contrast, OKT3 failed to show such benefit. However, induction therapy with either ATG or OKT3 did not exhibit a significant beneficial effect on long-term patient survival.

Haploidentical allogeneic hematopoietic cell transplantation in adults using CD3/CD19 depletion and reduced intensity conditioning: an update.

Haploidentical hematopoietic cell transplantation (HHCT) after high dose conditioning with CD34-selected stem cells has been complicated by high regimen related toxicities, slow engraftment and delayed immune reconstitution leading to increased treatment related mortality (TRM). A new regimen using reduced intensity conditioning (RIC) and graft CD3/CD19 depletion with anti-CD3 and anti-CD19 coated microbeads on a CliniMACS device may allow HHCT with lower toxicity and faster engraftment. CD3/CD19 depleted grafts not only contain CD34+ stem cells but also CD34 negative progenitors, natural killer, graft facilitating and dendritic cells. RIC was performed with fludarabine (150-200 mg/m(2)), thiotepa (10 mg/kg), melphalan (120 mg/m(2)) and OKT-3 (5 mg/day, day -5 to +14) and no posttransplant immunosuppression. Twenty nine patients (median age=42 (range, 21-59) years) have been transplanted with this regimen. Diagnosis were AML (n=16), ALL (n=7), NHL (n=3), MM (n=2) and CML (n=1). Patients were "high risk" with refractory disease or relapse after preceding HCT. The CD3/CD19 depleted haploidentical grafts contained a median of 7.6x10(6) (range, 3.4-17x10(6)) CD34+ cells/kg, 4.4x10(4) (range, 0.006-44x10(4)) CD3+ T cells/kg and 7.2x10(7) (range, 0.02-37.3x10(7)) CD56+ cells/kg. Donor-recipient KIR-ligand-mismatch was found in 19 of 29 patients. The regimen was well tolerated with maximum acute toxicity being grade 2-3 mucositis. Because of severe neurotoxicity in 4 patients treated with 200 mg/m(2) fludarabine, the dose was reduced to 150 mg/m(2). Engraftment was rapid with a median time to >500 granulocytes/microL of 12 (range, 10-21) days, >20,000 platelets/microL of 11 (range, 7-38) days and full donor chimerism after 2-4 weeks in all patients. Incidence of grade II-IV degrees GVHD was 48% with grade II degrees =10, III degrees =2 and IV degrees =2. One patient, who received the highest T-cell dose, developed lethal grade IV GVHD. TRM in the first 100 days was 6/29 (20%) with deaths due to idiopathic pneumonia syndrome (n=1), mucormycosis (n=1), pneumonia (n=3) or GVHD (n=1). Overall survival is 9/29 patients (31%) with deaths due to infections (n=7), GVHD (n=1) and relapse (n=12) with a median follow-up of 241 days (range, 112-1271). In conclusion, this regimen is promising in high risk patients lacking a suitable donor, and a prospective phase I/II study is ongoing.

Monoclonal antibodies as targeting and therapeutic agents: prospects for liver transplantation, hepatitis and hepatocellular carcinoma.

1. Monoclonal antibodies (mAbs) of high specificity and stability have become key resources in the therapeutic, diagnostic and drug discovery fields to treat various immunological disorders and malignancies of different organs. 2. The latest genetic engineering technology applied in antibody design and production, such as phage display technology and genetically modified mouse, have revolutionized the clinical applicability and feasibility of the use of mAbs in humans. 3. Innovative antibody products in the forms of single-chain or super-humanized antibody therapeutics having a higher affinity for target antigens and minimal antigenicity in hosts have been introduced for experimental purposes and/or clinical trials. 4. Although there are successful examples of antibody therapeutics in the market, the use of mAbs in treating hepatitis-related disease and hepatocellular carcinoma is rare and remains to be exploited.

OKT3 treatment in refractory pediatric heart transplant rejection.

BACKGROUND: The anti-lymphocyte monoclonal antibody OKT3 has been shown to be effective in the management of steroid-resistant and/or fulminant heart transplant rejection in adults. In addition, some studies suggest that OKT3 may have a role in the management of transplant coronary artery disease (TxCAD). To date, there are limited data regarding the use of OKT3 treatment of refractory rejection or graft failure in children. Our study examines OKT3 treatment in steroid-resistant rejection, rejection with hemodynamic compromise, and TxCAD in children. METHODS: Thirty-eight patients received 53 courses of OKT3 for treatment of rejection and/or graft dysfunction. Primary indications for OKT3 were steroid-resistant rejection (n = 27), rejection with hemodynamic compromise (n = 22), and TxCAD (n = 4). Resolution of rejection was considered absence of biopsy-proven rejection (< grade 2) or resolved TxCAD. RESULTS: OKT3 use in steroid-resistant rejection was associated with a lower incidence of rejection in the 3 months after OKT3 than 3 months before OKT3, median rejection episodes of 2.5 vs 0, p < 0.0001. In rejection with hemodynamic compromise, 20 subjects (91%) demonstrated improved hemodynamics after OKT3 and survived to hospital discharge. The use of OKT3 treatment for TxCAD failed to demonstrate resolution or improvement in angiographic TxCAD in any subject. Only 5 OKT3 treatment courses were stopped secondary to severe adverse side effects. CONCLUSIONS: OKT3 treatment in refractory pediatric heart transplant rejection is efficacious in acute rejection. OKT3 management in pediatric TxCAD is less clear, with no proven benefit identified in this study. OKT3 use in pediatric refractory heart rejection has significant side effects, but is tolerable and safe with close monitoring.

OKT3 muromonab as second-line and subsequent treatment in recipients of stem cell allografts with steroid-resistant acute graft-versus-host disease.

We retrospectively evaluated response to monoclonal antibody directed against CD3 (OKT3) treatment in 43 patients with steroid-resistant acute graft-versus-host disease (aGvHD) following allogeneic hematopoietic cell transplantation. Median duration of OKT3 therapy was 9 (range, 1-20) days. In all, 20 cycles were administered as second-line and 28 as third-plus line treatment. Side effects were mild to moderate. Overall response rate was 69 with 12% complete remissions and best response in skin involvement. Proportional reduction of concomitant steroids was higher in responding patients. Five patients (12%) achieved durable responses. Pharmacokinetic studies of OKT3 showed adequate plasma levels (> or = 1000 ng/ml) in 13 of 17 evaluable patients after a median of 6 (1-11) days on treatment. OKT3 became undetectable shortly after discontinuation of therapy. Median survival for all patients was 80 (2 to 2474+) days. There was a trend for better survival for patients on second-line vs third-plus line treatment (146 vs 46 days; P=0.07) and significant longer survival for patients with grade II when compared to those with grade III/IV aGvHD (206 vs 47 days; P=0.039). We conclude that salvage treatment with OKT3 shows considerable efficiency, however, sometimes of transient nature, and is well tolerated in patients with corticosteroid-resistant aGvHD.

Early discontinuation of steroids is safe and effective in pediatric kidney transplant recipients.

In pediatric kidney transplantation, steroid induced growth retardation and cushingoid features are of particular concern. In children, gradual steroid withdrawal late after kidney transplantation increases the risk of rejection. In this pilot study, we investigated the outcome of pediatric renal transplantation with an early steroid withdrawal protocol. This is a retrospective case-control study of pediatric renal transplants with age-matched historical control. Groups were comparable in terms of HLA matching, donor type and graft ischemia time. In the steroid withdrawal group (SWG, n = 13), induction therapy included mycophenolate mofetil (MMF) and a 5-day course of steroids with Thymoglobulin in 11 and basiliximab in two other patients. In the steroid group (SG, n = 13), in addition to steroids, four patients were given basiliximab, eight were given Thymoglobulin, and one OKT3. Maintenance therapy included tacrolimus (SWG n = 11, SG n = 3) or cyclosporine (SWG n = 2, SG n = 10). Azathioprine was given to all the patients in the SG, except the last two patients of this series who were prescribed MMF. MMF was given to all in the SWG. Patient and graft survival rates were 100% in both groups. In the SWG, no acute rejection episode was detected. In the steroid group, three patients (25%) presented with an acute rejection episode. All but one patient in either group showed immediate graft function. Patients in the steroid-withdrawal group exhibited a significantly higher creatinine clearance at 6 and 12 months post-transplant (95.8 +/- 23.3 vs. 71.3 +/- 21.9, p = 0.03; and 91.3 +/- 21.6 vs. 69.6 +/- 28.6, p = 0.04). In the SWG delta BMI was significantly lower and delta height Z score was significantly higher, and we observed significantly less hyperlipidemia, body disfigurement, and need for anti-hypertensive medication. Early steroid withdrawal in pediatric renal transplant recipients is efficacious and safe and does not increase risk of rejection, preserving optimal growth and renal function, and reducing cardiovascular risk factors.