OKT3 Treatment Research Articles

Post-renal Transplantation Diabetes Mellitus - A Retrospective Study

590 A total of 846 renal transplantations, 713 living-related (LRT) and 133 cadaveric donor (CRT), were performed at our center between October 1985 and January 1998. All patients received the same immunosuppressive drug regimen of 5 mg/kg cyclosporine, 1 mg/kg prednisolone, and 2-2.5 mg/kg azathioprine. Rejection episodes were treated with steroid pulse therapy (500 mg methylprednisolone i.v. daily for 3 days) and/or OKT3 treatment (5 mg/day). Our outpatient department routinely controls 291 of these patients. Post-transplantation diabetes mellitus (PTDM) was diagnosed in 18 (6.1%) kidney recipients who were known to be nondiabetic prior to transplantation. We performed a retrospective study of these cases looking at various parameters, including demographics and historical background, HLA typing, and laboratory findings. LRT had been performed in 15 patients and the remaining 3 had undergone CRT. The mean age of the individuals with PTDM was 34.6 years, and there were 14 male and 4 female patients. Two patients who were second-degree relatives had a family history of diabetes mellitus. Four(22.2%) of the PTDM patients required insulin treatment, while a diabetic oral diet was adequate for regulating blood glucose levels in the other 14 individuals. None of the patients received oral anti-diabetic medication. Steroid pulse treatment had been administered to 12 of the 18 (66.6%) individuals at a mean steroid dosage of 2,270.8 mg. All patients who received insulin treatment had also undergone steroid pulse therapy. Comparing the PTDM group to nondiabetic renal graft recipients, the frequency of steroid pulse treatment and dosage of steroid was higher for the PTDM group. Kidney recipients with PTDM had a mean blood glucose level of 145.8 mg/dl, serum creatinine levels for the PTDM and control groups were 1.66 mg/dl and 1.54 mg/dl, respectively (p > 0.05), and the groups' respective 5-year graft survival rates were 66.6% and 88.8% (p < 0.005). HLA groups A3 and B51 were the most frequent tissue types identified in the PTDM individuals, however, we were unable to pinpoint any specific HLA association in the patient group. In conclusion, although there were no significant differences in serum creatinine levels between the PTDM and control groups, the graft survival rate was significantly lower for those afflicted with PTDM.

MYCOPHENOLATE MOFETIL (MMF) IN PAEDIATRIC LIVER TRANSPLANTATION

146 MMF is a new non-nephrotoxic immunosuppressant. We report our experience of using MMF in 18 children (age 9 months - 15 years, median 2.5 yr). Ten had refractory acute rejection (AR), defined as histologic persistence of changes of ongoging cellular rejection following bolus methylprednisolone and 2 weeks of Tacrolimus blood levels 10-15 ng/dl ug/L (IMx II assay), and would have been candidates for OKT3 or ATG treatment; two had persistent chronic rejection (CR), defined as >25% duct loss on two or more biopsies; two were converted from Tacrolimus to Neoral and MMF for suspected EBV related lymphoproliferative disease (PTLD), but developed acute cellular rejection; four had severe nephrotoxicity (mean GFR 43.5ml/min/1.73m2, range 28-65) while on cyclosporin. MMF was started at 20 mg/kg/day bid and increased after 1 week to 40 mg/kg/day bid. Following addition of MMF no child with AR has experienced relapse (median follow up 5 months, range2-16 months). Median interval from initiation of therapy to normal transaminases was 15 days and range 10-28 days. Neither patient with CR had sustained improvement of liver function: MMF was discontinued in one after 3 weeks because of leucopenia and the other received 3 months therapy when tuberculosis was diagnosed. Both patients with suspected PTLD are well 13 and 15 months after Tacrolimus withdrawal, without evidence of PTLD or rejection. Both children with CR have died. The children with nephrotoxicity have tolerated a mean reduction of trough cyclosporin levels of 50% (pre MMF mean trough level 143 ug/l to 73ug/l monoclonal TDX method) after 6 weeks of MMF treatment, and remain rejection free, median 5 months, (range 1-9months) with improvement in GFR from 65 to 115ml/min/1.73m2 in one when tested after 6 months. 3 others are awaiting repeat GFR studies. Transient diarrhoea was observed in 4 patients and leucopenia in 3 which responded to transient dose reduction with restarting full dose in 3 weeks. Conclusion: MMF should be considered in the treatment of AR and in the presence of cyclosporin or Tacrolimus induced nephrotoxicity. Prospective trials are indicated to see whether earlier introduction of MMF and maintaining lower trough cyclosporin or Tacrolimus levels could avoid the nephrotoxicity.

Decreased Incidence of Early Onset PTLD in Pancreas Transplant Recipients After Initiating Universal IV/Oral Ganciclovir Prophylaxis

699 We previously reported the development of early onset post-transplant lymphoproliferative disorder (PTLD) within 62 days of pancreas transplantation, associated with both a significantly higher total muromonab-CD3 (OKT3) dose and a lack of antiviral prophylaxis with IV ganciclovir. Because our data indicated that ganciclovir may help to prevent this potentially fatal disorder, in July 1996 we initiated a protocol using ganciclovir prophylaxis (5 mg/kg IV until oral intake, then 1000 mg PO TID for a total of 14 weeks) for all pancreas transplant recipients regardless of CMV serostatus. We now report the incidence of early onset PTLD in these patients and compare it to PTLD incidence in the earlier group (in which ganciclovir prophylaxis was given only to patients for which either the donor or recipient was positive for CMV). One hundred and thirty-one pancreas transplants were performed at our institution January 1, 1994 - June 30, 1996, and 90 were performed July 1, 1996 - September 30, 1997 (since the initiation of “universal” ganciclovir prophylaxis). All patients in both groups received a similar immunosuppressive regimen including OKT3 treatment for early rejection. The diagnosis of PTLD was confirmed by biopsy of lymph nodes or other involved organs, and positive staining of atypical lymphocytes for Epstein-Barr virus encoded RNA (EBER) and/or Epstein-Barr virus (EBV) late membrane protein-1. All 6 cases of PTLD in pancreas transplant recipients occurred in the 131 patients transplanted prior to July 1, 1996 (5 of whom had not received any ganciclovir prophylaxis), with none of the 90 patients given IV/oral ganciclovir developing this disorder (p =.04 by one-tailed Fisher's exact test). These data indicate that ganciclovir prophylaxis can prevent the development of early onset PTLD in pancreas transplant recipients.

Clinical role of immunologic monitoring during OKT3 treatment

Clinical role of immunologic monitoring during OKT3 treatment

Acute renal allograft rejection in patients with Epstein‐Barr virus associated post‐transplant lymphoproliferative disorder

Background. There is a reciprocal relationship between posttransplant lymphoproliferative disorder (PTLD) and rejection: aggressive treatment of rejection can result in PTLD, while treatment of PTLD by reducing immunosuppression can result in recrudescence of rejection. The literature on the relationship between PTLD and rejection episodes is limited. Methods. The clinical course and outcome of rejection episodes occurring prior to and following a diagnosis of PTLD were studied in 20 renal transplant recipients. Results. The diagnosis of PTLD was preceded by rejection in 12/20 (60%) patients. OKT3 treatment was associated with early onset PTLD, which involved the allograft in 6/7 patients (86%). The risk of rejection following reduced immunosuppression was 7/14 (50%). Post‐ PTLD rejection left untreated led to graft loss in 3 patients. The remaining 4 patients responded satisfactorily to anti‐rejection therapy. Conclusions. Reduction of immunosuppression for PTLD is frequently, but not invariably, complicated by rejection. The clinical outcome of PTLD does not correlate with the occurrence or reversibility of rejection episodes.

Clinical role of immunologic monitoring during OKT3 treatment

Clinical role of immunologic monitoring during OKT3 treatment

Early signs and risk factors for the increased incidence of Epstein-Barr virus-related posttransplant lymphoproliferative diseases in pediatric liver transplant recipients treated with tacrolimus.

Posttransplant lymphoproliferative disease (PTLD) is a life-threatening condition the incidence of which in pediatric solid organ transplantation may be related to the immunosuppressive load. It has been suggested that tacrolimus, a new and potent immunosuppressor, causes an increased incidence of this syndrome. The incidence, early signs, and risk factors for lymphoproliferative disease were reviewed in a cohort of 89 pediatric liver transplant recipients treated with tacrolimus. Eighteen patients (20%) developed a PTLD-16 concomitant to a primary Epstein-Barr virus (EBV) infection and 2 with previous immunity against EBV. Three additional patients had preliminary signs of PTLD concomitant to primary EBV infection, but did not develop individualized lymphoid masses. Six patients died (6.7% of all tacrolimus-treated patients). Mean tacrolimus blood level during the 3 months preceding EBV infection reached 11.8+/-1.8 ng/ml in PTLD patients versus 9.4+/-3.4 ng/ml in non-PTLD patients (0.05<P<0.1). Previous OKT3 or antithymocyte globulin treatment was also significantly associated to PTLD. There was no association with age, rejection episodes, steroid-resistant rejection, prior cytomegalovirus infection, HLA mismatch, living donor or cadaveric organ transplantation, United Network for Organ Sharing status at the time of orthotopic liver transplant, and primary or rescue tacrolimus treatment. A significant increase of total gamma-globulin level occurred in PTLD patients, and mono/oligoclonal production was significantly associated to PTLD. In EBV-infected pediatric liver transplant recipients, use of OKT3 or antithymocyte globulin and high tacrolimus blood levels are risk factors for a significant increase in the incidence of PTLD. An increase in total gamma-globulin level and appearance of mono/oligoclonal immunoglobulin production are the major preliminary signs of the syndrome.

Efficacy of OKT3 as primary therapy for histologically confirmed acute renal allograft rejection.

OKT3 is often used as primary treatment for acute renal allograft rejection. In a retrospective study, we sought to determine the efficacy of OKT3 as a first-line agent in reversing histologically confirmed acute renal allograft rejection. Patients with mild to moderate, moderate, or severe acute cellular and acute vascular rejection who had not received any other anti-rejection treatment were included in this analysis. A total of 88 patients, who received OKT3 between 1987 and 1995, fulfilled these criteria. Seventy of these patients were renal transplant recipients, and 18 were combined kidney and pancreas transplant recipients. The median time to the diagnosis of rejection from transplantation was 32 days (range, 6 days to 13 years). On histology, 6 were graded as mild to moderate, 36 as moderate, 29 as moderate to severe, and 17 as severe rejection. The mean baseline serum creatinine was 1.62 mg/dl (range, 0.7-10.1 mg/dl), and the mean serum creatinine at the time of diagnosis of rejection was 2.60 mg/dl (range, 1.4-12.7 mg/dl) (P=<0.0001). The mean duration of OKT3 treatment was 11.2 days (range, 8-18 days). The mean serum creatinine at the end of OKT3 treatment was 1.73 mg/dl (range, 0.6-5.0 mg/dl; P=0.24 compared with baseline serum creatinine). Rejection was reversed in 86 (98%) patients. Graft survival at 1 year after OKT3 therapy was 87.5% (77 of 88). At a mean follow-up of 38 months, 8 patients had died and 26 grafts were lost. The mean serum creatinine level in the 64 patients with a functioning graft was 1.76 mg/dl (range, 0.8-4.0 mg/dl) at the last follow-up. OKT3 when utilized as first-line therapy reversed 98% of the acute rejection episodes, with a 1-year post-OKT3 graft survival of 87.5%.

A model of human anti‐T‐cell monoclonal antibody therapy in SCID mice engrafted with human peripheral blood lymphocytes

A chimeric severe combined immunodeficient mouse engrafted with human peripheral blood (hu‐PBL‐SCID) model has been developed to test anti‐T‐cell monoclonal antibody (mAb) effects on systemic symptoms. of the host and the survival of human skin grafts. To obtain consistent engraftment without lethal acute graft‐versus‐host disease (GVHD), SCID mice were pretreated with a combination of total body irradiation (2.5 Gy, day 0) and anti‐asialo GM1 (anti‐mouse natural killer cell) antiserum (50) ug i.p., day 3) before the intraperitoneal injection of 40‐50 × 106 human PBL on day 4. With this protocol, the engraftment rate was 82% with 5‐98% human CD45‐positive cells in the peripheral blood. Mortality at 30 days was 0% in the mice bearing 5‐50% human cells compared with 70% in those with more than 50%. Using hu‐PBL‐SCID mice with 5‐50% human cells in their peripheral blood, we demonstrated the following results: 1) Human T cells isolated from these mice proliferated in response to immobilized OKT3 stimulation in vitro. 2) Hu‐PBL‐SCID mice but not normal SCID mice were able to reject human skin grafts in vivo 16‐21 days after grafting. 3) Both OKT3 (anti‐human CD3 mAb) and T10B9 (anti‐human αβ T‐cell receptor mAb) treatment prevented human skin graft rejection in hu‐PBL‐SCID mice. 4) OKT3 but not T10B9 induced first dose reactions characterized by hypothermia and hypoactivity which were consistently observed within 90 min of intravenous injection into hu‐PBL‐SCID mice. 5) Human cytokines were detected in the serum of the hu‐PBL‐SCID mice treated with anti‐T‐cell mAbs. The close similarity of these responses to human clinical mAb immunosuppressive therapy suggests that the hu‐ PBL‐SCID mouse model may be an excellent tool for investigating the immunosuppression, side effects, and mechanism of action of agents that are specific for human and higher apes and not reactive with lower animals.

Physiologic human T-cell responses to OKT3 in the human peripheral blood lymphocyte-severe combined immunodeficiency mouse model.

Our goal was to study physiologic responses of human T lymphocytes to OKT3 in the human peripheral blood lymphocyte-severe combined immunodeficiency (hu-PBL-SCID) mouse model. SCID mice were pretreated with anti-asialo-GM1 (alpha-ASGM1) and radiation, then engrafted with human peripheral blood lymphocytes (PBLs). Seven to 14 days after engraftment, when most human T cells in the spleen of these mice are CD3+/CD4+ and CD3+/CD8+, mice were treated with OKT3 or control antibody. Mice were killed for histopathologic examination, for flow cytometric assessment of the engrafted human lymphocytes, and for analysis of human tumor necrosis factor-alpha serum levels. Intravenous injection of 5 microg of OKT3 resulted in early antigenic modulation of engrafted human T lymphocytes, with the emergence of CD3-/CD4+ and CD3-/CD8+ cells in the spleen of hu-PBL-SCID mice. There was an increase in the serum concentration of human tumor necrosis factor-alpha within 4 hr after OKT3 injection, suggesting early T-cell activation. Antigenic modulation and activation of the human lymphocytes in the spleen was followed by their depletion within 24 hr. This human T-cell response to OKT3 in hu-PBL-SCID mice is analogous to the response in humans treated with OKT3 and in BALB/c mice injected with an anti-murine CD3 monoclonal antibody. Graft-versus-host disease in the mice was abrogated by OKT3 treatment, and OKT3-treated mice lived longer than controls. Histopathologic studies showed clearance of lymphocytic infiltration in the liver and lungs of OKT3-treated mice. These findings provide further evidence of functional human immune T cells in the hu-PBL-SCID mouse. This model may have useful applications in the study of transplantation immunology.

RISK FACTORS FOR THE INCREASED INCIDENCE OF POST-TRANSPLANT LYMPHOPROLIFERATIVE DISEASE IN PEDIATRIC LIVER TRANSPLANT RECIPIENTS TREATED WITH TACROLIMUS

Among eighty nine paediatric liver transplant recipients treated with Tacrolimus, eighteen (20%) developed a post transplant lymphoproliferative disease (PTLD), 16 (41%) among 39 with primary Epstein Barr virus (EBV) infection and two who had previous immunity against EBV. Three additional patients had preliminary signs of PTLD concomitant to primary EBV infection, but did not develop individualised lymphoid masses. Six patients died (6.7% of all Tacrolimus treated patients). Mean Tacrolimus blood level during the three months preceding EBV infection reached 11.8 ± 1.8 ng/ml in PTLD patients versus 9.4 ± 3.4 ng/ml in non PTLD patients (0.05<p<0.1). Eighteen of 31 (58%) extrahepatic biliary atresia children developed PTLD versus 1 of 8 (12.5%) non biliary atresia children (p<0.05). Previous OKT3 or ATG treatment was also significantly associated to PTLD. There was no influence of age, rejection episodes, steroid resistant rejection, prior cytomegalovirus infection, HLA mismatch, living donor or cadaveric organ transplantation, UNOS status at the time of transplantation, primary or rescue Tacrolimus treatment. Significant increase of total gammaglobulin level occurred in PTLD patients, and mono/oligoclonal production was significantly associated to PTLD. Conclusion: The incidence of PTLD is markedly increased in Tacrolimus treated patients, as compared to our historical series (incidence of 3.8%)*. Among patients undergoing a primary EBV infection after transplantation, previous biliary atresia, use of OKT3 or ATG and high Tacrolimus blood levels are significantly associated to the development of PTLD.

Development of anti-OKT3 antibodies after OKT3 treatment.

The development of IgG and IgM anti-OKT3 antibodies the first 90 days after start of OKT3 treatment for acute cellular rejection was determined by ELISA in 25 consecutive renal transplant patients. The ELISA positive sera were then tested for neutralizing OKT3 antibodies by immunofluorescence inhibition assay utilizing the FACScan. The number of IgM positive patients was highest, four (16%) after 10 days of treatment and then declined. The highest number of patients, thirteen (56%) with IgG antibodies was found after 60 days. Sera with only IgM antibodies or with low IgG titers (< 1:100) did not neutralize OKT3. Five patients (20%) developed neutralizing antibodies. All of these patients had received OKT3 during an earlier transplantation. In four of these patients, the ACR had been reversed successfully before the development of antibodies, and in the last patient the ACR was reversed by a second course of Minnesota-ALG and increasing the dose of Cyclosporine. Monitoring the development of neutralizing anti-OKT3 antibodies is valuable in patients who have previously received OKT3 treatment.

OKT3 treatment for allograft rejection is a risk factor for cytomegalovirus disease in liver transplantation.

The role of OKT3 monoclonal antibody administration was studied as a risk factor for symptomatic cytomegalovirus (CMV) infection in 229 consecutive liver transplant recipients not receiving specific CMV prophylaxis. Twenty-six patients (11.4%) received OKT3 and 17 of them developed CMV infection, 11 (4.8%) being symptomatic. OKT3 use was a significant risk factor for symptomatic CMV infection by both univariate (relative risk [RR], 2.9; 95% confidence interval [CI], 1.5-5.8; P = .002) and multivariate time-dependent (RR, 3.4; 95% CI, 1.7-7.1; P = .001) analyses. A subgroup analysis revealed that OKT3 use was a significant risk factor for symptomatic CMV infection in CMV-seropositive but not seronegative recipients. OKT3 therapy for steroid-resistant rejection is a risk factor for symptomatic CMV infection in liver transplant recipients who are seropositive for CMV before transplantation. This group should be targeted for antiviral prophylaxis when OKT3 antirejection therapy is used.

Lack of correlation and soluble E-selectin level with renal transplant rejection

E-Selectin is a 115-kDa cell surface glycoprotein transiently expressed on vascular endothelium in response to interleukin-1 and tumour necrosis factor-α with a peak in expression at four hours. Its distribution in transplant biopsies has been associated with inflammatory events such as allograft rejection. Recently, a soluble isoform of E-selectin has been detected in the culture medium of cytokine activated endothelial cells by an ELISA method. In this study soluble E-selectin levels in renal allograft recipients were compared with the incidence of rejection, acute tubular necrosis (ATN), cyclosporin A (CyA) toxicity, and use of orthoclone OKT3 (muromonab-CD3) to establish whether early endothelial activation and inflammatory damage could be detected. The mean soluble E-selectin level in normal volunteers was 89 ng/ml serum compared to 120 ng/ml for a group of chronic renal failure patients. Soluble E-selectin levels declined upon transplantation but this was not significant, nor was the difference in samples from patients experiencing rejection, ATN or CyA toxicity. A dramatic and sustained rise in soluble E-selectin levels was found within 24 hours of the first dose of OKT3 treatment. This study shows that soluble E-selectin does not provide early unequivocal indication of pathological sequelae in renal transplantation, although extensive endothelial activation can be demonstrated with OKT3 treatment.

Analysis of the inflammatory leucocyte mobilization in 838 fine needle aspiration biopsies in non-rejecting (day 1–90) kidney grafts and 465 biopsies in grafts before, during and after acute cellular rejection

A total of 1303 fine needle aspiration biopsies (FNABs) were performed in all 105 kidney transplanted patients at our institution during 1990–1992: 838 were in patients who never had an acute cellular rejection (ACR), and 465 were in patients who had experienced an ACR; 393 of these FNABs were performed in first rejections and 72 in second rejections. The immunosuppressive protocol included monotherapy with cyclosporin A and an initial, additional course of Minnesota-ALG during the first ten days after transplantation (Tx). OKT3 was first-line antirejection therapy accompanied for a short period with prednisolone and azathioprine to oppose the development of anti-OKT3 antibodies. FNABs were taken each day for the first three days after Tx, then twice a week for the first month, and then at each visit to the outpatient clinic for the next three months. In non-rejecting grafts the total corrected increment (median) of the inflammatory response (TCI) increased from 1 to a maximum of 3.5, 17–21 days after Tx followed by a slight decrease. The inflammatory response was mainly due to non-activated lymphocytes. In the rejecting grafts the TCI (median) increased from three days before ACR to a maximum of 7 on the day of ACR, followed by a decrease when OKT3 treatment was started. The infiltrating cells were activated lymphocytes, other lymphocytes and, in smaller amounts, macrophages and monocytes.

Variations in Serum OKT3 Concentration Based upon Age, Sex, Transplanted Organ, Treatment Regimen, and Anti-OKT3 Antibody Status

An essential parameter of the efficacy of OKT3 therapy is serial determinations of serum OKT3 levels. We hypothesized that precise monitoring of these levels would optimize treatment protocols. Therefore, enzyme-linked immunosorbent assay (ELISA) technology was utilized to measure OKT3 serum concentrations daily during 263 OKT3 treatment courses in recipients of solid organ grafts. Patient characteristics were: mean age 33 years (0.1-71), 147 male/116 female, 134 kidney/82 liver/47 heart, 122 prophylaxis/141 rejection, and 213 conventional dosing/50 increased dosing. Mean OKT3 levels were higher in women than in men at all time points from day 1 to day 14, reaching the greatest difference between groups on day 7 (849 versus 598 ng/ml, p = 0.004). Patients receiving OKT3 as a component of a prophylactic protocol had higher levels than those receiving the drug for treatment of rejection from day 1 to day 6, with the greatest difference between groups occurring on day 1 (678 versus 333 ng/ml, p < 0.00001). However, from day 7 to day 14 patients receiving OKT3 prophylactically had lower mean OKT3 levels than did those receiving OKT3 for rejection, with the greatest difference between groups occurring on day 11 (555 versus 784 ng/ml, p < 0.05). Liver transplant recipients had significantly higher OKT3 levels than did kidney or heart transplants at all time points. However, more liver patients required increased OKT3 doses to modulate peripheral blood CD3+ cells to < 25/mm3. Kidney recipients had higher levels than did heart recipients. Children < 10 years of age had higher OKT3 levels than did older patients at all time points.(ABSTRACT TRUNCATED AT 250 WORDS)

Low-dose OKT3 induction therapy following renal transplantation: a controlled study

In a prospective clinical study we tested the immunosuppressive properties and toxicity of low-dose OKT3 induction therapy in renal transplant recipients. 50 consecutive renal transplant recipients were alternatingly assigned to low-dose OKT3 induction or prednisolone/cyclosporin. Low-dose OKT3 induction treatment consisted of 0.5 mg OKT3 twice daily for 10 days, initially combined with azathioprine and prednisolone maintenance immunosuppression that was converted to prednisolone/cyclosporin at the end of the course. During a 15-29-month follow-up period, low-dose OKT3 induction therapy was found to reduce significantly the incidence of acute rejections, as compared to the usual prednisolone/cyclosporin maintenance immunosuppression (21 versus 52%, P = 0.02). There also was a tendency towards an improved graft function after low-dose OKT3, although no significance was reached. Furthermore, compared to a historical control group of renal transplant patients in whom acute rejection was treated with 5 mg OKT3 daily, low-dose OKT3 appeared to cause fewer side-effects. We conclude that low-dose OKT3 induction therapy is superior to prednisolone/cyclosporin in preventing acute rejection after renal transplantation and that it is better tolerated than conventional OKT3 treatment.

Primary failure of OKT3 antibody for rejection prophylaxis in orthotopic heart transplantation

Cytolytic immunosuppression with OKT3 antibody has been shown to be highly effective in reducing the frequency of early allograft rejection in cardiac transplantation. Failure of OKT3 immunosuppression in the absence of anti‐OKT3 antibodies is a rare event, having been reported in only 3 patients who manifested predominantly vascular (humoral) rejection during OKT3 therapy. We report the first case of hemodynamically serious cellular rejection, without a demonstrable vascular rejection component, in a cardiac allograft recipient during OKT3 treatment. This case underscores the need to remain vigilant for signs of rejection in cardiac recipients during OKT3 immunosuppression.

Corticosteroid inhibition of the OKT3‐induced febrile and nephrotoxic responses during treatment of renal allograft rejection

The anti‐CD3 monoclonal antibody OKT3, highly effective at treating renal allograft rejection, is associated with a severe first‐dose reaction (FDR), two components of which are high fever and nephrotoxicity. This FDR is thought to be caused by lymphokines (LK) released following administration of OKT3. High‐dose corticosteroids (HDS) block LK release when used as part of a renal transplant OKT3 induction protocol. The effect of HDS on the febrile response and renal function of established transplants has not been well studied. We sought to lest the hypothesis that HDS would also block the FDR when OKT3 was used for the treatment of biopsy proven, acute cellular, renal allograft rejection. Forty‐two renal transplant recipients were retrospectively analyzed. Background immunosuppression consisted of prednisone, azathioprine (AZA), and cyclosporine (CyA). At the time of rejection, the oral prednisone dose was increased to 1–2 mg/kg/d. and both CyA and AZA doses were maintained at pre‐rcjection levels. HDS (&gt;5 mg/kg. mean 24.9±6. n = 29) and low‐dose (LDS) (&lt;5 mg/kg. mean 0.8±0.4, n = 13) groups were defined by the dose of intravenous steroids given at the time of OKT3 treatment. Premedication also included diphenhydramine and acetaminophen. Maximum temperature (Tmax) on days 1 and 2 after OKT3, total days febrile, the serum Creatinine (Cr) on days 0, 1.2, 3, 7, 14, and 28, and the frequency of anli‐OKT3 antibody formation and infections were compared using ANOVA or Chi Square. HDS decreased Tmax on day 1 (37.5 C vs. 38.3°C. p = 0.03) but not on day 2 (38.2 ± 1 vs. 38.6 ±0.7. p = 0.18). There was no effect on the number of days febrile (2.7 vs. 2.8. p = 0.8). The optimal steroid dose for complete suppression was about 25 mg/kg. The degree of suppression decreased with time over the interval of 0.5 to 5.75 hours indicating an optimal time of 1 hour or less. The protective effect of HDS on renal function was seen as a significantly reduced increase in Cr on day 2 after OKT3 (0.2±0.4 mg/dl vs. 0.8±0.9. p = 0.008) in the HDS group. The nephrotoxicity was not completely inhibited even at the highest doses of steroids. The rate of OKT3Ab formation was substantially less in the HDS group (10% vs. 38%, p=0.03). The incidence of infections requiring hospitalization was similar (38% vs. 46%, p = 0.62). No post‐OKT3 lymphomas occurred to date in this cohort. In conclusion. HDS at the time of OKT3 dulled the initial febrile response, decreased the nephrotoxicity, and protected against OKT3Ab formation. These advantages of HDS were achieved without a short term increase in the rate of infections or the appearance of lymphomas. The lack of complete suppression of the nephrotoxicity, even at dose of steroids that completely suppressed the febrile response, suggests that its mechanism might be different from that of the febrile response.

Phosphorylation of serine 59 of p56lck in activated T cells.

p56lck, a member of the src family of non-receptor protein tyrosine kinases, is expressed almost exclusively in cells of lymphoid origin. Recent evidence has implicated p56lck in a critical role both in T cell development and activation. A variety of T cell stimuli induce a shift in the electrophoretic mobility of p56lck from an apparent molecular mass of 56 kDa (p56lck) to 60 kDa (p60lck). This shift in electrophoretic mobility correlates with an increase in the phosphoserine content of the p60lck. We have shown that both 4 alpha-phorbol 12 beta-myristate acetate and OKT3 treatment of Jurkat cells, as well as 4 alpha-phorbol 12 beta-myristate acetate treatment of 171.CD4 and LSTRA cells, induced phosphorylation of serine-59 on p56lck in vivo, which correlated with the shift to p60lck. We also demonstrated that the same serine residue could be phosphorylated in vitro with mitogen-activated protein kinases and that this event was capable of reducing p56lck activity in vitro. Combined, these data suggest a novel pathway for the in vivo regulation of p56lck activity.