Panel reactive antibodies in predicting hepatitis C virus treatment outcome in kidney transplant candidates

OBJECTIVES

Chronic hepatitis C virus infection compromises hemodialysis patients and increases liver-related mortality. Interferon treatment is associated with improved sustained virological response rates and increased risk of graft loss after kidney transplant. This may be related to the development of antihuman leukocyte antigen antibodies, which may be a surrogate marker of potent immune response. We evaluated panel reactive antibody 1 and 2 levels for prediction of sustained viral response in patients with kidney transplant.

MATERIALS AND METHODS

In this retrospective cohort study, we reviewed data from hepatitis C virusinfected hemodialysis patients who received interferon treatment before kidney transplant. Panel reactive antibody > 20% was considered positive. Sustained viral response rates for interferon treatment were obtained and compared with panel reactive antibody 1 and 2 values.

RESULTS

There were 40 patients (16 female and 24 male patients; mean age, 41.5 y; range, 18-65 y). Sustained viral response rate was 18/40 (45%). Panel reactive antibody 1 was negative in 31 patients and positive in 9 patients. Sustained viral response ratio was not correlated with panel reactive antibody 1 positivity. Panel reactive antibody 2 was negative in 31 patients (sustained viral response: present, 11 patients; absent, 20 patients) and positive in 9 patients (sustained viral response: present, 7 patients; absent, 2 patients). Sustained viral response ratio was significantly correlated with panel reactive antibody 2 positivity.

CONCLUSIONS

We showed a correlation between panel reactive antibody 2 positivity and sustained viral response rates that may be a predictive tool for hepatitis C virus treatment response. In patients with other complications that compromise hepatitis C virus treatment, panel reactive antibody 2 may be a surrogate marker for sustained viral response prediction. The induction of cellular immunity may cause clearance of hepatitis C virus infection and formation of high panel reactive antibody 2 levels.

Living-donor kidney transplant in T-cell and B-cell flow cytometry crossmatch-positive patients

OBJECTIVES

Complement-dependent cytotoxic crossmatch is an important indicator for kidney transplant. However, there is controversy about treatment for flow cytometry crossmatch-positive cases.

MATERIALS AND METHODS

This was a retrospective study of 127 living-donor kidney transplant recipients from May 2007 to July 2011. We divided patients into 115 flow cytometry crossmatch T-cell and B-cell-negative cases, and 12 T-cell and B-cell-positive cases. Both groups were given 20 mg basiliximab the day of surgery and 4 days after surgery. Common oral immunosuppressive agents used were tacrolimus, mycophenolate mofetil, and methylprednisolone. Flow cytometry crossmatch T-cell and B-cell-negative recipients started immunosuppression 7 days before surgery, T-cell and B-cell-positive recipients started immunosuppression 14 days before surgery. T-cell and B-cell-positive patients also received 200 mg rituximab 1 week before surgery, had 3 plasma exchange sessions before transplant, and received intravenous immunoglobulin 20 g/day during surgery and after surgery for 5 days. We measured flow-panel reactive antibodies of T-cell and B-cell-positive patients just before surgery to check desensitization efficiency. We evaluated patient survival, graft survival, graft function, and frequency of rejection and infectious diseases.

RESULTS

Patient survival and graft survival were 100% in both groups. Flow cytometry crossmatch T-cell and B-cell-positive cases had no rejection events, but T-cell and B-cell-negative groups developed rejection. There was no statistical difference in the incidence of infection and graft function. Flow-panel reactive antibody demonstrated improvement in all T-cell and B-cell-positive cases.

CONCLUSIONS

In living-donor kidney transplant, flow cytometry crossmatch T-cell and B-cell-positive patients are still considered to be at high risk. Although this is a short-term outcome, all T-cell and B-cell-positive patients in this study achieved excellent results with appropriate preoperative and postoperative treatment.

Long-term post transplant alloantibody monitoring: a single center experience

Between 2000 and 2010, 4241 sera from 597 renal transplant (RTx) recipients were monitored for DSA development. The patients were selected in the absence of immunological memory to donor HLA before RTx and were divided into two groups: the historic group, consisting of patients transplanted before December 1996 and the study group, consisting of those transplanted after December 1996. Ninety-two out of 597 (15.4%) patients developed de novo DSA post-RTx, while 196 had third party anti-HLA antibodies. DSA were more frequent in the historic group compared with the study group (P < 0.001). Anti-HLA class-III DSA predominated in both groups (84.6% vs. 69.7%) and were directed preferentially against donor HLA-DQ (65/92,70.6%). Recipients of class II-incompatible grafts developed DSA more frequently than those receiving class II-compatible grafts (P = 0.003). DSA production was not different between pre-sensitized and non-sensitized patients (P = 0.842). DSA class I (HR = 31.78), DSA class II (HR = 20.92), and non-DSA (HR = 5.94) were the only independent predictors for graft failure. In conclusion, this study shows the results of long-term post-transplant alloantibody monitoring, and confirm the strong association of DSA and graft loss. Protocols that remove anti-HLA antibodies from RTx recipients may benefit allograft survival.

Understanding the significance of low-level preformed donor-specific anti-HLA antibodies in renal transplant patients

This is a single center, retrospective cohort study showing the impact of pre-transplant HLA-DSA (detected by the SAFB) on early posttransplant rejection rates. Our results showed that low level pretransplant DSA detected by SAFB is associated with a high risk of early clinical AMR. However, not all patients with pretransplant DSA will go on to develop AMR. Post-transplant with a decrease/removal of DSA within one month will lead to a low rate of AMR. Conversely, those who have a high DSA MFI are at the highest risk of early AMR. These findings support using SAFB for pretransplant assessment and early posttransplant monitoring.

De novo donor specific antibodies and patient outcomes in renal transplantation

Single antigen identification of HLA antibodies is used to detect donor specific antibodies (DSAs). However, the impact of DSA elements such as class, relative strength, duration, and longitudinal effect on graft function and survival, remains unclear. Routine DSAs (LabScreen, One Lambda, Inc., Canoga Park, CA) and metabolic studies were performed at 1, 3, 6, 9, and 12 months post-transplant, and every 6 months for renal transplant recipients from 7/2007-7/2010 (n = 389). Biopsies were evaluated by updated Banff 2005 guidelines after two consecutive positive DSAs. Based on these tests, 25% of recipients developed de novo DSA. Those with DSA had increased acute rejection episodes (AR), higher creatinine (Scr), and worse graft survival. Three subgroups of these patients were identified based on duration: persistent DSA (> 1), isolated DSA, or no DSA. Persistent DSA patients were more likely to be African American, and have higher mean fluorescence intensity (MFI) and AR rates. Persistent DSA patients, with or without AR, had elevated Scr. Recipients with DQ-only DSA had higher rates of antibody mediated rejection (AMR). From this, we conclude that routine posttransplant DSA monitoring identifies recipients at risk for graft damage or loss. Persistent de novo DSAs correlated with inferior graft outcomes and AMR. With or without AR, DSA persistence was associated with worse outcomes, possibly warranting intervention. De novo DQ-DSA may be a biomarker for chronic damage and/or AMR, while an isolated DSA determination appears clinically insignificant.

Annual literature review of donor-specific HLA antibodies after organ transplantation

The literature review of post-transplant DSA published in 2011 shows: Observations after kidney and lung transplant in non-sensitized transplant recipients show that monitoring post-transplant HLA antibodies offers limited benefit in predicting acute rejection episodes. It remains to be seen if a different monitoring schedule and/ or studying other organs may show otherwise. Nevertheless, others have shown that monitoring post-transplant antibodies does identify patients at higher risk for chronic rejection. Studies in kidney, heart, and liver patients transplanted in the presence of preformed DSA show that detecting these antibodies early after transplant identifies a group of patients with greater risk for allograft dysfunction. New and larger studies using bortezomib and eculizumab to treat acute antibody-mediated rejection confirm earlier observations that these two therapies are effective in treating and preventing rejections. In general, identification of HLAantibodies and DSA after transplant is associated with higher rates of rejection and poor allograft survival in all organs examined. IgM antibodies appear to play an important role after lung transplants.

Antibodies to human leukocyte antigens in lung transplantation

Bronchiolitis obliterans syndrome (BOS) is the leading cause of death beyond the first year after lung transplantation. The development of antibodies to human leukocyte antigens (HLA) after transplantation has been recognized as an independent risk factor for BOS development. To review the literature on the potential role of HLA antibodies on BOS development and other outcomes after lung transplantation, a MEDLINE search was performed. Multiple retrospective clinical studies from different centers have identified the development of HLA antibodies as a significant and independent risk factor for BOS. In addition, HLA antibodies have been linked to an increased risk of acute rejection and lymphocytic bronchiolitis. Furthermore, experimental studies suggest that HLA antibodies have a pathogenic role in BOS development and are not merely an epiphenomenon of cellular immunity. Lastly, findings from a single-center study suggest that the early depletion of HLA antibodies may mitigate the risk of BOS. HLA antibodies clearly play an important role in lung allograft rejection, and early antibody depletion may favorably influence clinical outcomes. However, future research will need to corroborate the benefits of antibody-directed therapy before this approach becomes widely accepted.

The influence of bortezomib on donor specific antibody reduction in patients with antibody mediated rejection

Renal allograft biopsy is the gold standard for monitoring and diagnosing antibody mediated rejection (AMR), yet a biopsy is invasive, expensive, and may result in complications. Monitoring antibodies may aid in diagnosing and monitoring AMR, although many questions remain unanswered regarding the clinical utility of antibody monitoring. The purpose of this review is to examine the influence of bortezomib on reduction of donor specific antibody after AMR in renal transplant recipients. A retrospective review of patients was performed. Patients who received bortezomib after suffering AMR refractory to intravenous immunoglobulin and plasmapheresis from 2009 to 2011 were selected. Seven patients were identified. Three patients had antibodies tested after IVIG treatment with a mean antibody lowering of 29 percent from baseline. Five of the seven patients had antibodies tested after bortezomib treatment and the mean antibody reduction was 47 percent from baseline. Four patients were biopsied after treatment and all were C4d negative. The other three patients were not biopsied. Renal function improved in most patients. One patient returned to dialysis 16 months after transplant and treatment and another patient died with a functioning graft, due to pneumonia five months after transplant and treatment. In these seven cases, the use of intravenous immune globulin, plasmapheresis, and bortezomib appear to decrease antibodies, improve renal function, and reverse histological markers for rejection. Long-term, prospective follow-up is warranted to determine the influence of bortezomib on donor antibody removal, histological changes, and graft survival.

The acceptable reactive crossmatch (ARC), post-transplant monitoring, and their impact on kidney transplantation: a single center experience

Although the adverse allograft outcomes associated with HLA antibodies are well documented, some controversy exists regarding the importance of low-level donor specific anti-HLA antibodies (DSA). To provide further detail on this controversy, we prospectively looked at low-level DSA in negative T- and B-cell flow cytometric crossmatch (FCXM) or acceptable reactive crossmatch (ARC) patients who each underwent protocol based post-transplant antibody monitoring. HLA Class I and II antibody screening and specificity determination was conducted via a solid phase assay (SPA) and FCXM versus donor and autologous T and B cells. Post-transplant patients were immunosuppressed with quadruple maintained immunosuppressive therapy, rabbit anti-thymocyte globulin induction, and HLA antibody monitoring. Out of 31 ARC patients transplanted, 65% had a PRA > 50% and 26% showed increased DSA at 7-14 days post-transplant. Antibody mediated rejection (AMR) was treated with pharmacological and/or plasmapheresis (PP) therapy. DSA were lowered and remained at low-levels (MFI 1000- 3000) or below FCXM cutoffs. None of the 31 patients transplanted developed de-novo antibodies. Two patients lost their allografts, one to polyoma (BK) virus, and one to antibody mediated rejection (AMR). In conclusion, our experience demonstrates that patients deemed higher risk for an immunological event due to low-level DSA should be transplanted with an ARC and followed post-transplant according to an established alloantibody monitoring protocol. With close monitoring, 5-year outcomes can be expected to approach that of low-immunologic risk transplant patients.

Donor-specific anti-HLA antibody monitoring and removal in solid organ transplant recipients

Based on our knowledge that donor specific anti-HLA antibodies (DSA) are a major cause of allograft loss, determining how to monitor patients for DSA and how to treat them is important. Current published studies indicate that patients with preformed DSA differ from those without. Approximately 15-18 percent of transplant patients will have preformed DSA, which increases risk for early antibody mediated rejection (AMR) and allograft loss. The fact that nearly all AMR episodes occur in the first 1-2 months, coupled with the finding that a reduction in preformed DSA intensity within the first few weeks post-transplant decreases the risk of AMR, makes early testing important. It has also been shown that clearance of DSA at 6 months and 1 year can result in a decreased risk of transplant glomerulopathy and therefore, these times may be prime testing points. This monitoring schedule differs slightly from that of the patients who do not have performed DSA (i.e. low risk patients). Low risk patients who develop de novo DSA are most likely to do so in the first 6 months. However, more frequent sampling in the early months does not improve predictability of acute rejections in low risk patients and therefore, it is not as essential. Rather, testing at 6 months and then annually or biannually, would be beneficial, as it would serve to identify the 5 percent of new patients who develop DSA annually. Once these patients are identified, studies have shown that preemptive treatment to a goal of antibody clearance can be used to improve graft function and survival. In addition to screening for new DSA, monitoring for clearance of DSA along with histologic reversal of rejection in patients with AMR is important. In sum, there is substantial evidence suggesting that all patients need to have some monitoring for DSA to identify new onset of DSA or clearance of DSA. Additionally, in all DSA scenarios, treatment of persistent DSA is important, as it can lead to improved allograft survival.

Antibody-mediated rejection in heart transplant patients: long-term follow up of patients with high levels of donor-directed anti-DQ antibodies

Antibody-mediated rejection (AMR) is a complication of orthotopic heart transplantation. There is no standard for treatment and it is unclear what role monitoring of donor-directed antibodies (DSA) should play in guiding treatment decisions. In this case series, we describe three patients transplanted at our center who developed AMR and received rituximab as one component of the treatment regimen. We found in these three patients that despite clinical resolution of AMR, high levels of class II donor-directed antibodies persisted. We also summarize our retrospective analysis of 110 heart allografts that had pre- and post-transplant DSA measurements with corresponding EMB and immunofluorescence (IF) during 2005-2011. Our analysis of a subpopulation of 50 informative patients (with DSA measurements, EMB, and corresponding IF) revealed that moderate and severe cardiac allograft vasculopathy were identified more frequently in grafts with DSA than compared to those without DSA.

A report of the epidemiology of de novo donor-specific anti-HLA antibodies (DSA) in "low-risk" renal transplant recipients

The donor specific anti-HLA antibody (DSA) has been increasingly recognized as the major cause of allograft loss. Despite this, no published reports exist describing the true epidemiology of de novo DSA.Here we describe the epidemiology of DSA based on the results of one of the longest running antibody study in consecutive renal transplant recipients. The study includes 224 non-sensitized, non-HLA-identical patients who received a primary kidney transplant between 3/1999-3/2006. Protocol testing for DSA was done pre-transplant, at 1, 3, 6, 9, and 12 months, and then annually. DSA was tested using single antigen beads. Data from the East Carolina University transplant cohort indicate that the prevalence of DSA in the first year post-transplant is 12.1 cases per 100. The average annual incidence of DSA is 4.7 per 100 cases, per year. The highest incidence of DSA was in the first year post transplant. Although deceased donors and African-Americans have a higher incidence rate of DSA than the comparator living donors and non-African American groups, respectively, these factors were not associated with DSA onset. The one factor found to be predictive of DSA was DQ mismatch (p = 0.036). Based on these epidemiologic findings in combination with previous reports showing DSA is a cause of allograft failure, it seems reasonable that at least annual testing should be done even in "low-risk" transplant patients, because every year a new 5% of patients will develop DSA.

A novel post-transplant alloantibody surveillance and intervention strategy that improves graft outcomes in sensitized renal transplant recipients

Chronic rejection, the leading cause of renal graft failure, is mediated by alloantibody graft destruction. Monitoring alloantibodies posttransplant might facilitate early diagnosis of alloantibody mediated graft destruction and provide an opportunity for intervention. Herein, we describe our alloantibody surveillance and intervention protocol that has improved graft survival. Patients (n = 69) with preoperatively positive FCXM and DSA were transplanted. Patient compatibility with donors was assessed by FCXM and donor specific antibody using single antigen bead Luminex. FCXM and DSA levels were monitored quarterly posttransplant. We identified a posttransplant profile strongly associated with chronic rejection. We then implemented a point-based formula that indicated when to initiate preemptive treatment with IVIG and plasmapheresis. The results of posttransplant antibody surveillance revealed 2 profiles. Most patients (65%) showed complete elimination of FCXM reactivity and DSA levels within 12 months of transplant. Three-year graft survival exceeded 95% and patients were chronic rejection-free. In contrast, the remaining patients failed to eliminate antibody as assessed by FCXM and DSA levels. Graft survival was inferior and chronic rejection was diagnosed in 43% of the group. Subsequent inclusion of preemptive treatment using the point-based system improved 3-year graft survival from 50% to 90%. In conclusion, the data show that implementation of an evidence based antibody surveillance protocol and an intervention protocol successfully improved graft survival.

Collagen gel coating or cyclosporine A for improving histocompatibility of chicken calamus keratin

OBJECTIVE

To improve the histocompatibility of chicken calamus keratin (CCK) graft by collagen-gel coating or using of cyclosporine A (CsA).

METHODS

Thirty SD rats were equally randomized into 5 groups, and in 4 of them, CCK implantation into the bilateral erector spinae was performed on different treatment protocols. In group A, the rats received daily intraperitoneal injection of CsA (5 mg/kg) for two consecutive weeks after CCK implantation; in group B, CCK was soaked in CsA (2.5 mg/ml) solution at 4 degrees Celsius; for 48 h before grafting; in group C, CCK coated with collagen gel was grafted; and in group D, only CCK was implanted. Rats in the fifth group received only cutaneous incision as well as muscular dissection to serve as the blank control. CCK degradation and its effect on the surrounding tissues were observed at 2, 4 and 8 weeks after grafting. Immunohistochemistry was performed to identify T lymphocyte infiltration in the host tissues.

RESULTS

All the rats survived the operation. Numerous macrophages, especially multinucleated giant cells occurred on the peripheral of the CCK grafts, and small degraded CCK pieces were observed in their cytoplasm. Only a few inflammatory cells were seen in the host tissues. At 2, 4 and 8 weeks after CCK implantation, only a few CD3-positive cells were found in all the groups, and in group A and B, the density of T lymphocytes was significantly lower than that in group D, and there was no significant difference between group A and the blank control group.

CONCLUSIONS

CsA significantly improves the histocompatibility of CCK material, and short-term systemic CsA administration achieves the best results. Macrophages, especially multinucleated giant cells participate in CCK degradation in vivo.

Physiological incompatibilities of porcine hepatocytes for clinical liver support

In fulminant hepatic failure, the use of bioartificial liver support (BAL) with porcine hepatocytes is the subject of a current and controversial debate.1 Specifically, the issue of cross-species physiological incompatibilities has not been addressed so far. We therefore investigated the effects of species-specific cytokines in single and cocultures on hepatocyte function. Hepatocyte cultures were isolated from human resection specimens and from Landrace pigs. Single and cocultures were exposed to porcine and human interleukin (IL)-6 or tumor necrosis factor (TNF)-alpha. Changes in expression of C-reactive protein (CRP), albumin, CCAAT enhancer binding protein (C/EBP)-alpha and C/EBP-beta and metabolic competence of cultured cells was studied by measuring testosterone metabolite production. After human or porcine IL-6 dosing, CRP was induced up to 100-fold in human hepatocyte cultures, while porcine hepatocytes responded marginally (2- to 5-fold). Treatment with human or porcine IL-6 or TNF-alpha resulted in reduced albumin production, albeit at different levels when human and porcine hepatocytes were compared (P = 0.001). Unlike human, porcine hepatocytes produced less of 6alpha-hydroxytestosterone (6alpha-HT) (P < 0.001) and 7alpha-HT (P < 0.001) after human or porcine IL-6 dosing and treatment with species-specific TNF-alpha induced (human hepatocytes) or decreased (porcine hepatocytes) 6beta-HT production (P = 0.021). In coculture with free exchange of metabolites, porcine hepatocytes produced less 6alpha-HT (P = 0.048) and 16alpha-HT (P = 0.033), whereas after treatment with human IL-6 reduced CRP gene and protein expression was observed with human hepatocytes (P = 0.013). In conclusion, species-specific responses of hepatocytes to cytokines and interactions with xenobiotic metabolites may limit the clinical effectiveness of porcine hepatocytes in BAL.

Effect of chemical treatment of silicon gel on tissue compatibility

BACKGROUND

Silicon gel is unfavourable for cell attachment and growth. This study was to study if pretreating the surface of silicon gel with chemical agents affects the proliferation of epithelial cells.

METHODS

Silicon gel was made and treated with either mixed acid solution (containing 232 g/dm(3) of H(2)SO(4) and 8 g/dm(3) of K(2)Cr(2)O(7)) or 300 cm(3)/dm(3) peroxide for 5, 10, and 15 minutes or 10, 15, and 20 minutes, respectively. The cultured corneal epithelial cells were seeded onto those silicon gels and kept for 13 days. Immunohistochemical investigations were then carried out for integrin (alpha 6 or beta 4) and actin.

RESULTS

Growth of the epithelial cells in silicon gels treated with mixed acid solution for 10 minutes and 15 minutes was much significant than that in the untreated gels. After a 12-hour culture, a small number of corneal epithelial cells were proliferated on the surface of the silicon gels that had been treated with peroxide for 15 minutes. After a 3-day culture, those cells were further proliferated and fused together. The corneal epithelial cells did not grow well in the silicon gels treated with peroxide for 10 or 20 minutes. Immunostaining revealed the expression of actin and integrin alpha 6 or beta 4 on the silicon gels that were treated with mixed acid solution for 10 minutes or peroxide for 15 minutes.

CONCLUSION

Silicon gels treated either with mixed acid solution for 10 or 15 minutes or with peroxide for 15 minutes improves cell proliferation.

Hemocompatibility of titanium oxide films

Hemocompatibility is a key property of biomaterials that come in contact with blood. Surface modification has shown great potential for improving the hemocompatibility of biomedical materials and devices. In this paper, we describe our work of improving hemocompatibility with Ti-O thin films prepared by plasma immersion ion implantation and deposition and by sputtering. The structure and surface chemical and physical properties of the films were characterized by X-ray diffraction, Auger electron spectroscopy, atomic force microscopy (AFM), contact angle measurement, and Hall effect measurement. The behavior of fibrinogen adsorption was investigated by 125I radioactive isotope labeling and AFM. Systematic evaluation of hemocompatibility, including in vitro clotting time, thrombin time, prethrombin time, platelet adhesion, and in vivo implantation into dog's ventral aorta or right auricle from 17 to 90 days, proved that Ti-O films have excellent hemocompatibility. It is suggested that the significantly lower interface tension between Ti-O films and blood and plasma proteins and the semiconducting nature of Ti-O films give them their improved hemocompatibility.

Peripheral blood stem cell allograft rejection mediated by CD4(+) T lymphocytes recognizing a single mismatch at HLA-DP beta 1*0901

Little is known about the molecular characteristics of alloantigens recognized by alloreactive T cells mediating hematologic stem cell graft rejection. In particular, it has never been shown that such alloantigens can be encoded by HLA-DP beta alleles. Indeed, matching for HLA-DP antigens is generally not considered to be of functional importance for the outcome of allogeneic bone marrow or peripheral blood stem cell transplantation. In this study, a case of peripheral blood stem cell allograft rejection was investigated in which the patient and donor differed for a single mismatch at HLA-DP in the rejection direction. Patient-derived T lymphocytes circulating at the time of rejection showed direct ex vivo cytotoxic activity against donor-derived B-lymphoblastoid cells as well as other HLA-DP beta 1*0901--expressing targets. The presence of HLA-DP beta 1*0901--specific effectors in vivo was further confirmed by in vitro stimulation experiments. CD4(+) T-cell lines and clones with specific cytotoxic activity against HLA-DP beta 1*0901--expressing targets including donor B-lymphoblastoid cells were generated both by nonspecific and by donor-specific in vitro stimulation. Taken together, these data demonstrate that HLA-DP can be the target antigen of cytotoxic CD4(+) T lymphocytes involved in peripheral blood stem cell allograft rejection. (Blood. 2001;98:1122-1126)

Alternative donor transplants for patients with advanced hematologic malignancies, conditioned with thiotepa, cyclophosphamide and antithymocyte globulin

Preparative regimens without total body irradiation (TBI) have been reported for alternative donor hemopoietic stem cell transplants (HSCT). Between 7 September 1994 and 7 June 1999 48 patients with advanced hematologic malignancies were conditioned with thiotepa (THIO) 15 mg/kg, cyclophosphamide (CY) 150 mg/kg and antithymocyte globulin (ATG). Donors were HLA mismatched family members (1-2 antigens) (FAM) (n = 24, median age 31 years) or HLA matched unrelated donors (UD) (n = 24, median age 34 years). GVHD prophylaxis was cyclosporine and methotrexate. Stem cell source was peripheral blood (n = 8) or bone marrow (n = 40). Hematologic recovery was seen in 42/46 (91%) evaluable patients and complete chimerism in 31/37 patients (85%). Acute GVHD grades III-IV were seen in 10/46 patients surviving 10 days (21%) and extensive chronic GVHD in 2/36 patients surviving 100 days (5%). Twenty-six patients died (54%), eight of recurrent disease (17%) and 18 of transplant-related complications (37%): main causes of TRM were GVHD (15%), infections (15%) and graft failure (4%). Twenty-two patients (46%) survive with a median follow-up of 877 days (287-1840). The actuarial 3-year survival is 49% for FAM and 42% for UD transplants. Results obtained with this regimen in unrelated grafts for advanced CML (n = 15) were not significantly different when compared to 21 concurrent UD grafts for advanced CML prepared with CY-TBI. In conclusion, the combination of THIO-CY-ATG allows engraftment of alternative donor hemopoietic stem cells. Results are similar when using unrelated matched donors or partially mismatched family donors, and not significantly different when compared to patients conditioned with CY-TBI.

An immunoablative regimen of fludarabine and cyclophosphamide prevents fully MHC-mismatched murine marrow graft rejection independent of GVHD

The prevention of graft rejection in the setting of nonmyeloablative transplant approaches might be mediated by chemotherapy-induced host immunoablation and by the graft-promoting effects of graft-versus-host disease (GVHD). To evaluate whether host immunoablation alone might allow for alloengraftment, we developed an F1-into-parent murine marrow rejection model using host preparative regimens of lethal total body irradiation (TBI; 950 cGy), sublethal irradiation (600 cGy), or combinations of fludarabine (Flu) and cyclophosphamide (Cy). A preparative regimen selectivity index (SI) was calculated to determine whether host lymphocytes were preferentially depleted relative to myeloid cells (SI = number of host myeloid/number host T lymphoid cells remaining after preparative regimen administration). Saline-treated recipients were assigned an SI value of 1.0. Recipients of lethal TBI had reduced myeloid cells relative to T cells (SI = 0.6). In contrast, all Flu/Cy regimens preferentially depleted host T cells: recipients of Flu (100 mg/kg per day)/Cy (50 mg/kg per day) for 10 days (SI = 28.1); recipients of Flu (100 mg/kg per day)/Cy (100 mg/kg per day) for 10 days (SI = 64.1); and recipients of Flu (100 mg/kg per day)/Cy (50 mg/kg per day) for 19 or 27 days (SI = 74.6). The 10-day regimen of Flu/Cy (50 mg/kg per day) did not severely reduce host T cell numbers, nor did it prevent F1 marrow rejection (<1% chimerism, n = 14). In contrast, the 10-day regimen of Flu/Cy (100 mg/kg per day) reduced T-cell numbers below that of lethal TBI recipients and prevented F1 marrow rejection (11.4% chimerism, n = 15); donor chimerism was predominant in lymphoid cells and was stable through day 240 post-BMT. Additionally, the 19- or 27-day regimen of Flu/Cy, which most selectively depleted host T cells, also prevented F1 marrow rejection (6.3% chimerism, n = 15). These results therefore demonstrate that optimized Flu-containing, immunoablative preparative regimens can prevent fully MHC-disparate marrow rejection independent of GVHD.

Tacrolimus does not abrogate the increased risk of acute graft-versus-host disease after unrelated-donor marrow transplantation with allelic mismatching at HLA-DRB1 and HLA-DQB1

One hundred patients of median age 34 years (range, 14-53) received bone marrow transplants from unrelated donors serologically matched for human leukocyte antigen HLA-A, HLA-B, and HLA-DR using tacrolimus and minimethotrexate for prevention of acute graft-versus-host disease (GVHD). Sixty-eight patient-donor pairs had allelic matches at HLA-DRB1 and HLA-DQB1, 20 pairs had a single mismatch at HLA-DRB1 or HLA-DQB1, and 12 were mismatched at both HLA-DRB1 and HLA-DQB1. Minimum follow-up time was 6 months. Grades 2 to 4 GVHD occurred in 43% of patients with matched donors, 69% with single allele-mismatched donors, and 71% with double allele-mismatched donors; grades 3 to 4 GVHD occurred in 22%, 43%, and 64%, respectively. On multivariate analysis, the relative risk of grades 2 to 4 GVHD was 2.2 (95% CI, 1.1-4.5; P = .03) with a single allele mismatch and 2.7 (95% CI, 1.2-6.0; P = .02) with a double allele mismatch. The relative risks of grades 3 to 4 GVHD were 3.0 (95% CI, 1.2-7.6; P = .02) and 5.0 (95% CI, 1.9-12.6; P = .001), respectively. Day 100 treatment-related mortality was also adversely affected by allelic mismatching, occurring in 21% of those with matched donors, 50% with single allele-mismatched donors, and 42% with double allele-mismatched donors (P = .02), but overall survival at day 180 did not differ significantly among the 3 groups. Tacrolimus does not abrogate the adverse impact of allele mismatching at HLA-DRB1 and HLA-DQB1 on the risk of moderate-to-severe acute GVHD.

Transplantation of anergic histoincompatible bone marrow allografts

BACKGROUND

Successful allogeneic bone marrow transplantation relies on global immunosuppression or elimination of T cells. In contrast, the induction of anergy can inactivate specific sets of alloreactive T cells in the donor marrow. Previous work has shown that anergy can be induced by blocking the interaction of the B7 molecule on the surface of antigen-presenting cells with the CD28 molecule on the surface of T cells, thus preventing key signaling events essential for the activation of T cells. To investigate the feasibility of this approach with respect to transplantation of histoincompatible bone marrow, we undertook a clinical trial of ex vivo induction of anergy in T cells present in donor marrow to recipient alloantigens.

METHODS

Outcomes in 12 transplant recipients were evaluated. The recipients' peripheral-blood lymphocytes were collected before myeloablation and served as alloantigen-presenting cells. To induce alloantigen-specific anergy, bone marrow from a donor mismatched with the recipient for one HLA haplotype was cocultured with irradiated cells from the recipient for 36 hours in the presence of CTLA-4-Ig, an agent that inhibits B7:CD28-mediated costimulation. After conventional myeloablation and immunoprophylaxis, the treated donor cells were transfused into the recipient.

RESULTS

After the induction of anergy, the frequency of T cells capable of recognizing alloantigens of the recipient in donor marrow was sharply reduced (P<0.001), whereas the responsiveness to alloantigens from persons unrelated to the recipient or the donor was unaffected (P=0.51). In the 11 patients who could be evaluated, the haploidentical bone marrow cells engrafted. Of these 11 patients, 3 had acute graft-versus-host disease (GVHD) confined to the gastrointestinal tract. No deaths were attributable to GVHD. Five of the 12 patients were alive and in remission 4.5 to 29 months after transplantation.

CONCLUSIONS

Donor bone marrow treated ex vivo to induce anergy to alloantigens from the recipient can reconstitute hematopoiesis in vivo with a relatively low risk of GVHD.

An alloimmunized, thrombocytopenic patient successfully transfused with acid-treated, random-donor platelets

Alloimmunized, thrombocytopenic patients, refractory to random-donor platelet transfusion, often respond to HLA-identical single-donor platelets. HLA-compatible platelets are expensive, take time to prepare, and donors are sometimes not to be found. We have used random-donor platelets and 'peeled' the HLA-antigen off the platelets, using a modified laboratory method (incubation of platelets with citric acid solution at 0 degrees C). Platelet recovery in two healthy subjects was 72.0% for acid-treated platelets, and 73.5% for untreated control platelets, using 111In-labelled autologous platelets. Survival time (multiple hit) was 6.25 and 7.95 d, respectively. Random-donor platelets that were strongly positive in the crossmatch with serum from a patient became negative after treatment with the acid solution. Furthermore, transfusion of these platelets gave a post-transfusion, platelet-count increment comparable with transfusion of HLA-compatible single-donor platelets.

A controlled trial of cyclosporine in renal transplantation with conversion to azathioprine and prednisolone after three months

Thirty-five patients given an HLA-DR-incompatible cadaver kidney that was diuresing immediately after transplantation were randomly allocated to treatment with cyclosporine alone for 3 months followed by conversion to azathioprine and prednisolone (AP), or to conventional treatment with AP. Although many patients had to be converted to AP before 90 days because of rejection requiring more than two treatment courses of high-dose i.v. methylprednisolone, 16 of 21 grafts were functioning at 3 months, and 12 of 14 grafts in the control group were functioning. However 3 further grafts were lost from chronic rejection in the control group, and none were lost from chronic rejection in the cyclosporine group. All but one patient on cyclosporine had depressed renal function, and in all these patients function improved on conversion to AP. This depression of renal function is attributed both to cyclosporine nephrotoxicity and to a low-grade rejection reaction, the latter suggesting that the addition of steroids to cyclosporine might be beneficial in some patients. The strategy of a three-month course of cyclosporine followed by conversion to AP provides satisfactory immunosuppression, and it may be of value if long-term side effects of cyclosporine emerge with further experience.

Histoincompatible skin and marrow grafts in rabbits on cyclosporin A

Cyclosporin A (Cy A; 15 mg/kg s.c.) allows allogeneic histoincompatible skin graft survival in 10 of 10 rabbits as long as the drug is given. The same dose of Cy A does not affect acute graft-versus-host disease (GVHD) and increase survival of rabbits after allogeneic bone marrow transplantation between the same two strains, when two groups of 15 animals are tested. Median survival of 14 engrafted animals without Cy A was 23 days, of 12 engrafted animals with Cy A 22 days (not significant). Cryopreservation of bone marrow delays the onset of GVHD and increases survival of engrafted animals. Median survival of 5 engrafted animals without Cy A was 33 days, of 14 engrafted animals with Cy A 35 days. Our hypothesis is that one part of early GVHD as well as of early graft rejection is mediated by a subclass of cells which is resistant to Cy A. This hypothesis is supported by the finding that most transplanted skins show a self-limited period of infiltration and induration. Skin grafts survive this period of infiltration. If the same potentially self-limited process occurs in the liver or the intestine during acute GVHD, animals die. this hypothesis could explain why Cy A allows skin graft survival but does not affect acute GVHD.

The effect of anti-thrombotic drugs on prosthetic grafts in the canine inferios vena cava

The effect of phenylbutazone, an anti-thrombotic agent, on the occlusion rate of knitted Dacron grafts placed in the infrarenal inferior vena cava of dogs was studied. Grafts places in dogs treated with phenylbutazone remained patent significantly longer than those in untreated animals. All the grafts in the untreated group occluded, but 2 remained patent in the treated animals.