Neurologic complications after allogeneic hematopoietic stem cell transplantation: risk factors and impact.

Neurologic complications (NCs) may be a significant source of morbidity and mortality after hematopoietic cell transplantation (HCT). We performed a retrospective study of 263 consecutive patients undergoing allogeneic HCT for hematological malignancies to determine the incidence, risk factors and clinical impact of NCs in the first 5 years after HCT. We determined the incidence of central nervous system (CNS) infection, intracranial hemorrhage, ischemic stroke, metabolic encephalopathy, posterior reversal encephalopathy syndrome, seizure and peripheral neuropathy. In all, 50 patients experienced 63 NCs-37 early (⩽day +100), 21 late (day +101 to 2 years) and 5 very late (2 to 5 years). The 1- and 5-year cumulative incidences of all NCs were 15.6% and 19.2%, respectively, and of CNS complication (CNSC; all of the above complications except peripheral neuropathy) were 12.2 and 14.5%. Risk factors for CNSC were age (hazard ratio (HR)=1.06 per year, P=0.0034), development of acute GvHD grade III-IV (HR=2.78, P=0.041), transfusion-dependent thrombocytopenia (HR=3.07, P=0.025) and delayed platelet engraftment (>90th centile; HR=2.77, P=0.043). CNSCs negatively impacted progression-free survival (HR=2.29, P=0.0001), overall survival (HR=2.63, P<0.0001) and non-relapse mortality (HR=8.51, P<0.0001). NCs after HCT are associated with poor outcomes, and usually occur early after HCT.

Prognostic understanding, quality of life and mood in patients undergoing hematopoietic stem cell transplantation.

Little is known about how patients undergoing hematopoietic stem cell transplantation (HCT) and their family caregivers (FC) perceive their prognosis. We examined prognostic understanding in patients undergoing HCT and their FC and its relationship with quality of life (QOL) and mood. We conducted a longitudinal study of patients (and FC) hospitalized for HCT. We used a questionnaire to measure participants' prognostic understanding and asked the oncologists to estimate patients' prognosis prior to HCT. We assessed QOL and mood weekly and evaluated the relationship between prognostic understanding, and QOL and mood using multivariable linear mixed models. We enrolled 90 patients undergoing (autologous (n=30), myeloablative (n=30) or reduced intensity allogeneic (n=30)) HCT. About 88.9% of patients and 87.1% of FC reported it is 'extremely' or 'very' important to know about prognosis. However, 77.6% of patients and 71.7% of FC reported a discordance and more optimistic prognostic perception compared to the oncologist (P<0.0001). Patients with a concordant prognostic understanding with their oncologists reported worse QOL (ß=-9.4, P=0.01) and greater depression at baseline (ß=1.7, P=0.02) and over time ((ß=1.2, P<0.0001). Therefore, Interventions are needed to improve prognostic understanding, while providing patients with adequate psychological support.

Expression of α4ß7 integrin on memory CD8(+) T cells at the presentation of acute intestinal GVHD.

Acute intestinal GVHD remains a major source of morbidity after allogeneic hematopoietic cell transplantation (HCT). α4ß7 integrin is a cell surface molecule that mediates lymphocyte trafficking to intestinal tissue. In this analysis, peripheral blood was collected at the time of presentation of symptoms of acute GVHD and before any treatment. In all, 45 samples were collected and divided into three groups on the basis of subsequent evaluation: intestinal GVHD (n=15), skin GVHD (n=20) and no GVHD (n=10). Two patients developed intestinal GVHD after DLI. The no-GVHD group comprised 10 patients who presented with suspicious symptoms, but evaluation yielded other etiologies. Analysis by flow cytometry showed that intestinal GVHD patients had a significantly higher percentage of α4ß7 integrin-expressing memory CD8(+) T cells (median 7.69%; lower and upper quartiles, 1.06% and 11.64%, respectively) compared with patients with skin GVHD (1.26%; 0.57% and 2.49%) and no GVHD (0.96%; 0.44% and 1.85%), P=0.03. No differences were found in α4ß7 expression in any CD4(+) T-cell subsets or naive CD8(+) T cells. This study adds to the evidence that α4ß7 integrin is involved in lymphocyte trafficking in acute intestinal GVHD.

Removal of an impacted distal airway foreign body using a guidewire and a balloon angioplasty catheter.

Airway aspiration of foreign bodies is relatively common in young children. Visible objects are commonly removed under direct vision using grabbing forceps inserted through a rigid bronchoscope. We describe a case of aspiration of the hollow tip of a plastic pen which lodged distally in the right main bronchus of an older child. This object was located so distally that it could only be visualised using flexible fibreoptic bronchoscopy. A novel method was required for successful retrieval, which involved the passage of a guidewire through the centre of the foreign body. A balloon angioplasty catheter was then railroaded over the guidewire through the foreign body and the balloon inflated with saline. This allowed the foreign body to be pulled proximally out of the airway.

Autologous SCT with a dose-reduced BU and CY regimen in older patients with non-Hodgkin's lymphoma.

Autologous SCT is a potentially curative procedure for patients with relapsed lymphoma (NHL). We analyzed the outcomes of 34 patients > or =60 years old, including eight patients > or =70 years old, who received BU and CY and SCT for NHL. Patients received BU 0.8 mg/kg i.v. (n=25) or 1 mg/kg p.o. (n=9) q 6 h x 14 doses and CY 60 mg/kg i.v. q day x 2 days. The median age was 66 (range, 60-78) years. Twenty-two patients had large cell, 10 follicular and two-mantle cell lymphoma. Fifteen patients were in a second or greater CR and 19 patients were in a PR. The median days to ANC >500/microl and platelet count >50,000/microl were 10 and 13 days respectively. The 100-day transplant-related mortality was 0%. Toxicities included interstitial lung disease (n=2), seizures in a patient with CNS lymphoma (n=1), mild veno-occlusive disease (n=2), and transient atrial fibrillation (n=4). With a median follow-up of 40 months, the 2-year overall survival and PFS were 67 and 54% respectively. BU/CY is a well-tolerated conditioning regimen for older patients with NHL. Age alone should not be used as an exclusion criterion for autologous SCT.

Clinical outcomes of late rather than early full-donor chimerism in patients with advanced lymphomas receiving nonmyeloablative allogeneic hematopoietic SCT.

Allogeneic hematopoietic SCT (HSCT) can ideally provide long-term remission in advanced lymphoma patients by capturing a graft-vs-tumor (GVT) effect. On the basis of a murine model, we attempted to optimize a GVT effect through nonmyeloablative therapy and HLA-matched related donor HSCT with intentional induction of mixed chimerism followed by prophylactic donor lymphocyte infusion. A total of 26 advanced lymphoma patients were separated into an early and late full-donor chimerism (FDC) group using a median of 45 days post-HSCT as the defining point for FDC. Upon generating these groups, analysis by Student's t-test demonstrated that they were statistically distinct in time to develop FDC (P<0.01). There was a trend toward improved CR rates in the late group relative to the early group (62 vs 31%; P=0.12). A trend toward improved progression-free survival at 5 years was also observed in the late compared to the early group by Kaplan-Meier analysis (38 vs 8%; P=0.081). However, this did not correlate to a significant overall survival benefit. In conclusion, these data support the observation from our mouse models that the most potent GVT effect occurs in mixed chimeras with late chimerism conversion.

Preinfusion variables predict the predominant unit in the setting of reduced-intensity double cord blood transplantation.

Double cord blood transplantation (DCBT) may overcome the slow hematopoietic recovery and engraftment failure associated with infusion of a single cord blood unit. In DCBT, only one unit typically contributes to long-term hematopoiesis, but little is known about factors affecting cord predominance. As results from a phase I trial suggested that order of infusion may affect cord predominance, we analyzed the effect of preinfusion variables on chimerism patterns of 38 patients enrolled in the initial study and a subsequent phase II trial. All patients were treated with a reduced-intensity conditioning (RIC) regimen of fludarabine, melphalan and thymoglobulin followed by DCBT. By day 100, 66% of patients had hematopoiesis derived from a single cord blood unit. Higher post-thaw total nucleated cell and CD34+ cell dose were associated with cord predominance and in 68% of patients (P=0.03); the predominant cord blood unit was infused first. Only the post-thaw CD34+ cell dose of the predominant unit predicted time to both neutrophil and platelet engraftment. Although based on a small number of patients, our results identify parameters that may affect cord predominance and engraftment in the setting of DCBT following RIC and suggest possible strategies for selecting infusion order for cord blood units.

Comparison of outcomes after transplantation of peripheral blood stem cells versus bone marrow following an identical nonmyeloablative conditioning regimen.

This is the first study to examine the outcomes in 54 patients with hematologic malignancies who received an HLA-matched related donor bone marrow (BM, n = 42) or GCSF-mobilized peripheral blood stem cells (PBSC, n = 12) following identical nonmyeloablative conditioning with the intention of induction of mixed chimerism (MC) followed by prophylactic donor leukocyte infusion (pDLI) to convert MC to full donor chimerism (FDC) and capture a graft-versus-tumor effect without clinical graft-versus-host disease (GVHD). Neutrophil and platelet recovery were faster and transfusion requirement was less in PBSC recipients (P < 0.05). A total of 48% of BMT recipients achieved FDC with a median conversion time of 84 days, including 13 following pDLI. In contrast, 83% (P = 0.04) in the PBSC group had spontaneous FDC at a median of 14 days, precluding the administration of pDLI. There was no significant difference in the incidences of acute or chronic GVHD, though the rates of chronic GVHD were considerably higher in PBSC group than in the BM group (6/7, 86% vs 10/24, 42%). CD4 and CD8 T-cell recovery was faster in PBSC recipients. In PBSC recipients, a higher number of CD34+ cells was associated with increased rates of severe, grade III-IV acute GVHD.

Myeloma responses and tolerance following combined kidney and nonmyeloablative marrow transplantation: in vivo and in vitro analyses.

Six patients with renal failure due to multiple myeloma (MM) received simultaneous kidney and bone marrow transplantation (BMT) from HLA-identical sibling donors following nonmyeloablative conditioning, including cyclophosphamide (CP), peritransplant antithymocyte globulin and thymic irradiation. Cyclosporine (CyA) was given for approximately 2 months posttransplant, followed by donor leukocyte infusions. All six patients accepted their kidney grafts long-term. Three patients lost detectable chimerism but accepted their kidney grafts off immunosuppression for 1.3 to >7 years. One such patient had strong antidonor cytotoxic T lymphocyte (CTL) responses in association with marrow rejection. Two patients achieved full donor chimerism, but resumed immunosuppression to treat graft-versus-host disease. Only one patient experienced rejection following CyA withdrawal. He responded to immunosuppression, which was later successfully withdrawn. The rejection episode was associated with antidonor Th reactivity. Patients showed CTL unresponsiveness to cultured donor renal tubular epithelial cells. Initially recovering T cells were memory cells and were enriched for CD4+CD25+ cells. Three patients are in sustained complete remissions of MM, despite loss of chimerism in two. Combined kidney/BMT with nonmyeloablative conditioning can achieve renal allograft tolerance and excellent myeloma responses, even in the presence of donor marrow rejection and antidonor alloresponses in vitro.

High-dose carboplatin and regimen-related toxicity following autologous bone marrow transplant.

Pharmacokinetic analysis of carboplatin dosing suggests a more accurate prediction of toxicity when the dose is based on the area under the plasma concentration vs time curve (AUC) instead of body surface area (BSA). We retrospectively calculated the carboplatin AUC of 117 patients who received an autologous stem cell transplant following a conditioning regimen consisting of carboplatin 1800 mg/m(2) and cyclophosphamide 6000 mg/m(2) to identify whether higher carboplatin exposure resulted in an increase in regimen-related non-hematologic toxicities. The most common non-hematologic toxicities were gastrointestinal and hepatic. Twenty (17%) patients experienced additional > or =grade 2 toxicity, specifically, renal toxicity significantly associated with a higher median AUC of 10.2 mg/ml(-1) min (P = 0.001). Prior platinum therapy was also significantly associated with toxicity (P = 0.052). While carboplatin dose based on BSA varied minimally (median 990 (range 450-1340) mg, the calculated AUC showed a near four-fold range of exposure (median 7.8 (range 3.6 to 13.8) mg/ml(-1) min). These data suggest a relationship between non-hematologic adverse events and the estimated AUC. Prospective trials will be necessary to identify the target carboplatin AUC which optimizes outcome and minimizes toxicity in the autologous transplant setting.

Successful pregnancy after high-dose cyclophosphamide, carboplatinum, and taxol with peripheral blood stem cell transplant in a young woman with ovarian carcinoma.

BACKGROUND: Both ovarian carcinoma and high-dose chemotherapy tend to preclude future pregnancies. CASE: We report a case of a young woman with borderline ovarian carcinoma and invasive tumor implants who underwent surgical debulking with preservation of future fertility followed by carboplatinum, paclitaxel (Taxol), and subsequent high-dose chemotherapy with subsequent peripheral blood stem cell rescue as part of a phase I clinical trial. After a brief period of amenorrhea, the patient had a successful pregnancy that was complicated by a spontaneous abortion in the first trimester. Several months later she conceived and delivered a healthy baby at term. CONCLUSIONS: To our knowledge this is the first reported case of pregnancy after high-dose chemotherapy with stem cell transplant in a woman with ovarian carcinoma.

Successful allogeneic stem cell transplantation with nonmyeloablative conditioning in patients with relapsed hematologic malignancy following autologous stem cell transplantation.

The use of myeloablative preparative therapy and allogeneic stem cell transplantation (alloSCT) as salvage therapy for adult patients with relapsed hematologic malignancy after autologous stem cell transplantation (autoSCT) is generally unsuccessful due to very high treatment-related mortality rates. We evaluated the outcome of HLA-matched related donor alloSCT following nonmyeloablative preparative therapy in 13 patients (median age, 38 years) with relapsed hematologic malignancies (Hodgkin's disease, n = 4; Hodgkin's disease and advanced myelodysplastic syndrome, n = 1; non-Hodgkin's lymphoma, n = 6; multiple myeloma, n = 2) after initial autoSCT. Median time from autoSCT to alloSCT was 12 months (range, 3-24 months); 6 patients had chemotherapy-refractory disease following autoSCT, 6 were in untreated relapse, and 1 had a partial response from salvage chemotherapy. Preparative therapy consisted of cyclophosphamide, 150-200 mg/kg; peritransplantation anti-thymocyte globulin; thymic irradiation (in patients who had not received previous mediastinal irradiation); and a very short course of cyclosporine as GVHD prophylaxis. All patients achieved initial mixed chimerism as defined by greater than 1% donor peripheral white blood cells. Seven patients, who had no evidence of GVHD, received prophylactic DLI beginning 5 to 6 weeks after transplantation for conversion of mixed chimerism to full donor hematopoiesis and to optimize a graft-versus-tumor effect. Six patients showed conversion to full donor chimerism and 1 lost the graft. Grade II or greater acute GVHD occurred in 9 patients. Seven patients achieved a complete response; 6 had no response. The median survival time of the 13 patients is currently 10 months (range, 3-39 months), with an overall survival probability at 2 years of 45% (95% confidence interval [CI], 19%-73%) and a disease-free survival probability at 2 years of 37.5% (95% CI, 12%-65%). Thus, this novel nonmyeloablative alloSCT strategy followed by prophylactic DLI was well tolerated and can result in durable disease-free survival among patients with advanced hematologic malignancies after a failed autoSCT. Further follow-up and evaluation of additional patients are required to conclusively establish the role of this strategy in the treatment of hematologic malignancies after an autologous transplantation.

Intentional induction of mixed chimerism and achievement of antitumor responses after nonmyeloablative conditioning therapy and HLA-matched donor bone marrow transplantation for refractory hematologic malignancies.

Mixed lymphohematopoietic chimerism can be induced in mice with bone marrow transplantation (BMT) after a nonmyeloablative preparative regimen that includes cyclophosphamide, anti-T-cell antibody therapy, and thymic irradiation. These mixed chimeras are resistant to the induction of graft-versus-host disease (GVHD) after delayed donor leukocyte infusions (DLIs), despite a potent lymphohematopoietic graft-versus-host reaction that converts the mixed chimeric state to a full donor one. Based on this animal model, we initiated a trial of nonmyeloablative therapy with HLA-matched or -mismatched donor BMT and DLI for refractory hematologic malignancies. Twenty-one of 36 patients enrolled in this trial received a genotypically (n = 20) or phenotypically (n = 1) HLA-matched donor transplant; results reported here are for those patients only. Preparative therapy consisted of cyclophosphamide in doses of 150 to 200 mg/kg; peritransplant antithymocyte globulin; thymic irradiation (in patients who had not received previous mediastinal radiation therapy); and cyclosporine. Eighteen of 20 evaluable patients developed persistent mixed lymphohematopoietic chimerism as defined by >1% donor peripheral white blood cells until at least day 35 posttransplantation. Ten patients received prophylactic DLI beginning 5 to 6 weeks after BMT for conversion of mixed chimerism to full donor hematopoiesis and to optimize a graft-versus-leukemia effect. Fourteen of 20 evaluable patients (70%) achieved an antitumor response; 8 of these responses were complete, and 6 were partial. Of the 8 evaluable patients who received prophylactic DLI, 6 showed conversion to full donor chimerism. Five of the 9 evaluable patients (56%) who received prophylactic DLI achieved a complete response, compared with 3 of 11 patients (27%) who did not receive prophylactic DLI. Currently 11 patients are alive, and 7 of these are free of disease progression at a median follow-up time of 445 days (range, 105-548 days) posttransplantation. Transplantation-related complications included cyclophosphamide-induced cardiac toxicity in 3 of 21 patients (14%) and grade II or greater GVHD in 6 patients (29%). One patient (5%) died from a complication of BMT, and 1 patient (5%) died from GVHD after 2 prophylactic DLIs were given for conversion of chimerism. In summary, mixed lymphohematopoietic chimerism was reproducibly induced after a novel nonmyeloablative preparative regimen incorporating chemotherapy, peritransplant antithymocyte globulin, and thymic irradiation, allowing for early administration of DLI in 10 of 21 patients. After treatment, striking antitumor responses were observed in the majority of patients with chemotherapy-refractory hematologic malignancies.

High-dose cyclophosphamide + carboplatin and interleukin-2 (IL-2) activated autologous stem cell transplantation followed by maintenance IL-2 therapy in metastatic breast carcinoma - a phase II study.

While high-dose chemotherapy and stem cell transplantation is associated with higher complete response rates than conventional chemotherapy in patients with metastatic breast cancer (MBC), its role in conferring a survival advantage is unproven. We report the results of a prospective phase II trial of 33 patients accrued between 1996 to 1998 with chemosensitive MBC, who received cyclophosphamide (Cy) 2000 mg/m2/day and carboplatin (Cb) 600 mg/m2/day for 3 consecutive days, followed by infusion of peripheral blood stem cells cultured in IL-2 for 24 h on day 0 as adoptive immunotherapy. Low-dose interleukin-2 (IL-2) was administered from day 0 to +4 and/or +7 to +11, +14 to +18, +21 to +25, then 5 days per month for 11 months to augment a graft-versus-tumor effect. The results of this study were compared to those of a historical control group treated with an identical high-dose Cb + Cy regimen with SCT but without IL-2 treatment. Only gastrointestinal (GI) toxicity was more frequent in the IL-2 cohort (P = 0.0031). At a median follow-up of 18.6 months, the median progression-free survival (PFS) is 9 months (2.4-40) and the median OS has not been reached yet. The Kaplan-Meier estimated 2 year PFS is 35%, compared with 17% in the control arm (P = 0.73), and the estimated 2 year OS is 78%, compared with 61% in the control arm (P = 0.22). Multivariate analysis showed that ER status was an independent predictor for OS and PFS, and less chemotherapy prior to HDCSCT predicted for a better PFS. These results show that augmenting HDC with IL-2 activated SCT is well-tolerated. Whether a therapeutic advantage is achievable in patients with MBC remains to be determined. Bone Marrow Transplantation (2000) 25, 19-24.

A prospective randomized trial comparing the toxicity and safety of atovaquone with trimethoprim/sulfamethoxazole as Pneumocystis carinii pneumonia prophylaxis following autologous peripheral blood stem cell transplantation.

Pneumonia due to Pneumocystis carinii is an infrequent complication following autologous stem cell transplantation (ASCT) which is associated with a high mortality. Although administration of trimethoprim/sulfa- methoxazole (TMP/SMX) is an effective prophylactic strategy for Pneumocystis carinii pneumonia (PCP), treatment-associated toxicity frequently results in discontinuation of therapy. We have conducted a prospective randomized trial comparing atovaquone, a new anti-Pneumocystis agent, with TMP/SMX for PCP prophylaxis following autologous peripheral blood stem cell (PBSC) transplantation. Thirty-nine patients were studied. Twenty patients received atovaquone suspension and 19 patients received TMP/SMX. The median ages were 44 (range 20-68) and 47 (range 32-63) years, respectively. A similar number of patients with solid tumors (14 vs 15) and hematologic malignancies (five vs five) were treated in each group. Either TMP/SMX (160/800 mg) or atovaquone (1500 mg) was administered daily from transplant day -5 until day -1, discontinued from day 0 to engraftment, then resumed 3 days per week until day +100 post-transplant. The median time to engraftment (ANC >0.5 x 109/l) was similar in both groups. Eighty percent of the patients randomized to atovaquone prophylaxis completed the study. Four atovaquone-treated patients were removed from study; two patients (10%) did not receive a transplant and two patients (10%) were removed due to a protocol violation. None of the 16 patients treated with atovaquone experienced treatment-associated adverse effects. Of the 19 patients randomized to receive TMP/SMX, 55% completed the study. Nine TMP/SMX-treated patients were removed from the study; one patient (5%) did not receive a transplant and eight patients (40%) were removed due to drug intolerance (P < 0.003). The rate of intolerance to TMP/SMX led to the early discontinuation of this randomized trial. Intolerance of TMP/SMX included elevated transaminase levels (n = 1), nausea or vomiting (n = 3), thrombocytopenia (n = 2) and neutropenia (n = 2). All episodes of TMP/SMP intolerance occurred following transplantation after a median duration of 17.5 (range 2-48) days and a median of 7 (range 1-20) doses. Resolution of adverse side-effects occurred in all eight patients within a median of 7 (range 2-20) days following discontinuation of therapy. Neither PCP nor bacterial infections were identified in any of the patients treated. This prospective randomized study demonstrated that atovaquone is well-tolerated for anti-Pneumocystis prophylaxis in autologous PBSC transplant patients intolerant of TMP/SMX.

Late onset veno-occlusive disease following high-dose chemotherapy and stem cell transplantation.

The original definition of hepatic veno-occlusive disease (VOD), which is still widely accepted, includes onset of the clinical syndrome before day +20 following high-dose chemotherapy (HDC) and stem cell transplantation (SCT). We retrospectively identified four patients following HDC and SCT presenting with late onset VOD occurring at day +24, day +27, day +34 and day +42 post SCT. All patients had moderate VOD, with successful resolution of the VOD before day +100 with optimal supportive therapy. Common risk factors for VOD shared by all four patients included an older age (median age: 60 years), and use of a busulphan-containing regimen. Mean and maximum bilirubin levels for all patients during the VOD syndrome were 2.02, 1.76, 5.09, 2.87 mg/dl and 2.5, 2.2, 8.9 and 4.1 mg/dl, respectively, which correlated well with duration of VOD. All patients encountered platelet transfusion-dependent thrombocytopenia during VOD. Ursodeoxycholic acid was used as VOD prophylaxis beginning at a mean of 33 days prior to onset of VOD. As the cellular target of hepatic VOD is as yet unidentified, it is uncertain whether ursodiol or other common characteristics of patients with late onset VOD influence the pathogenesis and natural history of this disease. We believe that the uncommon clinical entity of late onset VOD, a potentially fatal regimen-related toxicity, should not be ignored as a diagnosis of liver disease after 3 or more weeks following HDC and SCT.

Combined histocompatibility leukocyte antigen-matched donor bone marrow and renal transplantation for multiple myeloma with end stage renal disease: the induction of allograft tolerance through mixed lymphohematopoietic chimerism.

BACKGROUND: Experimental and clinical evidence has demonstrated that the establishment of allogeneic chimerism after bone marrow transplantation may provide donor-specific tolerance for solid organ allografts. METHODS: Based on the preliminary results of a clinical trial using nonmyeloablative preparative therapy for the induction of mixed lymphohematopoietic chimerism, we treated a 55-year-old woman with end stage renal disease secondary to multiple myeloma with a combined histocompatibility leukocyte antigen-matched bone marrow and renal transplant after conditioning with cyclophosphamide, antithymocyte globulin, and thymic irradiation. RESULTS: The posttransplant course was notable for early normalization of renal function, the absence of acute graft-versus-host disease, and the establishment of mixed lymphohematopoietic chimerism. Cyclosporine, which was the only posttransplant immunosuppressive therapy, was tapered and discontinued on day +73 posttransplant. No rejection episodes occurred, and renal function remains normal on day + 170 posttransplant (14 weeks after discontinuing cyclosporine). Although there is presently no evidence of donor hematopoiesis, there is evidence of an ongoing antitumor response with a recent staging evaluation showing no measurable urine kappa light chains. The patient remains clinically well and is off all immunosuppressive therapy. CONCLUSION: This is the first report of the deliberate induction of mixed lymphohematopoietic chimerism after a nonmyeloablative preparative regimen to treat a hematological malignancy and to provide allotolerance for a solid organ transplant.

Mixed lymphohaemopoietic chimerism and graft-versus-lymphoma effects after non-myeloablative therapy and HLA-mismatched bone-marrow transplantation.

BACKGROUND: HLA-mismatched donor bone-marrow transplantation after standard myeloablative conditioning therapy for haematological malignant disorders has been limited by severe graft-versus-host disease (GVHD) and graft failure. We tested a new approach to find out whether lymphohaemopoietic graft-versus-host reactions could occur without excessive GVHD in mixed haemopoietic chimeras produced across HLA barriers with non-myeloablative conditioning. METHODS: Five patients with refractory non-Hodgkin lymphoma underwent bone-marrow transplantation from haploidentical related donors sharing at least one HLA A, B, or DR allele on the mismatched haplotype. Conditioning included cyclophosphamide and thymic irradiation before transplantation, and antithymocyte globulin before and after transplantation. The only other GVHD prophylaxis was cyclosporin. FINDINGS: Four of five patients were evaluable and showed engraftment. Mixed haemopoietic chimerism was established, with a predominance of donor lymphoid tissue and varying degrees of myeloid chimerism. Two patients were in GVHD-free states of complete and partial clinical remission at 460 and 103 days after bone-marrow transplantation. INTERPRETATION: Mixed chimerism can be induced in adult recipients of HLA-mismatched bone-marrow transplantation by a non-myeloablative conditioning regimen. The antilymphoma responses seen in two patients suggest that allogeneic bone-marrow transplantation without myeloablative conditioning might have potent immunotherapeutic benefits.