Whole blood gene expression within days after total-body irradiation predicts long term survival in Gottingen minipigs

Gottingen minipigs mirror the physiological radiation response observed in humans and hence make an ideal candidate model for studying radiation biodosimetry for both limited-sized and mass casualty incidents. We examined the whole blood gene expression profiles starting one day after total-body irradiation with increasing doses of gamma-rays. The minipigs were monitored for up to 45 days or time to euthanasia necessitated by radiation effects. We successfully identified dose- and time-agnostic (over a 1-7 day period after radiation), survival-predictive gene expression signatures derived using machine-learning algorithms with high sensitivity and specificity. These survival-predictive signatures fare better than an optimally performing dose-differentiating signature or blood cellular profiles. These findings suggest that prediction of survival is a much more useful parameter for making triage, resource-utilization and treatment decisions in a resource-constrained environment compared to predictions of total dose received. It should hopefully be possible to build such classifiers for humans in the future.

Acute Radiation-induced GI-ARS and H-ARS in a Canine Model of Mixed Neutron/Gamma Relative to Reference Co-60 Gamma Radiation: A Retrospective Study

Studies performed decades ago in the canine and nonhuman primate established the dose response relationships for the hematopoietic acute radiation syndrome in response to mixed neutron/gamma, x-radiation, and Co gamma radiation. There were no published studies that determined the dose response relationships for the gastrointestinal acute radiation syndrome in response to either noted radiation quality. This analysis of a retrospective, unpublished study provided the dose response relationships in a canine model for the acute gastrointestinal syndrome relative to the acute hematopoietic syndrome due to mixed neutron/gamma radiation. Canines were exposed to total-body, steady state, bilateral, 0.40 Gy min, mixed neutron/gamma (5.4:1) radiation from a TRIGA reactor. The average neutron/gamma energy (MeV) was 0.85/0.9, and exposure was reported as midline tissue dose. Medical management was not administered. The mixed neutron/gamma exposure resulted in an estimated LD50/6 of 2.83 Gy [2.76, 2.94] and LD50/30 of 2.16 Gy [2.01, 2.24] for the GI- and H-ARS respectively. The mean survival times for decedents after mixed neutron/gamma exposure approximate to the LD50/6 were 8.5 d, 10.5 d, and 4 d for 2.75 Gy, 2.80 Gy, 3.00, and 3.12 Gy exposures, respectively. The mean survival times for decedents for mixed neutron/gamma exposure approximate to the LD50/30 were 21.3 d and 15.6 d for 2.00 Gy and 2.25 Gy, respectively. Furthermore, the dose response relationships for the acute hematopoietic syndrome due to mixed neutron/gamma exposure (0.85/0.9 MeV; 5.4:1) resulted in an estimated relative biological effectiveness of 1.2 as compared with reference Co gamma radiation.

Total Body Irradiation Is Safe and Similarly Effective as Chemotherapy-Only Conditioning in Autologous Stem Cell Transplantation for Mantle Cell Lymphoma

Autologous stem cell transplant (ASCT) consolidation has become a standard approach for patients with mantle cell lymphoma (MCL), yet there is little consensus on the role of total body irradiation (TBI) as part of high-dose transplantation conditioning. We analyzed 75 consecutive patients with MCL who underwent ASCT at our institution between 2001 and 2011 with either TBI-based (n = 43) or carmustine, etoposide, cytarabine, melphalan (BEAM; n = 32) high-dose conditioning. Most patients (97%) had chemosensitive disease and underwent transplantation in first remission (89%). On univariate analysis, TBI conditioning was associated with a trend toward improved PFS (hazard ratio [HR], .53; 95% confidence interval [CI], .28-1.00; P = .052) and similar OS (HR, .59; 95% CI, .26-1.35; P = .21), with a median follow-up of 6.3 years in the TBI group and 6.6 years in the BEAM group. The 5-year PFS was 66% in the TBI group versus 52% in the BEAM group; OS was 82% versus 68%, respectively. However, on multivariate analysis, TBI-based conditioning was not significantly associated with PFS (HR, .57; 95% CI .24-1.34; P = .20), after controlling for age, disease status at ASCT, and receipt of post-transplantation rituximab maintenance. Likewise, early toxicity, nonrelapse mortality, and secondary malignancies were similar in the 2 groups. Our data suggest that both TBI and BEAM-based conditioning regimens remain viable conditioning options for patients with MCL undergoing ASCT.

Radiobiologic effects of GS-nitroxide (JP4-039) on the hematopoietic syndrome

BACKGROUND/AIM

Total-body irradiation (TBI) doses in the range of 2-8 Gy are associated with a drop in peripheral blood counts, decreased bone marrow cellularity, and hematopoietic syndrome. Radiation mitigators must be safe for individuals likely to recover spontaneously.

MATERIALS AND METHODS

Female C57BL/6HNsd mice exposed to 9.0 and 9.15 Gy TBI, received intraperitoneal (10 mg/kg) JP4-039, a novel radiation mitigator, 24 hours after irradiation and were followed for hematopoietic recovery.

RESULTS

Irradiated mice showed reduced peripheral blood lymphocytes and neutrophils and bone marrow cellularity at day 5. Serum electrolytes, liver and renal function tests showed no deleterious effect of JP4-039-after irradiation, and no reduction in survival compared to irradiated controls. Marrow recovery measured as cellularity, and hematopoietic colony-forming cells including primitive granulocyte-erythroid-megakaryocyte-monocytes (GEMM), reached pre-irradiation levels by day 30 in JP4-039 treated groups. Mice receiving single or multiple administrations of JP4-039 showed an early return of CFU-GEMM.

CONCLUSION

JP4-039 (GS-Nitroxide) is a safe radiation mitigator in mice warranting studies in larger animals and potentially a Phase I Clinical Trial.

Whole body protection against lethal ionizing radiation in mice by REC-2001: a semi-purified fraction of Podophyllum hexandrum

The current study has concentrated on assessment of the radioprotective potential of REC-2001, a semi-purified fraction of rhizomes of Podophyllum hexandrum, in Swiss albino Strain 'A' mice exposed to 10 Gy whole-body gamma radiation. Animals were treated with 10 and 15 mg/kg b wt (i.p.) of REC-2001 1h prior to exposure to a lethal dose of gamma-radiation (10 Gy) and observed upto 30 days. For analysis of maximum tolerable dose (MTD), LD(50) and acute toxic dose, different concentrations of the extract were administered to animals and their mortality and morbidity status was observed upto 72 h and one week, respectively. Dose reduction factor (DRF) was determined by exposing REC-2001 pre-treated mice to supra-lethal doses of gamma-radiation. Endogenous spleen colony forming units (CFU), DNA strand breaks in thymocytes (alkaline halo assay) and lipid degradation was studied to understand the mechanism of radioprotection. A single dose of REC-2001 (10 and 15 mg/kg b wt i.p.) exhibited >90% survival in the pre-treated irradiated group versus no survival in radiation control group. Single doses of upto 75 mg/kg b wt (i.p.) did not cause any mortality (MTD) in mice. REC-2001, a dose of 90 mg/kg b wt, resulted in 50% mortality (LD(50)), while the LD(100) was 115 mg/kg b wt REC-2001 exhibited a DRF of 1.62. CFU counts in the REC-2001 treated group were found significantly high (5.33/spleen) as compared to controls. Exposure of thymocytes to 10 Gy radiation resulted in increased halo diameter (45+/-3 microm) in comparison to untreated controls (8+/-1 microm). REC-2001 administration (500 microg/ml) decreased the halo diameter to 15+/-2 microm. Radiation-induced lipid degradation was also inhibited by REC-2001. The present study has revealed that REC-2001 is a promising radioprotective fraction that can be effectively used against lethal doses of gamma-radiation after further investigations in higher animal models.

Pulmonary function following total body irradiation (with or without lung shielding) and allogeneic peripheral blood stem cell transplant

Our purpose was to determine if total body irradiation (TBI) with lung dose reduction protects against subsequent radiation-induced deterioration in pulmonary function. Between July 1997 and August 2004, 181 consecutive patients with hematologic malignancies received fractionated TBI before allogeneic peripheral blood stem cell transplant. The first 89 patients were treated to a total dose of 13.6 Gy. Thereafter, total body dose was decreased to 12 Gy with lung dose reduction to 9 or 6 Gy. All patients underwent pulmonary function test evaluation before treatment, 90 days post-treatment, then annually. Median follow-up was 24.0 months. Eighty-nine patients were treated with lung shielding, and 92 without. At 1-year post transplant, there was a small but significant difference in lung volume measurements between patients with lung shielding and those without. This was not observed at the 2-year time point. When stratified by good (>100% predicted) or poor (</=100% predicted) baseline lung function, patients with poor function demonstrated protection at 1 year with lung shielding, while those with good initial lung function did not. TBI with or without lung dose reduction has a small but statistically significant effect on pulmonary function measured at 1 year but not 2 years post irradiation.

Pretransplant pulmonary function tests predict risk of mortality following fractionated total body irradiation and allogeneic peripheral blood stem cell transplant

PURPOSE

To determine the value of pulmonary function tests (PFTs) done before peripheral blood stem cell transplant (PBSCT) in predicting mortality after total body irradiation (TBI) performed with or without dose reduction to the lung.

METHODS AND MATERIALS

From 1997 to 2004, 146 consecutive patients with hematologic malignancies received fractionated TBI before PBSCT. With regimen A (n=85), patients were treated without lung dose reduction to 13.6 gray (Gy). In regimen B (n=35), total body dose was decreased to 12 Gy (1.5 Gy twice per day for 4 days) and lung dose was limited to 9 Gy by use of lung shielding. In regimen C (n=26), lung dose was reduced to 6 Gy. All patients received PFTs before treatment, 90 days after treatment, and annually.

RESULTS

Median follow-up was 44 months (range, 12-90 months). Sixty-one patients had combined ventilation/diffusion capacity deficits defined as both a forced expiratory volume in the first second (FEV1) and a diffusion capacity of carbon dioxide (DLCO)<100% predicted. In this group, there was a 20% improvement in one-year overall survival with lung dose reduction (70 vs. 50%, log-rank test p=0.042).

CONCLUSION

Among those with combined ventilation/diffusion capacity deficits, lung dose reduction during TBI significantly improved survival.

Reduced-intensity conditioning followed by unrelated umbilical cord blood transplantation for advanced hematologic malignancies: rapid engraftment in bone marrow

Reduced-intensity (RI) conditioning followed by cord blood transplantation (CBT) is a new treatment modality, but failure to engraft is a major concern. We describe 12 patients with advanced hematologic malignancies who underwent RI conditioning and CBT with a conditioning regimen consisting of 200 mg/m(2) fludarabine (Flu), 50 mg/kg cyclophosphamide (CY), and 3 Gy total body irradiation (TBI). Cyclosporin A and/or methotrexate were used for graft-versus-host disease prophylaxis. Cord blood grafts were not mismatched for more than 2 serologically defined HLA alleles but were later found by high-resolution DNA typing to be mismatched for 2 to 4 alleles in most cases. Short tandem repeat analysis of bone marrow cells at day 14 showed complete donor chimerism in 6 of the patients and mixed chimerism in 5, indicating rapid engraftment in the bone marrow, whereas the remaining patient experienced graft rejection. Neutrophil recovery was achieved at a median of day 17 (range, days 11-24) in 10 of the 11 patients with marrow chimerism at day 14. Of these 10 patients, however, transplantation-related mortality within 100 days occurred in 4 patients who showed failed platelet recovery and a lack of durable engraftment. Overall survival and disease-free survival rates were 41.7% and 33.3%, respectively. These results show that CB mismatched at 2 to 4 HLA alleles and transplanted with the Flu/CY/3 Gy TBI regimen is able to engraft in the bone marrow as early as day 14.

Autologous stem cell transplantation in patients with chronic lymphocytic leukaemia: the Finnish experience

Although autologous stem cell transplantation (ASCT) has gained some popularity as a treatment option in patients with chronic lymphocytic leukaemia (CLL), limited multicentre data are available on the feasibility and efficacy of this approach. Between January 1995 and June 2005, 72 patients with CLL received ASCT in five Finnish centres. There were 45 men and 27 women with a median age of 57 years (38-69). The median time from diagnosis to ASCT was 32 months (6-181) and the median number of prior regimens 1 (1-4). All patients received blood stem cell grafts and CD34+ selection had been performed in 44 patients (61%). The most common high-dose regimen was a total body irradiation plus cyclophosphamide (38 patients, 53%). No early treatment-related deaths were observed. With a median follow-up of 28 months from ASCT, a relapse or progression has been observed in 27 patients (37%). The projected progression-free survival is 48 months (confidence interval (CI) 30-66). The projected median overall survival is 95 months (CI 74-101) from ASCT and is not influenced by graft selection or conditioning regimen used. Autologous stem cell transplantation is a feasible treatment option for CLL. Randomized trials against alternative treatments are needed to assess the impact of ASCT on the clinical course of CLL.

The Outcome of Sibling and Unrelated Donor Allogeneic Stem Cell Transplantation in Adult Patients with Acute Myeloid Leukemia in First Remission Who Were Initially Refractory to First Induction Chemotherapy

The optimal management of patients with initially refractory acute myeloid leukemia is unknown. We analyzed the outcomes of 68 adult patients (median age, 37 years) with acute myeloid leukemia in first complete remission with initially refractory disease who were treated with matched sibling (n=44) or unrelated donor (n=22) stem cell transplantation or who received transplants from other donors (n=2). Thirty-one patients took 2 courses of chemotherapy to achieve first complete remission, a further 31 took 3 courses, and 6 patients took 4 or 5 courses. Ten patients (15%) had adverse cytogenetics. Patients were mainly conditioned with cyclophosphamide and total body irradiation (87%). Four patients (6%) did not engraft by day 28; 2 of these engrafted at 47 and 60 days. Grades II to IV and III/IV acute graft-versus-host disease (GVHD) were seen in 34% and 14% of patients, respectively. Chronic GVHD was seen in 50% of patients. The estimated actuarial disease-free and overall survivals were 34% and 37%, respectively, at 4 years. The performance status of survivors is good; 82% of patients have Karnofsky scores of 90 to 100. On multivariate analysis, overall and disease-free survival were associated with adverse cytogenetics (P=.055 and .023). Approximately one third of patients survived 4 years after allogeneic stem cell transplantation for initially refractory acute myeloid leukemia in first complete remission: relapse and treatment-related mortality were the major causes of treatment failure. Further studies are needed to determine the optimal conditioning regimens and GVHD prophylaxis.

Tacrolimus and mycophenolate mofetil after nonmyeloablative matched-sibling donor allogeneic stem-cell transplantations conditioned with fludarabine and low-dose total body irradiation

We evaluated tacrolimus/mycophenolate mofetil (MMF) for graft-versus-host disease (GVHD) prophylaxis after a nonmyeloablative stem cell transplantation (NST) from a matched sibling donor (MSD). Thirty-two patients (median age, 57 years) with advanced hematologic malignancies, who were poor candidates for a conventional myeloablative transplantation, received fludarabine (30 mg/m(2), day -4 to day -2), total-body irradiation (TBI) (200 cGy, day 0), infusion of donor peripheral blood progenitor cells (day 0), oral tacrolimus 0.06 mg/kg twice daily (from day 3), and oral MMF at 15 mg/kg twice daily (days 0-+27). Tacrolimus was tapered from day +100 to day +180 in those patients with indolent malignancies (n = 25), and from day +35 to day +56 in those with aggressive tumors (n = 7). Regimen toxicities and myelosuppression were mild, allowing 75% of patients to have entirely outpatient transplantations. One patient (3%) experienced a nonfatal graft rejection. Rates of grades II-IV and III-IV acute GVHD were 15.6% and 3%, respectively. Acute GVHD was diagnosed at median day +78 (range, days +31-+84). Extensive chronic GVHD was observed in 10 of 24 evaluable patients (41.6%) at a median onset of day +198 (range, days +128-+277), either spontaneously (n = 5) or elicited after tumor progression (n = 5). Five patients experienced transplantation-related mortality (TRM) (15.6%) from either acute GVHD-related multiorgan failure (MOF) (n = 3) or infectious complications (n = 2). At median follow-up of 19 months (range, 2-41 months), the overall survival, progression-free survival, and disease-free survival rates are 62.5%, 50%, and 40%, respectively. In conclusion, the use of tacrolimus/MMF after MSD NST is associated with encouraging rates of GVHD control.

Influence of Radiation Dose Rate and Lung Dose on Interstitial Pneumonitis after Fractionated Total Body Irradiation: Acute Parotitis May Predict Interstitial Pneumonitis

This study evaluated patients for the influence of the dose rate and lung dose of fractionated total body irradiation (TBI) in preparation for allogeneic bone marrow transplantation (BMT) on the subsequent development of interstitial pneumonitis (IP). Sixty-six patients at our institute were treated with TBI followed by BMT. All of the patients received a total TBI dose of 12 Gy given in 6 fractions over 3 days and were divided into 3 groups according to the radiation dose rate and lung dose: group A, lung dose of 8 Gy (n = 18); group B, lung dose of 12 Gy at 8 cGy/min (n = 25); and group C, lung dose of 12 Gy at 19 cGy/min (n = 23). The overall survival rate, the cumulative incidence of relapse, and the cumulative incidence of IP were evaluated in relation to various potential indicators of future IP. There were no significant differences in survival and relapse rates between patient group A and combined groups B and C. Clinically significant IP occurred in 13 patients. The cumulative incidence of IP was significantly higher in patients who developed acute parotitis as indicated by either an elevation in the serum amylase level or parotid pain of grade 1 to 2. There was no difference in IP incidence among groups A, B, and C. There was no significant difference in IP incidence between lung dose values of 8 Gy (with lung shielding) and 12 Gy (without lung shielding) and between dose rate values of 8 cGy/min and 19 cGy/ min, at least when TBI was given in 6 fractions. The presence of acute parotitis during or just after TBI may be a predictor of IP.

Unrelated donor or partially matched related donor peripheral stem cell transplant with CD34+ selection and CD3+ addback for pediatric patients with leukemias

Unmodified peripheral stem cell transplants are associated with an increased risk of extensive chronic GVHD. T depletion may reduce this risk, but the risk of graft failure or relapse may increase. To decrease the risks of both extensive chronic GVHD and graft failure, we added back a defined dose of CD3+ cells to CD34+ selected PSCs. Twenty-four patients were evaluable for outcome analysis. Donors were unrelated (23) or related (1). Conditioning was thiotepa, cyclophosphamide, and total body irradiation. Cyclosporine was used post transplant. Following CD34+ selection, a total of 5 x 10(5)/kg CD3+ cells were infused. Donors were matched for 12 patients. The median CD34+ dose infused was 7.1 x 10(6)/kg. Engraftment occurred in all patients at a median of 14 days (10-19). Twelve patients are alive in remission 15-34 months (median, 25) post PSCT. GVHD occurred in 17 patients, but was >grade II in only 2. Chronic GVHD occurred in 61.5% of evaluable patients, but was limited to skin and perioral cavity. Two patients relapsed, and 10 patients died of non-relapse causes. This study demonstrates that PSCT with CD34+ selection and a defined dose of CD3+ results in prompt engraftment and may limit development of extensive chronic GVHD.

Alternative donor bone marrow transplant for children with Philadelphia chromosome ALL

Children with Philadelphia chromosome positive (Ph+) acute lymphocytic leukemia (ALL) have only a 20% event-free survival when treated with chemotherapy alone. Bone marrow transplant (BMT) for patients with matched siblings has been associated with significantly better long-term survival. We asked whether children who lack a matched sibling donor would do as well if an alternative donor was utilized. Between 1987 and 2002, we transplanted 29 children and adolescents using either an unrelated donor (23) or a mismatched family member (six). The conditioning regimen included cytosine-arabinoside, cyclophosphamide and total body irradiation. Graft-versus-host disease (GVHD) prophylaxis consisted of T-cell depletion (antibody T10B9 or OKT3 and complement) with post transplant cyclosporine (CSA). All patients engrafted. Four developed grades III-IV acute GVHD. Three of 24 evaluable patients developed extensive chronic GVHD. Two patients died of relapse (7%). Two long-term survivors (>6 years) died of malignant glioblastoma multiforme. Event-free survival at 3, 5, and 10 years is 56, 51, and 46%, respectively. Five of six patients in >CR2 or relapse at the time of transplant died. Our data should encourage the use of alternative donor transplants early in the course of disease for children with Ph+ ALL.

Macrophage apolipoprotein E reduces atherosclerosis and prevents premature death in apolipoprotein E and scavenger receptor-class BI double-knockout mice

OBJECTIVE

Mice null for both apolipoprotein (apo)E and scavenger receptor (SR)-BI (DKO) develop severe hypercholesterolemia, occlusive coronary atherosclerosis, myocardial infarction, and premature death. The current study examines the ability of macrophage apoE to improve the dyslipidemia, reduce atherosclerosis, and rescue the lethal phenotype of DKO mice.

METHODS AND RESULTS

Initially, bone marrow transplantation (BMT) was unsuccessful, because the DKO mice died from a rapidly fatal anemia 3 to 5 days after lethal irradiation. Therefore, probucol was used to rescue the DKO mice during BMT and was discontinued 2-weeks after BMT, allowing successful reconstitution with donor marrow. Twelve male apoE(-/-)SR-BI(-/-) mice fed 0.5% probucol in a chow diet were lethally irradiated and transplanted with either wild-type (WT) or DKO bone marrow. Two-weeks after BMT, apoE was detected in serum in WT-->DKO mice, and mean serum cholesterol levels were reduced by 70% versus DKO-->DKO mice. Lipoprotein profiles and HDL subpopulations in WT-->DKO mice were similar to apoE(+/+)SR-BI(-/-)-->DKO mice and resembled those of SR-BI(-/-) mice. In WT-->DKO mice, aortic atherosclerosis was reduced by 88% to 90% versus DKO-->DKO mice. Furthermore, the DKO-->DKO mice died &8 weeks after BMT, whereas WT-->DKO mice exhibited a life span >40 weeks after BMT.

CONCLUSIONS

Macrophage apoE is able to rescue the lethal phenotype of apoE(-/-)SR-BI(-/-) mice by improving the dyslipidemia and dramatically reducing atherosclerotic lesion development.

Prediction and prevention of transplant-related mortality from pulmonary causes after total body irradiation and allogeneic stem cell transplantation

Between July 1997 and August 2004, 146 consecutive patients with hematologic malignancies received a T cell-depleted peripheral blood stem cell transplant from an HLA-identical sibling by using total body irradiation (TBI) and cyclophosphamide conditioning regimens. Eighty-five patients received 13.6 Gy of TBI with no lung shielding, and 61 received lung shielding (total lung dose, 6-12 Gy). Ninety-four patients (65.5%) had standard-risk disease; the remainder had more advanced disease or unfavorable diagnoses. Of the 21 transplant-related deaths, 14 were from pulmonary causes (10 idiopathic pulmonary syndromes and 4 from infection) that occurred at a median of 90 days (range, 23-238 days) after transplantation. Independent risk factors for pulmonary transplant-related mortality (PTRM) were pretransplantation diffusion capacity for carbon monoxide (relative risk, 5.7 for diffusion capacity for carbon monoxide <85%), smoking (relative risk, 5.0), and CD34 cell dose (relative risk, 9.4 for a CD34 dose of <5 x 10(6) cells per kilogram). Patients receiving lung shielding had significantly lower PTRM (3.3% versus 14.1%; P = .02) and better overall survival (70% +/- 6% versus 52% +/- 5%; P = .04), but lung shielding was not a significant independent factor for determining PTRM. These results suggest that pulmonary mortality after TBI-based preparative regimens is predictable and that higher CD34 cell doses can reduce the risk.

The effects of total-body irradiation on the survival and skin wound healing of rats with combined radiation-wound injury

To investigate the effects of total body irradiation on the healing of skin wounds, rats were irradiated with a (60)Co gamma-ray source, in which single doses ranged from 1 to 8 Gy. After irradiation, two whole-thickness circular skin wounds, 22 mm in diameter and covering 2.5% of the total body surface area, were made immediately on the back of each animal. The average healing time for the simple wound was 18.3 +/- 2.1 days, whereas when the wound was combined with 1, 2, 3, 4, 5, and 6 Gy of radiation, the average wound healing time was delayed by 0.3, 0.8, 1.1, 3.5, 6.2, and 9.5 days, respectively. The average healing time was significantly decreased with irradiation doses exceeding 4 Gy, as compared with the healing time for the simple wound without irradiation (p < 0.05). The statistical results showed that the percentage of the unclosed wound with the increased doses in combined radiation injury was significantly proportional to the recovery time kinetics.

Transplanted BM and BM side population cells contribute progeny to the lung and liver in irradiated mice

BACKGROUND

BM cells have been shown to give rise to progeny of various cell lineages, including cells in lung and liver. This investigation evaluated whether purified BM mononuclear cells and side population (SP) cells that have hematopoietic stem-cell activity also had this property; whether a TBI preparative regimen was necessary for engraftment; and where BM-derived cells were engrafted.

METHODS

Either 1-3 million BM mononuclear cells or 2000 BM SP cells from transgenic enhanced green fluorescent protein-expressing (EGFP) mice were transplanted i.v. to unirradiated or 7-9.5 Gy irradiated recipients.

RESULTS

Flow cytometric analysis showed that lung cells (mean 45%, range 4-70%) and liver cells (mean 4%, range 0.4-8.3%) from irradiated, but not unirradiated recipients, were EGFP donor-derived. Similar results were obtained transplanting BM mononuclear cells or SP cells. Morphologically, donor-derived cells in the lung were primarily monocytes and macrophages. Additionally, lung fibroblasts and Type I, but not Type II, alveolar cells and rare cells in the bronchial epithelium were donor BM derived. In the liver, Kupffer cells, inflammatory cells and small clusters of hepatocytes, but not bile duct cells, were donor-derived.

DISCUSSION

BM mononuclear and SP cells generated progeny in some compartments of the lung and liver, but only in TBI recipients. Stem cells in BM can contribute to repair of tissue injury in some compartments, but not to the same extent in the lung and liver.

Radiation protective effect of an extract from Chelidonium majus

We earlier reported that CM-AIa isolated from Chelidonium majus had mitogenic activity, generated lymphokine-activated killer cells, and increased the number of granulocyte-macrophage colony-forming cells (GM-CFC). In an extended effort to search for other immunostimulatory effects, we evaluated the protective effects of in vivo injected CM-AIa against irradiation. CM-AIa was found to increase the number of bone marrow cells, spleen cells, GM-CFC, and platelets in irradiated mice. In addition, this agent induced endogenous production of cytokines such as interleukin 1 and tumor necrosis factor alpha, which are required for hematopoietic recovery. We also demonstrated that CM-AIa treatment 24 hours before irradiation protected mice with 80% survival at lethal dose 100/15. These findings indicate that CM-AIa may be a useful agent for reducing the time needed for reconstitution of hematopoietic cells after irradiation treatment.

Localized radiation increases morbidity and mortality after TBI-containing autologous stem cell transplantation in patients with lymphoma

The purpose of this study is to assess the relationship between involved field radiation therapy (IFRT) and treatment-related morbidity and mortality in patients receiving high-dose chemotherapy (HDC), total body irradiation (TBI) and autologous peripheral stem cell transplant (PSCT) for Hodgkin's and non-Hodgkin's lymphoma. Between January 1994 and May 2002, 156 patients underwent HDC, TBI and autologous PSCT. Localized external beam radiation therapy was given to 21 patients for consolidation, or to achieve control of symptomatic or active disease prior to or after transplant. Among patients who had IFRT prior to autologous PSCT, five treatment-related deaths were observed, compared to seven deaths in 135 patients who had autologous PSCT without IFRT (P<0.01). Most deaths were attributable to sepsis and multiorgan failure. A higher incidence of pneumonitis was also noted in patients exposed to mediastinal irradiation. No adverse impact on long-term survival could be demonstrated. Involved field radiation prior to TBI is associated with higher treatment-related mortality in lymphoma patients undergoing autologous peripheral stem cell transplant, necessitating careful monitoring.

Radioprotection effect of low level preirradiation on mammals: modeling and experimental investigations

This paper is devoted to experimental and theoretical studies of low level preirradiation effects on radiosensitivity of mammals. It is shown experimentally that a priming exposure to a low dose can induce radioresistance in mice in two (early and late) periods after preirradiation. The manifestation of such effects is reduced mortality of preexposed specimens after challenge acute irradiation, the reason of the animal death being the hematopoietic subsyndrome of the acute radiation syndrome. Therefore, proceeding from the radiobiological concept of critical system, the theoretical investigation of the influence of preirradiation on mammalian radiosensitivity is conducted by making use of the mathematical models of the vital body system, hematopoiesis. Modeling results obtained make it possible to elucidate the mechanisms of the radioprotection effect of low level priming irradiation on mammals. Specifically, the state of acquired radioresistance in mice is caused by reduced radiosensitivity of lymphopoietic and thrombocytopoietic systems in the early period and by reduced radiosensitivity of granulocytopoietic system, which is accompanied by slightly reduced or close to the normal level radiosensitivity of lymphopoietic system, in the late period after preirradiation. In turn, reduced radiosensitivity of above-noted hematopoietic lines is the consequence of hypercompensation of radiation damages of certain cell pools during the recovering processes running in these systems after priming irradiation. It is important to emphasize that the evaluations of the duration of the early and late periods of postirradiation radioresistance in mice, carried out on the basis of the modeling and experimental investigations, practically coincide. All this demonstrates the effectiveness of joint modeling and experimental investigations of such complicated radiobiological problems as acquired radioresistance.

Low-dose (550 cGy), single-exposure total body irradiation and cyclophosphamide: consistent, durable engraftment of related-donor peripheral blood stem cells with low treatment-related mortality and fatal organ toxicity

On the basis of observations of dog models and from earlier studies with humans, we hypothesized that a low-dose (550 cGy) TBI-based conditioning regimen would result in sustained engraftment of HLA-matched sibling peripheral blood stem cells (PBSC) with low treatment-related mortality (TRM) and low serious organ toxicity if the TBI was given as a single dose and at a high dose rate. The regimen included 550 cGy TBI administered as a single dose at 30 cGy/min and cyclophosphamide. Cyclosporine was given as GVHD prophylaxis. Twenty-seven good-risk (acute leukemia in first remission and chronic-phase chronic myelogenous leukemia) and 53 poor-risk (other) patients were accrued. Complete donor engraftment occurred in 93% to 100% of evaluable patients at each scheduled assessment and was durable through 4 years. Mixed chimerism (50% to 98% donor) was observed in 9 patients (11%). Without further intervention, all patients had complete donor engraftment on subsequent assessments. Graft failure did not occur. TRM through at least 2 years was 7% in the good-risk and 19% in the poor-risk diagnostic groups. Grade 4 (fatal) organ toxicity occurred in only 2 patients (2.5%). Other causes of TRM included infection and GVHD. Median follow-up for the surviving patients was 1234 days (range, 780-1632 days). Current status includes 39 patients (49%) alive and in complete remission, 2 alive in relapse, and 39 dead. Relapse occurred in 15% of the good-risk group and 45% of the poor-risk group. The Kaplan-Meier estimates of 3-year disease-free and overall survival of the good-risk group were 77% and 85%, respectively, and of the poor-risk group were 34% and 36%, respectively. Low-dose (550 cGy), single-exposure TBI given at a high dose rate with cyclophosphamide resulted in consistent durable engraftment of HLA-matched sibling PBSC with a low risk of fatal organ toxicity and TRM.

Administration of either anti-CD40 or interleukin-12 following lethal total body irradiation induces acute lethal toxicity affecting the gut

Interleukin (IL)-12 and antibodies against CD40 have demonstrated antitumor effects in a variety of in vivo model systems. However, both agents can also mediate significant toxicities either when used following lethal TBI or when administered in combination with other agents such as IL-2. In this study, we assessed the effects of anti-CD40 monoclonal antibody (MoAb) and IL-12 in lethally irradiated mice. Acute lethal toxicity was observed following the administration of either 10 microg anti-CD40 MoAb (FGK45) or 0.5 microg of recombinant murine (rm)IL-12 that resulted in 100% mortality of all mice within 4 to 6 days. Histological evaluation revealed destruction of the normal gut architecture in both anti-CD40 MoAb- and rmIL-12-treated mice. Analysis of serum cytokine levels in the lethally irradiated mice receiving anti-CD40 MoAb demonstrated a marked increase of interferon (IFN)-gamma and IL-12 p40, whereas mice receiving rmIL-12 demonstrated a marked increase of IFN-gamma. Lethally irradiated IL-12 p40 knock-out mice were resistant to anti-CD40-induced toxicity, suggesting that the lack of IL-12 p40 with no possibility of making functional IL- 12 p70 is key for this toxic reaction. Similarly, lethally irradiated IFN-gamma knock-out mice were completely resistant to rmIL-12-induced toxicity, suggesting that IFN-gamma is a major player in IL-12-mediated toxicity. These results suggest that both anti-CD40 MoAb and rmIL-12 induce an acute fatal toxicity characterized by similar intestinal pathology and mediated in part by IFN-gamma.

Radioprotective effect of chitosan in sub-lethally X-ray irradiated mice

The radioprotective effect of chitosan was studied in mice following whole-body X-ray irradiation. C3H/He mice were exposed to 7 Gy, and their survival rates were examined. The survival rates of chitosan-diet mice were about 20% higher than those of mice on a standard diet, and the rates dropped sharply to a plateau at day 10 after X-ray irradiation. The chitosan-diet mice had an increased weight ratio of spleen to body within the experimental period. The leukocyte, thrombocyte, and erythrocyte counts as well as the hematocrit and hemoglobin levels were recovered significantly and more rapidly in the chitosan-diet mice than the standard-diet mice at day 14 after irradiation. The scavenging abilities of chitosan were evaluated by the ESR spin-trapping method. These observations suggested that chitosan led to hematopoetic activation and leukocytogenesis in mice after sub-lethal dose irradiation, and that the biological response might be caused by radical trapping or scavenging.

The radioprotective activities of turpentine-induced inflammation and alpha2-macroglobulin: the effect of dexamethasone on the radioprotective efficacy of the inflammation

This work was aimed at the radioprotective efficacy of turpentine oil (TO), alpha2-Macroglobulin (alpha2-M), Amifostine (Ami) and/or dexamethasone (Dex). These agents were administrated, alone or in combination, prior to irradiation of rats with 6.7 Gy (LD(50/30)). The survival was recorded daily for 4 weeks after irradiation and body weight, peripheral leukocytes and thrombocytes were measured. The plasma concentration of alpha2-M and other acute phase proteins were determined by crossed immunoelectrophoresis. All rats receiving alpha2-M and Ami alone or in combination survived the radiation injury, whereas the rate of survival of TO-treated rats was 90%. Radiation and therapy-induced changes in the expression of acute phase protein genes were atypical for the acute phase reaction. Dex alone was lethal for 45% and 55% of control and irradiated rats, respectively. Pretreatment with 1mg Dex reduced radioprotective efficacy of TO and Ami to 30% and 40%, respectively. Given together TO and Ami provided 70% protection to rats receiving Dex. The TO and alpha2-M enhanced the rate of survival from 50% to 90% and 100%, respectively. In the presence of 1mg Dex the TO-induced radioprotectors and Ami exhibited radiosensitizing rather than radioprotecting activities.

Low-dose fractionated total body irradiation (TBI) adversely affects prognosis of patients with leukemia receiving an HLA-matched allogeneic bone marrow transplant from an unrelated donor (UD-BMT)

The optimal total body irradiation (TBI) regimen for unrelated donor bone marrow transplant (UD-BMT) is unknown. In the present study we analyze the outcomes of two different TBI regimens used in our center for patients with leukemia undergoing an UD-BMT. Between January 1994 and August 2001, 99 consecutive UD-BMT patients entered this comparative study. The conditioning regimen consisted of cyclophosphamide, 120 mg/kg followed by TBI on days -3, -2 and -1. Forty-six patients received TBI 12 Gy (2 Gy, twice a day) in six fractions (HF-TBI) and 53 patients received TBI 9.90 Gy (3.30 Gy per day) fractionated over 3 days (F-TBI). End-points were transplanted-related mortality (TRM), leukemia relapse rate (LRR) and overall survival (OS). At median follow-up of 22 months (58 months for HF-TBI and 17 for F-TBI, respectively), 60 patients were alive (32 in HF-TBI sub-group and 28 in F-TBI one). The actuarial 5-year TRM was 31% for HF-TBI and 41% for F-TBI (P = 0.1), whereas the 5-year LRR was 13% for HF-TBI and 31% for F-TBI (P = 0.04). The actuarial 5-year OS was 68% for patients treated with HF-TBI and 51% for those treated with F-TBI (P = 0.02). At multivariate analysis F-TBI schedule emerged as an adverse predictor for OS (P = 0.04) and LRR (P = 0.03). These data indicate that a lower total dose of TBI appears significantly less effective in leukemia eradication and associated with worse overall survival when compared with a higher dose of radiation.

Summary of latent effects in long term survivors of whole body irradiations in primates

The USAF School of Aerospace Medicine, Radiobiology Division, Brooks Air Force Base, Texas presently is maintaining a colony of over 450 primates in which the whole body has been exposed to various types of space radiation including protons and electrons. The majority of the primates (Macaca mulatta) were exposed during 1965. Types of radiation involved are 2 MeV X-rays, 5 MeV-2.3 GeV protons and 1.6 MeV electrons. Low energy proton dose range up to 3000 rad (50-100 rad min-1) whereas the penetrating energy doses range up to 700 rad (15-100 rad min-1). Primates from a simulated solar flare exposure are also included. In late 1970, a small group of primates exposed to 108 and 85 MeV alpha particles (eye and partial body only) were added to the colony. Data are available in the following areas: (i) chronic skin changes; (ii) testicular atrophy; (iii) cataractogenesis; (iv) hematological and serum biochemical analysis; (v) incidence of tumors; (vi) causes of death; (vii) body weight variations; and (viii) summary of alpha particle experiences.

Pathology effects at radiation doses below those causing increased mortality

Mortality data from experiments conducted at the Argonne National Laboratory (ANL) on the long-term effects of external whole-body irradiation on B6CF(1) mice were used to investigate radiation-induced effects at intermediate doses of (60)Co gamma rays or fission-spectrum neutrons either delivered as a single exposure or protracted over 60 once-weekly exposures. Kaplan-Meier analyses were used to identify the lowest dose in the ANL data (within radiation quality, pattern of exposure, and sex) at which radiation-induced mortality caused by primary tumors could be detected (approximately 1-2 Gy for gamma rays and 10-15 cGy for neutrons). Doses at and below these levels were then examined for radiation-induced shifts in the spectrum of pathology detected at death. To do this, specific pathology events were pooled into larger assemblages based on whether they were cancer, cardiovascular disease or non-neoplastic diseases detected within the lungs and pleura, liver and biliary tract, reproductive organs, or urinary tract. Cancer and cardiovascular disease were further subdivided into categories based on whether they caused death, contributed to death, or were simply observed at death. Counts of how often events falling within each of these combined pathology categories occurred within a mouse were then used as predictor variables in logistic regression to determine whether irradiated mice could be distinguished from control mice. Increased pathology burdens were detected in irradiated mice at doses lower than those causing detectable shifts in mortality-22 cGy for gamma rays and 2 cGy for neutrons. These findings suggest that (1) models based on mortality data alone may underestimate radiation effects, (2) radiation may have adverse health consequences (i.e. elevated health risks) even when mortality risks are not detected, and (3) radiation-induced pathologies other than cancer do occur, and they involve multiple organ systems.

Radioprotective action of curcumin extracted from Curcuma longa LINN: inhibitory effect on formation of urinary 8-hydroxy-2'-deoxyguanosine, tumorigenesis, but not mortality, induced by gamma-ray irradiation

PURPOSE

We evaluated the radioprotective action of curcumin [1,7-bis(4-hydroxy-3-methoxyphenyl)-1,6-heptadiene-3,5-dione] extracted from Curcuma longa LINN against the acute and chronic effects and the mortality induced by exposure to radiation using female rats.

METHODS AND MATERIALS

For the assay of 8-hydroxy-2'-deoxyguanosine (8-OHdG) in urine, a marker for acute effects, Wistar-MS virgin rats were fed the basal diet with exposure at 0 or 3 Gy to gamma-rays from a 60Co source as the control. Rats in the experimental groups received whole-body irradiation with 3 Gy and were fed a diet containing 1% (wt/wt) curcumin for 3 days before and/or 2 days after irradiation. The urine was collected for a 24-h period between 1 and 2 days after irradiation. Urine samples were used to determine the 8-OHdG level using an enzyme-linked immunosorbent assay and the creatinine level by a modified Jaffé reaction. For long-term effects, rats at Day 17 of pregnancy were fed a diet containing curcumin for 3 days before and/or 3 days after irradiation with 1.5 Gy, and received a pellet of diethylstilbestrol as the promoter. The rats were examined for mammary and pituitary tumors for 1 year. To determine survival, virgin rats received whole-body irradiation with 9.6 Gy and were fed a diet containing curcumin for 3 days before and/or 3 days after irradiation. After irradiation, all rats were assessed daily for survival for 30 days.

RESULTS

Acutely in virgin rats irradiated with 3 Gy, the creatinine-corrected concentration and total amount of 8-OHdG in the 24-h urine samples were higher (approximately 1.3-fold) than the corresponding values in the nonirradiated controls. Adding curcumin to the diet for 3 days before and/or 2 days after irradiation reduced the elevated 8-OHdG levels by 50-70%. The evaluation of the protective action of curcumin against the long-term effects revealed that curcumin significantly decreased the incidence of mammary and pituitary tumors. However, the experiments on survival revealed that curcumin was not effective when administered for 3 days before and/or 3 days after irradiation (9.6 Gy).

CONCLUSION

These findings demonstrate that curcumin can be used as an effective radioprotective agent to inhibit acute and chronic effects, but not mortality, after irradiation.

Administration of recombinant human IL11 after supralethal radiation exposure promotes survival in mice: interactive effect with thrombopoietin

In the present study, we evaluated the therapeutic potential of recombinant human IL11 in lethally irradiated C57BL6/J mice exposed to gamma rays. IL11 administered for 5 consecutive days beginning 2 h after total-body irradiation with 8 or 9 Gy 60Co gamma rays resulted in a significant increase in 30-day survival. When IL11 was administered, only a slight improvement in the hematopoietic status (both blood cell counts and progenitor cells) was observed after an 8-Gy exposure, and no improvement in hematopoietic reconstitution was observed after 9 Gy total-body irradiation. The enhancement of fibrinogen in the plasma of irradiated animals suggested the importance of infections in the death of animals. IL11 was able to limit the increase in fibrinogen levels. However, prevention of bacterial infections by antibiotic treatment, although it delayed death, was ineffective in promoting survival either in placebo-treated and IL11-treated mice. IL11 was administered along with thrombopoietin (TPO) or bone marrow transplantation to limit the hematopoietic syndrome, in addition to antibiotic treatment. When IL11 was combined with TPO, a potent stimulator of hematopoiesis, the survival of animals which had been irradiated with 10 Gy 137Cs gamma rays was increased significantly compared to those treated with IL11 or TPO alone. Furthermore, an interactive effect of TPO and IL11 on hematopoietic reconstitution was observed. Similarly, IL11 in combination with bone marrow transplantation enhanced survival after 15 Gy 137Cs gamma rays. These data suggest that the effect of IL11 on the hematopoietic system is only moderate when it is used alone in supralethally irradiated mice but that the effect is improved in the presence of a hematopoietic growth factor or bone marrow transplantation.

Lethal pulmonary complications significantly correlate with individually assessed mean lung dose in patients with hematologic malignancies treated with total body irradiation

PURPOSE

To assess the impact of lung dose on lethal pulmonary complications (LPCs) in a single-center group of patients with hematologic malignancies treated with total body irradiation (TBI) in the conditioning regimen for bone marrow transplantation (BMT).

METHODS

The mean lung dose of 101 TBI-conditioned patients was assessed by a thorough (1 SD around 2%) in vivo transit dosimetry technique. Fractionated TBI (10 Gy, 3.33 Gy/fraction, 1 fraction/d, 0.055 Gy/min) was delivered using a lateral-opposed beam technique with shielding of the lung by the arms. The median lung dose was 9.4 Gy (1 SD 0.8 Gy, range 7.8--11.4). The LPCs included idiopathic interstitial pneumonia (IIP) and non-idiopathic IP (non-IIP).

RESULTS

Nine LPCs were observed. LPCs were observed in 2 (3.8%) of 52 patients in the group with a lung dose < or = 9.4 Gy and in 7 (14.3%) of 49 patients in the >9.4 Gy group. The 6-month LPC risk was 3.8% and 19.2% (p = 0.05), respectively. A multivariate analysis adjusted by the following variables: type of malignancy (acute leukemia, chronic leukemia, lymphoma, myeloma), type of BMT (allogeneic, autologous), cytomegalovirus infection, graft vs. host disease, and previously administered drugs (bleomycin, cytarabine, cyclophosphamide, nitrosoureas), revealed a significant and independent association between lung dose and LPC risk (p = 0.02; relative risk = 6.7). Of the variables analyzed, BMT type (p = 0.04; relative risk = 6.6) had a risk predictive role.

CONCLUSION

The mean lung dose is an independent predictor of LPC risk in patients treated with the 3 x 3.33-Gy low-dose-rate TBI technique. Allogeneic BMT is associated with a higher risk of LPCs.

Absence of major histocompatibility class II expression does not impair hematopoiesis in mice

OBJECTIVE

Major histocompatibility class II (MHC II) molecules are among the earliest antigens to be expressed in hematopoietic progenitor cells; however, the functional role of these molecules in hematopoiesis remains controversial. We examined the role of MHC II antigens during hematopoiesis using a mouse model of MHC II deficiency related to the absence of the critical transcriptional activator, CIITA.

METHODS

Sca-1(-), Sca-1(+)lin(+), and Sca-1(+)lin(-) populations of marrow cells from CIITA(-)(/-) and wild-type mice were analyzed by immunofluorescence for MHC II expression. Hematopoietic capacity was assessed in CIITA(-/-) and wild-type mice by CFU-S, CFU-GM, and radiation sensitivity assays.

RESULTS

Flow cytometric characteristics of hematopoietic progenitors from CIITA(-/-) and wild-type mice were identical except for the absence of MHC II expression in CIITA null mice. There were no significant differences in capacity for hematopoietic reconstitution and clonogenicity as measured by radiation sensitivity, CFU-S, and CFU-GM assays among CIITA(-/-) and wild-type mice.

CONCLUSIONS

These experiments show that downregulation of MHC II gene transcription does not effectively alter normal hematopoiesis, and provide strong evidence that MHC II expression on hematopoietic progenitors is not required for normal hematopoietic development.

Marrow transplants from unrelated donors for patients with aplastic anemia: Minimum effective dose of total body irradiation

Patients with aplastic anemia who do not have suitably HLA-matched, related donors generally receive immunosuppressive treatment as first-line therapy and are considered for transplantation from an unrelated donor only if they fail to respond to immunosuppressive treatment. In this setting, rates of transplantation-related morbidity and mortality have been high. We conducted a prospective study to determine the minimal dose of total body irradiation (TBI) sufficient to achieve sustained engraftment when it is used in combination with 3 cycles of 30 mg/kg of antithymocyte globulin (ATG) and 4 cycles of 50 mg/kg of cyclophosphamide (CY). We also wanted to determine the tolerability and toxicity of the regimen. The starting dosage of TBI was 3 x 200 cGy given over 2 days following CY/ATG. The TBI dose was to be escalated in increments of 200 cGy if graft failure occurred in the absence of prohibitive toxicity, and de-escalated for toxicity in the absence of graft failure. Twenty-one female and 29 male patients aged 1.3 to 46.5 years (median age, 14.4 years) underwent transplantation at 14 medical centers. The time interval from diagnosis to transplantation was 2.8 to 264 months (median, 14.5 months). All patients had been transfused multiple times and all had received 1 to 11 courses (median, 4 courses) of immunosuppressive treatment and other modalities of treatment. In 38 cases, the donors were HLA-A, -B and -DR phenotypically matched with the patients, and, in 12 cases, the donor phenotype differed from that of the recipient by 1 HLA antigen. Recipients of mismatched transplants were considered separately for TBI dose modification, and this study is still ongoing. Seven patients did not tolerate ATG and were prepared with 6 x 200 cGy of TBI plus 120 mg/kg of CY. Of the HLA-matched recipients prepared with CY/ATG/TBI, all 20 who received 3 x 200 or 2 x 200 cGy of TBI achieved engraftment, and 10 are alive. Of the 13 patients who received 1 x 200 cGy of TBI, 1 failed to engraft, and 8 are alive. Each of 10 patients who received an HLA-nonidentical transplant achieved engraftment, and 3 of 6 who were given 3 x 200 cGy of TBI, and 4 of 4 who were given 2 x 200 cGy are alive. Pulmonary toxicity occurred in 8 of 30 patients who were given 3 x 200 or 2 x 200 cGy of TBI concurrently with ATG and CY at 200 mg/kg, and in 2 of 13 patients who received 1 x 200 cGy of TBI, a pattern that suggests a decrease in toxicity with TBI dose de-escalation. Overall, the highest probability of survival (73%) was observed among patients who underwent transplantation within 1 year of diagnosis, compared with patients who underwent transplantation after a longer period of disease. In addition, younger patients (aged < or = 20 years) were more likely to survive than older patients (aged > 20 years). Thus, for patients with an HLA-matched, unrelated donor, a TBI dose of 200 cGy (in combination with CY/ATG) was sufficient to allow for engraftment without inducing prohibitive toxicity. As in previous studies, patient age and pretransplantation disease duration remain important prognostic factors.

Total body irradiation before allogeneic bone marrow transplantation: is more dose better?

PURPOSE

This study was performed to retrospectively assess the potential influence of total-body irradiation (TBI) dose on overall survival in patients undergoing allogeneic bone-marrow transplants (BMT) for hematologic malignancies.

METHODS AND MATERIALS

Between October 1984 and December 1996, 116 patients were conditioned with high-dose chemotherapy and fractionated TBI before allogeneic BMT. The median age was 34 years (range 3-60). The TBI dose was given in 6 fractions, twice-a-day, over 3 days before BMT. The total dose was 10 Gy in 24 patients, 12 Gy in 66 patients, and 13.5 Gy in 26 patients.

RESULTS

TBI dose was inversely correlated with overall survival. Five-year survival was 62% for patients conditioned with 10 Gy, 55% for patients conditioned with 12 Gy, and 46% for patients conditioned with 13.5 Gy. Age at BMT was also independently correlated with survival, with the best outcome for patients < 40 years old.

CONCLUSION

A TBI dose (fractionated) > 10 Gy may not necessarily be associated with a better outcome in patients undergoing allogeneic bone-marrow transplant for hematologic malignancies.

Early growth response gene 1 stimulates development of hematopoietic progenitor cells along the macrophage lineage at the expense of the granulocyte and erythroid lineages

Using a variety of differentiation-inducible myeloid cell lines, we previously showed that the zinc-finger transcription factor early growth response gene 1 (Egr-1) is a positive modulator of macrophage differentiation and negatively regulates granulocytic differentiation. In this study, high-efficiency retroviral transduction was used to ectopically express Egr-1 in myeloid-enriched or stem cell-enriched bone marrow cultures to explore its effect on the development of hematopoietic progenitors in vitro and in lethally irradiated mice. It was found that ectopic Egr-1 expression in normal hematopoietic progenitors stimulates development along the macrophage lineage at the expense of development along the granulocyte or erythroid lineages, regardless of the cytokine used. Moreover, Egr-1 accelerated macrophage development by suppressing the proliferative phase of the growth-to-macrophage developmental program. The remarkable ability of Egr-1 to dictate macrophage development at the expense of development along other lineages resulted in failure of Egr-1-infected hematopoietic progenitors to repopulate the bone marrow and spleen, and thereby prevent death, in lethally irradiated mice. These observations further highlight the role Egr-1 plays in monocytic differentiation and growth suppression.

Is total body irradiation a necessary component of preparative therapy for autologous transplantation in non-Hodgkin's lymphoma

Between September 1986 and June 1998, 157 patients with low grade, intermediate grade, or high grade lymphoma underwent autologous transplantation at a single institution. Two preparative regimens were used: cyclophosphamide, etoposide, total body irradiation (CY-VP-TBI) (N=110) and cyclophosphamide, BCNU, etoposide (CBV) (N=47). The two groups were not significantly different with respect to source of stem cells, gender, stage at presentation, incidence of prior bone marrow involvement, sensitivity to salvage therapy, or histologic grade of lymphoma. The CBV group was significantly older, 49% of patients over age 50, as compared to 26% of patients over age 50 for the CY-VP-TBI group. Response rates and the incidence of fatal toxicity were similar for the two groups. Five year actuarial survival was 31% +/- 9% for CBV and 38% +/- 5% for CY-VP-TBI, p =.85. In a multivariate analysis, in which preparative regimen, age, histologic grade of lymphoma, and sensitivity to salvage therapy were the independent variables, TBI was not significantly associated with survival, and the direction of the trend was for TBI to be less effective than CBV. TBI does not appear to be an essential component of preparative therapy for autologous transplantation in patients with lymphoma.

Intensification of the stem cell transplant induction regimen results in increased treatment-related mortality without improved outcome in multiple myeloma

Randomized trials conducted by the Intergroupe Française du Myelome (IFM) demonstrate that the use of high-dose chemotherapy (HDCT) and stem cell transplantation (SCT) improves event-free (EFS) and overall survival (OS) in younger patients with multiple myeloma (MM). Nevertheless, current HDCT regimens remain inadequate as all patients ultimately relapse following SCT. In an attempt to improve the OS of MM patients post-SCT we used an escalated HDCT regimen incorporating both intensified melphalan (160 mg/m2) and fractionated total body irradiation (12 Gy) to maximize the dose response of myeloma cells to these agents and included infusional etoposide 60 mg/kg in an attempt to eradicate clonal B cells potentially contributing to the myeloma clone. One hundred patients with MM received this intensified SCT regimen. The 100-day treatment-related mortality was 12% predominantly reflecting the development of interstitial pneumonitis (IP) in 28% of patients of whom 7/28 (25%) died. The predicted 5-year OS and EFS following the diagnosis of MM were 60% and 35%, respectively. The median OS from the time of transplant is 41 months and the median EFS is 28 months. More than two prior chemotherapy regimens, previous radiation therapy (RT) and the presence of an abnormal karyotype involving chromosomes 11 or 13 were significantly predictive of poor outcome. Interferon maintenance was not associated with improved outcome. Intensification of the HDCT regimen utilizing etoposide together with escalated melphalan and TBI increases morbidity and mortality without increasing OS beyond that reported with less toxic regimens.

Thrombopoietin promotes hematopoietic recovery and survival after high-dose whole body irradiation

PURPOSE

The therapeutic potential of thrombopoietin (TPO), the major regulator of platelet production, was evaluated for hematopoietic recovery and survival in mice following lethal and supralethal total body irradiation (TBI).

METHODS AND MATERIALS

Hematopoietic recovery was studied in C57BL6/J mice after 8 Gy TBI (gamma-rays). Survival experiments were performed with C57BL6/J and BCBA F1 mice. Two protocols of TPO administration were evaluated: treatment for 7 consecutive days (7 x 0.3 microg/mice) beginning 2 h after exposure, or a single dose (0.3 microg/mice) administered 2 h after irradiation.

RESULTS

TPO improved the platelet nadir and accelerated the platelet reconstitution of irradiated mice in comparison to placebo-treated mice. Recovery of neutrophils and erythrocytes was stimulated as well. TPO induced an accelerated recovery of hematopoietic progenitors and immature multilineage progenitors in bone marrow and spleen. In addition, TPO administration induced approximately 90% survival of 8 Gy irradiated C57BL6/J mice, a TBI dose which resulted in 100% mortality within 30 days for placebo-treated mice. Single TPO administration was as effective as repeated injections for hematopoietic recovery and prevention of mortality. Dose-effect survival experiments were performed in BCBA F1 mice and demonstrated that TPO shifted the LD50/30 from approximately 9.5 Gy to 10.5 Gy TBI given as a single dose, and from 14 Gy to as high as 17 Gy when TBI was given in three equal doses, each separated by 24 h.

CONCLUSION

These results demonstrate that the multilineage hematopoietic effects of TPO may be advantageously used to protect against lethal bone marrow failure following high dose TBI.

Dose rate-dependent sparing of the gastrointestinal tract by fractionated total body irradiation in dogs given marrow autografts

PURPOSE

We compared gastrointestinal toxicity of single vs. fractionated total body irradiation (TBI) administered at dose rates ranging from 0.021 to 0.75 Gy/min in a canine model of marrow transplantation.

METHODS AND MATERIALS

Dogs were given otherwise marrow-lethal single or fractionated TBI from dual 60Co sources at total doses ranging from 8-18 Gy and delivered at dose rates of 0.021, 0.05, 0.10, 0.20, 0.40, and 0.75 Gy/min, respectively. They were protected from marrow death by infusion of previously stored autologous marrow cells and they were given intensive supportive care posttransplant. The study endpoint was 10-day mortality from gastrointestinal toxicity. Logistic regression analyses were used to jointly evaluate the effects of dose rate, total dose, and delivery regimen on toxicity.

RESULTS AND CONCLUSION

With increasing dose rates, mortality increased for either mode of delivery of TBI. With dose rates through 0.10 Gy/min, mortality among dogs given single vs. fractionated TBI appeared comparable. Beginning at 0.20 Gy/min, fractionation appeared protective for the gastrointestinal tract. Results in dogs given TBI at 0.40 and 0.75 Gy/min, respectively, were comparable, and dose fractionation permitted the administration of considerably higher total doses of TBI than were possible after single doses, an increment that was on the order of 4.00 Gy. The data indicate that the impact of fractionating the total dose at high dose rates differs from the effect of fractionation at low dose rates.

High-energy total body irradiation as preparation for bone marrow transplantation in leukemia patients: treatment technique and related complications

PURPOSE

Bone marrow transplantation with conditioning regimens that include total-body irradiation (TBI) is widely used in patients with acute lymphoblastic and acute myelocytic leukemias. The major causes of death in this population are relapse of leukemia, infection, and treatment related complications. Our purpose was to achieve a homogenous radiation dose distribution and to minimize the dose to the lungs, liver, and kidneys so that the incidence of organ injury was reduced.

METHODS AND MATERIALS

Dose to the bone marrow, midplane, and periphery was quantified by use of thermoluminescent detectors in a bone-equivalent tissue phantom. In an effort to reduce the risk of complications, we treated relapsed or refractory leukemia patients with TBI administered in fractionated, parallel opposed large fields with 24 MV photons, using tissue compensation and partial-transmission lung shielding. Tissue toxicities were then determined.

RESULTS

Dose quantitation in bone-equivalent and tissue-equivalent phantoms demonstrated that backscatter and pair production interactions adjacent to bone increased the bone marrow dose by 6 to 11%. At an SSD of 400 cm and at patient diameters of 20 to 40 cm, the percent inhomogeneity across the phantom with 24 MV photons was 0 to 0.3%, compared to 4 to 6% for 6 MV photons. End-organ toxicities consisted of clinical interstitial pneumonitis in six patients, idiopathic interstitial pneumonitis in three patients, renal toxicity in seven patients, and veno-occlusive disease of the liver in one patient. Toxicities did not correlate with fractionation schedule.

CONCLUSIONS

Total-body irradiation administered with 24 MV photons increases the dose deposition in bone marrow through pair production and backscatter interactions occurring in bone. Because percent depth dose increases with SSD, the 24 MV beam is more penetrating at a 400 cm distance than at 100 cm and dose homogeneity is improved with higher energies. Thus, the incidence of radiation-mediated injury to lung, liver, and kidney is reduced. This is an effective preparatory regimen for patients with high-risk leukemias requiring bone marrow transplantation.

Feeding mice palm carotene prevents DNA damage in bone marrow and reduction of peripheral leukocyte counts, and enhances survival following X-ray irradiation

This study examined the effects of palm carotene feeding on DNA damage of bone marrow, recovery of peripheral leukocyte counts, and the survival of mice that received whole-body X-ray irradiation. The palm carotene was composed of alpha- and beta-carotene in a ratio of 1:3. Mice were fed either a basal diet or a carotene diet (50 mg carotene/100 g diet) for 2 weeks, then irradiated. The carotene diet was prepared by the dietary protocol that markedly enhanced the accumulation of carotene in tissues (J. Nutr. 125, 3081, 1995). DNA damage in bone marrow was evaluated by micronucleus assay using peripheral blood. When mice received X-ray (1.5 Gy), marked DNA damage in bone marrow and reduction of peripheral leukocyte count were observed. These changes were significantly attenuated in mice fed the carotene diet. In addition, X-ray (6.5 Gy)-induced survival of mice fed the carotene diet was higher than those fed the basal diet. In mice fed the carotene diet, alpha- and beta-carotene were detected in bone marrow and liver, and concentration of vitamin A in liver was about four times higher compared with that in mice fed the basal diet. These findings suggest that feeding mice palm carotene prevents radiation-induced damages by way of its antioxidant activity and/or vitamin A activity.

Total lymphoid irradiation in rheumatoid arthritis. A ten-year followup

OBJECTIVE

To report the findings of a 10-year followup of patients enrolled in a randomized trial of total lymphoid irradiation (TLI) versus chemotherapy for rheumatoid arthritis (RA).

METHODS

A retrospective analysis of the charts of 19 patients who had been included in a randomized trial comparing TLI and chemotherapy for the treatment of RA.

RESULTS

Ten years after the start of the trial, a higher number of TLI-treated patients had died (7 of 10), compared with patients who had received chemotherapy (2 of 9). In addition, 3 of the TLI-treated patients developed B cell-related malignancies, whereas no such malignancies developed in the control group.

CONCLUSION

TLI was associated with a less-favorable long-term outcome than chemotherapy. These data stress the importance of careful long-term followup in experimental trials of immunosuppressive agents.

Effect of human cord blood transfer on survival and disease activity in MRL-lpr/lpr mice

The MRL-lpr/lpr mice have a genetic defect and by 6 months of age usually die after developing severe autoimmune disease and massively enlarged lymph nodes (Cohen, P. L., and Eisenberg, R. A., Annu. Rev. Immunol. 9, 243-269, 1991). Similarly as in some genetic diseases in humans, these mice, if given an appropriate marrow transplant from a mouse not having the defect, will have partial correction of the disease process and an extension of life (Cohen, P. L., and Eisenberg, R. A., Annu. Rev. Immunol. 9, 243-269, 1991; Lenarsky, C., Kohn, D. B., Weinberg, K. I., and Parkman, R., Hematol. Oncol. Clin. N. Am. 4, 589-603, 1990). Utilizing human umbilical cord blood as a donor source for marrow transplantation, we have been able to obtain significant correction of the MRL-lpr/lpr genetic defect and double the life span. By 11 months of age, 5 months beyond their usual life span, both the animals receiving congenic marrow (MRL-+/+) and the animals with human cord blood had mild lymphadenopathy, a decrease in double-positive T cells, and an increase in double-negative T cells. Granulomatous vasculitis could be identified in the animals receiving human cells and could not be found in the animals receiving MRL-+/+ marrow.

Murine Hertwig's anemia: premature death after normal bone marrow transplantation is radiation dose-dependent

Marrow transplantation therapy in mice with heritable blood disorders usually leads to rapid blood cell normalization, but is sometimes followed by pancytopenia and premature death. This is especially true in mice with Hertwig's anemia (an/an). Unlike the +/+ recipients, 100% of whom survive for over a year, 66% of the mutant mice die by 6 months posttransplantation, and the rest die soon thereafter. It is not clear whether premature death is due to the radiation dose (10 Gy) or to the fact that the F1 mutant mice receive parental-type cells known to induce hybrid resistance. In the present report, experiments were designed to determine whether the F1-an/an host is more sensitive to radiation and/or resistant to continued expansion of the parental-type +/+ cells. The mutant mice are, indeed, more sensitive to irradiation, with an LD100/30 of 7 Gy as compared with an LD100/30 of 10 Gy for the +/+ mice. The times of anemia onset and death for mutant mice implanted with +/+ cells postirradiation is also radiation dose-dependent. Further evidence that death is due to host radiation damage rather than F1 hybrid resistance was provided by transplanting cells from three morbid 10 Gy-irradiation recipients into unirradiated, anemic, stem cell-deficient, F1-W/Wv secondary hosts. All recipients were repopulated by the original parental cells, were cured of their anemia, and survived for 52 weeks posttransplantation. The an/an mouse's heightened susceptibility to radiation damage appears to be the major factor in early death after transplantation therapy.

[A cytofluorescence study of the peripheral blood in radiation exposure]

The cytofluorescent probing method has shown that the radiation action under sharp irradiation regime in experimental animals and chronic regime in people influences the level of synthetic processes in lymphocytes and granulocytes of peripheral blood, characterized by alpha-index (RNA/DNA). The correlation has been found between alpha-index, survivability, doses. alpha-Index can be used to estimate the radiation biological effects and radiosensitivity testing.

Marrow toxicity of fractionated vs. single dose total body irradiation is identical in a canine model

PURPOSE

We explored in dogs the marrow toxicity of single dose total body irradiation delivered from two opposing 60Co sources at a rate of 10 cGy/min and compared results to those seen with total body irradiation administered in 100 cGy fractions with minimum interfraction intervals of 6 hr. Dogs were not given marrow transplants.

RESULTS

We found that 200 cGy single dose total body irradiation was sublethal, with 12 of 13 dogs showing hematopoietic recovery and survival. Seven of 21 dogs given 300 cGy single dose total body irradiation survived compared to 6 of 10 dogs given 300 cGy fractionated total body irradiation (p = .18). One of 28 dogs given 400 cGy single dose total body irradiation survived compared to none of six given fractionated radiation (p > .20). With granulocyte colony stimulating factor administered from day 0-21 after 400 cGy total body irradiation, most dogs survived with hematological recovery. Because of the almost uniform success with granulocyte colony stimulating factor after 400 cGy single dose total body irradiation, a study of granulocyte colony stimulating factor after 400 cGy fractionated total body irradiation was deemed not to be informative and, thus, not carried out. Additional comparisons between single dose and fractionated total body irradiation were carried out with granulocyte colony stimulating factor administered after 500 and 600 cGy of total body irradiation. As with lower doses of total body irradiation, no significant survival differences were seen between the two modes of total body irradiation, and only 3 of 26 dogs studied survived with complete hematological recovery. Overall, therefore, survival among dogs given single dose total body irradiation was not different from that of dogs given fractionated total body irradiation (p = .67). Similarly, the slopes of the postirradiation declines of granulocyte and platelet counts and the rates of their recovery in surviving dogs given equal total doses of single versus fractionated total body irradiation were indistinguishable.

CONCLUSION

Within the limitations of the experimental design, we conclude that single-dose and fractionated total body irradiation have comparable marrow toxicity in dogs.

Regimen-related toxicity in patients undergoing BMT with total body irradiation using a sweeping beam technique

In our institution, total body irradiation (TBI) is performed by means of a sweeping beam technique. Toxicity of the procedure was evaluated according to the only grading system designed for high dose chemoradiotherapy. One hundred patients undergoing TBI and conditioned with a standard cyclophosphamide regimen before BMT were evaluated. Regimen-related toxicity was graded according to the Seattle transplantation toxicity system, from 0 to IV (fatal toxicity), in eight organs on days 0, 7, 14, 28 and 100 for lungs. Eighteen patients did not develop any toxicity. Grades III, IV toxicities were uncommon (9%) and were not influenced by dose of TBI, GVHD prophylaxis, disease status and allogenicity although no grade IV toxicity was observed among autologous marrow recipients. However, grade II toxicity was more common in patients receiving allogeneic vs autologous grafts (p < 0.01) because of increased mucosal (p = 0.002) and liver (p = 0.12) toxicities. Renal toxicity was unevaluable. When cumulative toxicity was equal or higher than 4, day 100 survival was worse (p = 0.05). These data confirm the safety of our TBI procedure and the validity of the grading system except for renal toxicity. We suggest that a more aggressive conditioning regimen may be tolerated by patients receiving autologous grafts.

Survival after total body irradiation: effects of irradiation of exteriorized small intestine

Rats receiving lethal irradiation to their exteriorized small intestine with pulsed 18 MVp bremsstrahlung radiation live about 4 days longer than rats receiving a dose of total-body irradiation (TBI) causing intestinal death. The LD50 for intestinal irradiation is approximately 6 Gy higher than the LD50 for intestinal death after TBI. Survival time after exteriorized intestinal irradiation can be decreased, by adding abdominal irradiation. Adding thoracic or pelvic irradiation does not alter survival time. Shielding of large intestine improves survival after irradiation of the rest of the abdomen while the small intestine is also shielded. The kinetics of histological changes in small intestinal tissue implicate the release of humoral factors after irradiation of the abdomen. Radiation injury develops faster in the first (proximal) 40 cm of the small intestine and is expressed predominantly as shortening in villus height. In the last (distal) 40 cm of the small intestine, the most pronounced radiation effect is a decrease in the number of crypts per millimeter. Irradiation (20 Gy) of the proximal small intestine causes 92% mortality (median survival 10 days). Irradiation (20 Gy) of the distal small intestine causes 27% mortality (median survival greater than 30 days). In addition to depletion of crypt stem cells in the small intestine, other issues (humoral factors, irradiated subsection of the small intestine and shielding of the large intestine) appear to influence radiation-induced intestinal mortality.