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Biomedical subjects

R Storb

Publications and source records attributed to R Storb.

At least 181 records · Page 10Linked to original sources
PubMed1996

Facilitation of DLA-incompatible marrow grafts by donor-specific serum transferrin?

Studies in mice have shown that donor-specific plasma transferrin (TF) given to the recipient in the peritransplant period facilitates engraftment of marrow from histoincompatible donors. Dogs given 920 cGy of total body irradiation (TBI) and infused with marrow from an unrelated major histocompatibility complex (DLA) different donor generally fail to engraft; only approximately 20% of dogs achieve sustained engraftment. We have now investigated in this model whether the infusion of donor-specific plasma TF would facilitate engraftment. Ten dogs were given TBI, followed at 23 h by an intravenous dose of TF, at 24 h by marrow from the same donor, and another dose of TF at 48 h; six dogs also received postgrafting methotrexate (MTX). Seven dogs (three of four without MTX, four of six with MTX) had sustained engraftment, and three dogs failed to engraft. A single dog given third-party TF failed to engraft. Among five dogs not given TF two achieved sustained engraftment. This pilot study suggests that donor-specific TF facilitates engraftment of DLA-incompatible marrow. Further studies are warranted.

Animals↗
PubMed1996

An anti-CD44 antibody does not enhance engraftment of DLA-identical marrow after low-dose total body irradiation.

920 cGy total body irradiation (TBI) is adequate for consistently successful engraftment of marrow from dog leukocyte antigen (DLA)-identical littermates; however, the dose is inadequate to ensure a marrow graft from DLA-nonidentical unrelated donors. Such mismatched grafts are successful only after 1800 cGy, given in three fractions. While anti-T-cell reagents enhance engraftment of DLA-identical littermate marrow after 920 cGy, they fail to be effective in the DLA-nonidentical setting. However, a monoclonal antibody (mAb) to CD44, S5, was found to be very effective in enhancing engraftment of DLA-nonidentical marrow. The current study asked whether mAb S5 was also effective in the setting of DLA-identical littermate transplants. To this purpose, the TBI dose was lowered to 450 cGy, a dose after which 70% of such grafts failed. Four dogs were treated with antibody S5, 0.2 mg/kg on days -7 through -2 (per previously published protocol), given 450 cGy TBI followed by marrow grafts from their DLA-identical littermates. All four dogs rejected their grafts; two of these died from marrow aplasia, and two survived with endogenous marrow recovery. This result was not statistically significantly different from that in 17, historical (n = 5) and concurrent (n = 12), control dogs where 11 of 17 animals rejected. Even if ten experimental animals were transplanted and all six remaining dogs engrafted, the results still would not have been significantly different from control. This result is in contrast to the successful engraftment promoted by pretreatment with antibody S5 of DLA-nonidentical unrelated dogs, consistent with the notion that different host cells are involved in graft rejection in the two disparate histocompatibility settings.

Animals↗
PubMed1996

Allogeneic marrow transplantation for aplastic anaemia associated with dyskeratosis congenita.

Eight patients with aplastic anaemia associated with dyskeratosis congenita received allogeneic marrow grafts from either HLA-identical siblings (six patients) or HLA-matched unrelated donors (two patients). Patients who received marrow from HLA-identical siblings were conditioned with cyclophosphamide (140-200 mg/kg), with or without antithymocyte globulin. Patients who received unrelated donor marrow were conditioned with cyclophosphamide (120 mg/kg) and total body irradiation (1200 cGy). The six patients who survived for >2 weeks following transplant all had haematological evidence of engraftment, and all three patients who survived for at least a year following transplant recovered normal haematological function. Three patients died with respiratory failure and pulmonary fibrosis at 70 d. 8 years and 20 years posttransplant; three patients died during the neutropenic period of invasive fungal infections; one patient died on day 44 of refractory acute graft-versus-host disease; and one patient remains alive 463 d following transplant. The surviving patient recently underwent surgical resection of a Dukes' stage C rectal carcinoma diagnosed 14 months posttransplant. The aplastic anaemia associated with dyskeratosis congenita can be successfully treated by allogeneic bone marrow transplantation; however, this approach does not reverse the other systemic manifestations of the syndrome. The pathogenesis of the intestinal lung disease observed in dyskeratosis congenita patients following marrow transplantation is not understood.

Adult↗
PubMed1996

Unrelated donor marrow transplantation for myelodysplasia (MDS) and MDS-related acute myeloid leukaemia.

Allogeneic marrow transplantation using related marrow donors for myelodysplasia (MDS) and acute myeloid leukaemia (AML) arising from MDS results in 35-56% actuarial disease-free survival. Because the use of unrelated donors has not been well-characterized, we report on the outcome of 52 patients with MDS or MDS-related AML consecutively treated between 1987 and 1993 with unrelated donor marrow transplantation. The median age was 33 (range 1-53) years. 33 patients received chemotherapy and total body irradiation and the remainder busulfan and cyclophosphamide. The donors were phenotypically identical at the HLA-A, B and Dw/DRB1 loci in 34 cases and mismatched for one HLA locus in 17 cases and two loci in one case. Marrow was non-T-cell depleted and methotrexate with cyclosporine or FK506 was used for postgrafting immunosuppression. The 2-year disease-free survival, relapse, and non-relapse mortality rates were 38%, 28% and 48%, respectively. One patient who relapsed survives disease-free after withdrawal of immunosuppressive therapy. 16/19 survivors have a performance status of 90-100%. Patients with MDS in transformation or with AML had a significantly higher risk of relapse than patients with less advanced disease (P = 0.0014). Increased non-relapse mortality was significantly associated with higher age, longer disease duration before transplant, lower neutrophil count on admission and, unexpectedly, being seronegative for cytomegalovirus. We conclude that the outcome with transplantation using unrelated donors is similar to reported results using related donors and that a meaningful proportion of eligible patients with an otherwise incurable disease may be cured with this treatment. However, mortality from the transplant procedure is high and future studies should focus on reducing toxicity.

Acute Disease↗
PubMed1996

Long-term persistence of canine hematopoietic cells genetically marked by retrovirus vectors.

In 1991 we reported gene transduction into autologous long-term repopulating marrow cells in dogs using amphotropic helper-free retrovirus vectors containing the bacterial neomycin phosphotransferase gene (neo) and the human adenosine deaminase gene (ADA). Two of the dogs are still alive and healthy now more than 5 years after transplantation of transduced autologous marrow cells. In one of the surviving dogs, polymerase chain reaction (PCR) analysis showed the neo and ADA genes to be present in peripheral blood granulocytes and lymphocytes up to the present time. The estimated percentage of neo-positive cells ranged from < 0.001% to 0.1%. ADA mRNA expression was detected by reverse transcriptase PCR (RT-PCR) in granulocytes 63 months after transplantation. The other surviving dog failed to show either persistence or expression of the transduced genes after 50 months. Three additional dogs have been transplanted according to the same transduction protocols and with the same retrovirus vectors, and persistence of the transduced neo gene has been documented in peripheral blood myeloid and lymphoid cells along with G418-resistant colony-forming unit-granulocyte/macrophage (CFU-GM) for now more than 2 years. These findings represent the longest follow-up of retrovirus-mediated gene transduction in any animal species. Long-term transduction efficiency, though, has remained low and will need to be improved for therapeutic application to be possible.

Adenosine Deaminase↗
PubMed1996

Preclinical large animal models for hematopoietic stem cell transplantation.

The use of large animal models for marrow and stem cell transplantation has become increasingly important. Large animal models have recently been used for studying the principles of hematopoiesis and illustrate the relative slow rate of stem cell turnover compared with mice. Furthermore, large animals are used to study the effectiveness of varying conditioning regimens, as well as the influence of growth factors and various immunosuppressive agents such as corticotropin-releasing factor and mycophenolate mofetil on graft-versus-host disease and graft rejection. Large animal models have become useful in studying the combination of hematopoietic stem cell and solid organ transplants for the establishment of long-term tolerance in major histocompatibility complex-mismatched settings.

Animals↗
PubMed1996

Molecular analysis and polymorphism of the DLA-DQA gene.

A full-length cDNA clone and two overlapping genomic clones corresponding to the canine DQA class II gene were isolated and sequenced. Restriction mapping and sequence data allow identification and orientation of the five exons corresponding to the alpha (alpha) chain. Sequence analysis of exon 2 amplified from 17 unrelated dogs of various breeds identified seven alleles. The structure of the canine DQA gene is similar to HLA-DQA1 and other mammalian DQA genes. This study will serve as a reference for developing a typing system for the DLA-DQA gene for donor and recipient matching in the canine model for organ and bone marrow transplantation.

Amino Acid Sequence↗
PubMed1996

Molecular analysis of the DLA DR region.

The dog is an important model for studying organ transplantation. In order to develop a DNA-based typing system, a genomic analysis of the canine DR region of the MHC was undertaken. Southern analysis suggests the presence of two DRB genes in most dogs and all have one DRA gene. One dog out of 200 examined contains only one DRB gene. The DRA gene was mapped in one lambda phage clone. One DRB gene (DRBB1) was localized to two overlapping phage clones. Another DRB gene (DRBB2) was localized to two overlapping phage clones. Sequence analysis of the two DRB genes suggests that one gene is intact (DRBB1) and one gene is a pseudogene (DRBB2) because it lacks a splice acceptor signal for exon 3 and lacks exons 2 and exon 4. Intron 1 and 2 sequence data from DRBB1 allow amplification of the polymorphic exon 2 which, in turn, can serve as a basis for developing a typing system for DRB.

Amino Acid Sequence↗
PubMed1996

Molecular analysis of DLA-DRBB1 polymorphism.

The polymorphism of the canine major histocompatibility complex class II DRB gene, DRBB1, was analyzed. Exon 2 that encodes the polymorphic beta 1 domain was amplified by the polymerase chain reaction (PCR). The PCR product from 250 dogs was cloned and sequenced. Eighteen alleles were identified. Most of the variation in amino acid composition occurred at positions in the peptide binding site. Inheritance of these sequences showed Mendelian segregation with one or two alleles per dog. Cluster analysis of the nucleotide and predicted amino acid sequences subdivided the canine DRBB1 alleles into three major allelic groups. The number of nonsynonymous changes was higher than the number of synonymous changes in the putative antigen recognition sites indicative of positive selection. The data generated can serve as a basis for developing a typing assay for the canine DRBB1 gene.

Alleles↗
PubMed1996

High-dose therapy followed by autologous hematopoietic stem-cell infusion for patients with multiple myeloma.

PURPOSE: To evaluate the outcome of patients with multiple myeloma (MM) who received high-dose therapy followed by autologous bone marrow (BM) or peripheral-blood stem-cell (PBSC) infusion. PATIENTS AND METHODS: Sixty-three consecutive patients with MM received autologous BM (n = 13) or PBSC with or without BM (n = 50) following regimens that contained busulfan (Bu) and cyclophosphamide (Cy) (n = 18), modified total-body irradiation (TBI) followed by Bu and Cy (n = 36), or Bu, melphalan, and thiotepa (n = 9). Two thirds of the patients had resistant disease and 69% had received more than 6 months of previous chemotherapy. RESULTS AND CONCLUSION: Recovery of peripheral-blood cell counts was more rapid in patients who received PBSC with or without BM than in patients who received BM alone. Sixteen of 63 patients (25%) died of complications of treatment within 100 days. Nineteen (40%) of 48 assessable patients achieved a complete response (CR), 23 (48%) had a partial response (PR), and six (12%) had no response. The probabilities of survival and survival without relapse or progression for all 63 patients at 3.0 years were .43 and .21, respectively. The probability of relapse or progression at 3 years was .69, and 17 patients (27%) have died of progressive MM. The probabilities of survival and relapse-free survival at 3 years for the 19 patients who achieved a CR were .42 and .17, respectively. In the multivariate analysis, beta2-microglobulin levels more than 2.5 micrograms/mL, more than two regimens of prior therapy and eight cycles of treatment, time to transplant longer than 3 years from diagnosis, and prior radiation were associated with adverse outcomes. Additional strategies, such as intervention earlier in the disease course, improved treatment regimens, sequential high-dose treatments, and posttransplant therapies may improve outcome of selected patients with MM.

Adult↗
PubMed1996

Busulfan, cyclophosphamide and fractionated total body irradiation for allogeneic marrow transplantation in advanced acute and chronic myelogenous leukemia: phase I dose escalation of busulfan based on targeted plasma levels.

A previous phase I study determined that the maximum tolerated dose (MTD) of busulfan (BU) that could be given with a fixed dose of cyclophosphamide (CY) of 50 mg/kg and total body irradiation (TBI) dose of 12.0 Gy was 7 mg/kg. A phase II study was carried out in patients with advanced myeloid malignancies receiving allogeneic transplants without improvement in outcome as compared to historical controls. In that study, steady-state concentration (Css) of BU in 13 patients receiving a fixed dose of BU varied from 209 to 735 ng/ml. In an attempt to decrease the variability of the Css of BU, a study of targeting specific plasma concentrations was performed. In this study, BU dose was adjusted up or down based on first dose pharmacokinetics. The first dose level evaluated was 7.5 mg/kg with a target BU plasma level of 460 ng/ml. Six patients were entered at this level and the median BU plasma concentration achieved was 410 (range 390-533). One of six patients developed grade 3-4 regimen-related toxicities (RRT). Dose level II was a target of 559 ng/ml with a starting oral dose of BU of 9.6 mg/kg. Twelve patients were entered at this level and median plasma BU level was 548 (range 427-689). Three of 12 (25%) patients developed grade 3-4 RRTs and this was considered to be the MTD. The actuarial probability of grade II-IV acute GVHD was 0.70. Eight of 21 evaluable patients (38%) developed chronic GVHD. Of 18 patients who died, seven died of relapse at a median of 160 days (range 65-353) and 11 (61%) died of causes other than relapse at a median of 152 days (range 18-570). The actuarial probabilities of DFS, relapse and relapse-free mortality at 2 years in all patients were 0.13, 0.50 and 0.75, respectively. This study showed that targeted BU plasma levels within 10% of target can reliably be achieved with a bias of -2.07% and mean absolute error of 7.47%. Overall, targeting made a -31.8% to 100% in plasma BU Css as compared to expected BU Css based on first dose pharmacokinetics if targeting were not performed in this study. Thus targeting avoided much of the variability in BU concentrations seen in other studies. When compared with our previous phase II experience in same group of patients receiving same regimen, dose escalation of BU based on targeted plasma levels did not improve the outcome.

Adolescent↗
PubMed1996

Busulfan, cyclophosphamide and fractionated total body irradiation for autologous or syngeneic marrow transplantation for acute and chronic myelogenous leukemia: phase I dose escalation of busulfan based on targeted plasma levels.

In a previous phase I study, it was concluded that tolerable doses of busulfan (BU), cyclophosphamide (CY) and total body irradiation (TBI) were 8 mg/kg, 60 mg/kg and 12.0 Gy, respectively, for autologous marrow transplant recipients. In an attempt to decrease the variability of BU steady-state concentration (Css) following oral dosing, a BU dose escalation study based on targeted plasma levels was performed in patients receiving autologous transplants for AML or syngeneic transplants for CML. In this study, the BU dose was adjusted up or down based on observed plasma concentration. All patients received a fixed dose of CY 60 mg/kg and TBI of 12 Gy. The first dose level evaluated was 8.6 mg/kg with a target BU Css of 511 ng/ml. Eight patients were entered at this level and the median BU Css achieved was 441 (range 253-566). One of eight patients developed grade 3-4 regimen-related toxicities (RRT). The oral dose of BU for dose level II was 10.6 mg/kg with a target Css of 632 ng/ml. Six patients were entered at this level and median BU Css achieved was 642 (range 566-674). One of six patients developed grade 3-4 RRT. The oral dose for dose level III was 12.6 mg/kg with a target BU Css of 754 ng/ml. Five patients with AML were entered at this dose level and the median plasma BU Css was 733 ng/ml (682-900). Two of five (40%) patients at dose level III developed grade 3-4 RRT which was considered excessive making dose level II the MTD. This study showed that targeted BU Css can reliably be achieved with a bias of -5.23% and mean absolute error of 11.3%. Overall, targeting made a -32.5% to 158.3% change in plasma BU Css as compared to expected BU Css based on first dose pharmacokinetics if targeting were not performed in this study. Thus, targeting avoided much of the variability in BU Css seen in other studies and appears to have allowed for an increase in oral dosing from 8 mg/kg to 10.6 mg/kg. Despite achieving higher and more uniform BU Css, there was no apparent effect on relapse or survival, although the number of patients evaluated was small.

Acute Disease↗
PubMed1996

Tacrolimus (FK506) and methotrexate regimens to prevent graft-versus-host disease after unrelated dog leukocyte antigen (DLA) nonidentical marrow transplantation.

We previously reported an synergism between methotrexate and tacrolimus (FK506) in preventing graft-versus-host disease (GVHD) in dogs given DLA-nonidentical unrelated marrow grafts after 9.2 Gy of total body irradiation (TBI). Methotrexate was given at 0.4 mg/kg i.v. on days 1, 3, 6 and 11 and FK506 at 0.15 mg/kg/day i.m. on days 0-8 and 0.5 mg/kg/day orally on days 9-90. Half of the dogs became long-term survivors. A major toxicity was gastrointestinal, and 25% of dogs died with intussusception. The current study addresses the problem of intussusception by making changes in drug doses used. In one group of dogs, FK506 was reduced to 0.075 mg/kg i.m. on days 1-8, while methotrexate was administered per original schedule. In a second group, methotrexate was reduced to a single dose on day 7, while FK506 was either administered per the original or reduced-dose schedule. None of the 17 current dogs developed intussusception, however, all but two dogs died with GVHD (n = 12) or graft failure (n = 3). Only two dogs survived after transient GVHD. Results show that there is little room for maneuvering FK506 or methotrexate doses, and hopes of reducing gastrointestinal toxicity by dose modifications while retaining the ability to prevent GVHD were not fulfilled.

Animals↗
PubMed1996

High-dose busulfan and cyclophosphamide followed by autologous transplantation in patients with advanced breast cancer.

This study was conducted to evaluate the efficacy of high-dose busulfan (BU) and cyclophosphamide (CY) in patients undergoing autologous hematopoietic stem cell transplantation for metastatic breast cancer. Twenty-two patients with stage IV breast cancer underwent autologous marrow (n = 13), peripheral blood stem cell (PBSC) (n = 6) or marrow plus PBSC (n = 3) transplantation following BU (14-16 mg/kg) and CY (120-180 mg/kg). Of 22 patients, 18 had refractory relapse, one had primary refractory disease, two had responding relapse and one had no evidence of disease (NED) at the time of transplant. Eight patients had bone only disease, six had bone plus visceral disease, and eight had loco-regional recurrent disease. The median time for diagnosis to transplant was 1124 days (range 210-2582). Staging for evaluation of response was performed 4-6 months after transplantation. Six patients were not evaluable (NE) for response because of NED at transplant (n = 1) or early death due to transplant-related complications (n = 5) (one of RSV interstitial pneumonia, two of fungal infection and two of regimen-related toxicities) occurring at a median of 17 days (range 14-59) post-transplant. The patient who was NED at time of transplant is still NED on day 336 post-transplant. Seven of the 16 evaluable patients achieved a complete response (CR) (44%), five achieved a partial response (PR) (31%) and five had no response (NR), with an overall response rate of 75%. Five of 18 (28%) patients treated in refractory relapse, and both patients treated in responding relapse achieved a CR. Of the seven patients who achieved CR, three are alive and disease-free on days 204, 276 and 752 and three relapsed on days 209, 715 and 1127 post-transplant. One patient in CR died of aspergillus pneumonia on day 306 post-transplant. The median day to progression in five patients who achieved a PR after transplantation was 335 (range 144-507). The probabilities of survival and event-free survival (EFS) at 2 years was 0.22 and 0.15, respectively for all 22 patients. The probability of EFS at 2 years for the eight patients achieving CR (including one patient who was NED at transplant) was 0.33. The probabilities of overall survival at 2 years in patients who did and did not achieve a CR after transplantation was 0.63 and 0.14, respectively (P = 0.004). These data suggest that high-dose BU-CY followed by autologous stem cell transplantation is an effective regimen in patients with advanced breast cancer demonstrating that BU is an active agent in this disease and could be incorporated into treatment regimens requiring hematopoietic stem cell support.

Adult↗