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Biomedical subjects

R Storb

Publications and source records attributed to R Storb.

At least 343 records · Page 19Linked to original sources

Biochemical characterization of a unique canine myeloid antigen.

In marrow transplantation, radioisotope-labeled monoclonal antibodies may provide a way to selectively deliver high doses of radiation to target tissues (marrow in the case of myeloid malignancies) without significant toxicity to other normal organs. This paper describes the production and characterization of a novel monoclonal antibody, DM5, that we have developed for use in an animal model of radiotherapy targeted to the marrow. DM5 recognizes three glycosylation variants, gp19,21,23DM5, of a polypeptide core that is expressed on canine cells of the myeloid lineage, but not on lymphoid cells. The antigen recognized by DM5 is not present on most progenitor cells as determined by CFU-GM assays of DM5 positive and negative cell populations.

Animals↗

Long-term follow-up of patients who received recombinant human granulocyte-macrophage colony stimulating factor after autologous bone marrow transplantation for lymphoid malignancy.

Twenty-seven patients with lymphoid neoplasia who underwent autologous bone marrow transplant (BMT) and who had received recombinant human granulocyte-macrophage colony stimulating factor (rhGM-CSF) were followed in order to examine the potential long-term consequences of rhGM-CSF. rhGM-CSF (15-240 micrograms/m2/day) was given daily either for 14 or 21 days after marrow infusion. All surviving patients who remained in remission had stable marrow graft function. The actuarial survival rate was 45% and the relapse incidence was 50% at a median of 774 days after autologous BMT. These findings suggest that treatment with rhGM-CSF does not have profound adverse long-term consequences.

Adolescent↗

Transfusions shortly before HLA-matched marrow transplantation for leukemia are associated with a decrease in chronic graft-versus-host disease.

The effect of random red cell transfusions given shortly before allogeneic bone marrow transplantation (BMT) was evaluated in 969 leukemic patients transplanted from an HLA-identical sibling donor. Patients were divided into two groups: 501 who received a transfusion shortly before BMT, and 468 who did not. Both groups had a similar incidence of acute graft-versus-host disease (GVHD), but the recently-transfused group had a significantly lower incidence of chronic GVHD (35.9% vs 48.9%). These differences remained significant in a multivariate analysis of time to chronic GVHD (p = 0.022), taking into account other differences between the two groups and known risk factors for chronic GVHD.

Adult↗

Prophylaxis of graft-versus-host disease by administration of the murine anti-IL-2 receptor antibody 2A3.

The efficacy of murine monoclonal IgG1 antibody 2A3 specific for the 55 kD chain of the human IL-2 receptor (CD25) was evaluated for prophylaxis of acute GVHD in patients with advanced leukemia transplanted with unmodified bone marrow from related HLA-haploidentical donors incompatible for two or three HLA loci of the nonshared haplotype. As GVHD prophylaxis, 36 patients (control) received standard cyclosporine and methotrexate (C + M) whereas 11 patients (study) received C + M plus antibody 2A3, 1.0 mg/kg on day -1, and 0.5 mg/kg daily from day 0 through day +19. Antibody administration was not associated with appreciable toxicity and did not adversely affect engraftment. During treatment, circulating CD25+ cells appeared saturated by the infused antibody. Patients receiving antibody 2A3 tolerated more cyclosporine than controls (p less than 0.001) with lower increase of serum creatinine (p less than 0.05) during the first month. Seven of 10 (70%) evaluable study patients developed acute GVHD of grade II-IV with onset at a median of 20 days compared to 27 of 31 (87%) control patients with onset at a median of 13 days (p = 0.11). Trough serum levels of antibody 2A3 ranged from 7.2 to 68.8 mg/l, and lower values correlated with occurrence of acute GVHD. A human anti-mouse immunoglobulin antibody response was detected in four patients but was not associated with lower levels of antibody 2A3 in the serum. Two study patients and two controls have survived more than 1 year (p = 0.92). These findings suggest that administration of antibody 2A3 suppressed and delayed activation of alloantigen-specific T cells but did not result in their elimination.

Adolescent↗

What role for prednisone in prevention of acute graft-versus-host disease in patients undergoing marrow transplants?

One hundred forty-seven consecutive patients with leukemia, myelodysplastic syndrome, or aplastic anemia were treated by marrow grafts from genotypically HLA-identical siblings (n = 122) or HLA-haploidentical family members (n = 25). Haploidentical recipients differed from their donors for no more than one HLA locus on the nonshared haplotype. All were given postgrafting immunosuppression with a combination of methotrexate and cyclosporine. In a randomized study we explored whether prednisone administered from day 0 through 35 along with methotrexate/cyclosporine could improve prevention of acute graft-versus-host disease (GVHD). The GVHD incidence in patients not given prednisone was comparable with that previously reported with methotrexate/cyclosporine. Unexpectedly, significant increases in acute and also chronic GVHD were seen in HLA-identical recipients administered prednisone, but not in the small number of patients administered HLA-nonidentical grafts. However, the resultant increase in transplant-related mortality in patients administered prednisone was offset by an increase in leukemic relapse in patients not administered prednisone, presumably related to the absence of a graft-versus-leukemia effect. Therefore, overall disease-free survival of the two groups of patients was comparable, with slightly more than 50% of the patients being alive at more than 2 years after transplantation. We speculated that prednisone adversely affected GVHD prophylaxis, interfering with methotrexate's cell cycle-dependent suppression of donor lymphocyte proliferation in response to host antigens. In a pilot study we explored whether beginning prednisone on day 15, after completion of methotrexate administration, would avoid this adverse effect. The GVHD incidence in patients administered methotrexate/cyclosporine along with "late" prednisone was comparable with that in patients not administered prednisone. We conclude that methotrexate/cyclosporine is effective in decreasing the incidence of grade II through IV GVHD, and that the addition of prednisone to this regimen is not beneficial in recipients of HLA-identical marrow grafts.

Acute Disease↗

Recombinant human granulocyte colony-stimulating factor accelerates hematopoietic recovery after DLA-identical littermate marrow transplants in dogs.

We studied whether treatment of dogs with recombinant human granulocyte colony-stimulating factor (rhG-CSF), after 920 cGy total body irradiation (TBI) and transplantation of 3.3 +/- 1.0 x 10(8) bone marrow cells per kilogram from a DLA-identical littermate, accelerated hematopoietic recovery and influenced the incidence of subsequent marrow graft failure or graft-versus-host disease (GVHD). Ten animals were treated with 100 micrograms rhG-CSF/kg/d from days 1 through 10 after TBI. Results were compared with those of historical control of 14 dogs not administered rhG-CSF. Neither group of dogs received GVHD prophylaxis. The median time to recovery of 1,000 neutrophils/mm3 was 8 days for dogs administered rhG-CSF compared with 14 days in controls (logrank test: P less than .03). The median time to reach 100 monocytes/mm3 was 17 days in G-CSF-treated dogs compared with 49 days in controls (P less than .002). The median time to attain 500 lymphocytes/mm3 was 15 days versus 31 days, respectively (P less than .01). The median time to reach 20,000 platelets/mm3 was 26 versus 20 days (P = .68). Graft failure occurred in 1 of 10 G-CSF-treated dogs versus 2 of 14 controls (two-tailed Fisher's exact test: P = 1.00). GVHD was seen in 4 of 9 rhG-CSF-treated dogs compared with 1 of 12 controls (P = .12). Two G-CSF-treated dogs died of GVHD versus none of the controls (P = .17). No unusual toxicities were seen in dogs receiving rhG-CSF. In summary, rhG-CSF significantly accelerated recovery of neutrophils, monocytes, and lymphocytes after DLA-identical littermate marrow transplantation without altering platelet recovery. Graft failure was not seen more often than in controls, but there was a trend toward an increased incidence of GVHD.

Animals↗

An antibody that facilitates hematopoietic engraftment recognizes CD44.

Pretreatment of recipients with the monoclonal antibody (MoAb) S5 facilitates engraftment of bone marrow from mismatched, unrelated donors in the canine transplantation model. In the direct comparisons reported here, the S5 glycoprotein (gp) was found to have structural homology to CD44 that in humans has been implicated in adhesive interactions of one type of effector cell, the lymphocyte. The S5 antigen and gp90Hermes-1 exhibited codistribution on canine peripheral blood cells. Both S5 and Hermes-1 (anti-CD44) MoAbs recognized 90-Kd species in radioimmune precipitations of 125I surface-labeled canine peripheral blood lymphocytes and bone marrow cells. Competitive antibody binding experiments showed that the epitope detected by S5 was distinct from that bound by Hermes-1 but overlapped with those defined by two other known anti-CD44 reagents, IM7 and Hutch-1. Sequential immunoprecipitation with S5 and Hermes-1 indicated that the two antibodies recognize the same or overlapping subsets of membrane gps. Tryptic digestion of S5 and anti-CD44 immunoprecipitates generated two major iodinated peptides of 27 and 35 Kd in both cases, a further indication of structural homology. Similarly, after N-glycanase digestion, S5 and CD44 immunoprecipitates were resolved to a single 68-Kd species. These findings suggest that CD44-mediated adhesive events may affect the fate of transplanted hematopoietic cells. The previous implications of this gp in T-lymphocyte activation and lymphocyte adhesion to endothelium thus provide useful paradigms to analyze its function in the bone marrow transplant setting.

Amino Acids↗

Use of recombinant human granulocyte-macrophage colony-stimulating factor in graft failure after bone marrow transplantation.

The effect of recombinant human granulocyte-macrophage colony-stimulating factor (rhGM-CSF) was evaluated in 37 patients with marrow graft failure after allogeneic (n = 15), autologous (n = 21), or syngeneic (n = 1) bone marrow transplantation. rhGM-CSF was administered by 2-hour infusion at doses between 60 and 1,000 micrograms/m2/d for 14 or 21 days. At doses of less than 500 micrograms/m2, rhGM-CSF was well-tolerated and did not exacerbate graft-versus-host disease in allogeneic transplant recipients. No patient with myelogenous leukemia relapsed while receiving rhGM-CSF. Twenty-one patients reached an absolute neutrophil count (ANC) greater than or equal to 0.5 x 10(9)/L within 2 weeks of starting therapy while 16 did not. None of seven patients who received chemically purged autologous marrow grafts responded to rhGM-CSF. The survival rates of GM-CSF-treated patients were significantly better than those of a historical control group.

Adolescent↗

Bone marrow transplantation for patients with myelodysplasia. Pretreatment variables and outcome.

STUDY OBJECTIVE: To determine the efficacy of allogeneic bone marrow transplantation for severe myelodysplasia, and to identify variables predictive of outcome. DESIGN: Case series study. SETTING: A referral-based bone marrow transplant center. PATIENTS: Consecutive series of 59 patients with myelodysplasia or closely related disorders and either life-threatening cytopenia or a progressive increase in marrow blast percentage. INTERVENTION: Patients were treated with high-dose cyclophosphamide and total body irradiation followed by allogeneic bone marrow transplantation from either an HLA-identical (n = 45) or HLA-partially matched (n = 14) donor. MEASUREMENTS AND MAIN RESULTS: The product-limit estimate for disease-free survival 3 years after transplant is 45% (95% CI, 32% to 59%). The commonest causes of death after transplant were disease recurrence, interstitial pneumonia, and graft-versus-host disease, accounting for eight deaths each. In a univariate analysis, younger patients, those with shorter disease duration, and those whose disease was characterized by an abnormal cytogenetic karyotype had better survival and disease-free survival than the group as a whole. In a multivariate analysis, younger age and abnormal karyotype were independent predictors of improved disease-free survival and overall survival. Patients who received transplants when they had fewer blasts in their bone marrow had a decreased chance for disease recurrence when compared with patients with excess blasts. CONCLUSIONS: Bone marrow transplantation offers a potential cure for many patients with myelodysplasia. Best results can be expected in younger patients who receive transplants relatively early in their disease course.

Adolescent↗

Allelic variation in the DR subregion of the canine major histocompatibility complex.

Allelic variation in the DR subregion of the canine major histocompatibility complex (DLA) has been analyzed by nucleic acid sequencing of cDNA clones of DRB genes amplified in vitro by the reverse transcriptase-polymerase chain reaction (RT-PCR). Sequence analysis of a panel of 19 homozygous typing cell dogs representing 12 different DLA-D types (defined by mixed leucocyte reaction) demonstrated the presence of one expressed DRB locus with at least nine distinct alleles in the dog. Unique DLA-DRB alleles were found in the DLA-D types Dw1, Dw3, Dw4, Dw8 (workshop assignments) and D4, D6, D7, D8, and D9 (Seattle assignments). In contrast, the DRB genes of the remaining three DLA-D types (D1, D10, and D16) were identical to those of Dw3/Dw4 (for D1), Dw8 (for D10), and D6 (for D16). The nucleotide sequences of all nine DLA-DRB alleles were typical of functional major histocompatibility complex (MHC) class II beta chains and contained three allelic hypervariable regions (HVRs) in the beta 1 domain at positions 8-16, 26-39, and 57-74. At each variable residue, two to five amino acid substitutions were found. The most polymorphic residues were located at positions 37 (with five amino acid substitutions), 11, 13, 28, and 71 (each with four substitutions). The DLA-DRB alleles had 96%-99% overall nucleotide sequence similarity and 93%-99% amino acid sequence similarity with each other. Cluster analysis of the nucleotide and predicted amino acid sequences subdivided the DLA-DRB alleles into three major allelic groups which may represent the canine counterparts of the supertypic groups described in man.

Alleles↗

Effect of HLA incompatibility on graft-versus-host disease, relapse, and survival after marrow transplantation for patients with leukemia or lymphoma.

We analyzed the relevance of HLA incompatibility to acute graft-versus-host disease, relapse, and survival in 281 patients with hematologic neoplasms who underwent bone marrow transplantation. Each patient received marrow from a family member who shared one HLA haplotype with the patient but differed to a variable degree for the HLA-A, -B, and -D antigens of the haplotype not shared; 29 were phenotypically identical, 119 were incompatible for one locus, 104 for two loci, and 29 for three loci. These 281 patients were compared with 967 patients who received marrow from siblings with identical HLA genotypes. All patients were treated with cyclophosphamide and total-body irradiation followed by the infusion of unmodified donor marrow cells. Occurrence of severe acute graft-versus-host disease was evaluated in patients who achieved sustained engraftment. In recipients of haploidentical grafts occurrence of severe acute graft-versus-host disease was associated with (1) graft-versus-host disease prophylaxis containing the combination of methotrexate plus cyclosporine versus standard methotrexate, relative risk = 0.35; 95% confidence interval, 0.21-0.57, p less than 0.0001; and (2) the degree of recipient HLA incompatibility, relative risk = 1.95 for each locus incompatible; 95% confidence interval, 1.52-2.50, p less than 0.0001; (3) patient age, relative risk = 1.23 per decade; 95% confidence interval, 1.05-1.44, p = 0.0094. Acute graft-versus-host disease was associated with lower leukemic relapse after transplant in patients with acute lymphocytic leukemia, and chronic graft-versus-host disease was associated with lower relapse after transplant for acute nonlymphocytic leukemia in relapse or chronic myelogenous leukemia in blast crisis. After transplantation for acute nonlymphocytic leukemia in remission, the rate of leukemic relapse was 22% in 61 recipients of "one-locus" (A, B, or D)-incompatible grafts compared to 37% in 561 recipients of HLA-identical sibling grafts. Survival was decreased as the degree of HLA disparity increased. Survival of "one-locus"-incompatible transplant recipients, however, was equivalent to that of HLA-identical sibling transplant recipients.

Bone Marrow Transplantation↗

Long-term transplantation of canine keratinocytes made resistant to G418 through retrovirus-mediated gene transfer.

We studied cultured canine keratinocytes to determine whether they could serve as targets for retrovirus-mediated gene transfer and whether infected cells could persist after transplantation into dogs, a large random-bred model for gene transfer studies. Canine keratinocytes obtained from skin biopsy samples were cultured in vitro with lethally irradiated NIH 3T3 cells used as a feeder layer. The keratinocyte colonies consisted of squamous epithelium with numerous desmosomes, tonofilaments, and keratohyalin granules. In addition, the cells were strongly reactive with monoclonal antibodies to cytokeratin intermediate filament proteins. For the infection studies, we grew the keratinocytes on a feeder layer of lethally irradiated PA317 retrovirus packaging cells, which produced a helper-free amphotropic retroviral vector containing the neomycin phosphotransferase (neo) gene. After cocultivation, 34% (range, 10-76%) of the keratinocytes were found to be resistant to the neomycin analogue G418. Infected keratinocytes were then transplanted into the dog of origin; 1% (range, less than 0.1-3%) of the keratinocytes obtained 27-130 days after transplantation from skin biopsy samples gave rise to G418-resistant colonies. We conclude that canine keratinocytes cultured in vitro can be infected efficiently with a neo gene-containing retroviral vector, and they show persistent G418 resistance for at least 130 days after transplantation into the skin donor.

Animals↗

Previous donor pregnancy as a risk factor for acute graft-versus-host disease in patients with aplastic anaemia treated by allogeneic marrow transplantation.

To determine if previous donor pregnancies influence the development of acute graft-versus-host disease (GVHD) we evaluated data from 136 patients with aplastic anaemia greater than 15 years of age and given marrow grafts from HLA-identical sibling donors. Of the 136 marrow donors, 30 were parous females (previous history of pregnancy), 30 were nulliparous females (no history of pregnancy or abortions), and 76 were males. The cumulative incidence of grade II-IV GVHD was 57%, 21% and 46% for patients with parous, nulliparous and male donors, respectively. A multivariate analysis of the data confirmed that the risk of grade II-IV acute GVHD was significantly increased among patients receiving marrow from parous females as compared to those from nulliparous females (relative risk = 2.5, P = 0.02). There was no statistically significant difference in the incidence of acute GVHD, however, between patients with parous donors and male donors (relative risk = 1.3, P = 0.26). Male patients given grafts from parous donors showed a higher incidence of acute GVHD (63%) than female patients (45%), though this difference was not statistically significant. The 5-year probability of survival was 47% for patients with parous donors, 68% for patients with nulliparous donors and 70% for those with male donors. We confirm that prior donor pregnancy represents an important factor in selecting marrow donors or designing clinical protocols for GVHD prophylaxis.

Acute Disease↗