JH Antin

Abstract We suggest that acute GVHD after marrow transplantation reflects (1) host injury due to the conditioning regimen followed by the production of inflammatory cytokines; (2) stimulation of mature donor T cells in the milieu of increased cell surface expression of leukocyte adhesion molecules and HLA molecules, followed by the autocrine production of IL- 2; and, finally, (3) recruitment and activation of additional mononuclear effector cells from donor marrow progenitors, which produce additional inflammatory cytokines, thus sustaining the response. The second step is critical for the amplification of the systemic inflammatory response, and it is absence in autologous, syngeneic, and T-cell-depleted transplants. These T cells may also contribute to the inflammatory cytokine network. Acute GVHD can occur in the absence of primary tissue injury in such settings as transfusion-related GVHD; however, it is likely that a greater HLA disparity between donor and host is required. We propose that inflammatory cytokine production is the final common pathway of acute GVHD. If this model is correct, control of cytokine dysregulation at any of several points should control GVHD. Further studies of GVHD and investigations of cytokine antagonists (eg, IL-4 or IL-10) or combinations of antagonists such as IL-1ra and soluble TNF receptor or pentoxifylline will allow us to determine the validity of this hypothesis.

Patients who undergo bone marrow transplantation are generally immunosuppressed with a dose of cyclophosphamide (CYA) which is usually calculated based on the patient's weight. At these high doses of CYA, serious cardiotoxicity may occur, but definitive risk factors for the development of such cardiotoxicity have not been described. Since chemotherapeutic agent toxicity generally correlates with dose per body surface area, we retrospectively calculated the dose of CYA in patients transplanted at our institution to determine whether the incidence of CYA cardiotoxicity correlated with the dose per body surface area. Eighty patients who were to receive CYA 50 mg/kg/d for four days as preparation for marrow grafting underwent a total of 84 transplants for aplastic anemia, Wiskott-Aldrich syndrome, or severe combined immunodeficiency syndrome. Fourteen of 84 (17%) patients had symptoms and signs consistent with CYA cardiotoxicity within ten days of receiving 1 to 4 doses of CYA. Six of the 14 patients died with congestive heart failure. The dose of CYA per body surface area was calculated for all patients and the patients were divided into two groups based on daily CYA dose: Group 1, CYA less than or equal to 1.55 g/m2/d; Group 2, CYA greater than 1.55 g/m2/d. Cardiotoxicity that was thought to be related to CYA occurred in 1/32 (3%) of patients in Group 1 and in 13/52 (25%) patients in Group 2 (P less than 0.025). Congestive heart failure caused or contributed to death in 0/32 patients in Group 1 v 6/52 (12%) of patients in Group 2 (P less than 0.25). There was no difference in the rate of engraftment of evaluable patients in the two groups (P greater than 0.5). We conclude that the CYA cardiotoxicity correlates with CYA dosage as calculated by body surface area, and that patients with aplastic anemia and immunodeficiencies can be effectively prepared for bone marrow grafting at a CYA dose of 1.55 g/m2/d for four days with a lower incidence of cardiotoxicity than patients whose CYA dosage is calculated based on weight. This study reaffirms the principle that drug toxicity correlates with dose per body surface area.

We performed a phase I/II study of the administration of recombinant human granulocyte-macrophage colony-stimulating factor (GM-CSF) to patients with aplastic anemia or myelodysplastic syndrome. Doses ranging from 15 to 480 micrograms/m2 were administered as a one-hour or four-hour intravenous infusion daily for 7 days or as a 12-hour infusion for 14 days. Temporary improvements were seen in granulocyte counts, monocyte counts, and reticulocyte counts in six of eight patients with aplastic anemia and five of seven patients with myelodysplastic syndromes. The patients with myelodysplastic syndromes had larger increases in granulocyte, monocyte, and reticulocyte counts than did those with aplastic anemia, and they also had increases in the numbers of eosinophils (two of seven), immature myeloid cells (two of seven), and myeloblasts (two of seven) that were not observed in patients with aplastic anemia. There was no reduction in erythrocyte transfusion requirements, and no effect was observed on platelet counts. There was only minimal toxicity consisting of transient low-back discomfort, anorexia, myalgias/arthralgias, and low-grade fever. Our data suggest that GM-CSF is well tolerated and is more likely to result in elevations of blood counts in patients with myelodysplasia than in patients with aplastic anemia, but the role of GM-CSF therapy in these disorders remains to be determined.

Summary of Published Data Using GVL for CML Mononuclear Cell Clinical bcr-ab/(-) Acute Therapy-Related n IFN Dose (X 1 08/kg) Response by PCR Cytopenia GVHD’ Death Kolb et alla Jiang et alZo Bar et aIz2 Drobyski et ai’’ Helg et aIz3 Porter et aIz4 Novotny et aI5’ Frassoni et aI5’ Summary 4.4, 5.1, 7.4 1.8, 2.7 0.34-5.2 2.5-5.0 3.8, 5.7, 12.3 NR 2-3 infusions 0.9-7.9 0.34-12.3 0 0 1 1 1 1 3 3 10146 122%) Abbreviations: IFN, interferon-a; NR, not reported; ND, not done + Grade I-IV GVHD. t Seven of ten were treated for CML. tive effect on leukemic cells, but it enhances cell-mediated immunity and the expression of both histocompatibility molecules and accessory cell molecules (eg, LFA-3, CD58).3’-33 As shown in Table 1, most patients receiving buffy coat also received interferon-a before and/or during mononuclear cell infusions. Because some patients re- sponded to buffy coat infusions without interferon-a ther- apy, it is very unlikely that interferon-a alone is responsible for the molecular genetic remissions. In contrast to patients receiving interferon-a al~ne,~” none of the patients that achieved a molecular genetic remission with buffy coat in- fusions have relapsed, although further follow-up will be required to estimate the durability of the response. Al- though it is appealing to think that interferon-a may aug- ment the GVL effect, the data are insufficient to estimate the extent of its contribution, and this is a fruitful area for future studies.

BACKGROUND: The recent report of hepatitis B transmission between hematopoietic progenitor and putative stem cell (HPC) components stored in liquid nitrogen led to the questioning of whether evidence existed for similar contamination by bacterial or fungal elements. STUDY DESIGN AND METHODS: Microbial contamination rates were reviewed for 704 HPC components from 255 patients over an 18-month period. Five liquid nitrogen freezers were surveyed for microbial contamination. The literature was reviewed to ascertain the published experience of other laboratories with HPC component contamination first documented on thawing. RESULTS: Seven (1.2%) of 583 thawed components were found to be contaminated with a variety of environmental or waterborne organisms, despite a meticulous protocol to prevent contamination during thawing. All of these components had been sterile on cryopreservation. Literature review revealed a similar incidence of post-thaw contamination from other centers. Microbial survey of liquid nitrogen freezers revealed low-level contamination in four of five. The organisms represented were similar to those cultured from thawed HPC components. One freezer was heavily contaminated by Aspergillus species. CONCLUSION: Liquid nitrogen freezers are not sterile, and both the liquid and vapor phases are potential sources of microbial contamination of HPC components. While low-level contamination by environmental organisms may be common, the occurrence of heavy contamination by potential pathogens such as Aspergillus species suggests that monitoring of liquid nitrogen sterility may be indicated. Strategies to assess and prevent microbial transmission from liquid nitrogen to HPC components need further development.