Joao L. Ascensao

Pancytopenia in allogeneic marrow transplant recipients: role of cytomegalovirus

SUMMARY. We describe the clinical course of three cytomegalovirus‐antibody‐positive allogeneic marrow graft recipients who developed progressive pancytopenia during the third month post‐transplant. Bone marrow biopsy cores were hypocellular without evidence of disease recurrence. Haemopoietic progenitor assays demonstrated a decrease of all assayable progenitors. Cytomegalovirus was identified from the blood and urine of all three patients. However, none of the patients developed other manifestations of cytomegalovirus infection such as pneumonitis, hepatitis and enteritis. The therapeutic use of ganciclovir and intravenous immunoglobulins resulted in prompt resolution of both viraemia and viruria in all three patients, and of pancytopenia in two patients.

Postextraction osteomyelitis in a bone marrow transplant recipient

This report describes a case of mandibular osteomyelitis after a dental extraction in a patient who subsequently underwent bone marrow transplantation (BMT) for lymphoblastic lymphoma. Surgical guidelines consistent with National Cancer Institute recommendations were followed for the extraction, which was performed before initiation of the myelosuppressive conditioning regimen. However, moderate tenderness developed at the extraction site beginning 10 days after marrow infusion. On day 26 the patient became febrile and blood culture-positive for Staphylococcus epidermidis. Radiographs exposed on day 28 demonstrated changes consistent with low-grade osteomyelitis, including diffuse loss of lamina dura and an irregular osseous rarefaction extending 1 cm posterior to the extraction site. Although the indwelling Hickman catheter was the presumed source for bacteremia, clinical and radiographic data led to consideration of mandibular osteomyelitis as an alternative cause. Characteristics of this infection in BMT recipients are reviewed. Recommendations for dental extractions and prophylactic antibiotic regimens for catheterized BMT recipients are also discussed. Although mandibular osteomyelitic lesions are not common in profoundly immunosuppressed BMT recipients, prompt recognition and treatment are essential when the disease occurs.

Pre-treatment of transplant bone marrow cells with hydrocortisone and cyclosporin A alleviates graft-versus-host reaction in a murine allogeneic host-donor combination

The aim of the study was to alleviate graft-versus-host reaction (GVHR) by pre-treatment of the bone marrow (BM) transplant with hydrocortisone (HC) and cyclosporin A (CsA) in C57BL/6J (donor)u2009→u2009CBA/J (recipient) mouse combination. BM cells were exposed to HC and CsA for 1u2009h at 37°C and then injected into lethally irradiated (9.5u2009Gy) mice at a dose of 2u2009×u2009106 BM cells/mouse. Haematopoietic recovery was assessed on day 12, and survival was followed for 100 days. Combinations of 1000u2009μg/ml HC and 100u2009μg/ml CsA, and 100 μg/ml HC and 10u2009μg/ml CsA significantly reduced MLR and additively mitigated GVHR in vivo, achieving 40% and 26% survival rates, respectively. However, HC and CsA altered neither the peripheral blood cell counts nor in vitro and in vivo BM cell clonogenic potential. Additional studies have shown that HC and CsA blocked con A-driven differentiation of CD8+ and CD4+CD8+lymph node cells (LNC) and progression of LNC to Su2009+u2009G2/M cell cycle phases, and inhibited IL-1, IL-2 and TGF-β while enhancing GM-CSF gene expression in BM cells. Taken together, these data indicate that the pre-treatment of the BM transplant with HC and CsA results in inactivation of GVHR effector cells and mitigation of GVHR while sparing BM repopulating capacity.

Erythropoiesis in Cancer Patients Undergoing Immunotherapy

We studied ten patients with various types of cancer who were being treated with Interleukin-2 (IL-2) and lymphokine activated killer cells (LAK). All patients developed a reticulocytopenic, normochromic, normocytic anemia. We noted some variability but no significant suppression of circulating erythroid progenitors. The levels of erythropoietin were lower than expected for the hemoglobin/hematocrit values. We could not detect Interferon or Tumor Necrosis Factor (TNF) in the serum of these patients; however, the supernatant of LAK cells did contain Interferon and TNF which could be neutralized with appropriate antibodies. These results suggest that the etiology of this anemia is multi-factorial. Administration of recombinant erythropoietin (Ep) may be of benefit in some of these patients.

Effect of pharmacological purging on natural killer cell number and activity in human bone marrow

We assayed natural killer (NK) cell activity and phenotype from human bone marrow (BM) following purge with 4-hydroperoxycyclophosphamide (4HC) at 60 micrograms/ml for 30 min in vitro. In all cases studied, lytic activity against the K562 cell line was either significantly decreased or abolished following 4HC purge. Although NK activity was significantly affected by 4HC treatment, no major differences in the phenotype between the purged and unpurged population were seen. Further, while in vitro culture of BM with IL2 resulted in a significant increment of NK activity, no IL-2 responsive cells were found in the 4HC purged BM after 14 days of culture. This study demonstrates that pharmacological purging of bone marrow results in a persistent functional decline of NK cell activity and may serve as a useful model for the study of the ontogeny of NK cells.