Takefumi Ishii

A combination of stem cell factor and granulocyte colony-stimulating factor enhances the growth of human progenitor B cells supported by murine stromal cell line MS-5

We have developed a long‐term culture system using the murine bone marrow stromal cells MS‐5 to support the growth of progenitor B cells with CD34–, CD10+, CD19+, and cytoplasmic μ chain (Cμ)‐negative surface phenotype from human CD34+ cells purified from umbilical cord blood (CB). When 103 CB CD34+ cells/well were seeded on MS‐5 stromal cells at the beginning of culture in the absence of exogenously added cytokines, progenitor B cells first appeared after 14 days, and the maximal cell production was achieved during the 6th week of culture. Intriguingly, the addition of recombinant human stem cell factor (rhSCF) and granulocyte colony‐stimulating factor (rhG‐CSF), but not rhIL‐7, strikingly enhanced the growth of progenitor B cells from CB CD34+ population cultured on MS‐5 stromal cells. The culture of progenitor B cells could be maintained until the 6th week of culture when some cells were revealed to have a Cμ+ phenotype, and a small number of cells had immunoglobulin μ chain on their cell surface in the presence of both rhSCF and rhG‐CSF. When CD34+ cells were cultured physically separated from the stromal layer by membrane, supportive effects of MS‐5 stromal cells for the growth of progenitor B cells were not observed. These results suggest that the present culture system could generate progenitor B cells to proliferate from CB CD34+ cells, that some of these progenitor B cells could differentiate into immature B cells in conjunction with rhSCF and rhG‐CSF, and that a species‐cross‐reactive membrane‐bound factor(s), which stimulates early human B lymphopoiesis, may exist in MS‐5 stromal cells. Further studies are required to investigate the mechanism how rhG‐CSF acts on progenitor B cells to allow their proliferation and differentiation.

Improvement in bronchiolitis obliterans organizing pneumonia in a child after allogeneic bone marrow transplantation by a combination of oral prednisolone and low dose erythromycin

We report a 13-year-old boy who developed dyspnea at rest 1 year after the occurrence of cGVHD following an allogeneic bone marrow transplant (BMT). Pulmonary function data, imaging studies, lung biopsy, and bronchoalveolar lavage were consistent with the diagnosis of bronchiolitis obliterans organizing pneumonia (BOOP). Although reports suggest that oral methylprednisolone or methylprednisolone pulse therapies improve BOOP after BMT, we treated our patient with a combination of oral prednisolone (1 mg/kg) and low dose erythromycin (10 mg/kg) to avoid the side-effects of high-dose steroids. With this therapy, our patient showed clinical and radiological improvements within 1 week. The steroids were tapered off 12 months later and erythromycin was given for 14 months. We conclude that therapy consisting of a combination of oral prednisolone and low-dose erythromycin for BOOP after BMT may minimize the dose and duration of steroid use. Bone Marrow Transplantation (2000) 26, 907–910.

Haemophagocytic lymphohistiocytosis in association with granular lymphocyte proliferative disorders in early childhood: characteristic bone marrow morphology

Five paediatric cases of haemophagocytic lymphohistiocytosis (HLH) which showed proliferation of granular atypical lymphocytoid cells in bone marrow are reported. All cases were girls aged 8 months to 4 years who had marked hepatosplenomegaly. Marker analysis on peripheral blood mononuclear cells revealed an increase in the CD3+HLADR+ subset in three cases and the CD3−CD56+ subset in one case. An Epstein‐Barr virus genome was detected in three cases, and monoclonality was confirmed in two cases. A characteristic morphology of large granular lymphocytes (LGL) was identified, with elongated bizarre features that resembled horsetail‐, tadpole‐, cucumber‐ or shooting star‐type configurations on the bone marrow smear. Serum concentrations of soluble interleukin‐2 receptor and interferon‐gamma were elevated in all cases. All five cases required multi‐agent chemotherapy which resulted in two complete remissions, two partial remissions and one no response. Refinement of treatment is required for these paediatric GLPD cases which probably comprise a specific high‐risk subgroup among secondary HLH patients which had previously escaped notice.

Prompt and durable hematopoietic reconstitution by unrelated cord blood transplantation in a child with Fanconi anemia

We describe here the case of an 8-year-old girl with Fanconi anemia (FA) whose hematopoiesis was successfully restored by unrelated umbilical cord blood (UCB) transplantation. The patient became resistant to androgen therapy, and developed intracranial hemorrhage and dyserythropoiesis. Her hematopoietic recovery after the transplantation was excellent and a complete chimerism has been durably maintained. UCB should be considered as a stem cell source for transplantation when a patient with FA does not have an HLA-identical unaffected sibling donor. Bone Marrow Transplantation (2001) 27, 767–769.

Treatment with Candesartan Combined with Angiotensin-Converting Enzyme Inhibitor for Immunosuppressive Treatment—Resistant Nephrotic Syndrome after Allogeneic Stem Cell Transplantation

Most cases of nephrotic syndrome following stem cell transplantation (SCT) occur 6 months after SCT. The patients are treated with immunosuppressive therapies; however, in some cases treatment is not effective. We used enalapril, an angiotensin-converting enzyme inhibitor (ACEI) and candesartan, an angiotensin II receptor blocker (ARB), for the control of proteinuria in a case of immunosuppressive treatment (IST)-resistant nephrotic syndrome. A 15-year-old boy with acute lymphoblastic leukemia underwent allogeneic peripheral blood SCT from a completely HLA-matched sibling after completion of a conditioning regimen composed of 12-Gy doses of total-body irradiation, 600 mg/m2 thiotepa, and 140 mg/m2 melphalan. Twenty-eight months after SCT, minimal-change nephrotic syndrome was diagnosed on the basis of biopsy findings. Although neither cyclosporine (trough level, 100–150 ng/mL) nor corticosteroid was effective, proteinuria disappeared 2 months after the beginning of treatment with tacrolimus (trough level, 13–20 ng/mL), and remission was maintained for 23 months. Nephrotic syndrome recurred, however, and was resistant to tacrolimus. Findings at the second renal biopsy revealed membranous nephropathy. An ARB (candesartan, 4 mg/day) in combination with an ACEI (enalapril, 5 mg/day) was started. Proteinuria improved within 2 weeks.We suggest that ARB combined with ACEI can be used to control proteinuria in patients with IST-resistant nephrotic syndrome after SCT.