Atsushi Komiyama

Development of Natural Killer Cytotoxicity during Childhood: Marked Increases in Number of Natural Killer Cells with Adequate Cytotoxic Abilities during Infancy to Early Childhood

ABSTRACT: The cytotoxicity of natural killer (NK) cells against X562 cells and their responsiveness to interferonα and interleukin 2 (IL-2) were studied throughout child-hood using 51Cr-release and single-cell assays. Although NK activity was extremely low in the neonatal period, it almost reached the adult level during 1 to 5 mo of age and remained at that level thereafter. At the single-cell level, the binding, lytic, and recycling abilities were also depressed in the neonatal period, but these abilities improved conspicuously after this period; in particular, the lysis and recycling were at higher levels during 6 mo to 4 y of age. The absolute numbers of circulating cytotoxic NK cells were high during infancy to early childhood: they were 54 ± 24 (mean ± SD/mm3) in neonates, 115 ± 48 in 1− to 5-mo-old infants, 121 ± 42 in 6− to 12-mo-old infants, 93 ± 26 in 1− to 4-y-old children, and 42 ± 16 in adults. Inter feron-α and IL-2 could enhance NK activity throughout childhood. The IL-2 enhancement was prominent especially in the neonatal period; IL-2 yielded a 2.5-fold in crease in the number of cytotoxic cells and improved the recycling to the adult level. At older ages, interferon-α and IL-2 yielded 1.4-and 1.9-fold increases in the number of eytotoxic cells, respecively, but did not enhance the recycling. The iacreased number of NK cells with adequate cytotoxic abilities during infancy to early childhood indicates the predominance of NK immunity during these periods. IL-2 is a cytokine that induces high levels of NK cytotoxicity even in neonates.

Leukemia and other malignancies among GH users.

The number of reported cases of leukemia developing in growth hormone (GH) users worldwide has reached 31. Twelve Japanese cases are briefly reviewed; five each of AML and ALL, and one each of CML and malignant histiocytosis. The underlying diseases of these patients consisted of 8 idiopathic disease, 3 tumors and one Fanconis anemia. Leukemia occurred during GH treatment in 9 cases and after cessation of GH in 3. The longest interval from the cessation of GH therapy was 10 years. GH administration from a younger age tended to be linked to myeloid type. Risk factors and possible mechanisms of leukemogenesis by growth hormone are discussed, and proposals for the future have been made by the Foundation for Growth Science in Japan.

T-cell-dependent production of IgG by human cord blood B cells in reconstituted SCID mice

Reconstitution of severe combined immunodeficient (SCID) mice with human lymphocytes has recently allowed the elucidation of abnormalities of immune responses in various immunological disorders. In the present study, mononuclear cells (MNC) from neonatal cord blood and adult peripheral blood were intraperitoneally injected into SCID mice to examine induction of human Ig in respective mice recipients. Human IgG was consistently detected in the serum of SCID transferred with adult MNC, but only a few SCID recipients of cord blood MNC showed detectable but low levels of IgG in the serum. The combination experiments of isolated B and T cells disclosed that some interactions between B and T cells might be necessary for IgG production in transferred SCID mice. Notably, transfer of cord blood B cells with adult but not cord blood T cells resulted in efficient induction of IgG, associated with a change in subclass distribution. The results suggest that inability of neonatal B cells to produce IgG can be overcome by transfer with adult mature T cells into SCID mice.

Improvement of neutropenia and neutrophil dysfunction by granulocyte colony-stimulating factor in a patient with glycogen storage disease type Ib

Patients with glycogen storage disease type Ib (GSD Ib) suffer from recurrent bacterial infections due to neutropenia and neutrophil dysfunction. To improve the quality of life in a 9-year-old boy with GSD Ib, we subeutaneously administered recombinant human granulocyte colony-stimulating factor (G-CSF). Daily injections of 100 μg/m2 of G-CSF significantly increased absolute neutrophil counts and augmented neutrophil mobility. The patient was then treated with 70 and 100 μg/m2 of G-CSF daily and twice-weekly. The treatment maintained absolute neutrophil counts at significantly higher levels than those without treatment for 22 months and markedly decreased the frequency of infections and the necessity for hospitalisation. No adverse effects were observed during treatment. These findings indicate that daily and twice-weekly treatment with G-CSF of long duration are safe and effective for patients with GSD Ib. G-CSF may be a useful therapeutic agent in patients with neutrophilic impairment as a consequence of a metabolic disorder.

Induction of granulocyte and granulocyte-macrophage colony-stimulating factors from human monocytes stimulated by Fc fragments of human IgG

The effect of human IgG on human haemopolesis has been studied in vitro. Dialysed purified IgG stimulated haemopoletic colony growth by bone marrow mononuclear cells (MNC) but not by monocyte‐depleted MNC. Culture media, conditioned by IgG‐stimulated peripheral blood MNC, augmented formation of neutrophil‐macrophage, eosinophil, and megakaryocyte colonies by monocyte‐depleted marrow MNC. Serum‐free IgG‐conditioned media also contained colony‐stimulating activity (CSA). IgG Fc fragments and heat‐aggregated IgG promoted the secretion of CSA, but F(ab′)2 fragments, Fab fragments or ultracentrifuged IgG did not. In the cell‐selection studies, CSA was produced by highly enriched monocytes following stimulation with Fc fragments. The antiserum against human granulocyte colony‐stimulating factor (G‐CSF) and/or granulocyte‐macrophage CSF (GM‐CSF) neutralized the CSA produced by Fc fragment‐activated monocytes. Enzyme immunoassays showed G‐CSF and GM‐CSF in media conditioned by monocytes stimulated with the Fc fragments, heat‐aggregated IgG and anti‐D‐sensitized red blood cells (RBC). Northern hybridization analysis showed mRNA encoding G‐CSF and GM‐CSF in RNA extracted from MNC and monocytes cultured with the Fc fragments, but not in the RNA from unstimulated cells or monocyte‐depleted MNC. These results indicate that IgG Fc fragments, aggregated IgG and antigen‐antibody complexes induce monocytes to produce G‐CSF and GM‐CSF in vitro. The CSFs release induced by IgG may be involved in the in vivo regulatory network in haemopoiesis.

Transient abnormal myelopoiesis and diffuse hepatic necrosis in Down's syndrome with prominent bleeding diathesis.

ABSTRACT. The first case known to us with Downs syndrome with transient abnormal myelopoiesis and diffuse hepatic necrosis is reported. The infant had prominent bleeding diathesis and hepatosplenomegaly. She died on the 7th day because of intractable bleeding. The autopsy disclosed extramedullary hematopoiesis and extensive hepatic cell necrosis. Characteristic in our case was the outstanding bleeding diathesis due to coagulopathy.

Ki-1 Positive Large Cell Anaplastic Lymphoma: Multiple Bone Lytic Lesions and Interleukin-6

Ki-1-positive large cell anaplastic lymphoma (Ki-1 LCAL) is recognized as a clinicopathologic syndrome with fever, peripheral lymphadenopathy and cutaneous nodules; the neoplastic cells express Hodgkins disease-associated antigen, Ki-1 (CD30). We review here a recent case of Ki-1 LCAL with multiple bone lesions with destruction and present additional information. Although bone absorption is reported in some cases of Ki-1 LCAL, the genesis of bone absorption is unclear. Interleukin-6 (IL-6) is an important regulator of osteoclast formation and activation and can induce bone absorption. In our case, the surgically removed tumor tissue was studied for IL-6 mRNA expression and IL-6 secretion without any stimulation. Northern blot analysis showed strong IL-6 mRNA expression in the tumor tissue and ELISA assay showed a large amount of IL-6 in culture supernatants of the tumor tissue. Based on these results, coupled with the reported evidence, we discuss the close relationship between the presence of osteolytic lesions and IL-6 production in Ki-1 LCAL.

Castleman's Disease and Interleukin 6

Castlemans disease is a rare condition characterized by benign hyperplastic lymph nodes. Based on the morphological features, it has been divided into hyaline-vascular, plasma cell and intermediate types. The latter two types are frequently associated with a wide variety of clinical pictures such as fever, anemia with hypotransferrinemia, hyperimmunoglobulinemia and an increase in the concentration of C-reactive protein (CRP). Although immunological disturbances have been suggested to play important roles in the pathophysiology of Castlemans disease, the precise mechanisms for the generation of its clinical pictures are still unsettled. In this respect, we have reported a pediatric case with spontaneous production of high levels of B cell differentiation factor (BCDF) activity by the hyperplastic lymph node, and we demonstrated here the strong expression of interleukin 6 (IL-6) gene in the lymph node cells. On the other hand, recent studies have revealed that IL-6 is a multifunctional cytokine; IL-6 not only induces the immunoglobulin production but also induces the acute phase reaction, and functions as an endogeneous pyrogen. In the acute phase reaction, IL-6 may induce an increase in CRP concentration and hypotransferrinemia. These studies indicate that the overproduction of IL-6 by the hyperplastic lymph node may be closely related to the pathophysiology of Castlemans disease. Therefore, it is considered that this disease is a disorder of IL-6 production.

Trisomy 14 in refractory anemia with excess blasts in transformation

Abstract We present a case of an 18-year-old patient with refractory anemia with excess blasts in transformation (RAEB-t). Trisomy 14 was the only abnormality found in bone marrow cells on five occasions in 15 months.

Decrease in number of CD16(LEU 11)+CD45RA(2H4)+ cells and defective production of natural killer cytotoxic factor in childhood acute lymphoblastic leukemia

CD16 or CD45RA is known to be a functional molecule, which provides activation signals in natural killer (NK) cells or T cells, respectively. To dissect the decreased NK activity in childhood acute lymphoblastic leukemia (ALL), the expression of CD16 (Leu 11) or CD45RA (2H4) and the production of natural killer cytotoxic factor (NKCF) were investigated. CD16+ cells or CD45RA+ cells in peripheral blood lymphocytes were not decreased as compared with controls, however, CD16+CD45RA+ cells in ALL (4%) were lower (p less than 0.05) than controls (17%). The production of NKCF in ALL patients (9.2%) was lower (p less than 0.05) than controls (16.5). These data suggest that the decreased NK activity in ALL patients can be attributable at least in part to the functional impairment of NK cells to produce NKCF.