Induction of Fc gamma R-III (CD16) expression on neutrophils affected by paroxysmal nocturnal haemoglobinuria by administration of granulocyte colony-stimulating factor

Effects of Granulocyte Colony-Stimulating Factor on Opsonin Receptor Expression and Neutrophil Antibacterial Activity in a Mouse Model of Severe Acute Pancreatitis

The antimicrobial function of neutrophils, which is dependent on opsonin receptors, deteriorates in severe acute pancreatitis (SAP). Granulocyte colony-stimulating factor (G-CSF) putatively enhanced levels of the opsonin receptors CD11b and CD32/16 in healthy human subjects, and provided protection against infection in animal models of SAP. A statistically convincing study of the effect of G-CSF on CD32/16 expression in an SAP model is lacking. We used a mouse model of SAP to investigate the association between G-CSF administration and CD32/16 levels on neutrophils and bacterial translocation. G-CSF or saline was subcutaneously injected into SAP-induced mice. The pancreases were histologically examined, and leukocytes were stained to count neutrophils. The expression of CD11b and CD32/16 on neutrophils was measured by flow cytometry, and bacterial translocation was observed by bacterial culture. The numbers of CD11b and CD32/16-positive neutrophils were significantly elevated in the SAP mice treated with G-CSF, and the mean fluorescence intensities of these receptors on neutrophils were significantly elevated. Bacterial translocations to cavity organs were suppressed from 17% to 6% by G-CSF treatment. Our results indicated that the number of neutrophils significantly increased with increasing expression of CD11b and CD32/16 and their mean fluorescence intensities (MFIs). This inhibited bacterial translocation to other organs. These results are in accord with other studies in SAP dogs and SAP mice. Our findings suggest that G-CSF was effective in protecting against bacterial infection in SAP mice.

Natural killer cell differentiation from hematopoietic stem cells: a comparative analysis of heparin- and stromal cell-supported methods

Natural killer (NK) cells differentiated from hematopoietic stem cells (HSCs) may have significant clinical benefits over NK cells from adult donors, including the ability to choose alloreactive donors and potentially more robust in vivo expansion. Stromal-based methods have been used to study the differentiation of NK cells from HSCs. Stroma and cytokines support NK cell differentiation, but may face considerable regulatory hurdles. A recently reported clinical-grade, heparin-based method could serve as an alternative. How the stromal-based and heparin-based approaches compare in terms of NK cell generating efficiency or function is unknown. We show that compared with heparin-based cultures, stroma significantly increases the yield of HSC-derived NK cells by differentiating less-committed progenitors into the NK lineage. NK cells generated by both approaches were similar for most NK-activating and -inhibiting receptors. Although both approaches resulted in a phenotype consistent with CD56(bright) stage IV NK cells, heparin-based cultures favored the development of CD56(+)CD16(+) cells, whereas stroma produced more NK cell immunoglobulin-like receptor-expressing NK cells, both of which are markers of terminal maturation. At day 21, stromal-based cultures demonstrated significantly more IL-22 production, and both methods yielded similar amounts of IFN-γ production and cytotoxicity by day 35. These findings suggest that heparin-based cultures are an effective replacement for stroma and may facilitate clinical trials testing HSC-derived NK cells.

A patient with paroxysmal nocturnal haemoglobinuria in whom granulocyte colony-stimulating factor administration resulted in improvement of recurrent enterocolitis and its associated haemolytic attacks

We report an elderly patient with paroxysmal nocturnal haemoglobinuria (PNH), having recurrent enterocolitis and haemolytic attacks associated with cellular immunodeficiency. On admission, the patient had normal neutrophil count and function but a decreased T-cell count, decreased mitogenic reactions, and a negative tuberculin test. Granulocyte colony-stimulating factor (G-CSF) was administered, resulting in an increased T-cell count, normalization of T-cell function, increased blood levels of helper T cell (Th)1 and Th2 cytokines and improvement in the enterocolitis and haemolytic attacks. This suggests that G-CSF may be useful in the treatment of elderly PNH patients with cellular immunodeficiency.

Circulating Primitive Stem Cells in Paroxysmal Nocturnal Hemoglobinuria (PNH) Are Predominantly Normal in Phenotype But Granulocyte Colony-Stimulating Factor Treatment Mobilizes Mainly PNH Stem Cells

Paroxysmal nocturnal hemoglobinuria (PNH) is an acquired hemolytic anemia resulting from a somatic mutation in a hemopoietic stem cell. In most cases of hemolytic PNH, the majority of the marrow cells are derived from the PNH clone. Recent evidence has indicated, however, that the majority of the most primitive peripheral blood stem cells (PBSCs) in PNH appear to be of normal phenotype. This has led to tentative suggestions that normal PBSCs could be collected and used for autologous transplantation. We have investigated this possibility in four PNH patients by treating them with granulocyte colony-stimulating factor (G-CSF) in an attempt to mobilize normal progenitors. The expression of glycosylphosphatidylinositol (GPI)-linked proteins was analyzed by flow cytometry on mature neutrophils, late stem cells (CD34+/CD38+), and primitive stem cells (CD34+/CD38−). The phenotyping and stem cell quantitation was performed in steady-state blood and post–G-CSF administration. The most primitive PBSCs (CD34+/CD38−) were almost all normal before G-CSF treatment, even when the patients' neutrophils were mainly PNH. However, after G-CSF, the cells that were mobilized into the peripheral blood were of a similar phenotype to the mature neutrophils, ie, mainly PNH. It is possible that PNH-stem cells are preferentially destroyed by complement in the peripheral blood leaving only normal cells in the circulation. After G-CSF, the PNH cells in the marrow are released into the blood. Our findings suggest that it would be difficult to collect sufficient numbers of normal stem cells for autologous transplantation.

Circulating Primitive Stem Cells in Paroxysmal Nocturnal Hemoglobinuria (PNH) Are Predominantly Normal in Phenotype But Granulocyte Colony-Stimulating Factor Treatment Mobilizes Mainly PNH Stem Cells

Paroxysmal nocturnal hemoglobinuria (PNH) is an acquired hemolytic anemia resulting from a somatic mutation in a hemopoietic stem cell. In most cases of hemolytic PNH, the majority of the marrow cells are derived from the PNH clone. Recent evidence has indicated, however, that the majority of the most primitive peripheral blood stem cells (PBSCs) in PNH appear to be of normal phenotype. This has led to tentative suggestions that normal PBSCs could be collected and used for autologous transplantation. We have investigated this possibility in four PNH patients by treating them with granulocyte colony-stimulating factor (G-CSF) in an attempt to mobilize normal progenitors. The expression of glycosylphosphatidylinositol (GPI)-linked proteins was analyzed by flow cytometry on mature neutrophils, late stem cells (CD34+/CD38+), and primitive stem cells (CD34+/CD38−). The phenotyping and stem cell quantitation was performed in steady-state blood and post–G-CSF administration. The most primitive PBSCs (CD34+/CD38−) were almost all normal before G-CSF treatment, even when the patients' neutrophils were mainly PNH. However, after G-CSF, the cells that were mobilized into the peripheral blood were of a similar phenotype to the mature neutrophils, ie, mainly PNH. It is possible that PNH-stem cells are preferentially destroyed by complement in the peripheral blood leaving only normal cells in the circulation. After G-CSF, the PNH cells in the marrow are released into the blood. Our findings suggest that it would be difficult to collect sufficient numbers of normal stem cells for autologous transplantation.

Stimulation of thrombocytopoiesis decreases platelet beta2 but not beta1 or beta3 integrins

The expression of CD29, CD61, CD18 and CD11a on platelets was examined by flow cytometry in mice treated with leukaemia inhibitory factor (LIF) or megakaryocyte growth and development factor (PEG-rHuMGDF or mpl-ligand). Treatment for 7-14 d with PEG-rHuMGDF or LIF increased the number of platelets in peripheral blood from 0.9 up to <2.0 x 10(6)/microl. These treatments decreased the expression of CD11a and CD18, whereas that of CD29 or CD61 was not markedly changed. Study after various doses or times of PEG-rHuMGDF administration indicated that a decrease of CD18 expression occurred when platelet counts started to rise. Platelet RNA content was increased in mice treated with PEG-rHuMGDF but double staining indicated that expression of CD18 was not correlated with RNA content. To evaluate integrin expression as a function of time in circulation, platelets were biotinylated in vivo. In normal or PEG-rHuMGDF-treated mice, the expression of CD29 or CD61 did not change, whereas that of CD18 decreased significantly as a function of time in circulation. These findings indicate, firstly, that stimulation of thrombocytopoiesis leads to the release of platelets with a low content of beta2 integrin and, secondly, that this integrin is also selectively lost while in the circulation.