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Bone marrow (BM) is a frequent site of metastasis in children with neuroblastoma (NB). Nonhematopoietic cell lines of the same neuroectodermal origin produce both stem cell factor (SCF) and its receptor, the product of the c-kit protooncogene (c-kit). Because recombinant SCF is likely to be soon clinically tested to accelerate BM recovery after high-dose chemotherapy, a treatment administered to children with disseminated NB, we addressed the question of whether SCF/c-kit complex could play a role in the proliferation and metastasis of NB cells. Northern blot analysis showed SCF mRNA transcripts in 7 of 8 (88%) NB cell lines and c-kit in 1 (13%). Neither c-kit nor SCF could be detected by Western blotting in cell extracts or by surface immunofluorescence and flow cytometry. Soluble SCF protein was detected by enzyme immunoassay at low concentrations in the cell supernatants in the same 7 NB cell lines. Treatment of 4 NB cell lines by SCF +/- cytokines relevant to BM physiology did not induce c-kit antigenic expression or modulate 3H-thymidine uptake. Likewise, the latter was not changed by incubating the cells with anti-c-kit neutralizing antibodies. Immunohistochemical analysis showed weak diffuse or focal staining for SCF and c-kit in few primary or metastatic tumor samples, only once simultaneously. We conclude that NB cell lines usually produce low levels of soluble SCF but do not express c-kit and that both proteins are rarely detected in NB tumors. The SCF/c-kit complex appears to be unlikely to stimulate NB growth or metastasis; thus, recombinant SCF could be safely administered to children with NB.

The relation of acute thrombocytopenic purpura (TP) to the use of drugs was investigated in a case-control study conducted in eastern Massachusetts, Rhode Island, and the Philadelphia region; 62 cases over the age of 16 years with acute onset and with a rapid recovery were compared with 2,625 hospital controls. After control for confounding by multiple logistic regression, use of the following drugs in the week before the onset of symptoms was significantly associated: trimethoprim/sulfamethoxazole (relative risk [RR] estimate, 124), quinidine/quinine (101), dipyridamole (14), sulfonylureas (4.8), and salicylates (2.6). The overall annual incidence of acute TP was estimated to be 18 cases per million population. The excess risks for the associated drugs were estimated to be 38 cases per million users of trimethoprim/sulfamethoxazole per week, 26 per million for quinidine/quinine, 3.9 per million for dipyridamole, 1.2 per million for sulfonylureas, and 0.4 per million for salicylates. Associations with sulfonamides, quinidine/quinine, sulfonylureas, and salicylates have been previously reported, but the present study has provided the first quantitative measures of the risk. The association with dipyridamole was unexpected. In general, despite large RRs, the incidence rates attributable to the drugs at issue (excess risks) were low, suggesting that TP is not an important consideration in the use of the various drugs.

Effective granulocyte transfusion (GT) therapy has been hampered by the low yield of neutrophil granulocytes (PMN) obtainable from normal donors even by use of corticosteroid prestimulation, hydroxyethyl starch (HES), and modern leukapheresis (LA) techniques. To increase the PMN yield we performed LA in 22 healthy volunteer donors after a single subcutaneous administration of 300 micrograms of granulocyte colony- stimulating factor (G-CSF) 12 to 16 hours before LA. Five to 7 L of blood was processed within 1.9 to 3 hours using the standard CS- 3000Plus (Baxter, Deerfield, IL) LA protocol including HES. The mean number of PMN harvested was 44.32 +/- 15.5 x 10(9), corresponding to 6.88 +/- 2.1 x 10(9)/L of blood processed. In the final product PMN functions (in vitro: chemotaxis, phagocytosis, chemiluminescence, superoxide anion production; in vivo: chemiluminescence, half-life) were at least normal. In all donors G-CSF induced a consistent increase of white blood cell (mean 16.46 +/- 3.8 x 10(9)/L) and PMN counts (15.94 +/- 3.6 x 10(9)/L). No G-CSF-related side effects were observed and LA was well tolerated. G-CSF prestimulation allows to harvest three to five times higher numbers of functionally normal PMN by LA compared with corticosteroid pretreatment. This may help to overcome one of the major limitations of an effective PMN support.

IL-6-PE4E is a recombinant protein consisting of interleukin-6 (IL-6) fused to a mutant form of Pseudomonas exotoxin in which four basic amino acids are changed to glutamate (PE4E). The chimeric toxin has been previously shown to specifically kill malignant hepatic, prostatic, epidermoid, and myeloma cell lines in vitro. To explore the possible clinical utility of IL-6-PE4E, particularly as an agent for ex vivo purging of marrow for autologous bone marrow transplantation (ABMT), we tested malignant cells from patients with multiple myeloma for sensitivity to this chimeric toxin. Ficoll-purified bone marrow cells were incubated with and without IL-6-toxin for 2 to 3 days. Eight of the 15 myeloma patients had cells that were sensitive to IL-6-toxin as measured by a decrease in the level of protein synthesis. Cells from five patients were very sensitive to IL-6-PE4E, with 50% inhibition of protein synthesis (ID50) achieved at or below 6 ng/mL (7 x 10(-11) mol/L). Cells from three additional patients showed moderate sensitivity, with ID50s between 30 and 140 ng/mL. The remaining seven samples showed little or no sensitivity, with ID50s greater than or equal to 400 ng/mL. Normal bone marrow cells or normal BFU-E and CFU-GM were resistant to the IL-6-toxin even at 1,000 ng/mL. Neither IL-6, IL- 2-PE4E, nor an enzymatically deficient mutant of IL-6-PE4E was cytotoxic toward the myeloma cells, indicating that the cytotoxic effect of IL-6-PE4E required the adenosine diphosphate-ribosylation function as well as the specific ligand. Our data suggest that IL-6- toxin could be effective in ex vivo marrow purging in selected multiple myeloma patients who are candidates for ABMT, and that this toxin should also be investigated further for in vivo therapy.

Eight unrelated patients with recurrent thromboembolism, a family history of thrombosis, and plasma antithrombin III (ATIII) activity/antigen levels consistent with a diagnosis of heterozygous type I ATIII deficiency were studied by polymerase chain reaction/direct sequencing of ATIII gene exon-coding regions. Frameshift mutations of one base and two bases, respectively, were found to have occurred in two unrelated patients at the same GAG codon (Glu 245) within exon 4 of the ATIII gene. A literature search showed six further hitherto unrecognized deletion “hotspots” in four other human genes. These deletion-prone sites exhibited sufficient sequence homology with each other to derive a consensus sequence (T G A/G A/G G A/C), suggesting that deletion in human genes may not only be non- random but also sequence-directed.

Granulocyte-macrophage colony-stimulating factor (GM-CSF) is a glycoprotein that is required for the survival, growth, and differentiation of hematopoietic progenitor cells. Although the primary structure of GM-CSF is known from cDNA cloning, the relationship between structure and function of GM-CSF is not fully understood. Fifteen different monoclonal antibodies (MoAbs) to human GM-CSF were generated to map immunologically distinct areas of the molecule. Each of the MoAbs was biotinylated and shown by enzyme-linked immunosorbent assay to bind to recombinant GM-CSF that had been affixed to a solid phase. Each of the 15 unconjugated MoAbs was then used to compete with each biotinylated MoAb for binding to GM-CSF. These cross-blocking studies identified eight distinct epitopes of native GM-CSF. Seven of these epitopes were also present in denatured GM-CSF by Western blotting, and four of the epitopes were at least partially conserved on GM-CSF that was reduced in beta-mercaptoethanol. MoAbs to four of eight epitopes neutralized both recombinant (glycosylated and nonglycosylated) and natural human GM-CSF in a GM colony-forming unit (CFU-GM) assay and blocked GM-CSF-induced activation of neutrophils. For most of the antibodies there was a good correlation between neutralizing activity and the capacity to block binding of 125I-GM-CSF to neutrophils or blasts. Non-neutralizing antibodies to one epitope partially blocked binding of 125I-GM-CSF to neutrophils. None of the MoAbs neutralized interleukin-3, G-CSF, or M-CSF. The locations of seven of the epitopes could be partially mapped with regard to the amino acid structure by determining reactivity to GM-CSF synthetic peptides or to human-mouse chimeric GM-CSFs. The neutralizing antibodies were found to map to amino acids 40–77, 78–94, or 110–127. Thus, these MoAbs are useful to identify functional domains of GM-CSF and in identifying regions that are likely to be involved in receptor interaction.

The weak D phenotype is caused by many different RHD alleles encoding aberrant RhD proteins, raising the possibility of distinct serologic phenotypes and of anti-D immunizations in weak D. We reported 6 new RHD alleles, D category III type IV, DIM, and the weak D types 4.1, 4.2.1, 4.2.2, and 17. The immunohematologic features of 18 weak D types were examined by agglutination and flow cytometry with more than 50 monoclonal anti-D. The agglutination patterns of the partial D phenotypes DIM, D(III) type IV, and D(IV) type III correlated well with the D epitope models, those of the weak D types showed no correlation. In flow cytometry, the weak D types displayed type-specific antigen densities between 70 and 4000 RhD antigens per cell and qualitatively distinct D antigens. A Rhesus D similarity index was devised to characterize the extent of qualitative changes in aberrant D antigens and discriminated normal D from all tested partial D, including D category III. In some rare weak D types, the extent of the alterations was comparable to that found in partial Ds that were prone to anti-D immunization. Four of 6 case reports with anti-D in weak D represented auto-anti-D. We concluded that, in contrast to previous assumptions, most weak D types, including prevalent ones, carry altered D antigens. These observations are suggestive of a clinically relevant potential for anti-D immunizations in some, but not in the prevalent weak D types, and were used to derive an improved transfusion strategy in weak D patients. (Blood. 2000;95:2699-2708)

We used a unique animal model, the hypotransferrinemic (Htx) mouse, to examine the role of transferrin (Tf) in gastrointestinal iron uptake. Despite the absence of Tf, Htx animals hyperabsorb iron. Transfusion of red blood cells sufficient to normalize the hematocrit and reticulocyte count resulted in a return of iron absorption to normal values. These studies indicate that Tf does not play an obligate role in iron absorption, either as a carrier or as a humoral signal regulating absorption. Transfer of plasma or whole blood from Htx mice or from other animal models of iron hyperabsorption to normal mice did not cause an increase in iron absorption in recipient animals. Using the plasma or blood transfer approach, we have been unable to detect a humoral regulator of gastrointestinal iron absorption.

The topoisomerase (topo) II-directed agents etoposide, daunorubicin (DNR), and amsacrine (m-AMSA) are widely used in the treatment of acute myelogenous leukemia (AML). In the present study, multiple aspects of topo II-mediated drug action were examined in marrows from adult AML patients. Colony-forming assays revealed that the dose of etoposide, DNR, or m-AMSA required to diminish leukemic colony formation by 90% (LD90) varied over a greater than 20-fold range between different pretreatment marrows. Measurement of nuclear DNR accumulation in the absence and presence of quinidine revealed evidence of P-glycoprotein (Pgp) function in 8 of 82 samples at diagnosis and 5 of 36 samples at first relapse, but the largest quinidine-induced increment in DNR accumulation (< 2-fold) was too small to explain the variations in drug sensitivity. Restriction enzyme-based assays and sequencing of partial topo II alpha and topo II beta cDNAs from the most highly resistant specimens failed to demonstrate topo II gene mutations that could account for resistance. Western blotting of marrow samples containing greater than 80% blasts revealed that the content of the two topo II isoenzymes varied over a greater than 20-fold range, but did not correlate with drug sensitivity in vitro or in vivo. In addition, levels of topo II alpha and topo II beta in 46 of 47 clinical samples were lower than in human AML cell lines. Immunoperoxidase staining showed that these low topo II levels were accompanied by marked cell-to- cell heterogeneity, with topo II alpha being abundant in some blasts and diminished or absent from others. There was a trend toward increasing percentages of topo II alpha-positive cells in pretreatment marrows that contained more S-phase cells. Consistent with this observation, treatment of patients with granulocyte-macrophage colony- stimulating factor for 3 days before chemotherapy resulted in increases in topo II alpha-positive cells concomitant with increases in the number of cells traversing the cell cycle. These observations have implications for the regulation of topo II in AML, for the use of topo II-directed chemotherapy, and for future attempts to relate drug sensitivity to topo II levels in clinical material.

The membrane inhibitor of reactive lysis (MIRL) is an 18-Kd glycosyl phosphatidylinositol anchored membrane glycoprotein that inhibits the cytolytic activity of complement. MIRL is expressed by all hematopoietic elements and by a wide variety of nonhematopoietic tissues. A deficiency of MIRL is primarily responsible for the greater sensitivity of the erythrocytes of paroxysmal nocturnal hemoglobinuria to complement mediated lysis. Because of its critical role in protecting host cells from injury by complement, we hypothesized that mechanisms exist that allow MIRL expression to be regulated. To investigate this hypothesis, both MIRL RNA and MIRL protein expression were analyzed following exposure of K562 erythroleukemia cells to a variety of potential stimulants. Incubation with dexamethasone, calcium ionophore, lipopolysaccharide, interleukin 1, tumor necrosis factor, hemin, and cyclic AMP had no effect on MIRL expression. However, incubation with phorbol 12-myristate 13 acetate (PMA), induced a marked increase in MIRL RNA as determined by Northern blot analysis. This enhanced expression of MIRL RNA was associated with an increase in MIRL protein expression as determined by immunoprecipitation of metabolically labeled proteins, Western blot analysis, and immunobinding assay. Enhanced MIRL RNA expression was first detected after 8 hours and increased through 24 hours of observation. Inhibitors of either protein synthesis or transcription abrogated the PMA-induced enhancement of MIRL RNA expression. Together, these results are consistent with a model in which PMA induces synthesis of a trans acting protein that enhances transcription of the MIRL gene.

Human mast cells have been purified from uterine tissues, and their surface marker profile and function have been evaluated as part of ongoing studies of mast cell heterogeneity. Using a panel of antibodies, purified uterine mast cells (UMC; 81% +/- 7% purity, n = 10) were analyzed by immunofluorescence and flow cytometry for surface expression of various antigens. Consistent with previous analyses of mast cells from other tissues, UMC expressed HLA class I, IgE, c-kit receptor, CD9, CD33, CD43, CD45, and CD54, while CD11a, CD11b, CD14, CD16, CD23, and CD64 were not detected. Unlike other mast cells, UMC expressed CD11c/CD18 (p150,95) and CD32 (Fc gamma RII). Additional antigens not previously studied on mast cells included the selectin LECAM-1 (Leu-8) and several beta 1 and beta 3 integrins; expression of very late activation antigen-4 (VLA-4) (CD49d/CD29), VLA-5 (CD49e/CD29), and the vitronectin receptor (CD51/CD61) was seen. Functional studies showed that treatment of human umbilical vein endothelial cells with interleukin-1 (5 ng/mL for 4 hours) resulted in a twofold to threefold increase in adhesiveness for UMC. Purification procedures did not alter histamine release responses to anti-IgE or the calcium ionophore A23187, and treatment of UMC with an anti-CD32 monoclonal antibody (IV.3) did not induce histamine release or alter anti-IgE-induced release. These data suggest that UMC may possess unique phenotypic characteristics, and support the concept of mast cell heterogeneity.

Children receive busulfan orally as part of myeloablative therapy before bone marrow transplantation for malignant and nonmalignant conditions. Children have been reported to have a low incidence of severe toxicity and significant rates of failure to achieve full engraftment. We evaluated the disposition of busulfan in children between 2 months and 3.6 years of age with lysosomal storage diseases, leukemia, and immunodeficiency disorders receiving oral doses of 1 or 2 mg/kg using a gas chromatographic assay. Peak concentrations were lower than those previously reported for adults, ranging from 1.4 to 5.2 mumol/L. The harmonic mean of the elimination half-life was 92 minutes, which is only slightly faster than that for adults (140 minutes). However, the area under the curve ranged from 400 to 1,000 (715 +/- 240) mumol.min/L, substantially lower than in adults receiving 1 mg/kg (range, 710 to 5,100 mumol.min/L; mean +/- SD, 2,180 +/- 1,200). The apparent volume of distribution (assuming complete bioavailability) ranged from 0.28 to 3.53 L/kg (1.42 +/- 0.86), which is more than twice that reported for adults (0.60 +/- 0.42). Busulfan clearance rate normalized to surface area is twice as high in children (200 +/- 100 mL/min/m2) as it is in adults (95 +/- 54 mL/min/m2). Alterations in bioavailability (absorption or first pass elimination) or in actual volume of distribution may account for these differences in drug disposition. The observed differences suggest the need for separate phase I dose escalation studies in children with accompanying pharmacokinetic assessment.

Background & Objective: Dental implant requires osseointegration for anchoring and human’s oral cavity has plenty of bacterial oral flora. Whether these bacteria have any effects on the human mesenchymal Stem Cells (MSCs) that can differentiate into osteoblasts remains unknown. We therefore investigated the effect of bacterial endotoxins commonly found in the oral cavity and gastrointestinal tract, namely lipopolysaccharides (LPS, Escherichia coli) and lipoteichoic acid (LTA, Streptococcus pyogenes), on the proliferation and osteogenic differentiation of MSCs. Methods: Human MSCs are derived from bone marrow (BM) of normal healthy donors. The culture condition, immunophenotyping determination and tests of differentiating functions of the human MSCs were similar to what we reported previously (Li J, Br J Haematol 2004). The proliferation of MSCs under either a 3-day or a prolonged 7-day endotoxins challenge was evaluated by XTT assay. The extent of osteogenic differentiation was examined under microscopy and measured by the increase in alkaline phosphatase (ALP) activity at day 10 and the calcium mineralization/deposition per unit volume of protein at day 14. Results: There was no significant effect of LPS and LTA on the growth and proliferation of MSCs, even under a relatively high dose. However, continued LPS challenge on MSCs under osteogenic culture condition was shown to increase the ALP activity and calcium deposition in a dose-dependent manner (100ng/ml, 1 ug/ml, 10ug/ml). No such phenomenon can be identified when LTA challenge was used. Conclusions: LPS and LTA did not show any significant effect on the proliferation and growth of human MSCs. However, LPS enhanced the osteogenic differentiation of MSCs in a dose-dependent manner. Our finding suggests that the endotoxin from bacteria commonly found in the oral cavity and gut does not have any negative impact on MSCs induced osteogenesis.

Over an average span of one year, we performed a prospective clinical and immunologic evaluation of 30 patients with hemophilia. No patient developed life-threatening opportunistic infection or malignancy; however, the immunologic abnormalities and lymphadenopathy initially present in nine patients (lymphadenopathy group) persisted. In addition, five patients, representing 24% of the initial group without lymphadenopathy, developed generalized lymphadenopathy (converter group). One episode of idiopathic thrombocytopenia (ITP) and one episode of staphylococcal sepsis occurred in this “converter” group; one episode of ITP also occurred in the lymphadenopathy group. Sixteen patients remained asymptomatic. At the time of the follow-up evaluation, those differences in mononuclear cell (MNC) percentages and numbers noted initially among the three hemophiliac groups were no longer present. Natural killer cell function alone or in the presence of biologic response modifiers was not different among hemophiliac and control groups. Before developing lymphadenopathy, the converter group of patients had significantly better lymphocyte mitogenic function than did the other two groups of patients with hemophilia. However, lymphocyte mitogenic responses of all groups of patients with hemophilia significantly deteriorated over the course of the study. The abnormal mitogenic responses noted in these patients was explained in part by higher levels of spontaneous suppressor cell activity in mononuclear cell preparations from patients with hemophilia. We conclude that long-term immunologic studies of this patient population requires both quantitative and qualitative evaluations. Our data show that patients with hemophilia have progressive dysfunction of cell- mediated immunity.

The records of 415 patients who received allogeneic marrow transplants for acute leukemia were reviewed to assess the risk of central nervous system (CNS) relapse and leukoencephalopathy after marrow transplantation. The Kaplan-Meier estimates of the probability of CNS relapse posttransplant were 13% for patients with acute lymphoblastic leukemia (ALL) and 2% for patients with acute nonlymphoblastic leukemia (ANL). Previous CNS disease was significantly correlated with an increased risk of CNS relapse in patients transplanted for ALL but not for ANL. In contrast, bone marrow involvement with leukemia at the time of transplant was associated with an increased risk of CNS relapse in patients with ANL but not in patients with ALL. Seventy-one patients with ALL did not receive posttransplant intrathecal methotrexate (IT- MTX) and 127 did. The probability of CNS relapse in these two groups was 38% and 7%, respectively (P less than .02). This protective benefit from IT-MTX was present in patients both with and without a history of CNS involvement or marrow involvement at the time of transplant. In patients with ANL, 116 patients did not receive posttransplant IT-MTX and 101 patients did, but no protection from CNS relapse was observed from IT-MTX irrespective of a patient's previous CNS history or marrow status at the time of transplant. Leukoencephalopathy was seen exclusively in patients who had received radiation and/or intrathecal chemotherapy to the CNS before preparation for marrow transplantation and posttransplant IT-MTX. In such patients the risk of leukoencephalopathy was 7%. From our data, it appears that posttransplant IT-MTX is a significant benefit for ALL patients in preventing CNS relapse after marrow transplantation. A similar benefit from posttransplant IT-MTX for ANL patients cannot be established from this study. In both groups, increasing total CNS therapy was associated with an increasing risk of leukoencephalopathy.