High-dose intravenous gammaglobulin (IVIgG) was given to 12 children and adults with chronic idiopathic thrombocytopenic purpura (ITP) to avoid splenectomy or because they either failed to respond to ...or required maintenance with high doses of steroids and/or immunosuppressives. The average platelet count increase to initial therapy was 239,500/μ1 (range 23,000–790,000). A concomitant IgG Fc receptor blockade, measured by IgG-sensitized 51Cr-labeled autologous erythrocytes, was seen in 11 of 11 patients tested, both splenectomized and not splenecto-mized, lasting 3–4 wk. Six or more months after treatment, 2 children are in remission, 2 children and 2 adults are stable requiring no therapy with platelet counts of approximately 50,000 and 30,000, respectively, 3 children require maintenance IVIgG therapy at 2–10-wk intervals, and 1 child and 2 adults have become refractory to further IVIgG. Splenectomy was not performed in 4 children. Two adults were able to discontinue daily prednisone. The 3 patients who became unresponsive to Swiss Red Cross gammaglobulin (IgSRK) therapy did so in conjunction with a markedly elevated platelet-associated IgG and IgM. Serum IgM increased an average of 103 mg/dl after the IVIgG infusions. No significant side effects were seen.
The association of platelets with leukocytes was investigated, using gel-filtered platelets stimulated with thrombin and then fixed with formaldehyde. Evidence is presented that stimulation of ...gel-filtered platelets with low concentrations of thrombin (0.01 to 0.1 U/mL) induces the expression of surface determinants interacting strongly with monocytes and polymorphonuclear leukocytes (PMNs) but only weakly with lymphocytes. Both monocyte-platelet binding and PMN-platelet binding occurred at 37 °C and more intensively at 0 °C; it was Ca2+-dependent and was unaffected by the addition of sodium azide. The binding also occurred with the monocytoid cell lines HL 60 and U 937 in exponential growth and was much less two days after induction of terminal differentiation by phorbol myristate acetate (PMA). No other tested cell lines (B cells, T cells, and myeloid cells) bound thrombin-stimulated platelets. Monocyte-derived macrophages kept in culture for one week also exhibited reduced binding of thrombin-stimulated platelets. IgG and fibronectin could be ruled out as ligands that mediate binding.
Intravenous gammaglobulin (IVIgG) was used to treat autoimmune neutropenia of infancy in two males with repeated infections. The neutrophil count increased significantly in both patients with the ...initial IVIgG therapy; 1 patient went into remission. The neutrophil count in the other remained above baseline for 3 wk, and a subsequent booster infusion also caused the neutrophil count to increase. The patients have remained clinically well since their treatment began. Serial studies of antineutrophil antibody and serum lysozyme, performed to elucidate the mechanism of action, suggested decreased neutrophil destruction, perhaps by Fc receptor blockade, as well as decreased synthesis of antineutrophil antibody. Neutrophil function was not impaired after the neutrophil count increased. Many patients with immune neutropenia have a benign course, but those who have significant infections could be treated, acutely or prophylactically, with intravenous gammaglobulin.
The activity of plasma membrane marker enzymes which are involved in purine metabolism (5'-nucleotidase, alkaline 5'-nucleotide phosphodiesterase), in active ion transport (Na-K-Mg-adenosine ...triphosphatase, ouabain-sensitive Na-K-adenosine triphosphatase), in aminoacid transport (gamma-glutamyltranspeptidase), and in basic physiologic functions (alkaline phosphomonoesterase) were assayed in mononuclear cells isolated from peripheral blood of normal donors and of patients with primary immunodeficiency. Irrespective of the clinical classification of the immunodeficiency, the cells of patients were characterized by significantly diminished 5'-nucleotidase and to a certain extent by lower alkaline phosphomonoesterase activities. Average activity levels of other enzymes were similar in cells of patients and controls, but scattering was more pronounced in the first group. Determination of substrate affinity revealed different kinetic properties of 5'-nucleotidase in cells from patients and normal donors; however, the extent of inhibition by beta-glycerophosphate or alpha, beta-adenosine-methylene diphosphate was comparable for both types of cells. The presence of inhibitory compounds in patients' serum was excluded by mixing experiments. When activities of the various plasma-membrane-associated enzymes were compared with each other, significant correlations emerged in normal lymphocytes. Most of these correlations were absent in cell membranes of immunodeficient patients. The findings indicate that the plasma membrane of lymphocytes from patients with immunodeficiency may be characterized by an altered distribution of enzymatic constituents.
Intravenous gamma-globulin (IVGG) effectively elevates the platelet count of most patients with chronic idiopathic thrombocytopenic purpura (ITP). This study examined whether this effect was related ...to changes in in vitro immunoglobulin secretion and suppression in coculture. Before treatment, patient in vitro immunoglobulin secretion was less than 50% of the concurrent control in all eight cases and the patients suppressed antibody synthesis in coculture an average of 39%. After treatment, increases in in vitro immunoglobulin secretion and decreases in suppression were closely related to a good response to IVGG therapy as measured both by acute increases in the platelet count (P less than 0.05) and by the long-term outcome from therapy (P less than 0.05). Decreases in platelet-associated IgG correlated with increases in in vitro immunoglobulin secretion (P less than 0.05). Data consistent with the lack of inhibition of in vitro immunoglobulin secretion following IVGG included long-term increases in both serum IgM and IgG (independent of transfused IgG) and maintenance of the percentage of total IgG that was IgG3. T-cell numbers and subsets and lymphocyte proliferation were unaffected by IVGG. IVGG tends to normalize in vitro immunoglobulin secretion and its suppression in those ITP patients with good clinical responses in conjunction with decreased levels of autoantibody. This evidence suggests that good responders to IVGG may have inhibition of antiplatelet antibody production. IVGG does not appear to interfere with normal antibody production.
Gamma-globulins for intravenous application (IgG-IV), processed by various methods, were tested for their ability to interact with human monocyte Fc receptors by determining the dose required to ...inhibit monocyte Fc receptor-mediated rosette formation and phagocytosis by half (ID50). Since dimeric and oligomeric IgG were found to be 2-3 times and 5-15 times more potent, respectively, than monomeric IgG, the varying proportions of polymeric IgG in intact IgG-IV were corrected for by calculation. The results of the rosette formation and phagocytosis tests were closely correlated, and insignificant differences between preparations processed by the same procedure were noted, while considerable differences were found between different procedures. The decreasing order of inhibitory activity was DEAE-Sephadex-treated IgG, acid-treated IgG, plasmin-digested IgG, polyethylene glycol(PEG)-precipitated IgG, IgG subjected to reduction/alkylation, IgG that underwent sulfitolysis, IgG treated with beta-propiolactone, and finally pepsin-treated IgG. Thus, while mild procedures preserve the capacity of IgG to interact with monocyte Fc receptors, chemical modification severely interferes with this important effector function.
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