In vitro effects of gammaglobulin (IgG) on human monocyte Fc receptor function. I. Effect on monocyte membrane-associated IgG and Fc receptor-dependent binding of antibody-coated platelets

Effects of dexamethasone and gamma globulin combined with prednisone on the therapeutic effect and immune function of Henoch-Schonlein purpura nephritis in children

Background

Henoch‐Schonlein purpura nephritis (HSPN) is a serious complication of Henoch‐Schonlein purpura (HSP), which is usually treated with immunosuppressant and glucocorticoid. This study was designed to explore the effect of dexamethasone and gamma globulin combined with prednisone in the treatment of pediatric HSPN.

Methods

According to the treatment plan, 60 children treated with dexamethasone and gamma globulin were included in the control group, and the rest 55 children treated with dexamethasone and gamma globulin combined with prednisone were selected as the research group. The clinical manifestations, therapeutic effect, immune function, serum inflammatory factors, blood coagulation function, urine routine, renal function, and adverse reactions were compared between the two groups.

Results

The clinical manifestations of children in the research group were significantly better than those in the control group after treatment (P < .05). The total effective rate in the research group (94.55%) was markedly higher than that in the control group (76.67%) (P < .05). CD3+, CD4+, CD8+, IL‐10, PT, and APTT increased while CD4+/CD8+, IgA, IL‐8, TNF‐α, FIB, urine protein, urine red blood cell, Scr, and BUN decreased in both groups after treatment, and the changes of all the above indexes in the research group were significant than those in the control group (P < .05). The incidence of adverse reactions in the research group was remarkably superior to that in the control group (P < .05).

Conclusion

Dexamethasone and gamma globulin combined with prednisone can improve the immune function of children with HSPN and promote the recovery of renal function.

[Acquired von Willebrand syndrome: from diagnosis to treatment]

Acquired von Willebrand syndrome is a rare bleeding disorder, which has been related in various diseases including lymphoproliferative disorders or autoimmune diseases. Its diagnosis is an important step before treatment of patients and particularly in case of bleeding. We report four cases from Caen Hemophilia Treatment Center, diagnosed and treated from 1999 to 2008. Mucocutaneous bleeds in every case were the same as in hereditary von Willebrand disease. All patients had no personal or family history of bleeding. Phenotype was identified as type 2 von Willebrand disease with a loss of high molecular weight multimers. Anti-von Willebrand factor inhibitor screening was positive for three patients. The etiological diagnosis was one chronic lymphocytic leukaemia, two monoclonal gammapathies of undetermined significance (MGUS) and one undetermined case. The management of patients need two stages: first infusions of factor von Willebrand/factor VIII concentrates to stop bleeds, then treatment of the underlying disease such as chemotherapy, corticotherapy and treatment with high doses of polyvalents immunoglobulins. In every case, treatment was effective and improved patient's quality of life.

Anti-HPA-1a-mediated platelet phagocytosis by monocytes in vitro and its inhibition by Fc gamma receptor (FcgammaR) reactive reagents

The study was undertaken to delineate mechanisms of platelet destruction by phagocytosis during fetal/neonatal alloimmune thrombocytopenia (FAIT/NAIT) because of maternal antibodies against human platelet antigen 1a (HPA-1a). By employing a platelet phagocytosis assay based on the ORPEGEN flow cytometric bacterial phagocytosis test, we measured monocyte ingestion of platelets mediated by anti-HPA-1a antibodies. Moreover, we tested, as potential therapeutic agents, FcgammaR reactive reagents, for their inhibition of this process. Four of six anti-HPA-1a sera tested mediated phagocytosis of HPA-1a-positive platelets in a concentration-dependent manner. Monocyte ingestion of platelets was almost completely inhibited by cytochalasin D. No anti-HPA-1a-mediated phagocytosis was observed with anti-HPA-1a-negative platelets. The humanised anti-FcgammaRI monoclonal antibody H22 at concentrations 1-100 microg/ml, completely inhibited anti-HPA-1a-mediated phagocytosis as did similar concentrations of ivIg. By contrast, a mouse monoclonal anti-FcgammaRII (IV.3, Fab) at 10 microg/ml caused little or no suppression of platelet phagocytosis mediated by two anti-HPA-1 sera. Furthermore, the addition of anti-FcgammaRII (10 microg/ml) to sub-optimal concentrations of H22 did not significantly increase the inhibitory effect of the latter compound. Monomeric IgG (0.1-10 microg/ml) failed to suppress anti-HPA-1 mediated platelet ingestion by the phagocytes, as did anti-FcgammaRIII. To our knowledge this is a rare example of an assay that measures platelet phagocytosis in vitro. The results suggest that FcgammaRI plays a major role in anti-HPA-1a-mediated platelet phagocytosis by monocytes while FcgammaRIIa, is of little or minor importance only. Moreover, the findings indicate the use of H22 as an alternative to interavenous Ig (ivIg) in the management of FAIT/NAIT.

Down regulation of a harmful variant protein by replacement of its normal protein

To compensate for the hypoprotein and hypoalbuminemia of familial amyloidotic polyneuropathy (FAP) patients, 800 ml of fresh frozen plasma (FFP) was intravenously administered and change in total and variant transthyretin (TTR) levels were measured in the plasma. After injection of FFP, total plasma TTR levels were elevated and variant TTR levels decreased from 24 to 48 h, accompanied by an elevation of plasma total protein, albumin levels and TTR levels. To elucidate the mechanism of this phenomenon, a large amount of purified normal TTR from normal human plasma was intravenously injected in mice and FAP patients. By intravenous injection of 3 mg of the purified TTR to C57Black6, the expression of TTR mRNA decreased from 6 to 24 h post injection, and gradually increased up to 48 h post injection. After injecting 400 mg of normal TTR in each of 3 FAP patients, total plasma TTR levels were elevated and variant TTR levels decreased significantly from 24 to 48 h. These results suggested that down regulation of the harmful protein by replacement of its normal form of the protein occurred by this method. This phenomenon should be applied as the basis for one of the useful methods for decreasing the harmful proteins in the circulation.

Effectiveness of high-dose intravenous immunoglobulin in a case of acquired von Willebrand syndrome with chronic melena not responsive to desmopressin and factor VIII concentrate

A patient with benign monoclonal IgG lambda paraproteinemia, acquired von Willebrand syndrome (AVWS), and chronic melena successfully responding to high-dose intravenous immunoglobulin (lvlg) is reported. Coagulation parameters at admission were APTT (ratio) 1.68; VIII:C 11 IU/dL; vWF:Ag 7 IU/dL:Ricof less than 3 IU/dl. RIPA was greater than 1.8 mg/ml, and bleeding time (BT) was prolonged (18 min). No evidence for an in vitro inhibitor against the VIII/vWF complex was observed. VIII/vWF measurements showed a short-lived increase after both DDAVP and Hemate P, and BT was transiently normalized. After intravenous Ig (1 g/kg for 2 days), VIII/vWF measurements, hemostatic parameters and multimeric pattern were completely corrected (VIII/C 106 IU/dl, vWF:Ag 168 IU/dl, RiCof 147 IU/dl, APTT ratio 0.89, BT 5'), with a return to pre-infusion values after 15 days. Hemoccult test became negative and packed red cell transfusions, of which 130 units were administered during the last year, were no longer required. After 18 months the patient is on maintenance treatment with repeated courses of Ig, at 3 to 4-week intervals based on VIII/vWF and BT monitoring.

Modulation of functional activity of human polymorphonuclear and mononuclear phagocytes by intravenous gamma globulin

Intravenous gamma-globulin was tested in a range of concentrations compatible with the increments obtained after therapeutic infusions for modulation of phagocytic functions of human polymorphonuclears (PMNs) and monocytes. Intravenous gammaglobulin in concentrations of 3.0 mg/ml or more increased adhesiveness and suppressed chemotaxis of PMNs. There was marked dose-dependent enhancement of opsonization of gram-positive and gram-negative microorganisms. Preincubation of PMNs with intravenous gamma-globulin caused enhancement of the total bacteria ingested, total bacteria killed, phagocytosis, and phagocytic index, when gram-positive and gram-negative bacteria were tested. During phagocytosis, there was no release of LDH or lysozyme; however, there was release of beta-glucuronidase. No significant difference in phagocytic enhancement was found when filtered and native intravenous gamma-globulin preparations were compared. There was marked enhancement of the superoxide anion generation by intravenous gamma-globulin above the concentration of 0.01 mg/ml. Intravenous gamma-globulin also markedly enhanced phagocytic activity of monocytes. Therefore, intravenous gamma-globulin modulates not only opsonization-related phenomena, but also exerts a complex influence on other aspects of phagocytic activity.

Differentiation of HL-60 cells is associated with an increase in the 35-kDa protein lipocortin I

Lipocortin I, a 35-kDa protein, has been detected in terminally differentiated monocytes and neutrophils. This calcium-phospholipid binding protein appears to be identical to a 35-kDa protein that can serve as a substrate for the EGF-receptor/tyrosine kinase. We have used the human myelocytic cell line HL-60 to explore whether differentiation of hematopoietic cells is associated with changes in the level of lipocortin I. We find that differentiation of HL-60 cells toward the macrophage lineage by the addition of phorbol esters or vitamin D3 or toward neutrophils with dibutyryl cyclic AMP or dimethyl sulfoxide is accompanied by an increase in the cellular content of lipocortin I. In comparison, treatment of HL-60 cells with bryostatin 1, a compound that activates protein kinase C but does not differentiate HL-60 cells, did not effect the level of 35 kDa protein. We have developed a radioimmunoassay to quantitate this protein by using a polyclonal antibody to a synthetic amino terminal peptide of the 35-kDa protein. This antibody recognizes purified pig lung 35-kDa protein as well as a single 35-kDa protein in HL-60 and A-431 cells as determined by Western blotting and immune precipitation. Differentiated HL-60 cells contain 2.6-fold the amount of 35-kDa protein found in undifferentiated HL-60 cells. Our findings that the addition of phorbol esters to HL-60 cells results in an increase in the mRNA for the 35-kDa protein and in an increase in the incorporation of 35S-methionine into the protein suggest that transcriptional activation or increased stability of the mRNA is responsible for the increased rate of synthesis and accumulation of lipocortin I during differentiation of these cells. In the absence of added divalent cations, we have determined that in differentiated HL-60 cells 79% of lipocortin I protein is located in the cytosol while 21% of the total cellular protein is bound to the particulate fraction. The 35-kDa protein can be removed from the particulate fraction by incubation with chelators or treatment with phospholipase A2 or phospholipase C. Addition of the calcium ionophore A23187 to intact differentiated HL-60 cells causes the 35-kDa protein to associate with the particulate fraction of the cell, suggesting that modulation of intracellular calcium levels may play a role in changing the intracellular location of this protein.

Effect of commercial immunoglobulin G preparation on human monocyte Fc-receptor dependent binding of antibody coated platelets

This study examined the in vitro effect of a commercial immunoglobulin preparation on human monocytes and the Fc-receptor dependent binding of antibody coated platelets. Monocytes were exposed to Sandoglobulin in vitro and subsequently examined for membrane surface bound IgG. Dramatic increments of surface IgG were found which were maximal with 18 h exposure and somewhat higher at 4 degrees C than 37 degrees C. Ultracentrifugations of Sandoglobulin immediately prior to monocyte exposure reduced the monocyte membrane IgG by 75%. The 18 h exposure at 37 degrees C produced dramatic impairment of monocyte Fc-receptor binding of IgG coated platelets (P less than 0.001) while exposure for 18 h at 4 degrees C produced a modest impairment of Fc-receptor function. These studies indicate that Sandoglobulin contains IgG aggregates which are able to firmly bind to the monocyte surface in a time and temperature dependent fashion. The dramatic impairment of Fc-receptor function at 37 degrees C and not at 4 degrees C suggests that Fc-receptor modulation, as well as competitive inhibition/steric hindrance, contribute to impairment of monocyte Fc-receptor function.

Intravenous high-dose IgG therapy induced alterations of spleen lymphocyte IgM secretion and T cell subsets in patients with idiopathic thrombocytopenic purpura

High-dose intravenous (IV) IgG therapy is an effective possible means of raising platelet counts in patients with idiopathic thrombocytopenic purpura (ITP). In order to elucidate further the mechanism of action of such treatment we comparatively studied spleen mononuclear cells (SMC) from two groups of ITP patients. Group I consisted of 9 patients who had not received any recent treatment before splenectomy. The 8 patients in group II had received IV IgG infusions 1-5 days before splenectomy. The SMC were cultured either unstimulated or stimulated by pokeweed-mitogen (PWM), and proliferation (as assessed by 3H-thymidine uptake), and IgG and IgM secretion were measured. In addition T lymphocyte subsets were determined in the SMC by indirect immunofluorescence using monoclonal antibodies (OKT3,4,8). By comparison with group I SMC, our results in group II SMC mainly showed a significant decrease in proliferation and IgM secretion, in both unstimulated and PWM stimulated cultures. In addition, a significant decrease in the proportion of T helper-inducer lymphocytes (OKT4+ cells) was also found in group II SMC, as compared to group I SMC. However, these immunological alterations in group II SMC were paradoxically more pronounced in those patients who failed to respond to IV IgG infusions. Thus, these results suggest that, although immune suppression takes place in the SMC of ITP patients following IV IgG therapy, it has not a pronounced effect on the increase of platelet.

Immune thrombocytopenia: effects of maternal gamma globulin infusion on maternal and fetal serum, platelet, and monocyte IgG

A 24-year-old woman with lupus-like serologic abnormalities had immune thrombocytopenia that resolved after splenectomy, but increased quantities of platelet surface IgG persisted. Three years later, during the 36th week of her first pregnancy, gamma globulin (400 mg/kg daily for 5 days) was administered intravenously to decrease the risk and/or severity of immune thrombocytopenia in her infant. The infusion produced marked but transient elevations of maternal concentrations of serum IgG and quantities of monocyte surface IgG, but no significant changes in Fc receptor-mediated rosetting of peripheral blood monocytes with antibody-sensitized platelets occurred. Modest increases in quantities of platelets and plasma platelet-specific IgG were demonstrated. The infant, delivered by cesarean section 2 days after the end of the infusion, had a normal platelet count; cord blood had a normal concentration of serum IgG, but an elevated quantity of platelet surface IgG (by comparison with values for normal adults). Infant values of plasma platelet-specific IgG, monocyte surface IgG, and monocyte/platelet rosettes also were within the range of normal for adults. Anticytomegalovirus antibody was present in large amounts in the gamma globulin infused, first appeared in maternal serum after therapy, and was detected in cord serum. The significance of these observations to the management of immune neonatal thrombocytopenia is discussed.