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Biomedical subjects

G Starkebaum

Publications and source records attributed to G Starkebaum.

At least 55 records · Page 3Linked to original sources
PubMed1987

Evaluation of splenectomy in large granular lymphocyte leukaemia.

We performed splenectomy in four patients with severe neutropenia (less than 0.5 X 10(9)/l), recurrent infections, and splenomegaly associated with large granular lymphocyte leukaemia. Prior to splenectomy, elevated levels of neutrophil-reactive IgG were detected in sera of all three patients tested. In all patients, enlargement of the spleen was due to a characteristic lymphoid infiltration of red pulp cords. Splenectomy resulted in an increased neutrophil count greater than 0.5 X 10(9)/l in all patients; this response was sustained in two patients who benefited clinically by a dramatic reduction in frequency of infections. Poor clinical response was associated with elevated levels of antineutrophil antibody post-splenectomy. All four patients had an increase in number of circulating large granular lymphocytes post-splenectomy; one patient who had attained a sustained neutrophil response died of an accelerated lymphoproliferative disorder 19 months post-splenectomy. We conclude that splenectomy may be of value in correcting severe neutropenia and reducing infections in some patients with large granular lymphocyte leukaemia. However, splenectomy appeared to be of no value in treatment of the underlying lymphoproliferative disorder.

Evaluation Studies as Topic↗
PubMed1987

Depressed superoxide radical generation by neutrophils from patients with rheumatoid arthritis and neutropenia: correlation with neutrophil reactive IgG.

Neutrophils of 31 patients with neutropenia and rheumatoid arthritis (RA) have been studied to assess their ability to generate superoxide radicals (O-2) on activation. Seventeen patients had classical Felty's syndrome and 14 presumed chrysotherapy related neutropenia. Results were compared with those from age and sex matched controls with uncomplicated RA and from normal subjects. Neutrophils from patients with Felty's syndrome had a significantly reduced ability to generate superoxide radicals when compared with the other three groups. In addition, serum levels of IgG polymorphonuclear leucocyte binding activity (IgG PBA) were also raised in the group with Felty's syndrome. A statistically significant inverse correlation existed between O-2 generation and IgG PBA. It is concluded that neutrophil reactive IgG may have an important role in both quantitative and qualitative defects in neutrophil function in Felty's syndrome.

Agranulocytosis↗
PubMed1987

Suppression of superoxide generation by normal polymorphonuclear leukocytes preincubated in plasma from patients with Felty's syndrome.

Polymorphonuclear leukocytes (PMN) isolated from patients with Felty's syndrome (FS) generate fewer superoxide anions (O-2) upon stimulation with fmet-leu-phe than PMN from normal controls or patients with rheumatoid arthritis (RA). In this study, plasma samples were obtained from 12 patients with RA and 12 patients with FS. Incubation of normal PMN in plasma from Felty patients resulted in a significant reduction in both the rate and total quantity of O-2 generation when activated with fmet-leu-phe. This was not observed with plasma from RA patients. The capacity of a plasma sample to suppress O-2 generation correlated with plasma IgG-PMN-binding activity (IgG-PBA) and, to a lesser extent, with the content of circulating immune complexes (CIC). These data suggest that IgG-PBA and possibly CIC have a pathogenetic role in both qualitative and quantitative defects in PMN in Felty patients.

Aged↗
PubMed1987

Induction of NK activity in large granular lymphocyte leukemia: activation with anti-CD3 monoclonal antibody and interleukin 2.

Large granular lymphocyte (LGL) leukemia is a rare disease characterized by clonal expansion of LGL associated with chronic neutropenia, multiple auto-antibodies, and occasionally polyarthritis. We studied cell surface antigen expression and functional activity of leukemic LGL from ten such patients. Using two-color flow cytometric analysis, we found that leukemic LGL from all ten patients expressed the CD3 and HNK-1 markers, while cells from only four patients expressed IgG Fc receptors (FcR). The LGL leukemic cells had little or no NK activity (defined as MHC-nonrestricted cytotoxicity against K562 target cells); however, NK activity could be induced in leukemic LGL by in vitro treatment with as little as 0.05 microgram/mL of anti-CD3 monoclonal antibody. Cell sorting experiments demonstrated that NK activity was induced in CD3+ leukemic LGL (either CD3+, HNK-1+ or CD3+, FcR+) with anti-CD3 monoclonal antibody but not in normal CD3+, FcR- T cells. Treatment with purified interleukin 2 (IL 2) also caused direct activation of some CD3+ leukemic LGL. Despite induction with anti-CD3 MAb or IL 2, activated leukemic LGL did not proliferate or express high density IL 2 receptors detectable by cell sorter analysis. Treatment with alpha interferon had minimal effect on NK activity of LGL leukemic cells. These results suggest that leukemic LGL may provide a useful model for examining the signals required for LGL maturation and activation.

Antibodies, Monoclonal↗
PubMed1987

Large granular lymphocyte leukemia. Report of 38 cases and review of the literature.

LGL leukemia results from a chronic, clonal proliferation of LGL. Chronic neutropenia with recurrent bacterial infection and splenomegaly are common clinical manifestations. Rheumatoid arthritis coexists in some of these patients, who thus resemble patients with Felty syndrome. Other hematologic abnormalities that may occur include pure red-cell aplasia and adult-onset cyclic neutropenia. Lymphoid infiltration of bone marrow, splenic red pulp cords, and hepatic sinusoids is characteristic; lymph node and skin involvement are rare. Multiple serologic abnormalities are frequently present, including positive tests for rheumatoid factor and/or antinuclear antibody, polyclonal hypergammaglobulinemia, and circulating immune complexes. Antineutrophil and antiplatelet antibodies are often present. Leukemic LGL exhibit phenotypic heterogeneity; the most common phenotype in our patients is CD2+, CD3+, CD8+, HNK-1+, CD16-. Despite markedly increased numbers of LGL, functional activity of the cells is usually decreased. The mechanism of cytopenias is uncertain: in pure red-cell aplasia, it appears to be due to suppressive effect on erythropoiesis by abnormal LGL, but in patients with chronic neutropenia it may be antibody-mediated. Although most patients appear to have a relatively benign clinical course, mortality from infections and progressive lymphoproliferation is substantial. Optimal therapy remains undefined. Some preliminary evidence suggests that LGL leukemia may be associated with infection with a retrovirus similar to HTLV-I. Although relatively rare, LGL leukemia is of interest because a better understanding of this disease process may contribute to our knowledge of autoimmune diseases, the immunoregulatory functions of LGL, and the mechanisms controlling normal hematopoiesis.

Aged↗
PubMed1986

Endothelial cell injury due to copper-catalyzed hydrogen peroxide generation from homocysteine.

We have examined whether the toxic effects of homocysteine on cultured endothelial cells could result from the formation and action of hydrogen peroxide. In initial experiments with a cell-free system, micromolar amounts of copper were found to catalyze an oxygen-dependent oxidation of homocysteine. The molar ratio of homocysteine oxidized to oxygen consumed was approximately 4.0, which suggests that oxygen was reduced to water. The addition of catalase, however, decreased oxygen consumption by nearly one-half, which suggests that H2O2 was formed during the reaction. Confirming this hypothesis, H2O2 formation was detected using the horseradish peroxidase-dependent oxidation of fluorescent scopoletin. Ceruloplasmin was also found to catalyze oxidation of homocysteine and generation of H2O2 in molar amounts equivalent to copper sulfate. Finally, homocysteine oxidation was catalyzed by normal human serum in a concentration-dependent manner. Using cultured human and bovine endothelial cells, we found that homocysteine plus copper could lyse the cells in a dose-dependent manner, an effect that was completely prevented by catalase. Homocystine plus copper was not toxic to the cells. Specific injury to endothelial cells was seen only after 4 h of incubation with homocysteine plus copper. Confirming the biochemical studies, ceruloplasmin was also found to be equivalent to Cu++ in its ability to cause injury to endothelial cells in the presence of homocysteine. Since elevated levels of homocysteine have been implicated in premature development of atherosclerosis, these findings may be relevant to the mechanism of some types of chronic vascular injury.

Animals↗
PubMed1985

Pancytopenia associated with low dose pulse methotrexate in the treatment of rheumatoid arthritis.

Low dose pulse MTX was associated with the development of pancytopenia in six patients with RA. Two patients died. Factors implicated in the occurrence of this complication were renal impairment in five patients, medication errors by two patients, preexisting marrow injury from occult alcoholism in one patient, and an apparent idiosyncratic reaction to the drug in another. Medication errors were associated with the use of five or more medications, and the unusual schedule of administration of low dose MTX may also have been contributory. From a consideration of the clinical pharmacokinetics of MTX, we suggest other factors that may predispose to the occurrence of marrow toxicity: the presence of hypoalbuminemia, interactions between MTX and other protein bound or weakly acidic drugs, and the repetitive dosing schedule of low dose MTX. Based on our experience, patients with impaired renal function (creatinine greater than or equal to 2.0 mg/dL) should not receive MTX. Renal function should be monitored regularly during treatment with MTX, and blood counts should be observed carefully if a new drug is added or substituted. A 5 mg test dose of MTX before initiating weekly therapy may identify patients with severe hypersensitivity to the drug. The potential risks of using MTX in a patient unwilling to accept blood products should be acknowledged and discussed with the patient. Furthermore, we recommend the use of leucovorin if pancytopenia occurs, even if low or undetectable serum levels of MTX are present.

Adult↗
PubMed1985

Leukemia of large granular lymphocytes: association with clonal chromosomal abnormalities and autoimmune neutropenia, thrombocytopenia, and hemolytic anemia.

Three patients had leukocytosis of large granular lymphocytes and chronic neutropenia. Clonal chromosomal abnormalities (trisomy 8 and trisomy 14) and lymphocytic infiltration of splenic red pulp, hepatic sinusoids, and bone marrow indicated the neoplastic nature of the large granular lymphocytes. Demonstration of a T3+, T8+, HNK-1 + phenotype and low natural killer cell activity that was augmented by interferon treatment showed the leukemic cells to be immature natural killer cells. Multiple autoantibodies were present and included rheumatoid factor and antinuclear, antineutrophil, antiplatelet, and antierythrocyte antibodies, suggesting a defect of B-cell immunoregulation. In addition, in-vitro studies showed impaired suppression of immunoglobulin biosynthesis by abnormal cells from one patient. Antineutrophil antibodies and absence of direct cell-mediated inhibition of granulocyte-macrophage colony formation supported a humoral immune mechanism for the neutropenia. In these patients the syndrome of splenomegaly, multiple autoantibodies with neutropenia, and lymphocytosis of large granular lymphocytes is due to a neoplastic proliferation of immature natural killer cells.

Adult↗
PubMed1985

D-Penicillamine: analysis of the mechanism of copper-catalyzed hydrogen peroxide generation.

Recent studies have suggested that the inhibition of lymphocyte mitogenesis by D-penicillamine in the presence of copper could be mediated by the formation and action of hydrogen peroxide. To explore this possibility further, we first sought evidence of H2O2 generation by D-penicillamine in a cell-free system by a) measurement of copper-catalyzed D-penicillamine oxidation and the requirement for oxygen in this process; b) direct measurement of H2O2 formation during D-penicillamine oxidation by the peroxidase-mediated oxidation of fluorescent scopoletin; and c) evaluation of the possible synthesis of O2- during D-penicillamine oxidation. The addition of copper to D-penicillamine in physiologic buffer catalyzed D-penicillamine oxidation in a dose-dependent fashion. D-penicillamine oxidation was accompanied by O2 consumption with a molar ratio of approximately 2:1, but did not occur under anaerobic conditions. Furthermore, D-penicillamine oxidation resulted in the formation of amounts of H2O2 stoichiometrically equivalent to oxygen consumption (i.e., 1:1). Copper-catalyzed D-penicillamine oxidation caused reduction of nitroblue tetrazolium in a reaction blocked by superoxide dismutase, suggesting the formation of O2-. Additional studies confirmed that D-penicillamine inhibited PHA-induced mitogenesis of lymphocytes in the presence of copper, and that catalase protected the cells from this action. Furthermore, when polymorphonuclear leukocytes were incubated with D-penicillamine plus copper, hexose monophosphate shunt activity increased up to threefold with abrogation of this stimulation by catalase. None of the effects of D-penicillamine plus copper on cells were diminished by hydroxyl radical scavengers mannitol or benzoate. These results are consistent with oxygen-dependent copper-catalyzed oxidation of D-penicillamine in aqueous solutions leading to the formation of O2- and H2O2. H2O2 produced by this reaction can inhibit lymphocyte mitogenesis and stimulate neutrophil hexose monophosphate shunt activity in vitro and may be relevant to the therapeutic effects of D-penicillamine in vivo.

Catalase↗
PubMed1985

Thromboangiitis obliterans associated with idiopathic hypereosinophilia.

A 47-year-old male smoker with chronic eosinophilia developed progressive ischemia in his extremities. Pathologic examination of vessels in amputated limbs revealed changes of thromboangiitis obliterans. Focal segments of some arteries, however, revealed infiltration of thrombus and vessel wall by eosinophils. Furthermore, the patient developed a totally occluded right temporal artery, which on biopsy specimen showed marked infiltration by eosinophils within the vessel wall. In contrast to most patients with the hypereosinophilic syndrome, however, this patient had no evidence of endomyocardial thrombosis or fibrosis. In view of recent evidence that eosinophil granule proteins are toxic to endothelial cells, the findings in this patient suggest the possibility that eosinophils may be involved in the pathogenesis of thromboangiitis obliterans.

Eosinophilia↗
PubMed1983

Chronic lymphocytosis with neutropenia: evidence for a novel, abnormal T-cell population associated with antibody-mediated neutrophil destruction.

A 67-year-old man with stable chronic neutropenia, lymphocytosis, multiple auto-antibodies, and recurring infections was studied in order to characterize the abnormal lymphocytes and the mechanism of neutropenia. One-half of the circulating mononuclear leukocytes were large granular lymphocytes that did not rosette with sheep erythrocytes and did not have surface immunoglobulin or receptors for C3 or IgG Fc. Virtually all of the mononuclear leukocytes, however, reacted with three monoclonal antibodies specific for mature T lymphocytes--OKT3, 3A1, and 12.1--the latter with a bimodal pattern on FACS analysis. The nonadherent, non-E-rosetting lymphocytes consisted of a homogeneous population of T cells with a novel phenotype: 3A1+, OKT3+, OKT8+, Ia+, 12.1+, OKT4-, 9.6-, 10.2-, Fc gamma receptor-. The abnormal phenotype of these cells suggested that they may have developed clonally. In spite of their OKT8+ phenotype, these lymphocytes were functionally abnormal, since they did not suppress B-cell immunoglobulin production in vitro. A humoral immune mechanism of neutropenia was indicated by increased levels of neutrophil-reactive IgG and in vivo kinetic studies with autologous neutrophils demonstrating shortened intravascular survival. The granulocyte turnover was normal, however, suggesting a blunted marrow response to the neutropenia. Corroborating the kinetic data, in vitro cultures of the patient's blood and marrow cells showed reduced numbers of granulocytic progenitors (CFU-C). Neither blood lymphocytes nor serum from the patient suppressed growth of allogeneic CFU-C nor did removal of OKT8+ cells from the marrow increase CFU-C expression. Thus, the disorder in this patient is characterized by proliferation of abnormal OKT8+ lymphocytes with impaired suppressor function. Our findings suggest that the neutropenia was due to anti-neutrophil autoantibodies that may have resulted from abnormal T-cell immunoregulation.

Aged↗
PubMed1981

Stimulation of human neutrophil chemiluminescence by soluble immune complexes and antibodies to neutrophils.

Activation of the neutrophil surface membrane may occur with a variety of stimuli, leading to enhanced glucose oxidation via the hexose monophosphate shunt and production of toxic oxygen radicals such as superoxide anion. This metabolic stimulation may be accompanied by light emission or chemiluminescence. The objective of these studies was to determine the effects of soluble and insoluble immune complexes, IgG aggregates, and rabbit anti-neutrophil serum on neutrophil activation as measured by chemiluminescence. Also, the uptake of immune complexes by neutrophils was determined and was correlated with the solubility of the complexes and the levels of induced chemiluminescence. The results indicate that stimulation of neutrophil chemiluminescence and uptake of immune complexes by neutrophils were both closely correlated with the percent precipitation of the immune complexes. Insoluble immune complexes that were avidly ingested by neutrophils also stimulated maximum levels of chemiluminescence. Nevertheless, elevated levels of chemiluminescence were induced by soluble immune complexes that were poorly ingested by neutrophils. Similarly, soluble aggregated IgG induced elevated levels of neutrophil chemiluminescence in a dose-dependent manner. Aggregated IgG induced up to sixfold higher levels of neutrophil chemiluminescence than did equal amounts of monomeric IgG. Finally, rabbit anti-neutrophil serum also caused increased levels of neutrophil chemiluminescence. Since previous studies have shown that sera from some patients with rheumatoid arthritis and Felty's syndrome have increased amounts of neutrophil-binding IgG due to the presence of both immune complexes and neutrophil-reactive antibodies, the effect of these sera on neutrophil chemiluminescence was studied. Positive correlations were observed between the level of neutrophil chemiluminescence induced by the sera and the amount of serum IgG neutrophil-binding activity (r = 0.72, p less than 0.001) as well as the level of immune complexes determined by C1q binding (r = 0.76, p less than or equal to 0.001). Such neutrophil activation by immune complexes or antibodies may reflect production of toxic oxygen radicals and could subsequently affect neutrophil function.

Antibodies↗
PubMed1980

Characterization of immune complexes and immunoglobulin G antibodies reactive with neutrophils in the sera of patients with Felty's syndrome.

These studies were performed to determine the relative contribution of immune complexes or antibodies reactive with PMNs to the elevated levels of IgG PMN-binding activity seen with sera from some patients with Felty's syndrome. Twenty-one sera from 19 patients with Felty's syndrome were fractionated by gel filtration on Sephadex G-200. Fourteen of the sera had elevated levels of IgG PMN-binding activity as measured by a sensitive IgG-specific antiglobulin inhibition technique. Ten of the G-200 excluded pools and eight of the G-200 IgG pools had levels of IgG PMN-binding activity greater than 2 S.D. above the mean value for normals.Significant correlations were observed between the levels of IgG PMN-binding activity in the sera and the values for both the G-200 excluded pools (r = 0.51) and the IgG pools (r = 0.69). These data suggested that both soluble immune complexes and antibodies reactive with PMNs contributed to the elevated serum levels of IgG PMN-binding activity seen with sera from some patients with Felty's syndrome. Further evidence for the presence of PMN-binding immune complexes in the sera of patients with Felty's syndrome was the strong correlation between the values of serum IgG PMN-binding activity and the levels of immune complexes as detected by C1q binding (r = 0.71) or analytical ultracentrifugation (r = 0.60). Studies of G-200 excluded samples adsorbed with human IgG coupled to Sepharose 4-B indicated that immune complexes containing rheumatoid factors contributed only in part to the increased levels of IgG PMN-binding activity and of C1q-binding activity. Confirmation of the presence of antibodies reactive with neutrophils was the finding of significantly greater binding to PMN with F(ab')2 fragments of IgG from four sera of patients with Felty's syndrome compared to F(ab')2 from normal sera. Adsorption studies suggested that the PMN-reactive antibodies did not possess rheumatoid factor activity.

Adsorption↗
PubMed1980

Humoral and cellular immune mechanisms of neutropenia in patients with Felty's syndrome.

The objective of these studies was to assess the relative role of humoral or cellular immune mechanisms in the neutropenia of Feltry's syndrome. The amounts of neutrophil-bound IgG were measured by a sensitive antiglobulin inhibition assay. These values were increased in eight out of seventeen patients with Felty's syndrome over the highest values seen with seventeen patients with rheumatoid arthritis without leukopenia or twenty-six normal individuals. The levels of serum IgG neutrophil-binding activity from thirteen out of twenty-one patients with Felty's syndrome were greater than the highest values seen with normal sera compared to six out of thirty sera from patients with rheumatoid arthritis alone. A strong correlation was observed between the levels of direct neutrophil-bound IgG and the serum IgG neutrophil-binding activity for the seventeen patients with Felty's syndrome. Inhibition of normal marrow granulocyte colony growth greater than 40% was seen with the peripheral blood mononuclear leucocytes from five out of eleven patients with Feltry's syndrome. All five patients had normal levels of neutrophil bound IgG and normal to moderately increased levels of serum IgG neutrophil binding activity. In contrast, of the six patients whose mononuclear leucocytes did not inhibit granulocyte colony growth, three had markedly elevated levels of neutrophil-bound IgG and four had elevated levels of serum IgG neutrophil binding activity. These results suggest that humoral and cellular immune mechanisms of neutropenia may be present in different subsets of patients with Felty's syndrome.

Agranulocytosis↗