Neutrophilic phagocytosis in autoimmune thrombocytopenia purpura

In vivo neutrophil phagocytosis was demonstrated by transmission electron microscopy (TEM) in the peripheral blood of two half-sibs with hereditary thrombocytopenia. These sibs have had a lifetime documented history of thrombocytopenia. Light microscopy morphology and histochemistry studies of blood and marrow were normal, similar studies of blood from available members of the kinship were also normal. Scanning electron microscopy (SEM) of platelets from each member of the kinship showed normal dendritic and spreading formation. In the TEM thin sections of platelet buffy coats, neutrophil ingestion of platelets was common and all stages of the phagocytic process were noted--from platelet-neutrophil intimacy to the formation of myelin bodies in phagosomes. The clinical courses over a 10-year period were mild, requiring rare therapeutic interventions. The chronic thrombocytopenia, lengthy mild course, modestly elevated platelet-associated immune globulin, normal aggregation and survival studies, and autoimmune neutrophil reaction to platelets allowed classification of these patients as hereditary thrombocytopenia purpuras.

Immunoregulatory abnormalities in children with thrombocytopenic purpura

Twenty-eight children with idiopathic thrombocytopenia and 51 members of their immediate families were studied for immunologic function and expression of autoimmune phenomena and disease. Among patients with active ITP, 64% had defective immunoregulatory lymphocytes. The majority of patients (23/28) and family members had one or more immunologic abnormalities, including autoantibodies, other autoimmune disorders, and abnormalities in complement, immunoglobulins, or regulatory T lymphocytes. These data suggest that a genetic predisposition to autoimmunity is present in the majority of children with ITP.

Blood platelets cause retraction of collagen gel

Human blood platelets cause the collagen gel retraction (CGR) with concomitant exclusion of fluid. CGR is positively related to the number of incorporated platelets and inversely to collagen concentration. Disruption of platelets, EDTA and cytochalasin B inhibit CGR. Platelets from patients with Glanzmann's thrombasthenia are active in CGR. The similarities and differences of CGR and fibrin retraction are discussed.

Baka, a new platelet-specific antigen involved in neonatal allo-immune thrombocytopenia

A family is described in which the mother developed platelet-specific antibodies, not directed against the antigens of the Zw(PlA) or the Ko system. The antibodies were only detectable in the immumofluorescence test and the radioactive antiglobulin test on platelets, and proved to be mainly IgG1 antibodies, although weak IgM antibodies of the same specificity were also detected. By cross-absorption studies, investigation of the family and a small-scale population study, it appeared that the antibodies were directed against a new antigen which we have called Baka. The frequency of the Baka phenotype in the Dutch population was 90.76%, the calculated genotype frequency 0.696. The Baka phenotype was neither sex-linked nor, so far as evaluable, closely linked to other platelet, red-cell, granulocyte, or HLA groups. The first child of this mother died of neonatal thrombocytopenia, the second child was unaffected. During the second pregnancy, the titre of the antibodies did not rise. The platelets of this child were found not to carry the Baka antigen.

HLA antigens in immunologic thrombocytopenic purpura (ITP)

79 patients with definite ITP were investigated for HLA-A, -B, -C antigens. There was an increased frequencey of HLA-B5 in the entire groups (27.8% vs. 16.5% in controls and for HLA-B12 in male patients. However, after correction for the number of antigens tested, the difference of antigen frequencies became insignificant.

Cycles of agglutination-disagglutination induced by ristocetin in thrombasthenic platelets

An oscillatory pattern of platelet agglutination-disagglutination in response to Ristocetin (R) at narrow concentration ranges was observed in citrated platelet rich plasma (PRP) of 10 patients with Glanzmann's thrombasthenia. The cyclic pattern decreased in intensity over time, was reproducible, and was not pH dependent. Formalin-fixed thrombasthenic platelets agglutinated with R but did not show a cyclic pattern. Incubation with 2.5 microM ADP inhibited R oscillation response, but small increases in R dose overcame this inhibition. The addition of ATP or creatine phosphate/creatine phosphokinase to thrombasthenic platelets inhibited by ADP restored the R oscillation response. In the platelets of a single patient, intracellular levels of ADP and ATP were shown to diminish during an oscillation response to R. There was an increase in AMP levels during the same period of time. The changes in these three intracellular nucleotides were gradual over time and did not vary with phases of the oscillation. Acetyl salicylic acid (ASA), at concentrations shown to block cyclooxygenase activity in control platelets, enabled thrombasthenic platelets to respond to R with full agglutination without oscillations. Lower concentrations of ASA in the PRP gave a return of the oscillation response. Our data suggest that the disagglutination phase of the R response of thrombasthenic platelets is not a function of the known glycoprotein membrane defect, but depends on materials originating in the platelet whose release is blocked by ASA.

[Obstetrical problems in patients with Glanzmann's thrombasthenia. A casuistic presentation (author's transl)]

Glanzmann's thrombasthenia is a rare, autosomal recessive disorder of bleeding arrest. The differential diagnosis of this platelet defect with respect to recently gained knowledge is presented in the case of a pregnant woman. Because of pelvic presentation a cesarean section was performed after adequate platelet substitution, which did not involve excessive blood loss. A severe puerperal infection necessitated an abdominal hysterectomy after appropriate platelet transfusion. The difficulties in testing platelet function in the newborn are discussed. The effectiveness of a commercially available homologous phospholipide complex (Fibraccel) was tested on the patient in a noncritical phase. The results appear important for general procedure when pregnancy and platelet dysfunction concur.

HLA antigens in idiopathic thrombocytopenic purpura

A group of 40 patients with idiopathic thrombocytopenic purpura (ITP) was examined. Typing for HLA A and B antigens was performed. The frequencies of 24 HLA antigens in this group were compared with those of a group of 13 patients with drug-induced thrombocytopenia and two large groups of healthy controls. Differences of statistical significance between these groups were not found. Thus, associations of ITP and particular HLA antigens were not observed. The associations reported by others could not be confirmed.

HLA frequencies and haplotypes in children with idiopathic thrombocytopenic purpura (ITP)

26 patients with an acute reversible ITP and 6 with chronic ITP were tissue typed, together with their healthy first-degree relatives. The HLA frequencies of the different groups were compared with those of a normal control population. The only significant difference between the groups was an increase in the frequency of Aw32 in acute ITP patients. HLA-Aw32 was present in 26.9% of patients, but in only 0.8% of the controls (corrected P = 0.000027). The possible importance of associations between antigens of the HLA-A locus with certain diseases are discussed. Family analyses and haplotype determinations proved to be unproductive because no familial clustering of ITP was found.

Effect of shear rate on platelet interaction with subendothelium in citrated and native blood. I. Shear rate--dependent decrease of adhesion in von Willebrand's disease and the Bernard-Soulier syndrome

Previous studies have demonstrated impaired adhesion of platelets to the subendothelium in von Willebrand's disease. These studies were performed by circulating (in a closed system) citrated whole blood through a chamber containing everted segments of rabbit aorta from which the endothelium had been removed by balloon catheter. The average wall shear rate was 800 sec-1, and the perfusion time was 10 min. In the present study we measured the interaction of platelets with subendothelium in native (nonanticoagulated) blood, using a recently described technique in which the vessel segments are perfused with directly sampled venous blood. The system was open; that is, the blood was not recirculated. We used blood flow rates of 20, 40, and 50 ml/min, which correspond to calculated shear rates of 1300, 2600, and 3300 sec-1 and perfusion times of 3, 2, and 2 min, respectively. For comparison, parallel studies at 1300 sec-1 were also obtained with citrated blood. In normal subjects, at a shear rate of 1300 sec-1, platelet adhesion was less in native blood than in citrated blood, but thrombus formation was greater. Platelet adhesion in five patients with von Willebrand's disease was decreased in both citrated and native blood. The magnitude of the adhesion defect was strongly dependent on the shear rate. Thus, in citrated blood studied at a shear rate of 1300 sec-1, adhesion was 75% less than in normal subjects, whereas in previous studies at 800 sec-1 the reduction in adhesion was 29%. In native blood, adhesion in von Willebrand's disease was normal at a shear rate of 1300 sec-1, whereas 53% and 77% reductions in adhesion were obtained at shear rates of 2600 and 3300 sec-1, respectively. The latter shear rates studied, adhesion of platelets in native blood was also decreased in the Bernard-Soulier syndrome but was normal in hemophilia and afibrinogenemia. Our findings with native blood provide further evidence that impaired adhesion of platelets to the vessel wall accounts for the hemostatic defect in von Willebrand's disease. In addition, this adhesion defect is shear rate-dependent.

[Twin pregnancy in a patient with Glanzmann disease (congenital thrombasthenia) (author's transl)]

Report on a 30-year old primigravida with a family history of bleeding and a personal history of nasopharyngeal bleeding since age four. Severe menorrhagia since her menarche. First seen at 20 weeks gestation with naso-pharyngeal bleeding and a twin pregnancy. The patient was found to have Glanzmann's disease (congenital thrombasthenia) with an excessive lack of factor XIII. Ambulatory treatment with packed cell transfusions until 35 weeks gestation. The thrombelastogram did not improve with transfusions of platelet concentrates. In-patient treatment from 35 to 37 weeks gestation, no vaginal bleeding throughout the pregnancy. Elective Caesarean hysterectomy at 37 weeks gestation with lo units fresh blood, 3 units platelet concentrate and 10 ampules factor XIII concentrate in readiness. Delivery of twin girls 3180 and 3050 g without signs of Glanzmann's disease. Treatment of the maternal bleeding by replacement. Factor XIII 80% of normal 8 weeks postpartum. This appears to be the first case of twin pregnancy in the presence of Glanzmann's disease and the fourth case in the world literature.

Chronic idiopathic thrombocytopenic purpura. A familial immunodeficiency syndrome?

We studied three children with chronic idiopathic thrombocytopenic purpura (ITP) and their immediate families. All three patients and 10/13 family members manifested at least one immunologic defect, eg, decreased numbers of T lymphocytes (1/3, 5/13), diminished in vitro response to phytohemagglutinin (2/3, 6/13), dysgammaglobulinemia (2/3, 4/13), altered autoantibodies (1/3, 5/13), and decreased serum properdin levels (3/3, 2/13). In addition, one parent and two asymptomatic siblings of two of the propositi had shortened platelet life spans with normal platelet counts. The HLA antigens A3 and B7 were identified in all three families. There also appeared to be an association between a familial haplotype and the immunologic defects. Chronic ITP appears to occur in families with underlying immunologic defects, which are genetically related.

[Adenyl cyclase activity of human blood platelets in various blood diseases]

Adenyl cyclase activity was estimated in blood platelets of healthy persons and of patients with myeloleukosis, osteomyelofibrosis and with Glanzmann's thrombasthenia. Six-fold decrease in the adenyl cyclase activity from the platelets was observed in chronic myeloleukosis. The enzymatic activity in platelets was similar to normal level in osteomyelofibrosis and Glanzmann's thrombasthenia.

Platelet membrane defects in Glanzmann's thrombasthenia. Evidence for decreased amounts of two major glycoproteins

Platelets from patients with Glanzmann's thrombasthenia have a distinct molecular alteration of the plasma membrane surface, namely decreased amounts of a major glycoprotein designated as IIb (apparent mol wt 142,000). To identify other possible surface defects of thrombasthenic platelets, we labeled the membrane polypeptides of normal and thrombasthenic platelets by two different techniques: lactoperoxidase-catalyzed iodination and galactose oxidase oxidation, followed by reduction with tritiated sodium borohydride. Labeling patterns were determined after the polypeptides were separated by two-dimensional polyacrylamide gel electrophoresis. Before the second dimension was run, platelet samples were incubated with a reducing agent, beta-mercapto-ethanol, to cleave the disulfide bonds of certain glycoproteins; the resulting changes in electrophoretic mobility permitted better resolution of individual molecules. Comparison of the labeled polypeptides of normal and thrombasthenic samples after reduction indicated decreased labeling of two major glycoproteins in thrombasthenic platelets: IIb and III (apparent mol wt 114,000). The relative proportions of radioactivity incorporated by these polypeptides were about 60 and 80% less than control values, respectively. With either Coomassie Blue or periodic acid-Schiff's reagent, glycoprotein III stained much less intensely in thrombasthenic compared to normal samples, indicating that the observed labeling deficit was caused by a decreased concentration of the molecule rather than steric inaccessibility on the membrane surface. Analysis of normal plasma membranes by affinity chromatography showed that glycoprotein IIb has receptors for lectin from Lens culinaris, the common lentil, whereas III does not. We conclude that a characteristic feature of Glanzmann's thrombasthenia is a decreased concentration of two discrete glycoproteins in the platelet plasma membrane.