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A patient with polycythemia rubra vera developed marked thrombocytosis and hemorrhage after splenectomy. Plateletpheresis with a blood processor proved to be a safe, efficient, and rapid method for the mechanical removal of large quantities of platelets prior to adequate control with chemotherapy.
With the use of platelet-phoresis, two microsurgical free-tissue transfers were successfully undertaken in a patient with postsplenectomy thrombocytosis that had initially caused flap failure. Rapid reduction in the platelet count allowed free-tissue transfer in this patient who required early wound coverage.
In 80 patients with different platelet counts serum and plasma potassium concentration was measured, 30 minutes after blood sampling and three and six hours of storage. Serum and plasma concentrations differed, depending on the platelet count. In reactive thrombocytosis the mean difference was 0.7 mmol/l, independently of the time since sampling. In myeloproliferative diseases and with platelet counts of more than 1000 X 10(9)/l is was time-dependent. The mean difference was between 0.8 and 1.8 mmol/l, in individual cases as much as 2.6 mmol/l. Plasma potassium levels were independent of time and platelet count. The possibility of pseudohyperkalaemia in serum must be kept in mind whenever the platelet count is increased, regardless of its cause. In case of doubt potassium must be measured in platelet-free plasma.
The chronic myeloproliferative disorders (MPD) are clonal hematopoietic stem cell disorders of unknown etiology. We have reported defective thrombopoietin receptor (Mpl) protein expression in MPD patients. To determine whether the basis of abnormal Mpl protein expression was due to mutations in the Mpl gene, we sequenced Mpl cDNA from MPD patients. We found a single nucleotide substitution (G1238T) that results in a change from lysine to asparagine at amino acid 39 (K39N) in three African-American women referred for an evaluation of an MPD. We subsequently screened more than 400 patients and controls and found that the K39N substitution is a polymorphism restricted to African Americans and that approximately 7% of African Americans are heterozygous for K39N. African Americans with the K39N polymorphism had a significantly higher platelet count than controls without the polymorphism (P < 0.001) and reduced platelet protein Mpl expression. Expression of an Mpl cDNA containing the K39N substitution in cell lines was associated with incomplete processing and a reduction in Mpl protein, recapitulating the Mpl protein defect observed in platelets from individuals with K39N. K39N represents an identified functional Mpl polymorphism and is associated with altered protein expression of Mpl and a clinical phenotype of thrombocytosis.
Langerhans' cell histiocytosis (LCH) is a disease with an unpredictable course and unpredictable reactivations. Since active disease may cause life-long sequelae, early detection of reactivation is important. The usefulness of erythrocyte sedimentation rate (ESR) and thrombocytosis as indicators of disease activity in patients with LCH were examined. The mean values for ESR and platelet count for each quarter of a year were compiled. The means of all the ESR estimates (n = 76) during each quarter of a year with active disease was 21 mm h(-1), with intermediate disease activity 11 mm h(-1) and with resolution 7 mm h(-1). The corresponding platelet count estimates (n = 139) were 433 x 10(9) l(-1), 365 x 10(9) l(-1) and 304 x 10(9) l(-1), respectively. In conclusion, elevated ESR and platelet count may be clinically valuable indicators of disease activity in LCH.
Diagnosis of essential thrombocythemia (ET) is controversial and remains mainly an exclusion diagnosis. Endogenous megakaryocyte colony (EMC) formation have been largely evaluated to identify specific criteria for ET, but results are impeded by the lack of medium standardization. We evaluated megakaryocyte (MK) colony formation in a serum-free collagen-based medium, without cytokine and in the presence of various concentrations of thrombopoietin (TPO). Thirty-six bone marrows from patients diagnosed with ET (n = 11), polycythemia vera (PV; n = 12), reactive thrombocytosis (RT; n = 6) and healthy donors (n = 7) were assessed. We demonstrate that 11 out 11 of the ET patients had spontaneous megakaryocyte colony-forming unit (CFU-MK) formation, in contrast to none of the RT patients and healthy donors. MK progenitors from ET patients remained responsive to TPO, because exogenous addition of TPO significantly increased cloning efficiency. Moreover, at low doses of TPO (0.5 ng/ml and 5 ng/ml), the number of positive cultures and mean number of TPO stimulated CFU-MK were significantly higher in cultures of cells from patients with ET than in patients with RT. In summary, we have described a standardized serum-free, collagen-based assay that allows differential diagnosis of ET and RT, according to endogenous CFU-MK formation and sensitivity to TPO.
The aim of the study was to investigate the influence of recombinant interferon-alpha 2C (rIFN-alpha 2C) on the in vivo Fc-dependent phagocytic activity of the reticuloendothelial (RE) system. Fourteen patients with excessive thrombocytosis due to myeloproliferative disorders were studied before and 3 months after initiation of therapy. RE function was determined by measuring the clearance of autologous red blood cells (RBC) labeled with 51Cr and sensitized with anti-D antibody. Eleven of the 14 patients responded to rIFN-alpha 2 treatment (platelets, less than 440 X 10(9)/liter). Rather in contrast to a shortening of platelet half-life and an increase (trendwise) in platelet-bound IgG, rIFN-alpha 2 caused a significant impairment of RE function. Although this finding could in part be accounted for by the treatment-related decrease in splenic volume, statistical analysis revealed a direct influence of rIFN-alpha 2 on RBC clearance (p less than 0.01). Our study results might be explained by an interferon (IFN)-induced, intensified expression of Fc receptors on platelet (and leukocyte) surfaces, possibly enhancing unspecific binding of IgG to their cellular membranes. The subsequent increased platelet uptake may lead to an overloading of the RE system causing impaired reactions to additional stimuli such as IgG-coated RBC.
Chronic myeloproliferative diseases (MPDs) are not associated with consistent cytogenetic or molecular abnormalities. Demonstration of clonal cell growth by analysis of X-chromosome inactivation (XCI) patterns in females provides a promising tool for diagnosis. However, this technique can be complicated by excessive lyonization of normal cells mimicking clonal cell growth: We analyzed XCI patterns at the human androgen receptor (HUMARA) locus in 146 healthy females, 65 women with secondary neutrophilia, 31 women with reactive thrombocytosis, and 86 women with chronic MPDs. A skewed XCI pattern with greater than 75% amplification of 1 allele (allele ratio > 3:1) was found in 22 (9.1%) of 242 control subjects. The incidence of skewing was statistically significantly lower in women younger than 30 years (2/73) compared with women older than 60 years (10/53). Of 86 patients with a chronic MPD, 71 (82%) exhibited an allele ratio greater than 3:1, whereas only 10 (12%) of 86 age-matched control subjects showed a skewed XCI pattern. Although statistical evaluation of the data showed a significant difference between patients with a chronic MPD and control subjects, proof of clonality in individual, especially elderly, patients is difficult.
Acute arterial occlusion can be the result of acute thrombosis or systemic embolism. Paradoxical embolism of a venous thrombosis through a right-to-left shunt is an important cause of acute limb ischemia. We describe a young patient with acute limb ischemia who was found to have multiple deep venous thromboses causing arterial embolization through a patent foramen ovale. Essential thrombocytosis was found to be the risk factor for venous thromboses in this patient. The patient was managed with embolectomy and anticoagulation along with chemotherapeutic cytoreduction of platelet count. This case illustrates the importance of considering the systemic embolism as a cause of acute arterial occlusion. The presence of a hypercoagulable status such as chronic myeloproliferative disorder does not eliminate the possibility of systemic embolism in the event of acute arterial occlusion. Patients presenting with acute limb ischemia should be evaluated for embolic sources. The presence of deep venous thrombosis in such a patient should prompt the evaluation for a patent foramen ovale.
We report the case of a relatively young man with multiple and fatal thrombosis associated with essential thrombocythaemia. The clinical and laboratory examinations performed before his death were in agreement with the diagnostic criteria proposed by PVSG. The autopsy revealed myocardial infarction and pulmonary embolisms. This case suggests that young patients with primary thrombocytosis should be treated with antiplatelet agents in spite of the absence of other thrombotic risks.
A patient with thrombocytosis, normal renal function, and severe ticarcillin-induced hemorrhage is described. Like carbenicillin, ticarcillin can cause severe bleeding in some individuals by creating a qualitative platelet defect. The template bleeding time is the most useful diagnostic test.
A patient with sickle cell beta+-thalassemia had thrombocytosis and erythrocytosis due to a myeloproliferative disorder best classified as polycythemia vera. RBC counts were 6 to 8 million/cu mm and the red cell mass was 33 ml/kg. A higher red cell mass and an increased hematocrit value were prevented probably by factors related to the hemoglobinopathy, such as microcytosis and hemolysis. The diagnosis of polycythemia vera in patients with sickle cell disease may be difficult to document and the association of these disorders has not been previously reported. This patient's high red blood cell and platelet counts did not result in recurrent vasoocclusive crises.
Spontaneous splenic rupture in hemophilia A is an uncommon occurrence which is difficult to diagnose. We have reported a case of hemophilic rupture of the spleen unaccompanied by thrombocytosis, which has been emphasized as a diagnostic clue to hemophilic splenic rupture. Hence, splenic rupture should still be considered in any hemophilic patient with pain in the left upper quadrant and a normal platelet count. Splenic rupture in hemophilia must be recognized because its treatment requires not only clotting factor infusion but also surgical intervention.
A patient who would otherwise be at low risk for cerebrovascular accident had a right hemiparesis and aphasia. Evaluation revealed iron deficiency anemia secondary to menorrhagia and marked thrombocytosis, which responded to intramuscular and, later, oral iron replacement. Hemiparesis and aphasia resolved after a month.
Platelet counts were obtained in 60 patients with gravitational ulceration (GU), 60 with gravitational eczema (GE), 56 with endogenous eczema (EE) and 60 normal controls. Mean platelet volume (MPV), a broad index of platelet size, was estimated in the last 40 patients in each group (29 with EE). Causes of a reactive thrombocytosis were excluded. Platelet counts were significantly higher in both gravitational groups than in the EE group or the normal controls (P = 0.001). Ulcer healing produced no significant changes in platelet count, and patients with non-gravitational ulcers had normal platelet counts. MPV was significantly higher in both gravitational groups than in controls after correction for platelet count, by analysis of co-variance (P = 0.01). These differences in platelet parameters in gravitational disease suggest a possible role for platelets in this disease, and platelet inhibiting therapy may be of value at an early stage in the development of the condition.
Elevated plasma beta thromboglobulin (betatg) and decreased intracellular platelet betatg were found in patients with various myeloproliferative disorders. In secondary thrombocytosis, similar, but less marked changes were found. The abnormalities were increased during episodes of clinical thrombosis and could be suppressed in two-thirds of cases by aspirin therapy.
A periodic fall of platelet number characterizes an acquired pathological condition named cyclic thrombocytopenia. We observed a patient in whom the episodes of thrombocytopenia (platelet number less than 50 x 10(9)/l) were followed regularly by thrombocytosis (700-2300 x 10(9) platelets/l). The period of platelet count fluctuation was about 40 d. Morphological examination of bone marrow showed the cyclic disappearance of mature and immature megakaryocytes; bone marrow cultures revealed a periodic severe defect of both multilineage and single-lineage progenitor cell growth. When platelet count was falling, a mild defect of platelet aggregation and ATP release was observed, while platelet function was normal when platelet count was rising. Prednisone, thymopentin, high-dose intravenous gamma-globulin and splenectomy were without effect. After 4 years of cyclic platelet and megakaryocyte fluctuations, stable amegakaryocytic thrombocytopenia developed and the patient died of haemorrhagic stroke.
Megakaryocyte and erythroid colony formation in vitro by progenitors from the bone marrow and/or blood was studied in 61 patients with essential thrombocythaemia (ET) and 22 patients with reactive thrombocytosis (RT) using the methyl cellulose assay. 47 (77%) of the patients with ET showed megakaryocyte and/or erythroid spontaneous colony formation while 14 (23%) patients did not have any kind of spontaneous colonies. Spontaneous megakaryocyte colony formation was seen in 42 (69%) of the patients and 36 (59%) ET patients showed spontaneous erythroid growth. 31 patients had both types of spontaneous colonies. 11 patients showed only spontaneous megakaryocyte colony formation, and five patients only spontaneous erythroid growth. None of the patients with RT or of the normal controls showed either type of spontaneous growth. Neither the presence of spontaneous megakaryocyte colony formation nor the number of spontaneous colonies correlated with the platelet count. Patients with spontaneous megakaryocyte growth had significantly more often thromboembolic or haemorrhagic problems than those without spontaneous colony formation. In conclusion, it was found that a great majority of patients with ET but none of those with RT grow spontaneous megakaryocyte and/or erythroid colonies. Spontaneous colony formation is strong evidence for a myeloproliferative disorder. The presence of spontaneous colony growth is associated with an increased risk of thromboembolic or haemorrhagic complications regardless of the platelet count, particularly among young patients.