Ultrastructural Alterations of Megakaryocytes in Some Hematologic Disorders

Bone marrow and peripheral blood samples of patients affected by hematologic disorders involving the megakaryocytic line were examined at the electron microscope. While in idiopathic thrombocytopenic purpura the megakaryocytes appeared almost normal, in primary thrombocythemia there were various ultrastructural alterations interpreted as a counterpart of ineffective thrombocytopoiesis. In one patient with blastic chronic myeloid leukemia and in another with acute megakaryoblastic leukemia, the electron microscope study was very useful in the identification of immature megakaryocytes. In fact, analysis of various ultrastructural parameters allowed some blast cells to be attributed to the megakaryocytic series. Furthermore, platelet demarcation system abnormalities and alterations of the circulating thrombocytes confirm the hypothesis that there is a block in megakaryocytic maturation.

Amegakaryocytic Thrombocytopenia and Subsequent Aplastic Anemia Associated with Apparent Epstein-Barr Virus Infection

Acquired amegakaryocytic thrombocytopenia (AAT), a rare entity characterized by severe thrombocytopenia and the absence of megakaryocytes in the bone marrow, may mimic or precede the diagnosis of aplastic anemia (AA). Here, we describe a patient who presented with apparent Epstein-Barr virus (EBV)-associated immune thrombocytopenia resistant to several lines of therapies, which was in fact a form of AAT with some features of AA. He eventually responded to therapy with eltrombopag, cyclosporine A (CSA), and antithymocyte globulin (ATG) and recovered completely. EBV infection is known to cause a variety of benign and malignant hematologic disorders, including bone marrow failure. However, to the best of our knowledge, this is the first case report of EBV-associated AAT. Treatment options for AAT are still not well defined, and even response to eltrombopag together with CSA and ATG does not always imply successful therapy. The natural history of EBV infection may well be sufficient to explain unexpected eventual recovery.

Acquired amegakaryocytic thrombocytopenia previously diagnosed as idiopathic thrombocytopenic purpura in a patient with hepatitis C virus infection

We report the first case of a patient with hepatitis C virus (HCV) infection and idiopathic thrombocytopenic purpura (ITP), who later developed acquired amegakaryocytic thrombocytopenia (AAMT), with autoantibodies to the thrombopoietin (TPO) receptor (c-Mpl). A 64-year-old woman, with chronic hepatitis C, developed severe thrombocytopenia and was diagnosed with ITP. She died of liver failure. Autopsy revealed cirrhosis and liver carcinoma. In the bone marrow, a marked reduction in the number of megakaryocytes was observed, while other cell lineages were preserved. Therefore, she was diagnosed with AAMT. Additionally, autoantibodies to c-Mpl were detected in her serum. Autoantibodies to c-Mpl are one of the causes of AAMT, acting through inhibition of TPO function, megakaryocytic maturation, and platelet formation. HCV infection induces several autoantibodies. HCV infection might also induce autoantibodies to c-Mpl, resulting in the development of AAMT. This mechanism may be one of the causes of thrombocytopenia in patients with HCV infection.

Vascular Lesions in Nine Göttingen Minipigs with Thrombocytopenic Purpura Syndrome

Tissues from 9 Göttingen minipigs, aged 7 weeks to 1 year, with clinically diagnosed thrombocytopenic purpura syndrome were examined microscopically. All pigs had a history of spontaneous cutaneous purpura that was generally accompanied by disseminated visceral hemorrhages. Hematologic abnormalities included anemia (8 out of 9 pigs) and thrombocytopenia (7 out of 9 pigs), with platelet counts consistently below 20,000/μ. Microscopically, degenerative vascular lesions with morphologic features of arteriosclerosis were present in all 9 pigs. Vascular lesions affected small- to medium-sized muscular arteries and arterioles in various organs and extraparenchymal tissues; vessels of the renal pelvis and coronary arteries were consistently involved. Microscopic lesions in small- to medium-sized muscular arteries consisted of neointimal proliferation, medial thickening, luminal stenosis, thrombosis, disruption and fragmentation of the internal elastic lamina, necrosis of the tunica media, and medial deposits of myxoid matrix material. Microscopic lesions in arterioles included concentric laminar thickening of vessel walls (onion-skin pattern), endothelial cell hypertrophy, smooth muscle cell vacuolation, necrosis of the tunica media, thrombosis, and partial to complete luminal stenosis. Arteritis and/or periarteritis were also noted in 4 out of 9 pigs. Additional microscopic lesions included membranoproliferative glomerulonephritis (3 out of 9), myocardial microinfarcts (4 out of 7), renal interstitial fibrosis (2 out of 9), extramedullary hematopoiesis (6 out of 9), and intracapillary hyaline thrombi (2 out of 9). Degenerative vascular lesions have not been previously described in Göttingen minipigs with thrombocytopenic purpura syndrome. The etiopathogenesis of both the vascular lesions and thrombocytopenic purpura syndrome is currently unknown.

[Dynamic beta-endorphin determination in hematologic patients]

AIM

To perform a dynamic study of beta-endorphin, hypoxia-inducible factor-1alpha (HIF-1alpha), and cytokines in hematologic patients.

SUBJECTS AND METHODS

Fifty-nine patients with different types of acute leukemia (AL), 30 with anaplastic anemia (AA), 24 with thrombocytopenic purpura, and 20 healthy volunteers were examined during their 40-day stay at 3200 m above sea level. beta-Endorphin and HIF-la were measured by a sandwich-type enzyme immunoassay using the Abcam antibodies. Cytokines (interleukin (IL)-2, IL-6, and tumor necrosis factor-alpha) were estimated by enzyme immunoassay applying the Pro Con kits (Saint Petersburg).

RESULTS

Serum beta-endorphin concentrations were 1.5-2-fold above the normal values in the majority of patients with AL. The patients with initial leukocytosis at onset of disease were noted to have elevated white blood cell beta-endorphin concentrations up to 85.9 +/- 22.4 pg/ml; moreover, during chemotherapy this index increased about two times (170.74 +/- 33.8 pg/ml). There was a direct correlation between the concentrations of beta-endorphin and HIF-1alpha (r = 0.9) and an inverse correlation between the levels of IL-6 and beta-endorphin (r = -0.7). On ascending to 3200 m, under the conditions of hypoxic hypoxia the patients with AA or idiopathic thrombocytopenic purpura showed a considerable increase in serum beta-endorphin concentrations, mainly in the acute period of being at high altitudes.

CONCLUSION

Stress factors (tumor, use of cytostatics, pain, anemia, hypoxia, high environment temperature) stimulate the elaboration of beta-endorphin, particularly in the white blood cells of patients with AL during chemotherapy. The highest elevation in the index was seen during acute adaptation to hypoxic hypoxia.

Tosufloxacin tosilate-induced thrombocytopenic purpura

Tosufloxacin tosilate, a member of the naphthyridine group, was developed in Japan and became commercially available in 1990. We experienced a 69-year-old male who developed thrombocytopenic purpura due to tosufloxacin tosilate. The diagnosis was made when similar symptoms (petechiae and thrombocytopenia) were induced by inadvertent challenge with tosufloxacin tosilate. In this paper, we report the first case of tosufloxacin tosilate-induced thrombocytopenic purpura and present a brief published work review.

Clinical surveillance of thrombotic microangiopathies in Scotland, 2003-2005

The prevalence, incidence and outcomes of haemolytic uraemic syndrome (HUS) and thrombotic thrombocytopaenic purpura (TTP) are not well established in adults or children from prospective studies. We sought to identify both outcomes and current management strategies using prospective, national surveillance of HUS and TTP, from 2003 to 2005 inclusive. We also investigated the links between these disorders and factors implicated in the aetiology of HUS and TTP including infections, chemotherapy, and immunosuppression. Most cases of HUS were caused by verocytotoxin-producing Escherichia coli (VTEC), of which serotype O157 predominated, although other serotypes were identified. The list of predisposing factors for TTP was more varied although use of immunosuppressive agents and severe sepsis, were the most frequent precipitants. The study demonstrates that while differentiating between HUS and TTP is sometimes difficult, in most cases the two syndromes have quite different predisposing factors and clinical parameters, enabling clinical and epidemiological profiling for these disorders.

Lack of clinical efficacy of rituximab in the treatment of autoimmune neutropenia and pure red cell aplasia: implications for their pathophysiology

We describe 11 patients with severe refractory autoimmune cytopenias treated with the anti-CD20 monoclonal antibody rituximab. Six patients had autoimmune neutropenia (AIN), two had pure red cell aplasia (PRCA), one had AIN and autoimmune haemolytic anaemia, one had AIN and immune thrombocytopaenia purpura (ITP) and one had PRCA and ITP. Rituximab was administered at a dose of 375 mg/m(2) as an intravenous infusion weekly for 4 weeks. Six of eight patients with AIN and all three patients with PRCA did not respond. Two patients died: one with resistant AIN and autoimmune haemolytic anaemia died of pneumocytis pneumonia infection, and one with PRCA and ITP died of an acute exacerbation of bronchiectasis. Rituximab in AIN and PRCA appears to be less effective than Campath-1H when compared to historical data from our group. This supports the hypothesis that T cells may be important in the pathophysiology of AIN and PRCA.

Novel ADAMTS-13 mutations in an adult with delayed onset thrombotic thrombocytopenic purpura

BACKGROUND

Thrombotic thrombocytopenic purpura (TTP) is associated with congenital and acquired deficiency of ADAMTS-13, a metalloprotease that cleaves von Willebrand factor (VWF) and reduces its adhesive activity. Mutations throughout the ADAMTS13 gene have been identified in congenital TTP patients, most of whom have initial episodes during infancy or in early childhood.

PATIENTS AND METHODS

We report the case of an adult male who was diagnosed with idiopathic thrombocytopenic purpura at age 34, and with TTP 14 years later. The patient was compound heterozygous for an 18 bp in-frame deletion (C365del) in the disintegrin domain and a point mutation of R1060W in the seventh thrombospondin domain of the ADAMTS-13 gene.

CONCLUSIONS

In vitro studies found that C365del and R1060W severely impair ADAMTS-13 synthesis in transfected Hela cells, whereas the deletion mutant also failed to cleave VWF under static and flow conditions.

Platelet dysfunction-eosinophilia syndrome in parasitized Venezuelan children

Platelet dysfunction was detected in six children with purpura and eosinophilia. We conducted clinical evaluations, hematologic and platelet function tests, clotting studies (bleeding time, prothrombin time, partial thromboplastin time, thrombin time, factor XIII, factor VIII, and von Willebrand factor), assays for IgG and IgM antibodies to platelets, and a search for stool parasites. Mild bleeding phenomena (ecchymoses, petechiae, epistaxis, and gingival) were transient. All children showed intestinal parasites and marked eosinophilia (mean count = 2,615.2 cells/muL, 95% confidence interval = 1,259.6-5,429.8). Main abnormalities included prolonged bleeding times (50%) and defective aggregation with collagen (100%) adrenaline (66%), or ADP (66%). Antibodies to platelets were not detected. Anti-parasite therapy reversed the hemorrhagic manifestations and normalized eosinophil counts and platelet alterations. No relationship could be established between excess eosinophils, intensity of bleeding, or type and degree of platelet abnormalities. Thrombocytopathic features mimicked the intrinsic defect of storage pool disease. The possible pathogenic roles of eosinophilia and parasitism are reviewed. This is the first report of this pathologic combination in Latin American children.

Platelet-associated CD154 in immune thrombocytopenic purpura

CD40-ligand (CD154) is expressed on activated CD4+ T lymphocytes and is essential for the T cell–dependent activation of B lymphocytes. CD154 is also expressed at the activated platelet surface. In this study, we show that platelet-associated CD154 is increased in immune thrombocytopenic purpura (ITP), a disease characterized by an autoimmune response against proteins of the platelet membrane. CD154 and its messenger RNA were also present in increased amounts in the megakaryocytes of patients with ITP. We found that platelet-associated CD154 is competent to induce the CD40-dependent proliferation of B lymphocytes, and we observed an in vitro CD154-dependent production of antibodies to the GPIIb/IIIa complex (integrin αIIbβ3) when platelets and peripheral blood B lymphocytes from ITP patients with circulating anti-GPIIb/IIIa antibody were cultured together. Therefore, platelet-associated CD154 expression is increased in ITP and is able to drive the activation of autoreactive B lymphocytes in this disease.

Autoimmune cytopenias associated with autoantibodies to nuclear envelope polypeptides

A subset of anti-nuclear autoantibodies (ANA) are directed against nuclear envelope (NE) polypeptides and display by indirect immunofluorescence (IIF) a ring-like fluorescent pattern. We report herein 19 patients with autoimmune cytopenias associated with antibodies (Abs) to NE polypeptides. Anti-NE specificity was determined by immunoblot, using NE preparations and purified lamina fractions. Eleven sera reacted with lamin B(1), and two reacted with both lamin B(1) and an unidentified 150-kDa protein (p150). One serum reacted with only p150. Four sera reacted with lamins A and C, and one reacted with and an unidentified 52-kDa NE polypeptide (p52). Autoimmune cytopenias included hemolytic anemia (7 cases), thrombocytopenia (13 cases), and neutropenia (6 cases). Five patients had 2 (3 cases) or 3 (2 cases) different cytopenias. Antiphospholipid antibodies (APLA) were detected in 14 patients, 2 of whom experienced thromboembolic events. A liver disorder was present in 7 patients. Systemic lupus erythematosus and lupus-like syndrome were diagnosed in 11 and 2 patients, respectively. Cytopenias responded to steroids alone (13 patients), or together with intravenous immunoglobulins (2 patients), or cyclophosphamide (2 patients). Two patients did not require treatment. Our results suggest that anti-NE Abs need to be sought for in patients with peripheral cytopenias, particularly when they are associated with APLA and/or liver disorders. Their detection strongly suggests an autoimmune process. Such cytopenias are often manifestations of a lupus or lupus-like disease and are responsive to steroids.

[Fatal untoward effect of furosemide: immunocytopenic purpura and cerebral hemorrhage]

A 74 year old man was admitted to the hospital for purpura. The history revealed coronary heart disease. Bypass surgery had been performed 18 months ago. Furosemide had recently been prescribed for cardiac insufficiency and the patient had taken the drug intermittently over two weeks. Laboratory analysis showed severe thrombocytopenia. Despite immediate treatment with intravenous prednisolone and platelet transfusions the patient succumbed to cerebral hemorrhage. Autopsy confirmed a diffuse hemorrhagic diathesis and a cellular response of the bone marrow typical for an acute immune reaction. The start of the purpura nine to ten days after the first dose of furosemide, the exclusion of other possible causes for purpura and the focal proliferation of T-lymphocytes in the bone marrow render it highly probable, that furosemide was responsible for the fatal thrombocytopenia. Furosemide is discussed to have a potential for autoimmunological untoward effects due to its sulfonamide structure. Few case reports describe vasculitic and allergic phenomena. The generation of antibodies against thrombocytes and the depression of megakaryocytic function are thought to be involved. Our patient had been treated with furosemide during the bypass surgery 18 months before the development of purpura. A sensitization to furosemide probably took place at that time.

Acquired amegakaryocytic thrombocytopenia purpura and eosinophilic fasciitis: a long relapsing and remitting course

Acquired amegakaryocytic thrombocytopenia purpura (AATP) is a rare disorder of unclear etiology characterized by severe thrombocytopenia, preservation of erythroid and myeloid cell lines, and absence of megakaryocytes in the bone marrow. We report herein a patient who developed eosinophilic fasciitis preceding a diagnosis of AATP. Longitudinal follow-up and treatment of this individual show a relapsing and remitting disease course which appears closely related to the dosing of cyclosporine. Later in the treatment course, dosing of anti-thymocyte globulin (ATG) appeared to have important beneficial contributions in the management of this patient's disease.

Low platelet counts alone do not cause bleeding in an experimental immune thrombocytopenic purpura in mice

BACKGROUND AND OBJECTIVES

The physiopathogenesis of hemorrhagic phenomena in patients with autoimmune thrombocytopenic purpura is associated with low platelet levels. In the present work the relation between thrombocytopenia and bleeding was examined. The possible participation of endothelial cells in bleeding was also investigated.

DESIGN AND METHODS

Immune thrombocytopenia and bleeding were studied in mice injected with anti-mouse and anti-human platelet polyclonal rabbit IgG. Platelet levels were measured at different times and bleeding signs were systematically recorded. ANOVA tests were used to compare platelet levels. Binding of anti-platelet antibodies to vascular endothelial cells was analyzed by immunohistochemistry.

RESULTS

Three different doses of anti-platelet IgG caused the same low platelet levels, but bleeding occurred only with high doses of anti-platelet IgG irrespective of the platelet levels. No inflammation around blood vessels was observed in paraffin-embedded tissue sections of organs. Immunohistochemistry demonstrated anti-platelet antibodies bound to vascular endothelium.

INTERPRETATION AND CONCLUSIONS

We showed lack of correlation between platelet counts and bleeding in a murine model. The binding of anti-platelet IgG to endothelial cells of small vessels is an indication that antibody-mediated endothelial activation, in addition to thrombocytopenia, could be participating in bleeding.

Successful treatment with interferon alfa in infiltrating angiolipoma: a case presenting with Kasabach-Merritt syndrome

We report a case of infiltrating angiolipoma who presented with a large mass on the shoulder and the signs of Kasabach-Merritt syndrome. She improved dramatically within one month and the mass completely disappeared after six months of interferon treatment.

Immune complex-associated thrombocytopenic purpura syndrome in sexually mature Göttingen minipigs

Eleven cases of thrombocytopenic purpura (TP) in sexually mature male or female Göttingen minipigs occurred sporadically over 3 1/2 years in a closed breeding colony protected by strict barrier conditions. Typical clinical signs of TP, including extensive subcutaneous haemorrhages, were seen in all affected animals. Haematological abnormalities included marked thrombocytopenia and anaemia. A consistent histopathological finding was the presence of membranoproliferative lesions in the renal glomeruli. Immunohistochemically, glomerular deposits were positively labelled for complement factor C1q and often also for immunoglobulins. Bone marrow findings consisting of increased numbers of immature and apoptotic megakaryocytes were compatible with a state of increased platelet consumption. Based on the combined presence of thrombocytopenia and renal immune complexes, it is suggested that the syndrome was related to a type III hypersensitivity reaction. However, further studies are needed to verify this hypothesis.

Membranous nephropathy associated with chronic immune thrombocytopenic purpura in childhood

Membranous nephropathy has been associated with many autoimmune diseases. We describe a child with membranous nephropathy associated with chronic immune thrombocytopenic purpura (ITP) and Coombs'-positive hemolytic anemia. After 3 years of ITP, the patient developed nephrotic syndrome during a flare of ITP. A biopsy specimen showed membranous nephropathy. Treatment with corticosteroids led to improvement of the thrombocytopenia and resolution of the proteinuria. Two years later, the patient again developed thrombocytopenia and proteinuria. Both conditions resolved after treatment with corticosteroids. This case suggests that ITP can cause membranous nephropathy.

Thrombocytopenic purpura associated with brucellosis: report of 2 cases and literature review

Mild hematologic abnormalities are common in the course of human brucellosis; however, they generally resolve promptly with treatment of the disease. Occasionally, thrombocytopenia is severe and can be associated with bleeding into the skin (purpura) and from mucosal sites. We describe 2 patients infected with Brucella melitensis who presented with thrombocytopenic purpura, and we review 41 additional cases from the literature. Patients ranged in age from 2 to 77 years, and both sexes were affected equally. In the majority of cases, examination of the bone marrow revealed abundant megakaryocytes. Possible mechanisms involved in thrombocytopenia include hypersplenism, reactive hemophagocytosis, and immune destruction of platelets. Recognition of this complication is essential, since hemorrhage into the central nervous system is associated with a high mortality rate.

Mathematical analysis of the relative contributions of decreased production and increased peripheral destruction in idiopathic thrombocytopenic purpura and implications in splenectomy

We utilize a model of platelet concentration kinetics and bone marrow production based on three terms (a constant loss term, a random loss term and a higher order loss term) to compare a hypoplastic bone marrow patient and a patient with Idiopathic Thrombocytopenic Purpura (ITP) for the same platelet concentration. We compare this model to published data and show that in many ITP patients there is an overall decrease in platelet production. However, for almost all cases of ITP there is an increase in peripheral platelet destruction, even in those cases where total bone marrow production is less than that in a normal individual or is severely depressed. We are able to graphically depict the variable contributions of decreased production and increased peripheral destruction in patients with ITP and hence give insight into their relative contributions in a given patient. We apply a unique feature of our model, the newly postulated destruction term proportional to the platelet concentration squared (the higher order loss term), to explain cases of antibody negative ITP. Application of our model to data on patients splenectomized as treatment for ITP shows promise in predicting which patients are likely to respond.

Human megakaryocyte polyploidization is associated with a decrease in GPIIIA expression

Megakaryocytes are platelet forming cells and are characterized by polyploidization, a phenomenon by which nuclear division occurs without corresponding cytoplasmic separation. Among the markers allowing to identify megakaryocytes, glycoprotein (GP) IIIa with GPIb and GPIIb are the most important. Using GPIIIa as a marker to recognize megakaryocytes in the bone marrow, we have estimated GPIIIa expression by flow cytometry in megakaryocyte populations from normal individuals and from patients with chronic myelogenous leukemia, immune thrombocytopenic purpura or polycythemia vera. We showed that the expression of GPIIIa is decreasing during megakaryocyte polyploidization in normal and pathological situations.

Transforming growth factor-beta1 (TGF-beta1) induces thrombopoietin from bone marrow stromal cells, which stimulates the expression of TGF-beta receptor on megakaryocytes and, in turn, renders them susceptible to suppression by TGF-beta itself with high specificity

The present study was designed to test the concept that platelets release a humoral factor that plays a regulatory role in megakaryopoiesis. The results showed that, among various hematoregulatory cytokines examined, transforming growth factor-beta1 (TGF-beta1) was by far the most potent enhancer of mRNA expression of bone marrow stromal thrombopoietin (TPO), a commitment of lineage specificity. The TPO, in turn, induced TGF-beta receptors I and II on megakaryoblasts at the midmegakaryopoietic stage; at this stage, TGF-beta1 was able to arrest the maturation of megakaryocyte colony-forming units (CFU-Meg). This effect was relatively specific when compared with its effect on burst-forming unit-erythroid (BFU-E) or colony-forming unit-granulocyte-macrophage (CFU-GM). In patients with idiopathic thrombocytopenic purpura (ITP), the levels of both TGF-beta1 and stromal TPO mRNA were correlatively increased and an arrest of megakaryocyte maturation was observed. These in vivo findings are in accord with the aforementioned in vitro results. Thus, the results of the present investigation suggest that TGF-beta1 is one of the pathophysiological feedback regulators of megakaryopoiesis.

Relationship between megakaryocyte mass and serum thrombopoietin levels as revealed by a case of cyclic amegakaryocytic thrombocytopenic purpura

Cyclic amegakaryocytic thrombocytopenic purpura is a rare syndrome characterized by periodic failure of megakaryocytopoiesis. In this report we describe a patient with cyclic amegakaryocytic thrombocytopenic purpura associated with a megakaryocyte specific serum IgG antibody, who responded to cyclosporin A therapy. Serial serum thrombopoietin assays during an episode of platelet cycling demonstrated a reciprocal relationship between serum thrombopoietin level and megakaryocyte mass, suggesting that megakaryocytes have an important role in the regulation of thrombopoietin metabolism.

Danazol therapy in cyclic acquired amegakaryocytic thrombocytopenic purpura: a case report

Cyclic acquired amegakaryocytic thrombocytopenic purpura (AATP) is a rare disorder characterized by periodic fluctuations in the platelet counts due to a defect in the platelet production. We describe a 42-year-old female with cyclic AATP, in whom the cyclic fluctuations in the platelet counts ceased with danazol therapy. The pathogenesis of the disease and the possible mechanisms of danazol action have been reviewed.

Thrombotic thrombocytopenic purpura: understanding a disease no longer rare

Serial studies of plasma samples from patients during episodes of thrombotic thrombocytopenic purpura (TTP) have often shown either the presence of unusually large (UL) von Willebrand factor (vWf) multimers or, alternatively, absence of the largest plasma vWf forms. The presence of ULvWf multimers in TTP patient plasma may reflect impaired processing of the ULvWf forms released from endothelial cells. The disappearance of ULvWf and large vWf multimers in some TTP patient plasma samples during acute TTP episodes may be predominantly because these ULvWf forms, along with the largest vWf multimers, bind to platelets and cause aggregation. Serial flow cytometry studies of EDTA-whole blood samples from patients with initial episode, intermittent, and chronic relapsing types of TTP confirm that vWf is the likely aggregating agent, perhaps in association with fluid shear stress. The amount of vWf bound to single platelets has been found to be significantly increased during TTP relapses relative to remission periods in patients with all types of TTP. A substance in normal platelet-poor plasma and the cryoprecipitate-depleted fraction of normal plasma (cryosupernatant) is capable in vitro of reversibly reducing the size of ULvWf multimeric forms released by endothelial cells into the somewhat smaller vWf multimers ordinarily in circulation. This activity has characteristics of a limited disulfide bond reductase. The process of ULvWf breakdown may be made irreversible by the tandem proteolysis, catalyzed by a vWf metalloproteinase, of partially reduced vWf multimers. Several patients with chronic relapsing TTP have decreased or absent plasma vWf metalloproteinase activity, apparently on a congenital basis. Adult initial episode and intermittent TTP patients have been found to have vWf metalloproteinase activity inhibited by an autoantibody during, but not after, TTP epidsodes.

A man with palpable purpuric hand lesions

A 75-year-old man with seronegative rheumatoid arthritis presented with a three-day history of low-grade fever, new arthralgias, mouth sores, and bilateral cutaneous hand lesions. He had not had hand trauma.

Immunological abnormalities in splenic marginal zone cell lymphoma

The clinical features of patients with splenic marginal zone cell lymphoma (SMZCL) have rarely been reported. In the present study, immunological abnormalities, particularly hematological abnormalities, observed in SMZCL were described. Autoimmune hemolytic anemia, immune thrombocytopenia, and appearance of lupus anticoagulant were observed in 2 of 3 patients with SMZCL. Other abnormal data including monoclonal gammopathy and cold agglutinin were also observed in 2 of the 3 patients. Immunological abnormalities may be characteristic complications in patients with SMZCL and must be followed carefully, since they may be a reliable marker of this type of lymphoma activity.

Thrombocytopenic coagulopathy (Kasabach-Merritt phenomenon) is associated with Kaposiform hemangioendothelioma and not with common infantile hemangioma

Children with a large vascular tumor and associated Kasabach-Merritt coagulopathy respond inconsistently to therapy and have a high mortality rate. For this reason, we undertook a retrospective study of 21 such patients, and focused on clinical, radiographic, and histopathologic features. The male to female ratio was 1:1.6. Tumor was noted at birth in 50 percent of patients; the remainder appeared throughout infancy. The location was cervicofacial (n = 2), shoulder/upper limb (n = 4), trunk including retroperitoneum (n = 11), and lower limb (n = 4). These tumors grew rapidly to large size and were characterized by cutaneous purpura, edema, and an advancing ecchymotic margin. In contrast to common hemangioma, magnetic resonance imaging showed diffuse enhancement with ill-defined margins, cutaneous thickening, stranding of subcutaneous fat, hemosiderin deposits, and small feeding and draining vessels. All tumors were Kaposiform hemangioendothelioma (KHE); none were infantile hemangioma. Light microscopy showed irregular lobules or sheets of poorly formed, small vascular channels infiltrating and entrapping normal tissues. Characteristic features included spindle-shaped endothelial cells, diminished pericytes and mast cells, microthrombi, and hemosiderin deposits. Wide endothelial intercellular gaps and incomplete basement membranes were seen by electron microscopy. Dilated, hyperplastic, lymphaticoid channels were prominent in one tumor. KHE in 14 infants was treated with interferon alpha-2a: 6 had accelerated regression; 2 had stabilization of growth; and 6 evidenced no response. The mortality rate was 24 percent (5 of 21); this included three infants with retroperitoneal KHE. Kasabach-Merritt phenomenon does not occur with common hemangioma. Rather it is associated with the more aggressive KHE and rarely with other vascular neoplasms. Variable response to current pharmacologic therapy underscores our inadequate knowledge of the pathogenesis of thrombocytopenia in KHE.

Magnetic resonance imaging of reticulo-endothelial system in patients with idiopathic thrombocytopenic purpura

Idiopathic thrombocytopenic purpura (ITP) is characterized by accelerated platelet destruction in the reticulo-endothelial system (RES). We performed magnetic resonance imaging (MRI) to estimate the degree of activated RES. MRI was performed with a Gyroscan S-15 (1.5 tesla) in 7 healthy volunteers and 22 patients with ITP. The 22 patients included 19 who were at initial diagnosis or were nonresponders to the therapy (non-DX group), and 3 who were responders. For the non-DX group, the T1 relaxation time of the spleen was initially significantly shorter than for healthy volunteers, but normalized after responding to the therapy. The initially shorter T1 values of the spleen for ITP patients correlated with a low platelet count (P < 0.05). This condition may indicate foam cells or fatty components due to platelet destruction. There was no significant relationship between the sequestration in (111)In-scan and T1 values of the liver or spleen. However, MRI is a noninvasive method, and it may be a clinically useful tool in the evaluation of RES in patients with ITP.

Abnormal gamma IFN and alpha TNF secretion in purified CD2+ cells from autoimmune thrombocytopenic purpura (ATP) patients: their implication in the clinical course of the disease

Gamma inferferon (gamma IFN), alpha tumor necrosis factor (alpha TNF), and interleukin 6 (IL-60) are cytokines produced by a wide variety of cells, including T lymphocytes and NK cells. These cytokines affect B-cell proliferation and differentiation into immunoglobulin secreting cells. In addition, gamma IFN and alpha TNF also enhance the function of macrophages, upregulating the expression of their IgG receptors. Abnormalities in the production of these cytokines may be involved in the clinical course of autoimmune thrombocytopenic purpura (ATP). This paper describes the production of these cytokines in PHA-stimulated peripheral blood CD2+ cells from ATP patients. Both gamma IFN and alpha TNF were significantly increased in PHA-stimulated CD2+ cells from therapy-dependent ATP patients (platelet counts < 50,000/microliter), as compared to ATP patients with stable disease (sustained platelet counts < 50,000/microliter without need treatment) (P < 0.05). No significant differences were found in gamma IFN production by PHA-stimulated CD2+ cells between therapy-dependent ATP patients and healthy controls (P < 0.05). However, the production of alpha TNF by PHA-stimulated CD2+ cells from therapy-dependent ATP patients was significantly higher compared to that found in healthy controls (P < 0.05). There were no significant differences in IL-6 production by PHA-stimulated CD2+ cells from ATP patients and healthy controls (P < 0.05). These findings demonstrate abnormal gamma IFN and alpha TNF secretion in purified CD2 cells from ATP patients. The clinical severity of the disease is associated with the altered secretion of these lymphokines by CD2 cells.

Thrombocytopenic purpura in lambs given bovine colostrum

Newborn lambs which had been given colostrum from a single cow developed thrombocytopenia and seven died. The clinical signs included purpura, haemoglobinuria, melaena, dullness and lethargy. The lambs died at one to two days old. Post mortem examination revealed widespread haemorrhages throughout the body. Lambs given small amounts of colostrum developed a transient thrombocytopenia but did not die.

Acquired amegakaryocytic thrombocytopenic purpura with humoral inhibitory factor for megakaryocyte colony formation

A 67-year-old man with thrombocytopenia, and amegakaryocytic but otherwise normal bone marrow, was evaluated. Antibody against thrombocytes was negative and the half-life of thrombocytes was normal. In vitro clonal culture of the patient's bone marrow cells yielded no megakaryocyte colony with normal granulocyte-macrophage and erythroid colony formation. Megakaryocyte colony formation of the control bone marrow cells was significantly suppressed by the addition of the patient's serum to the culture, suggesting the existence of humoral inhibitory factor(s) for megakaryocyte colony formation. Therapeutic trials with plasma exchange, cyclosporine, prednisolone, and cyclosporine plus prednisolone were all unsuccessful, but serious bleeding has been absent.

T suppressor activated lymphocytes (CD8+/DR+) inhibit megakaryocyte progenitor cell differentiation in a case of acquired amegakaryocytic thrombocytopenic purpura

Acquired amegakaryocytic thrombocytopenic purpura (AATP) is a rare disease, characterized by isolated thrombocytopenia and the absence of megakaryocytes in bone marrow. Recent studies suggest that this syndrome is due to diverse etiologies. Humoral or cellular mediated suppression has been alternately demonstrated using an in vitro colony assay for megakaryocytic progenitor cells (colony forming units megakaryocyte, [CFU-meg]). We studied a patient affected by AATP, who was not responsive to conventional therapy, but did respond to antilymphocyte globulin. The immunological characterization of marrow lymphocytes showed a marked increase of T activated suppressor cells (CD8+/DR+). Low density bone marrow mononuclear nonadherent cells (MNAC) from the patient, either in aplastic phase or in remission phase, were plated in plasma clot either directly or after T cell depletion (T-dep MNACs). Co-cultures with normal marrow cells were performed using either T lymphocytes from a normal volunteer donor or patient T lymphocytes. In some experiments we added autologous serum instead of fetal calf serum (FCS). In standard conditions, we observed increased colony formation, which was more evident in remission phase and especially significant after T cell depletion. The T lymphocytes from patient marrow did not modify the number of CFU-meg when co-cultured with allogeneic cells. These results indicate that an immune-mediated mechanism could be responsible for this case of AATP, and that the T cell subset CD8+/DR+ is capable of exerting suppression on megakaryocyte differentiation. This suppressive effect seems restricted to patient cells, suggesting a specific auto-sensitization.

Acute thrombocytopenic purpura in an infant with Cushing's syndrome: a case report

This paper describes the case of a female child who presented with severe thrombocytopenia and Cushing's syndrome. The underlying cause was found to be an adrenal cortical adenoma, removal of which was followed by complete recovery of both conditions. The pathogenesis of both presenting features in relation to the adrenal tumor is discussed.

Mononeuropathy multiplex complicating idiopathic thrombocytopenic purpura

Peripheral nerve hemorrhage has rarely been reported with idiopathic thrombocytopenic purpura (ITP). We describe a patient with severe ITP who developed mononeuropathy multiplex. At autopsy, multisystem hemorrhages were found, including intraneural hemorrhage, without evidence of extraneural hematoma. ITP represents an unusual cause for clinical mononeuropathy multiplex.

Thrombotic thrombocytopenic purpura first seen as massive vaginal necrosis

Thrombotic thrombocytopenic purpura is a hematologic disorder that affects the microcirculation. A 38-year-old woman was first seen with fever, thrombocytopenia, and vaginal bleeding. Pelvic examination revealed massive vaginal necrosis. Hematology consultation resulted in agreement with the diagnosis of thrombotic thrombocytopenic purpura. This is the first reported case of thrombotic thrombocytopenic purpura first seen as vaginal necrosis of which we are aware.

Studies of in vitro megakaryocytopoiesis in adult immune thrombocytopenic purpura (ITP)

In vitro megakaryocytopoiesis was studied in 8 patients with chronic immune thrombocytopenia (ITP). A significant increase of megakaryocyte (MK) colony formation was observed in 5/5 patients studied. Furthermore, the serum of these 8 patients was able to enhance MK colony formation by normal marrow cells. This effect was neither due to a decrease of inhibitors of megakaryocytopoiesis such as betathromboglobulin (beta TG) nor to the IgG fraction of patients' serum. In addition, the level of interleukin 6, which is above all a stimulus for MK maturation, was found within the normal range in 8/8 patients tested. These data suggest that in chronic ITP there is an increase of MK progenitor cell number which may be due to an increased level of MK colony-stimulating activity.