Increased risk of haematological malignancy in adults over age 60 with thrombocytopenia compared with matched controls: Time for an upfront bone marrow evaluation?

International societies have conflicting recommendations on whether bone marrow aspirate/biopsy (BMB) is needed during workup for isolated thrombocytopenia. Our objective was to determine if thrombocytopenia in patients aged ≥60 years is associated with an increased incidence of haematological malignancy. We performed a retrospective population-based cohort study in patients aged ≥60 years between January 1, 2009 to December 31, 2019. Exposed patients had specialist consultation for thrombocytopenia, with platelet count <100 × 109/L, but normal haemoglobin and white blood cell count. Unexposed patients were those who never had specialist consultation for thrombocytopenia and whose platelets were ≥100 × 109/L. The primary outcome was the diagnosis of haematological malignancy using a competing risk of death model. During 4.0 years (IQR 2.2-6.7) of follow-up, 378/4930 exposed (19.1/1000PY, 95% CI 17.1-21.0), and 204/17556 unexposed patients (2.5/1000PY, 95% CI 2.2-2.8) were diagnosed with haematological malignancy (HR 15.5 (95% CI 11.3-21.4, p < 0.0001) in year 1, and 5.3 (95% CI 4.4-6.6, p < 0.0001) in years 2+). This finding persisted in analyses stratified by sex, age, severity, or duration of thrombocytopenia, and treatment with corticosteroids within 2 weeks of consultation. This study found a strong association between isolated thrombocytopenia and haematological malignancy in patients ≥60 years, supporting consideration of diagnostic testing including BMB during outpatient specialist consultation.

Decreased plasma cytokines are associated with low platelet counts in aplastic anemia and immune thrombocytopenic purpura.

BACKGROUND: We previously found plasma levels of CD40 ligand (CD40L), chemokine (C-X-C motif) ligand 5 (CXCL5), chemokine (C-C motif) ligand 5 (CCL5) and epidermal growth factor (EGF) to be low in aplastic anemia (AA) patients and to be correlated with platelet count. OBJECTIVES: To study the association of CD40L, CXCL5, CCL5 and EGF with platelets. METHODS: We measured cytokines in the plasma of immune thrombocytopenic purpura (ITP) and AA patients using the Luminex assay and confirmed the results in a mouse model and in vitro experiments. RESULTS: Both ITP and AA showed similarly low levels of CD40L, CXCL5, CCL5 and EGF, compared with healthy controls. In ITP, levels of these proteins were significantly greater in patients with higher platelet counts than in those with lower platelet counts. In a murine thrombocytopenia model, levels of CD40L, CXCL5, CCL5 and EGF decreased with platelet count after immune-mediated destruction, while the cytokine levels increased when the platelet count recovered. In vitro, concentrations of these cytokines in the supernatants of platelet suspensions were proportional to platelet numbers, and levels in sera prepared by simple blood coagulation were equivalent to those in platelet-rich plasma-converted sera. mRNA expression for CXCL5, CCL5 and EGF was higher in platelets than in megakaryocytes, peripheral blood mononuclear cells, granulocytes and non-megakaryocytic bone marrow cells. CONCLUSIONS: Plasma CD40L, CXCL5, CCL5 and EGF are mainly platelet-derived, suggesting a role of platelets in immune responses and inflammation. Measurement of CD40L, CXCL5, CCL5 and EGF in human blood allowed testable inferences concerning physiology and pathophysiology in quantitative platelet disorders.

Differences in platelet function in patients with acute myeloid leukemia and myelodysplasia compared to equally thrombocytopenic patients with immune thrombocytopenia.

BACKGROUND: Severe thrombocytopenia is a major risk factor for hemorrhage, but platelet function and bleeding risk at low platelet counts are poorly understood, because of the limitations of platelet function testing at very low platelet counts. OBJECTIVES: To examine and compare platelet function in severely thrombocytopenic patients with acute myeloid leukemia (AML) or myelodysplasia (MDS) with that in patients with immune thrombocytopenia (ITP). METHODS: Whole blood flow cytometric measurement of platelet activation and platelet reactivity to agonists was correlated with the immature platelet fraction (IPF) and bleeding symptoms. RESULTS: Patients with AML/MDS had smaller platelets, lower IPF and substantially lower platelet surface expression of activated glycoprotein (GP)IIb-IIIa and GPIb, both with and without addition of ex vivo ADP or thrombin receptor-activating peptide, than patients with ITP. In both ITP and AML/MDS patients, increased platelet surface GPIb on circulating platelets and expression of activated GPIIb-IIIa and GPIb on ex vivo activated platelets correlated with a higher IPF. Whereas platelet reactivity was higher for AML/MDS patients with bleeding than for those with no bleeding, platelet reactivity was lower for ITP patients with bleeding than for those with no bleeding. CONCLUSIONS: AML/MDS patients have lower in vivo platelet activation and ex vivo platelet reactivity than patients with ITP. The proportion of newly produced platelets correlates with the expression of platelet surface markers of activation. These differences might contribute to differences in bleeding tendency between AML/MDS and ITP patients. This study is the first to define differences in platelet function between AML/MDS patients and ITP patients with equivalent degrees of thrombocytopenia.

6th International Immunoglobulin Symposium: poster presentations.

The posters presented at the 6th International Immunoglobulin Symposium covered a wide range of fields and included both basic science and clinical research. From the abstracts accepted for poster presentation, 12 abstracts were selected for oral presentations in three parallel sessions on immunodeficiencies, autoimmunity and basic research. The immunodeficiency presentations dealt with novel, rare class-switch recombination (CSR) deficiencies, attenuation of adverse events following IVIg treatment, association of immunoglobulin (Ig)G trough levels and protection against acute infection in patients with X-linked agammaglobulinaemia (XLA) and common variable immunodeficiency (CVID), and the reduction of class-switched memory B cells in patients with specific antibody deficiency (SAD). The impact of intravenous immunoglobulin on fetal alloimmune thrombocytopenia, pregnancy and postpartum-related relapses in multiple sclerosis and refractory myositis, as well as experiences with subcutaneous immunoglobulin in patients with multi-focal motor neuropathy, were the topics presented in the autoimmunity session. The interaction of dendritic cell (DC)-SIGN and alpha2,6-sialylated IgG Fc and its impact on human DCs, the enrichment of sialylated IgG in plasma-derived IgG, as wells as prion surveillance and monitoring of anti-measles titres in immunoglobulin products, were covered in the basic science session. In summary, the presentations illustrated the breadth of immunoglobulin therapy usage and highlighted the progress that is being made in diverse areas of basic and clinical research, extending our understanding of the mechanisms of immunoglobulin action and contributing to improved patient care.

T cell receptor VB repertoire diversity in patients with immune thrombocytopenia following splenectomy.

In recent years, a pathophysiological role for T cells in immune thrombocytopenia (ITP) has been established. We applied cDNA size distribution analysis of the T cell receptor (TCR) beta-variable (VB) complementarity-determining region 3 (CDR3) in order to investigate T cell repertoire diversity among immune thrombocytopenia patients who had either responded or not responded to splenectomy, and compared them to normal controls. ITP patients who had had a durable platelet response to splenectomy showed a mean 2.8 +/- 2.1 abnormal CDR3 size patterns per patient, similar to healthy volunteers (2.9 +/- 2.0 abnormal CDR3 size patterns). In contrast, patients unresponsive to splenectomy demonstrated evidence of significantly more clonal T cell expansions than patients who had responded to splenectomy or controls (11.3 +/- 3.3 abnormal CDR3 size patterns per patient; P < 0.001). Of the VB subfamilies analysed, VB3 and VB15 correlated with response or non-response to splenectomy, each demonstrating oligoclonality in non-responding patients (P < 0.05). These findings suggest that removal of the spleen may lead directly or indirectly to reductions in T cell clonal expansions in responders, or that the extent of T cell clonality impacts responsiveness to splenectomy in patients with ITP.

Fetal and neonatal thrombopoietin levels in alloimmune thrombocytopenia.

Thrombopoietin (Tpo) is the main hematopoietic growth factor for platelet production. Plasma Tpo levels in autoimmune thrombocytopenic patients are normal or slightly elevated. Although thrombocytopenia exists, Tpo levels are not increased because the produced megakaryocytes and platelets can bind circulating Tpo, thereby normalizing Tpo levels. In this study, plasma samples from fetuses and neonates with neonatal alloimmune thrombocytopenia (NAIT), a different form of immune thrombocytopenia, were measured. Umbilical cord samples from 50 fetuses before treatment because of severe thrombocytopenia and 51 fetuses after treatment, and peripheral blood samples of 21 untreated newborns with NAIT were analyzed. As controls, plasma Tpo levels were determined in 21 umbilical cord samples of 14 nonthrombocytopenic fetuses with hemolytic disease resulting from red blood cell alloimmunization and in umbilical cord samples of 51 healthy newborns. The values were also compared with the plasma Tpo levels in 193 healthy adults. Mean Tpo levels from the groups of fetuses and neonates, including both NAIT and control plasma, were slightly but significantly elevated compared with levels in healthy adults. Tpo levels in NAIT samples were not significantly different from the levels in hemolytic disease samples or in samples from healthy newborns. Thus, as in autoimmune thrombocytopenic patients, normal Tpo levels are present in NAIT patients.

Anti-platelet antibodies associated with the Canale-Smith syndrome bind to the same platelet glycoprotein complexes as those of idiopathic thrombocytopenic purpura patients.

The Canale-Smith syndrome (CSS) is an inherited disease characterized by massive lymphadenopathy, hepatosplenomegaly and systemic autoimmunity to erythrocytes and platelets. Idiopathic thrombocytopenic purpura (ITP) is an autoimmune disease in which approximately 60-80% of patients have anti-platelet antibodies directed against specific platelet glycoprotein complexes (GPCs) located on their membrane: GP IIb/IIIa, GPIb/IX, and GPIa/IIa. Almost all (95-100%) of the antibody-positive patients have antibodies directed against GPIIb/IIIa alone, or in combination with other glycoprotein targets. Our objective was to determine the specificities of the anti-platelet antibodies in CSS patients. The detection of anti-platelet antibodies was performed using a commercially available ELISA, the Pak-AUTO (GTI, Brookfield, WI), in which highly purified GPIIb/IIIa, GPIb/IX, and GPIa/IIa are immobilized on microtitre plates, incubated with serum or plasma, and subsequently developed with an antihuman polyclonal immunoglobulin. Of 14 CSS patients tested, 11 (79%) had anti-platelet antibodies in their serum directed toward at least one of the three major GPC, nine (82%) of which were against GPIIb/IIIa alone or in combination. Antibodies detected in the sera of ITP patients had similar specificities. No such antibodies were detected in samples from 25 consecutive normal controls. These results demonstrate that a genetically defined defect in lymphocyte apoptosis results in a humoral autoimmune response with anti-platelet specificities very similar to the common idiopathic form of autoimmune thrombocytopenia.

Novel approaches to refractory immune thrombocytopenic purpura.

Chronic immune thrombocytopenic purpura (ITP) is an organ-specific autoimmune bleeding disorder in which autoantibodies are directed against the individual's own platelets, resulting in increased Fc-mediated platelet destruction by macrophages in the reticuloendothelial system. Although ITP is primarily mediated by IgG autoantibodies, the production of these autoantibodies is regulated by the influence of T lymphocytes and antigen-presenting cells (APC). There is evidence that enhanced T-helper cell/APC interactions in patients with ITP may play an integral role in IgG antiplatelet autoantibody production. New therapies may improve platelet production, decrease platelet antibody production, and decrease monocyte function and/or B-cell and T-cell activities. Understanding these cellular immune responses in ITP may lead to the development of more specific immunoregulatory therapies for the management of this disease.

Platelets: an update on diagnosis and management of thrombocytopenic disorders.

Thrombocytopenia in the pregnant patient may result from a number of causes, most of which involve either immune-mediated platelet destruction or platelet consumption. Many of these disorders share clinical and laboratory features, making accurate diagnosis difficult. Moreover, uterine evacuation is indicated in the therapy of some disorders, while in others alternative interventions may allow the pregnancy to be carried to term. These and other issues are discussed as part of a comprehensive review of the differential diagnosis and management of thrombocytopenia in pregnancy. The term "refractory ITP" is used with reference to two distinct groups of patients: 1) patients in whom the platelet count cannot be easily increased, including those who are poorly responsive to initial single agent treatment, and 2) those with persistent thrombocytopenia despite the use of conventional therapies. An approach to management of the former group will be presented, followed by a discussion of patients with chronic refractory ITP. The latter will include presentation of new data on the role of Helicobacter pylori in ITP and whether its treatment ameliorates thrombocytopenia, as well as the use of rituximab and other modalities. Thrombotic microangiopathies such as thrombotic thrombocytopenic purpura (TTP) are rare, but life threatening causes of thrombocytopenia. Ultra-large multimers of von Willebrand factor (vWF) aggregate platelets intravascularly, and congenital or immune-mediated deficiencies of a metalloprotease that cleaves these ultra-large multimers may cause TTP. However, little information exists concerning the behavior of this protease in other physiological and pathological conditions. Levels of this protease have now been measured in healthy individuals of different ages, full-term newborns, pregnant women and a patients with variety of pathologic conditions, and these data will be reviewed herein. Heparin-induced thrombocytopenia/thrombosis (HIT/T) remains the most common antibody-mediated, drug-induced thrombocytopenic disorder, and a leading cause of morbidity and mortality. Based on clinical correlations and murine models, there is increasing evidence that antibodies to complexes between platelet factor 4 (PF4) and heparin cause HIT/T, and the molecular composition of the relevant antigen has also become better defined. However, the introduction of sensitive ELISAs to measure anti-PF4/heparin antibodies has complicated diagnosis in some settings in which the incidence of such antibodies in unaffected patients exceeds the incidence of the disease. In addition, the FDA approval of Lepirudin and Argatroban has expanded the repertoire of agents available for therapy of HIT/T and may change the approach to management of asymptomatic patients with thrombocytopenia. However, the optimal use of these drugs in commonly encountered settings remains in evolution, and a need for alternative approaches to prevention and treatment is evident.

Initial fetal platelet counts predict the response to intravenous gammaglobulin therapy in fetuses that are affected by PLA1 incompatibility.

OBJECTIVE: Fetal alloimmune thrombocytopenia is the result of maternal fetal platelet antigen incompatibility; intracranial hemorrhage is its most serious complication. Our previous studies have demonstrated an inability to accurately predict fetal platelet counts in this disorder. The goal of the present investigation was to identify factors that would predict the response of the fetal platelet count to therapy so that use of fetal blood sampling could be minimized. STUDY DESIGN: Patients who were eligible for the study were all those who (1) had alloimmune thrombocytopenia secondary to Pl(A1) (HPA-1a, Zw(A)) platelet antigen incompatibility, (2) were treated with maternally administered intravenous immunoglobulin at 1 g/kg of body weight per week, with or without low dose steroids, and (3) had percutaneous fetal blood sampling before the initiation of therapy (first fetal blood sampling) and again 3 to 7 weeks afterwards (second fetal blood sampling). RESULTS: In this retrospective review, 74 patients who were affected by alloimmune thrombocytopenia had a median platelet count of 21,000 per microliter at the first fetal blood sampling and 47,000 per microliter at the second fetal blood sampling, with a median increase in platelet count of 24,000 per microliter. Response to treatment was defined as either (1) an improvement in platelet count (the second fetal blood sampling greater than the first fetal blood sampling, and second fetal blood sampling > 20,000 per microliter) or (2) a minimal decline in platelet count (the first fetal blood sampling > or = 40,000 per microliter and the difference between the first and second fetal blood sampling < or = 10,000 per microliter). The first fetal blood sampling had prognostic value for the second fetal blood sampling (P = .0001), although the previous sibling birth platelet count and history of sibling intracranial hemorrhage did not predict the platelet count at the first or second fetal blood sampling or the change in platelet count between the samplings. When the patients were segregated to first fetal blood sampling of > 20,000 per microliter versus < or = 20,000 per microliter, the response rates for the 2 groups were 89% (33/37 patients) versus 51% (19/37 patients; P = .001). CONCLUSION: In fetal alloimmune thrombocytopenia secondary to Pl(A1) platelet antigen incompatibility, fetuses with platelet counts > 20,000 per microliter at the initiation of therapy were predicted to maintain their platelet count at the second fetal blood sampling at > 20,000 per microliter. The characteristics of the previous sibling, as previously reported, did not predict the initial fetal blood sampling, the second fetal blood sampling, or the response to treatment.

Alloimmune thrombocytopenia in the fetus and newborn.

Alloimmune thrombocytopenia is an interesting and challenging disease. Identification in the fetus and newborn by screening remains to be clarified. The primary clinical criterion for neonatal diagnosis appears to be a neonatal platelet count of <50 x 10(9)/L. Treatment of the neonate can be accomplished with intravenous immunoglobulin (IVIG) +/- steroids or with matched platelet transfusion. Cranial ultrasonography is important. Testing can be performed on the parents and requires a highly experienced laboratory. If an affected fetus is identified, based on a previous affected neonate and a homozygous father, antenatal management is needed. Studies have been completed that inform the still controversial decision. IVIG remains the basis of therapy but appears to require a higher dose (2 g/kg/week) and/or the addition of 1 mg/kg of prednisone in the highest risk cases, those with antenatal intracranial hemorrhage.

Anti-HPA-3A induces severe neonatal alloimmune thrombocytopenia.

OBJECTIVE: Fetal and neonatal alloimmune thrombocytopenia (AIT) caused by feto-maternal incompatibility at the HPA-1a (PLA-1) locus is well characterized. Alloimmunization and disease caused by HPA-3a is rare. STUDY DESIGN: We conducted a retrospective analysis of all known cases of AIT caused by HPA-3a incompatibility identified at 3 major reference laboratories from 1986 to 1996. Platelet antigen typing and antibody specificity were determined by serologic evaluation. In some cases confirmatory genotyping was performed. RESULTS: Fourteen cases of anti-HPA-3a-induced AIT in 11 families were identified. Five patients had a previous affected sibling, and 2 cases were firstborn children. All patients had severe thrombocytopenia at birth (platelet count <20 x 10(9)/L). Regardless of therapy, the median time to platelet recovery was 6 days (range, 3 to 23 days). Two (15%) patients had documented intracranial hemorrhage, 1 with severe sequelae including apnea and convulsions. A literature review describing 16 additional patients corroborates the finding of severe thrombocytopenia and a significant incidence of intracranial hemorrhage caused by HPA-3a incompatibility. CONCLUSION: AIT caused by incompatibility of HPA-3a is similar in severity to disease caused by incompatibility of HPA-1a. Affected families should be appropriately counseled and considered for antenatal therapy.

A pilot study of rhuIL-11 treatment of refractory ITP.

The objective of this research was to determine whether rhuIL-11 is an effective treatment in patients with refractory immune thrombocytopenic purpura (ITP). Platelet production is decreased in certain cases of refractory ITP. IL-11 stimulates megakaryocytopoiesis in vitro and was licensed for its clinical effects to ameliorate chemotherapy-induced thrombocytopenia. A pilot study was initiated, intending to enroll 12 patients with ITP. These patients were to receive rhuIL-11 (Neumega) at a dose of 50 microg/kg subcutaneously daily for 21 consecutive days and be observed afterward for 21 additional days. CBC with platelets were obtained twice weekly with visits and physical examinations weekly. The study was terminated after 7 patients were enrolled because of toxicity and lack of efficacy. All 7 patients had had ITP for >9 years and had failed splenectomy, intravenous gammaglobulin, corticosteroids, and a variety of other treatments. The patients at entry all had platelet counts <20,000/microl; 5 of 7 had counts <10,000/microl. The maximal median increase for any day of the study was 6,000/microl. No patient achieved a count of 30,000/microl, and only 3 patients achieved (once each) a platelet count >20,000/microl. Substantial toxicity was seen. The nadir hemoglobin decrease was a mean of 2 g/dl. rhuIL-11 was not effective at increasing the platelet count in any of these patients with refractory ITP. Toxicity was substantial. The lack of platelet response to rhuIL-11 in this study does not exclude the possibility of better effects at other doses and/or in less refractory patients.

Do the acute platelet responses of patients with immune thrombocytopenic purpura (ITP) to IV anti-D and to IV gammaglobulin predict response to subsequent splenectomy?

The acute platelet response to Intravenous Gammaglobulin (IVIG) has been reported to predict response to subsequent splenectomy of patients with ITP. The current study was undertaken to determine if the platelet response to IV anti-D (Winrho-SDF) predicts response to subsequent splenectomy. The 61 HIV-uninfected children and adults in this study had taken part in the pre-licensing studies of IV anti-D and were all those who not only had evaluable platelet responses to IV anti-D but also had undergone splenectomy and had information available describing its 1-year outcome. Results of treatment with IVIG were available in 38 of these 61 patients. Neither response to the initial infusion of IV anti-D, nor response to the initial or last IVIG, predicted the response in either children or adults to subsequent splenectomy. However, response to the last anti-D infusion in adults was strongly correlated (P = 0.003) to response to subsequent splenectomy as was hemolysis >/=2.0 gm/dl after IV anti-D (P = 0.03). There was no overall relationship between response to IV anti-D or IVIG, and response to subsequent splenectomy. However, a good platelet response in adults to the last IV anti-D and a hemoglobin decrease >/=2.0 gm/dl both appeared to predict response to subsequent splenectomy.

A dose of 75 microg/kg/d of i.v. anti-D increases the platelet count more rapidly and for a longer period of time than 50 microg/kg/d in adults with immune thrombocytopenic purpura.

Treatment with 75 microg/kg/d intravenous (i.v.) anti-D was compared with 50 microg/kg/d in a prospective randomized study of 27 RhD-positive, human immunodeficiency virus-negative, adult, acute, non-splenectomized patients with immune thrombocytopenic purpura (ITP) and platelet counts < or = 30 x 109/l. The higher dose resulted in greater median d 1 (43 x 109/l vs. 7.5 x 109/l; P = 0.012) and d 7 (153 x 109/l vs. 64.5 x 109/l; P = 0.001) platelet increases despite no greater haemoglobin decrease. Children with acute ITP receiving 75 microg/kg/d had overnight platelet increases in seven out of nine cases. The duration of effect at the 75 microg/kg/d dose was 46 d vs. 21 d (P = 0.03). Adverse events were mild to moderate and ameliorated with prednisone and acetaminophen premedication.

Th1 and Th2 cytokines in a patient with Evans' syndrome and profound lymphopenia.

A case of Evans' syndrome with IgM deficiency and lymphopenia was studied before and after splenectomy. The lymphopenia was as a result of profound reduction of CD4 and CD8 cells. Study of cytokine secretion before splenectomy revealed a spontaneous Th1- and Th2-type cytokine production, and complete suppression of transforming growth factor (TGF)-beta. After splenectomy, the patient achieved clinical remission, the natural killer (NK) cell number increased and the pattern of cytokine production showed normalization of interleukin (IL)-2, IL-4, IL-10, TGF-beta and abolition of interferon (IFN)-gamma production. We conclude that splenectomy had a beneficial effect owing to an increase in NK cells and an associated increase in TGF-beta production.

Spontaneous remission of congenital acute nonlymphoblastic leukemia with normal karyotype in twins.

BACKGROUND: Congenital acute nonlymphoblastic leukemia (cANLL) is an extremely rare event and represents only 0.5-1% of the leukemias in the first year of life. It is usually more common among patients with chromosomal abnormalities. Transient myeloproliferative disease (TMD) is an hyperleukocytosis entity that occurs almost exclusively in Down syndrome patients and remits spontaneously. Spontaneous remission of congenital leukemia has been reported and related to the presence of an extra chromosome 21. PROCEDURE: A pair of non-Down syndrome newborn twins presented with a clinical picture of skin rash and hyperleukocytosis. Twin B had full-blown cANLL with bone marrow, peripheral blood, skin, CSF, and placental invasion. Twin A presented transient peripheral blood and skin involvement by the same type of blast cells. No cytotoxic therapy was given. With 2 years follow-up, they continue to do well. RESULTS: Histologic and immunophenotypical analysis of placentas, cord blood, skin, CSF, bone marrows, and peripheral blood revealed a consistent picture of intrautero cANLL in twin B, with transplacental invasion of twin A. Normal and blast cells were found to be karyotypically normal. Spontaneous remission occurred. CONCLUSIONS: cANLL with karyotypically normal blasts can develop a self-limited clinical course, which has resemblances to TMD.