Immune thrombocytopaenic purpura: an autoimmune cross-link between infections and vaccines

Missing Cells: Pathophysiology, Diagnosis, and Management of (Pan)Cytopenia in Childhood

Peripheral blood cytopenia in children can be due to a variety of acquired or inherited diseases. Genetic disorders affecting a single hematopoietic lineage are frequently characterized by typical bone marrow findings, such as lack of progenitors or maturation arrest in congenital neutropenia or a lack of megakaryocytes in congenital amegakaryocytic thrombocytopenia, whereas antibody-mediated diseases such as autoimmune neutropenia are associated with a rather unremarkable bone marrow morphology. By contrast, pancytopenia is frequently associated with a hypocellular bone marrow, and the differential diagnosis includes acquired aplastic anemia, myelodysplastic syndrome, inherited bone marrow failure syndromes such as Fanconi anemia and dyskeratosis congenita, and a variety of immunological disorders including hemophagocytic lymphohistiocytosis. Thorough bone marrow analysis is of special importance for the diagnostic work-up of most patients. Cellularity, cellular composition, and dysplastic signs are the cornerstones of the differential diagnosis. Pancytopenia in the presence of a normo- or hypercellular marrow with dysplastic changes may indicate myelodysplastic syndrome. More challenging for the hematologist is the evaluation of the hypocellular bone marrow. Although aplastic anemia and hypocellular refractory cytopenia of childhood (RCC) can reliably be differentiated on a morphological level, the overlapping pathophysiology remains a significant challenge for the choice of the therapeutic strategy. Furthermore, inherited bone marrow failure syndromes are usually associated with the morphological picture of RCC, and the recognition of these entities is essential as they often present a multisystem disease requiring different diagnostic and therapeutic approaches. This paper gives an overview over the different disease entities presenting with (pan)cytopenia, their pathophysiology, characteristic bone marrow findings, and therapeutic approaches.

Eltrombopag as steroid sparing therapy for immune thrombocytopenic purpura in systemic lupus erythematosus

BACKGROUND

Eltrombopag activates the thrombopoietin (TPO) surface receptor on the megakaryocyte, which increases the production of platelets, and rapidly improves circulating platelet numbers in patients with immune thrombocytopenic purpura (ITP). This allows for rapid tapering and/or cessation of corticosteroid therapy. Less is known about the platelet response to this drug in ITP associated with systemic lupus erythematosus (SLE).

METHODS

A retrospective review was performed of the clinical course of three consecutive patients, each with SLE-associated ITP who were initially treated with corticosteroids or other immunomodulatory therapy. These patients were treated with eltrombopag at the DMC Center for Bleeding Disorders and Thrombosis. Eltrombopag was administered according the package insert, with an initial dose of 50 mg daily, with weekly, then monthly monitoring of platelet counts and dose adjustments. Some immunomodulatory agents (e.g. hydroxychloroquine) were continued to control non hematologic SLE manifestations.

RESULTS

All three patients maintained acceptable platelet counts (>50,000/mm(3) for >3 years) following tapering and cessation of corticosteroids. The drug was well-tolerated and there were no adverse events, and specifically no thrombotic events.

CONCLUSION

Eltrombopag is effective as a rapidly acting corticosteroid sparing therapy for patients with ITP associated with SLE. This is important in reducing corticosteroid related side effects and morbidities in treating SLE patients with ITP. Larger studies are needed to ascertain safety and efficacy of eltrombopag in SLE patients with ITP, particularly those with coexisting antiphospholipid antibodies.