Polarization and apoptosis of T cell subsets in idiopathic thrombocytopenic purpura

Identification of novel biomarkers in chronic immune thrombocytopenia (ITP) by microarray-based serum protein profiling

The pathological mechanisms underlying the development of immune thrombocytopenia (ITP) are unclear and its diagnosis remains a process of exclusion. Currently, there are no known specific biomarkers for ITP to support differential diagnosis and treatment decisions. Profiling of serum proteins may be valuable for identifying such biomarkers. Sera from 46 patients with primary chronic ITP and 34 healthy blood donors were analysed using a microarray of 755 antibodies. We identified 161 differentially expressed proteins. In addition to oncoproteins and tumour-suppressor proteins, including apoptosis regulator BCL2, breast cancer type 1 susceptibility protein (BRCA1), Fanconi anaemia complementation group C (FANCC) and vascular endothelial growth factor A (VEGFA), we detected six anti-nuclear autoantibodies in a subset of ITP patients: anti-PCNA, anti-SmD, anti-Ro/SSA60, anti-Ro/SSA52, anti-La/SSB and anti-RNPC antibodies. This finding may provide a rational explanation for the association of ITP with malignancies and other autoimmune diseases. While RUNX1mRNA expression in the peripheral blood mononuclear cells (PBMC) of patients was significantly downregulated, an accumulation of RUNX1 protein was observed in the platelets of ITP patients. This may indicate dysregulation of RUNX1 expression in PBMC and megakaryocytes and may lead to an imbalanced immune response and impaired thrombopoiesis. In conclusion, we provide novel insights into the pathogenic mechanisms of ITP that warrant further exploration.

Diagnosis, pathophysiology and management of children with refractory immune thrombocytopenic purpura

PURPOSE OF REVIEW

Refractory immune thrombocytopenic purpura is infrequent in children, but carries substantial morbidity and even mortality. Management of these children is controversial despite the availability of several treatment options as these strategies have not been directly compared and there are many definitions for refractory immune thrombocytopenic purpura. This review will provide an update on the pathogenesis, diagnosis and treatment options for children with severe, acute and chronic refractory immune thrombocytopenic purpura.

RECENT FINDINGS

Recent studies have demonstrated a number of immunologic alterations (dominant proinflammatory state, inadequate thrombopoiesis, and various B and T lymphocyte disturbances) in the pathogenesis of chronic immune thrombocytopenic purpura. New agents that target certain of these mechanisms (e.g. anti-CD20 monoclonal antibody, thrombopoietic agents) have shown promising results in recent clinical trials, primarily but not solely in adults.

SUMMARY

Management of refractory immune thrombocytopenic purpura often requires multiple agents that may provide only short-term benefit. Lack of clear views about the use of these medications, their unwanted side effects and an inability to specifically target a particular patient's disease all lead to frustration among patients, family and the physicians. Better understanding of pathogenesis with the availability of newer therapies with different mechanisms of effect should, however, allow improved management of these patients.