Impact of Eltrombopag in ITP Monocytes and Macrophages

Monocytes and macrophages play an established role in the pathophysiology of hematopoietic malignancies, including primary immune thrombocytopenia (ITP) and have been implicated as major drivers of platelet destruction. Researchers evaluated the effects of eltrombopag therapy on monocytes and macrophages in patients with ITP.

The study, published in Platelets, found that eltrombopag restored monocyte dynamics and related T-helper 1 (Th1) and T-helper 2 (Th2) imbalances and partially reversed TNF-α, IL-1β, IL-12β, CXCL9, and CXCL11-related features in ITP macrophages.

Eltrombopag Appears to Monocyte and Macrophage Plasticity

The study included 20 patients with primary ITP, 11 of which received eltrombopag 50 mg once daily for 4 weeks. Researchers assessed monocyte distributions and IFN-γ and IL-4 expression levels before and 4 weeks after eltrombopag therapy. The control group included 6 age- and gender-matched healthy individuals.

Reportedly, the peripheral monocyte count was significantly higher in patients with active ITP compared with healthy controls (P<.05), though no significant differences were observed in monocyte proportions. The authors highlighted that both peripheral monocyte proportion (r=-0.469; P=.037) and monocyte count (r=-0.539; P=.014) were negatively correlated with platelet count, potentially suggesting a significant role of monocytes in ITP.

In addition, the researchers reported that several genes associated with phenotypes in ITP macrophages exhibited diverse responses, and ITP macrophages further demonstrated more M1 gene-related characteristics.

Given the observed impact of eltrombopag in patients with ITP, the authors suggested “the potential vital roles of [thrombopoietin receptor agonists] in regulating the monocyte/macrophage plasticity in ITP.”

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