Thrombopoietin Levels in HIV-associated Thrombocytopenia in Children

Objectives: To determine the mechanism of human immunodeficiency virus (HIV)-associated thrombocytopenia by using thrombopoietin (TPO) levels.

Study Design: TPO levels were measured in 14 HIV+ children with thrombocytopenia (TCP+), 28 HIV+ children without thrombocytopenia (TCP-), and 15 matched control subjects.

Results: For the patients with moderate symptoms, TPO levels were similar for the TCP+ and TCP- groups (251 pg/mL vs 263 pg/mL; P =.98) and similar to those of control subjects. For the patients with severe symptoms, TPO levels were significantly higher for the TCP+ group versus the TCP- group (1172 pg/mL vs 222 pg/mL; P =.03). Patients with severe symptoms and thrombocytopenia had significantly higher TPO levels than those with moderate symptoms and thrombocytopenia (P <.005), were more likely to require growth factors, and did not respond to treatment with intravenous immunoglobulin.

Conclusions: TPO levels can distinguish 2 groups of patients with HIV-associated thrombocytopenia. Patients with severe disease had elevated TPO levels, did not respond to treatment with intravenous immunoglobulin, and were more likely to be growth factor-dependent, suggesting marrow failure.