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 thrombocyto penia (TCP+), 28 HIV+ children without thrombocytopenia (TCP-), and 15 matc hed control subjects. Results: For the patients with moderate symptoms, TPO levels were similar f or the TCP+ and TCP- groups (251 pg/mL vs 263 pg/mL; P = .98) and similar t o those of control subjects. For the patients with severe symptoms, TPO lev els were significantly higher for the TCP+ group versus the TCP- group (117 2 pg/mL us 222 pg/mL; P = .03). Patients with severe symptoms and thrombocy topenia had significantly higher TPO levels than those with moderate sympt oms and thrombocytopenia (P < .005), were more likely to require growth fac tors, and did not respond to treatment with intravenous immunoglobulin. Conclusions: TPO levels can distinguish 2 groups of patients with HIV-assoc iated thrombocytopenia. Patients with severe disease had elevated TPO level s, did not respond to treatment with intravenous immunoglobulin, and were m ore likely to be growth factor-dependent, suggesting marrow failure.