Predictive factors of response to IVIG in pediatric immune thrombocytopenic purpura

Immune thrombocytopenic purpura (ITP) is commonly treated with i.v. immunoglobulin (IVIG).

We retrospectively evaluated whether pretreatment clinical and laboratory finding could predict the short- and long-term response to IVIG.

Short-term response was estimated by platelet count 2 weeks after IVIG, and long-term response was assessed on thrombocytopenia-free survival (TFS). TFS was defined as the probability of survival without treatment failure after initial IVIG, such as relapse, requirement for additional therapeutic interventions, or progressing to chronic ITP. Seventy-six patients with newly diagnosed ITP who were initially treated with IVIG were evaluated. Fifty-three patients (69.7%) were determined as responders at 2 weeks after IVIG. On multivariate analysis, age ≥23 months (P = 0.020) and platelet count <9.0 × 10⁹ /L (P = 0.018) were considered to be unfavorable factors for short-term response. Cumulative proportion of long-term (1 year) good prognosis was estimated at 53.0% (95%CI: 40.8-65.2). On multivariate analysis of unfavorable factors for long-term response, age ≥23 months (P = 0.020) was the only significant factor.

For new-onset ITP in patients aged >2 years, corticosteroid therapy in addition to IVIG may be considered as the initial treatment.