Identification of a morphometrical parameter that predicts the response to splenectomy in patients with idiopathic thrombocytopenic purpura.

Idiopathic thrombocytopenic purpura (ITP) is an isolated thrombocyte disease that has no correlation with other causes of clinical thrombocytopenia in adults. About 70% of patients with ITP were successfully treated by medical care and splenectomy, but nearly 30% of ITP patients do not respond to these treatments. The aim of this study is to evaluate the predictive factors that affect the success of treatment in 26 patients with ITP. Thirteen patients with ITP responded to splenectomy (responsive group), whereas 13 other patients were resistant to medical treatment and splenectomy (resistant group). The control group consisted of 13 patients who had undergone posttraumatic splenectomy. Age, sex, spleen weight, the number of follicles per mm(2), and the length of time between diagnosis and splenectomy were retrospectively analyzed. No significant difference was found between the groups with respect to these variables. Mean maximum follicle diameter (MMaFD), mean minimum follicle diameter (MMiFD), and the number and distribution of CD56 (+) cells were evaluated for each spleen specimen. There was no statistical difference in the distribution of CD56 (+) cells between the ITP patients and the control group, but the number of CD56 (+) cells was significantly higher in the control group than in patients with ITP. While MMiFD showed no statistical difference between the groups of ITP patients, a MMaFD of 350 microm and above was significantly more likely in the resistant group than in the other groups. In conclusion, this study has shown that the MMaFD is a significant predictor of the response to splenectomy.