Monocyte and Basophil Counts as Predictors of Neutrophil Count Recovery in Patients with Thiamazole-Induced Agranulocytosis.

Thiamazole (MMI) is frequently used for the treatment of Graves' disease, but it occasionally induces agranulocytosis at the beginning of the treatment. To date, the predictive factors of recovery from MMI-induced agranulocytosis remain unclear. The primary aim of this study was to evaluate the predictive factor of the recovery time from MMI-induced agranulocytosis. This was a retrospective cohort study performed in a university hospital and a thyroid hospital. We included 27 Japanese patients with Graves' disease with MMI-induced agranulocytosis diagnosed during follow-up. All patients were administrated recombinant human granulocyte colony-stimulating factor daily until they had a neutrophil count>1 000/μL, which was defined as recovery. The predictive factors associated with recovery time were estimated using multivariable regression analysis. At the onset of agranulocytosis, the median administration period of MMI was 33 days, the average white blood cell count was 1 896/μL, and the median neutrophil count was 22/μL. The median recovery time was 4 days. Stepwise multivariate regression analysis identified the monocyte and basophil counts to be significant predictors of MMI-induced agranulocytosis. Patients with agranulocytosis and decreased monocyte and basophil counts at onset may recover late and require careful treatment.