The effect of anti-thyroid antibodies positivity on children with primary immune thrombocytopenia.

Primary immune thrombocytopenia (ITP) is the most common cause of acquired thrombocytopenia in children. Anti-thyroid antibodies (aTA) have previously been found to be present in various autoimmune diseases. Our aim was to study the effect of aTA positivity (which are anti-thyroid peroxidase (aTPo) and/or anti-thyroglobulin (aTg)) on children with primary immune thrombocytopenia and their relation to treatment response. Sixty-one children with primary ITP were enrolled in the present study. They were further subdivided into: ND&P group (newly diagnosed and persistent) and chronic ITP group. Seventy-five apparently healthy children were enrolled as control group. aTPo and aTg antibodies were significantly higher and more frequently positive in all children with ITP and in each ITP group than the control group (P <.05 in all). But, there were no statistically significant differences between the two ITP subgroups (P >.05). aTA positive children with ITP had significantly lower platelet count: at the start of treatment (P =.009), after receiving methylprednisolone or intravenous immunoglobulin (P =.02) and at one month follow-up (P =.003) than aTA negative children with ITP. Lastly, aTA positive children had more relapses (P =.03), continued more frequently to have relapses after one year in the ND&P group (P =.02) and required immunosuppressive therapy more frequently in the chronic ITP group (P =.005).