Background: Dependent on the absence or presence of associated diseases, autoimmune thrombocytopenia (ITP) can be classified as primary or secondary form. The manifestation of the associated diseases is not temporally defined and may occur during observation. Thus the question which disease is the primary one remains unanswered.
Methods: All 386 patients included in this study were treated by a single primary physician between 1996 and 2015 at the Charité Berlin and met current ITP criteria. Medical records and investigations were reviewed to assess diseases associated with ITP.
Results: Initially, the vast majority of patients presented with primary ITP (isolated disease). Based on our findings, ITP was found to be associated with other abnormalities in most cases. These abnormalities included: positive direct antiglobulin test in 49 of 386 tested patients (13%), affections of the thyroid gland in 41 of 386 tested patients (11%), infections in 30 (8%), solid malignancies in 20 (5%) and hematological malignancies in 10 patients (3%), as well as many other miscellaneous diseases. Moreover, of 160 patients who did not receive prior intravenous immunoglobulin treatment, 40 (25%) showed antibody deficiency.
Conclusion: In conclusion, the incidence of 'true' ITP as a primary disease is less common than has yet been suggested. Additionally, there is evidence that ITP itself predispose affected subjects toward development of other diseases.
Keywords: Antibody deficiency syndrome; Autoimmune thrombocytopenia; Evans syndrome; Platelets; Secondary autoimmune thrombocytopenia.