Incidence and Prevalence Of Immune Thrombocytopenia In a MS Clinic Cohort

Background: An association of Multiple Sclerosis (MS) with other autoimmune illnesses has been observed, but data are limited. In the era of new MS therapeutics, there is concern regarding induction of autoimmunity, including Immune Thrombocytopenia (ITP).

Objectives: To report the incidence, prevalence, and severity of ITP in a typical, predominantly adult, MS clinic cohort, most all on currently approved MS therapies.

Methods: A retrospective study of 382 active patient charts from 2010 and 2011 was completed.

Results: During this time period, three patients experienced new incident ITP, mild, with platelet counts >50,000<100,000/microliter (mcl). One patient was on Glatiramer Acetate and also had a history of Alcoholism and Lyme Disease. The other two patients were on Natalizumab, one also having a low positive Antinuclear Antibody titer of 1:80 (normal < 40). Six additional patients had prior evidence of  ITP, ranging from mild to severe (two patients had  platelet counts of 2000/mcl and 4000/mcl respectively, with signs of bleeding). These two severe patients were both on Glatiramer Acetate with negative re-challenge. One patient was on Beta Interferon 1B and switched to Beta Interferon 1A weekly. One patient was treated with Beta Interferon 1B and switched to Natalizumab. One patient received Beta Interferon 1B and also took Carbamazepine for Trigeminal Neuralgia. One patient was on Beta Interferon 1A weekly. 

Conclusions: The incidence of  ITP in this cohort is 3/382 or 0.8% over 2 years (0.4% per year). The prevalence is 9/382 or 2.4%. Three patients were on Beta Interferon, three on Glatiramer Acetate, and three on Natalizumab. No single agent can be implicated as the causative factor. These data provide some perspective regarding the incidence, prevalence and severity of  ITP in the MS population.