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Immune thrombocytopenia (ITP) is an acquired,immune-mediated disease that is characterized by increased destruction of platelets by autoantibodies. ITP is characterized by mucocutaneous bleeding. Rarely, life-threatening bleeding such as central nervous system bleeding can occur. Typically, patients have isolated thrombocytopenia. The diagnosis of ITP is one of exclusion. Corticosteroids are chosen as a first-line therapy for adult patients who require treatment. Responses to first line therapy with corticosteroids is about 80% with approximately 20% to 30% long term complete remission. Most patients finally relapse, requiring second-line therapy.

We retrospectively evaluated 43 ITP patients who were followed-up at our institution. All patients’ thrombocyte counts were below 30 x10⁹/L at diagnosis. All patients received initially methylprednisolone(MP) 1 mg/kg/day. For patients who responded with platelet count ≥150 x10⁹/L methylprednisolone was tapered over 3 months. Those who were unresponsive to MP or relapsed after a complete response, were treated with second line therapies that splenectomy or medical treatment agents. The platelet counts of the patients on day 0, 3 and 7 were evaluated by complete blood counts and were confirmed with peripheral smears examination. Effect of the platelet counts on day 3 and 7 were compared in terms of second line therapy requirement or not. A platelet count of >30x10⁹/L on day 3 and >100x10⁹/L on day 7 was considered as a complete response. Vaccination against encapsulated organisms was given and imaging was done to detect accessory spleen before splenectomy.

Baseline characteristics of the cohort of 43 patients with an initial diagnosis of ITP are shown in Table 1. The mean age at diagnosis was 51 years (18-84) with female/male : 25/18. All patients presented with severe thrombocytopenia (platelet counts below 30.0x 10⁹/L). Most patients presented with mucocutaneous bleeding (n=39), only three patients had genitourinary or gastrointestinal tract bleeding and one patient was asymptomatic. Bone marrow aspiration and biopsy was done in 14 (%32.6) patients due to various reasons mainly, failure to respond to ITP treatment (7 patients) and advanced age (7 patients). On third and seventh day of MP therapy, median platelet counts were 30x10⁹/L (2,0 x10⁹/L -150 x10⁹/L ) and 100 x10⁹/L (1,0 x10⁹/L-347 x10⁹/L), respectively. When platelet counts on the 3rd and 7th day in each patient were compared, a significant association was found in correlation analysis (p<0.05). 21 patients (%48.8) required second line therapy which were splenectomy (76.2%) or medical treatment (23.8%). Medical therapy consisted of rituximab, eltrombopag, danazol. There was a statistically significant difference between the patients with platelet count below and over 30x10⁹/L on 3rd day of the MP therapy in terms of requirement for a second line therapy. (p=0.04). On the other hand, when 7th day was taken into consideration, there was not a statistically significant difference when cut off was taken as 100 x10⁹/L (p=0.09) or 50 x10⁹/L (p=0.06).

In the era of novel therapies used as second line, predicting the prognosis of an ITP patient at diagnosis has been a challenge. If disease related factors at diagnosis can be identified, then patients can be rescued from long term corticosteroid exposure and its adverse effects. Early response of platelet counts after starting corticosteroids seems to predict long-term complete remission. Expanding the study population may contribute more to our findings.