TAFRO syndrome is characterized by thrombocytopenia with unknown etiology. The assessment of immature platelet fraction (IPF) is useful for differential diagnoses that include thrombocytopenia. However, the significance of IPF in cases of TAFRO syndrome remains to be reported. We present a case of TAFRO syndrome wherein the patient demonstrated a marked increase in IPF without thrombocytopenia, which offers vital information concerning TAFRO diagnosis and the serial measurements of IPF during treatment. A 65-year-old man presenting with fever was admitted to our hospital. He exhibited mild splenomegaly and lymphadenopathy, as well as rapidly worsening renal failure and fluid retention. These indications prompted the initiation of corticosteroid therapy. A normal platelet count and aberrantly high IPF implied abnormal thrombopoiesis, and subsequent bone-marrow findings suggested TAFRO syndrome. The platelet counts started to decrease following the corticosteroid therapy, but the treatment refractoriness prompted the urgent administration of rituximab. Thereafter, the platelet count nadir remained for approximately one month, whereas the decreasing IPF trend preceded platelet recovery. In the present case, a high pre-treatment IPF was demonstrated before the emergence of thrombocytopenia, and a decreasing trend of IPF was observed before platelet recovery during treatment. Therefore, serial IPF measurements could be useful for the early diagnosis and prognostication of TAFRO syndrome.
Keywords: Immature platelet fraction; Reticulated platelet; TAFRO syndrome; Thrombocytopenia.