Hypomegakaryocytic thrombocytopenia (HMT): an immune‐mediated bone marrow failure characterized by an increased number of PNH‐phenotype cells and high plasma thrombopoietin levels. (28th June 2016)

• Record Type: Journal Article
• Authors: Saito, Chizuru; Ishiyama, Ken; Yamazaki, Hirohito; Zaimoku, Yoshitaka; Nakao, Shinji
• Is Part Of: British journal of haematology. Volume 175:Number 2(2016)
• Page Start: 246
• Page End: 251
• Publication Date: 2016-06-28
• Subjects: hypomegakaryocytic thrombocytopenia -- PNH‐type cells -- thrombopoietin -- ciclosporin; Hematology -- Periodicals; Blood -- Diseases -- Periodicals; 616.15
• DOI: 10.1111/bjh.14210
• Languages: English
• ISSNs: 0007-1048

Abstract

Summary: Patients with mild hypomegakaryocytic thrombocytopenia (HMT) that does not meet the diagnostic criteria for a definite disease entity may potentially progress to aplastic anaemia (AA) that is refractory to therapy. To clarify the clinical picture of HMT, we prospectively followed 25 HMT patients with white blood cell count >3·0 × 10 9 /l, haemoglobin level >100 g/l and platelet count of <100·0 × 10 9 /l in the absence of morphological and karyotypic abnormalities in the bone marrow. Glycosylphosphatidylinositol‐anchored protein‐deficient blood cells [paroxysmal nocturnal haemoglobinuria (PNH)‐type cells] were detected in 7 of the 25 (28%) patients and elevated plasma thrombopoietin (TPO, also termed THPO) levels (>320 pg/ml) were observed in 11 (44%) patients. Five (four PNH+ and one PNH−) of six TPO high patients who were treated with ciclosporin (CsA) showed improvement. Among the 21 patients who were followed without treatment, thrombocytopenia progressed in four of ten TPO low patients and four of 11 TPO high patients. The 3‐year failure‐free survival rate of the CsA‐treated TPO high patients (100%) was significantly higher than that of the untreated TPO high patients (20%). These results suggest that a significant population of HMT patients has an immune pathophysiology that is similar to AA and may be improved by early therapeutic intervention with CsA.