Association between megakaryocyte abnormalities on bone marrow smear and response to thrombopoietin receptor agonists in adult patients with primary immune thrombocytopenia.

Impaired platelet production is a mechanism of immune thrombocytopenia (ITP). Morphological abnormalities of megakaryocytes (MKs) are sometimes observed in this disease. Two studies have suggested an association between MK abnormalities and response to corticosteroids in primary ITP, but none have investigated this association for thrombopoietin-receptor agonists (TPO-RAs). This was the aim of this study. The source of population was the French CARMEN registry with prospective follow-up of adult patients with incident ITP. We included patients with primary ITP, treated by TPO-RA and with a bone marrow smear before initiating TPO-RA. MK abnormalities were categorized by the presence of dysplasia and by the stage of maturation. Among 451 patients screened, 38 were included in the analysis. There was no difference in the median percentage of dysplastic MKs between responders to TPO-RA (4.0%, 95% confidence interval - CI: 2.3-6.4) and non-responders (4.5%, 95% CI: 0.7-7.1). There was a slightly higher proportion of granular MKs (4.5%, 95% CI: 3-6) and basophilic MKs (30.1%, 95% CI: 21.9-39.1) in non-responders compared to responders (granular: 2.0%, 95% CI: 0-4.1; basophilic: 21.3%, 95% CI: 11.4-40.7). In conclusion, MK abnormalities were not associated with response achievement in ITP patients treated with TPO-RA in this series of 38 patients.

Effect of a Red Blood Cell Transfusion on Biological Markers Used to Determine the Cause of Anemia: A Prospective Study.

BACKGROUND: Blood test results required for the evaluation of anemia are considered difficult to interpret after red blood cell transfusion. However, this hypothesis is neither supported by a strong physiological rationale nor is it evidence based. METHODS: We conducted a prospective multicenter study to compare the values of key assays prior to and after a course of red blood cell transfusion in the emergency or internal medicine units in 4 university hospitals. The following parameters were measured prior to and within 48 to 72 hours after transfusion: complete blood count with reticulocyte count, direct Coombs' test, ferritin, transferrin saturation, soluble transferrin receptor, serum and erythrocyte folate, cobalamin, lactate dehydrogenase, bilirubin, haptoglobin, and C-reactive protein. We investigated the impact of transfusion on these parameters and assessed whether abnormal values prior to the transfusion became normal after transfusion (or conversely). RESULTS: There were 77 patients included in the study. Changes in mean values of mean corpuscular volume, soluble transferrin receptor, erythrocyte folate, cobalamin, haptoglobin, lactate dehydrogenase, C-reactive protein, and direct Coombs' test were not statistically significant. Changes in reticulocyte count, ferritin, transferrin saturation, serum folate, and total bilirubin concentrations were statistically significant, but they remained in the same diagnostic category (normal or abnormal) in 79% to 98% of the cases; 97% of patients with iron deficiency still had low ferritin or transferrin saturation after a transfusion. CONCLUSION: Blood tests performed after a one-time red blood cell transfusion can be used to establish the cause of anemia when they have not been performed before.

Cryptic and partial deletions of PRDM16 and RUNX1 without t(1;21)(p36;q22) and/or RUNX1-PRDM16 fusion in a case of progressive chronic myeloid leukemia: a complex chromosomal rearrangement of underestimated frequency in disease progression?

Chronic myeloid leukemia (CML) is a myeloproliferative disorder characterized by the presence in leukemic stem cells of the Philadelphia chromosome (Ph) and the formation of the BCR-ABL1 fusion. Untreated, the disease progresses to accelerate phase and blast crisis in which hematopoietic differentiation has become arrested. CML progression is frequently associated with cytogenetic evidence of clonal evolution, defined as additional chromosomal aberrations. We here report a CML resistant to tyrosine kinase inhibitors that rapidly progressed to blastic phase. At this time, array CGH performed on CD34(+) cells revealed cryptic partial deletions of both PRDM16 and RUNX1 and duplication of the der(21) chromosome. These genomic rearrangements were confirmed by FISH with probes targeting the deletion on chromosome 21 (24 kb), and with BAC probes flanking the deletion on 1p36 (220 kb). However, no cryptic t(1;21)(p36;q22) and/or RUNX1-PRDM16 were detected, suggesting that these deletions are the residual hallmarks of a more complex mechanism of chromosomal rearrangement, as indicated by the additional inversion of the region bounded by 1p36.32 and 1p36.12 breaks. At the molecular level, these abnormalities lead to the overexpression of the PR-domain negative oncogenic isoform of PRDM16, associated with two deleted copies within the runt domain of C-teminal aberrant RUNX1. These events are not detectable by conventional cytogenetic and molecular strategies, and may be of underestimated frequency in disease progression.

RUNX1 DNA-binding mutations and RUNX1-PRDM16 cryptic fusions in BCR-ABL+ leukemias are frequently associated with secondary trisomy 21 and may contribute to clonal evolution and imatinib resistance.

Acquired molecular abnormalities (mutations or chromosomal translocations) of the RUNX1 transcription factor gene are frequent in acute myeloblastic leukemias (AMLs) and in therapy-related myelodysplastic syndromes, but rarely in acute lymphoblastic leukemias (ALLs) and chronic myelogenous leukemias (CMLs). Among 18 BCR-ABL+ leukemias presenting acquired trisomy of chromosome 21, we report a high frequency (33%) of recurrent point mutations (4 in myeloid blast crisis [BC] CML and one in chronic phase CML) within the DNA-binding region of RUNX1. We did not found any mutation in de novo BCR-ABL+ ALLs or lymphoid BC CML. Emergence of the RUNX1 mutations was detected at diagnosis or before the acquisition of trisomy 21 during disease progression. In addition, we also report a high frequency of cryptic chromosomal RUNX1 translocation to a novel recently described gene partner, PRDM16 on chromosome 1p36, for 3 (21.4%) of 14 investigated patients: 2 myeloid BC CMLs and, for the first time, 1 therapy-related BCR-ABL+ ALL. Two patients presented both RUNX1 mutations and RUNX1-PRDM16 fusion. These events are associated with a short survival and support the concept of a cooperative effect of BCR-ABL with molecular RUNX1 abnormalities on the differentiation arrest phenotype observed during progression of CML and in BCR-ABL+ ALL.