Isocitrate dehydrogenase 1 and 2 (IDH1 and IDH2) interfere with cellular metabolism contributing to oncogenesis. Mutations of IDH2 at R140 and R172 residues are observed in 20% of acute myeloid leukemias (AML), and the availability of the IDH2 inhibitor Enasidenib made IDH2 mutational screening a clinical need. The aim of this study was to set a new quantitative polymerase chain reaction (PCR) technique, the drop-off digital droplet PCR (drop-off ddPCR), as a sensitive and accurate tool for detecting IDH2 mutations. With this technique we tested 60 AML patients. Sanger sequencing identified 8/60 (13.5%) mutated cases, while ddPCR and the amplification refractory mutation system (ARMS) PCR, used as a reference technique, identified mutations in 13/60 (21.6%) cases. When the outcome of IDH2-mutated was compared to that of wild-type patients, no significant difference in terms of quality of response, overall survival, or progression-free survival was observed. Finally, we monitored IDH2 mutations during follow-up in nine cases, finding that IDH2 can be considered a valid marker of minimal residual disease (MRD) in 2/3 of our patients. In conclusion, a rapid screening of IDH2 mutations is now a clinical need well satisfied by ddPCR, but the role of IDH2 as a marker for MRD still remains a matter of debate.

No abstract

Persistent polyclonal B-cell lymphocytosis (PPBL) is a rare clinical condition, characterized by a persistent, generally moderate lymphocytosis, generally due to stimulation of central memory B-lymphocytes, and by a moderate increase of polyclonal IgM. In some patients, slight or moderate splenomegaly is observed. A variable percentage of circulating, bone marrow and splenic lymphocytes display an abnormal nucleus (generally bilobated) or are binucleated. The clinical course is benign in most cases and transformation into splenic B-cell lymphoma occurs in few cases. In the current paper we report the first case of pregnancy in PPBL. Our patient became pregnant 18 months after diagnosis. In the course of pregnancy, a marked down-regulation of lymphocytosis (from 6 × 10(9)/L to 2.1 × 10(9)/L) and a decrease in B-lymphocyte number was observed (from 3.6 × 10(9)/L to 1 × 10(9)/L), mainly due to a marked reduction in the percentage and absolute number of central memory B-cells. Such modifications were similar to those described in normal pregnant women. One year after the delivery of a healthy female baby, the number of total lymphocytes and B-lymphocytes showed an inverse behavior, with a new expansion of central memory B-cells. Our case shows that a normal pregnancy can occur in patients with PPBL and that pregnancy can induce marked modifications in B-lymphocyte kinetics and phenotype.

We report a case of de novo diffuse large B-cell lymphoma (DLBCL) in leukemic phase, positive for both CD5 and CD13. Morphologic evaluation, flow cytometric immunophenotyping, karyotyping and polymerase chain reaction studies were performed. Neoplastic lymphocytes appeared as blast-like cells, positive for CD19, CD20, CD5, CD13, CD79a, HLADR, and with restriction for surface immunoglobulin K light chains. Rearrangement of IgH gene, BCL2/IgH translocation and complex karyotype were found. The patient was treated with RCOMP regimen and achieved complete remission. However, only one month after the first restaging of disease, the patient presented with symptoms attributable to central nervous system involvement and her clinical conditions worsened rapidly. While both CD5 expression and leukemic presentation are uncommon findings in DLBCL, positivity for CD13 is very rare. The outcome of our patient shows the poor prognosis of CD5+ DLBCL with leukemic presentation. The possible role of CD13 coexpression is discussed.

Acute monoblastic leukemia (AMoL) is characterized by cells with highly undifferentiated morphology. Cytochemistry with non-specific esterases is negative in up to 20% of cases. Immunophenotyping by flow cytometry has an essential role in diagnosing such a subtype of leukemia and a multiparametric approach with a wide monoclonal antibody panel is necessary. We describe a case of AMoL with morphology resembling either plasma blasts or very immature erythroblasts. Diagnosis was made by alpha-naphtyl-acetate esterase staining and with immunophenotyping, which was made with a wide monoclonal antibody panel. Blasts were positive for monocytic markers. Most of leukemic cells, however, were positive for Glycophorin-A. The presence of Glycophorin-A, which is considered as a specific marker of the erythroid lineage, has never been reported previously in cases of AMoL. This peculiar immunophenotype might be interpreted as deriving from a common myelo-erythroid precursor undergone leukemic transformation.