Mutational landscape of patients with acute promyelocytic leukemia at diagnosis and relapse.

Despite the high probability of cure of patients with acute promyelocytic leukemia (APL), mechanisms of relapse are still largely unclear. Mutational profiling at diagnosis and/or relapse may help to identify APL patients needing frequent molecular monitoring and early treatment intervention. Using an NGS approach including a 31 myeloid gene-panel, we tested BM samples of 44 APLs at the time of diagnosis, and of 31 at relapse. Mutations in PML and RARA genes were studied using a customized-NGS-RNA panel. Patients relapsing after ATRA-chemotherapy rarely had additional mutations (P = .009). In patients relapsing after ATRA/ATO, the PML gene was a preferential mutation target. We then evaluated the predictive value of mutations at APL diagnosis. A median of two mutations was detectable in 9/11 patients who later relapsed, vs one mutation in 21/33 patients who remained in CCR (P = .0032). This corresponded to a significantly lower risk of relapse in patients with one or less mutations (HR 0.046; 95% CI 0.011-0.197; P < .0001). NGS-analysis at the time of APL diagnosis may inform treatment decisions, including alternative treatments for cases with an unfavorable mutation profile.

Essential thrombocytemia following immune thrombocytopenia with JAK2V617F mutation.

JAK2V617F mutation is found in about 60% of cases of essential thrombocytemia (ET) and represents a driving mutation. Immune thrombocytopenia (ITP) is an autoimmune disease characterized by a low platelet (PLT) count. So far, only 2 reports described ET following ITP. For the first time we analyzed in a patient the JAK2V617F allele burden at ITP onset occurred 13 years before the ET diagnosis and found the presence of a small clone JAK2V617F positive clone (3%) raised to 27% in the following years. The association of ET and ITP could suggest similar pathogenetic mechanisms that should be further investigated.

CLLU1 expression has prognostic value in chronic lymphocytic leukemia after first-line therapy in younger patients and in those with mutated IGHV genes.

CLLU1, located at chromosome 12q22, encodes a transcript specific to chronic lymphocytic leukemia and has potential prognostic value. We assessed the value of CLLU1 expression in the LRF CLL4 randomized trial. Samples from 515 patients with chronic lymphocytic leukemia were collected immediately before the start of treatment. After RNA extraction and cDNA synthesis, CLLU1 expression was assessed by quantitative polymerase chain reaction. In total, 247 and 268 samples were identified as having low and high CLLU1 expression, respectively. The median follow-up was 88 months. High CLLU1 expression was significantly correlated with unmutated IGHV genes, ZAP-70 and CD38 positivity, and absence of 13q deletion (all r>0.2, P<0.0001). At 6 years, patients with high CLLU1 expression had significantly worse progression-free survival (9% versus 17%; P=0.03) and overall survival (42% versus 57%; P=0.0003) than patients with low CLLU1 expression. Among patients with mutated IGHV genes, overall survival at 6 years was 50% in those with high CLLU1 expression and 76% in those with low CLLU1 expression (P=0.005). However, CLLU1 expression was not an independent predictor of overall survival in a multivariate model including TP53 aberrations, beta-2 microglobulin level, age and IGHV mutation status. Nor did it predict response to treatment. CLLU1 expression analysis helps to refine the prognosis of patients with chronic lymphocytic leukemia who have mutated IGHV genes.

Delayed attainment of full donor chimaerism following alemtuzumab-based reduced-intensity conditioning haematopoeitic stem cell transplantation for acute myeloid leukaemia and myelodysplastic syndromes is associated with improved outcomes.

This prospective study evaluated the kinetics of lymphoid (CD3) engraftment in 110 patients with acute myeloid leukaemia (AML) and myelodysplastic syndromes (MDS) after allogeneic transplantation and conditioning with fludarabine, busulphan and alemtuzumab, using ciclosporin for post-transplant immunosuppression. Declining donor CD3 chimaerism beyond day+100 was treated with pre-emptive donor lymphocyte infusion (pDLI). The median age of patients was 53.0 years (range: 19-72 years), and the median follow-up was 690 d (range:168-1470 d). Patients achieving full CD3 donor chimaerism (FDC, n = 46) by day+100 had a significantly inferior disease-free survival (DFS) and overall survival (OS) compared to patients with mixed donor chimaerism (MDC, n = 59). Twenty patients had stable MDC and did not require pDLI. Patients attaining early FDC had a higher transplant-related mortality compared to those who maintained stable levels of MDC (P = 0.02), with no difference between the FDC and pDLI groups (P = 0.07). There was no difference in relapse between all three groups (P = 0.21). On multivariate analysis, only CD3 chimaerism status at day+100 and disease status at transplantation had a significant effect on DFS and OS. In patients with AML/MDS undergoing alemetuzumab based-RIC HSCT, prolonged MDC beyond day+100 is associated with an improved OS. Future studies need to be directed towards establishing the underlying factors that dictate T-cell engraftment, expansion and homing post-transplantation.