Kinetics of humoral deficiency in CART19-treated children and young adults with acute lymphoblastic leukaemia.

CD19-CAR T-cell therapy (CART19) causes B-cell aplasia (BCA) and dysgammaglobulinemia but there is a lack of information about the degree of its secondary immunodeficiency. We conducted a prospective study in children and young adults with acute lymphoblastic leukaemia treated with CART19, analysing the kinetics of BCA and dysgammaglobulinemia during therapy, as well as the B-cell reconstitution in those with CART19 loss. Thirty-four patients were included (14 female) with a median age at CART19 infusion of 8.7 years (2.9-24.9). Median follow-up after infusion was 7.1 months (0.5-42). BCA was observed 7 days after infusion (3-8), with persistence at 24 months in 60% of patients. All patients developed a progressive decrease in IgM and IgA: 71% had undetectable IgM levels at 71 days (41-99) and 13% undetectable IgA levels at 185 days (11-308). Three of 12 patients had protective levels of IgA in saliva. In two of three patients who lost CART19, persistent B-cell dysfunction was observed. No severe infections occurred. In conclusion, BCA occurs soon after CART19 infusion, with a progressive decrease in IgM and IgA, and with less impairment of IgA, suggesting the possibility of an immune reservoir. A persistent B-cell dysfunction might persist after CART19 loss in this population.

Outcome and toxicities associated to chemotherapy in children with acute lymphoblastic leukemia and Gilbert syndrome. Usefulness of UGT1A1 mutational screening.

BACKGROUND: Acute lymphoblastic leukemia (ALL) is the most frequent cancer in childhood. Although intensive chemotherapy has improved survival in those patients, important side effects, including hyperbilirubinemia, are frequent. Gilbert syndrome (GS) is a frequent condition that causes a reduction in glucuronidation and intermittent hyperbilirubinemia episodes. This could provoke a greater exposure to some cytotoxic agents used in ALL, increasing the risk of toxicity. On the other hand, unexplained hyperbilirubinemia could lead to unnecessary modifications or even treatment withdrawals, which could increase the risk of relapse, but data regarding this in ALL pediatric population are scarce. METHODS: Retrospective study to analyze toxicity, outcome and treatment modifications related to GS in children diagnosed with ALL. RESULTS: A total of 23 of 159 patients were diagnosed with GS. They had statistically higher hyperbilirubinemias during all treatment phases (P < 0.0001) and a slower methotrexate clearance when it was administered during a 24-hr infusion at high doses (patients with GS: 74 hr ± 19 vs. patients without GS: 64 hr ± 8; P < .002). However, no relevant toxicity or delays in treatment were found in them. Finally, changes in treatment due to hyperbilirubinemia were only done in 5 patients with GS. CONCLUSIONS: Differences in outcome were not found in patients with GS. Universal screening for GS appears to be not necessary in pediatric patients with ALL. However, when hyperbilirubinemia is observed, it must be rule out in order to avoid unnecessary changes in treatment.

Multiplex real-time PCR for prompt diagnosis of an outbreak of human parainfluenza 3 virus in children with acute leukemia.

INTRODUCTION: Human parainfluenza virus type 3 (HPIV-3) causes significant morbimortality in immunocompromised patients. Outbreaks of severe pneumonitis have been previously described in this setting. MATERIALS AND METHODS: Retrospective observational study in children diagnosed with acute leukemia and a documented HPIV-3 infection in the context of a nosocomial outbreak occurred in a single center. RESULT: During summer 2012, an HPIV-3 infection was detected in six hospitalized children with acute leukemia. All the patients had respiratory symptoms and one of them suffered from parotitis. CONCLUSION: Early diagnoses using multiplex real-time polymerase chain reaction (PCR) let us control this outbreak. A phylogenetic analysis confirmed person-to-person transmission of a single HPIV-3 variant.

Acute myeloid leukemia with translocation (8;16)(p11;p13) and MYST3-CREBBP rearrangement harbors a distinctive microRNA signature targeting RET proto-oncogene.

Acute myeloid leukemia (AML) with t(8;16)(p11;p13) (t(8;16) AML) has unique clinico-biological characteristics, but its microRNA pattern is unknown. We analyzed 670 microRNAs in seven patients with t(8;16) AML and 113 with other AML subtypes. Hierarchical cluster analysis showed that all t(8;16) AML patients grouped in an independent cluster. Supervised analysis revealed a distinctive signature of 94-microRNAs, most of which were downregulated, including miR-21 and cluster miR-17-92. The mRNA expression analysis of two known transcription factors of these microRNAs (STAT3 and c-Myc, respectively) showed significant downregulation of STAT3 (P=0.04). A bioinformatic analysis showed that 29 of the downregulated microRNAs might be regulated by methylation; we treated a t(8;16) AML sample with 5-aza-2'-deoxycytidine (5-AZA-dC) and trichostatin A and found that 27 microRNAs were re-expressed after treatment. However, there was no difference in methylation status between t(8;16) and other AML subtypes, either overall or in the microRNA promoter. Cross-correlation of mRNA and microRNA expression identified RET as a potential target of several microRNAs. A Renilla-luciferase assay and flow cytometry after transfection with pre-microRNAs confirmed that RET is regulated by miR-218, miR-128, miR-27b, miR-15a and miR-195. In conclusion, t(8;16) AML harbors a specific microRNA signature that is partially epigenetically regulated and targets RET proto-oncogene.