Evaluation of Minimal Residual Disease by Real-Time Quantitative PCR of Wilms’ Tumor 1 Expression in Patients with Acute Myelogenous Leukemia after Allogeneic Stem Cell Transplantation: Correlation with Flow Cytometry and Chimerism

Relapse remains the main cause of treatment failure in patients with acute myelogeous leukemia (AML) after allogeneic hemopoietic stem cell transplantation (SCT). The Wilms’ tumor 1 gene (WT1) is reportedly overexpressed in >90% of patients with AML and thus can be useful for minimal residual disease (MRD) monitoring. The aim of this study was to evaluate the usefulness of WT1 expression as a relapse predictor marker in patients with AML after SCT and compare it with flow cytometry (FC) and chimerism studies. WT1 expression was assessed retrospectively using quantitative RT-PCR in bone marrow and peripheral blood from 21 patients. Patients were classified according to WT1 dynamics posttransplantation. Eleven of the 21 patients had low and stable WT1 levels. All of these 11 patients showed complete chimerism and negative MRD by FC and remained in complete remission with a median follow-up of 27 months (range, 18-98 months). In contrast, 10 of 21 patients showed WT1 overexpression after SCT, and 9 of these 10 patients relapsed. The incidence of relapse differed significantly between the 2 groups of patients according to WT1 expression post-SCT (P = .00003). Relapse in the 9 patients occurred at a median of 314 days (range, 50-560 days). Interestingly, in these patients, relapse was first predicted by WT1 (with negative FC and complete chimerism) in 7 patients. WT1 overexpression was correlated with disease burden in patients with AML before and after allogeneic SCT. In patients who relapsed, both medullary and extramedullary relapse were better anticipated by WT1 overexpression compared with FC and chimerism

The Genotype of the Donor for the (GT)n Polymorphism in the Promoter/Enhancer of FOXP3 Is Associated with the Development of Severe Acute GVHD but Does Not Affect the GVL Effect after Myeloablative HLA-Identical Allogeneic Stem Cell Transplantation

The FOXP3 gene encodes for a protein (Foxp3) involved in the development and functional activity of regulatory T cells (CD4+/CD25+/Foxp3+), which exert regulatory and suppressive roles over the immune system. After allogeneic stem cell transplantation, regulatory T cells are known to mitigate graft versus host disease while probably maintaining a graft versus leukemia effect. Short alleles (≤(GT)15) for the (GT)n polymorphism in the promoter/enhancer of FOXP3 are associated with a higher expression of FOXP3, and hypothetically with an increase of regulatory T cell activity. This polymorphism has been related to the development of auto- or alloimmune conditions including type 1 diabetes or graft rejection in renal transplant recipients. However, its impact in the allo-transplant setting has not been analyzed. In the present study, which includes 252 myeloablative HLA-identical allo-transplants, multivariate analysis revealed a lower incidence of grade III-IV acute graft versus host disease (GVHD) in patients transplanted from donors harboring short alleles (OR = 0.26, CI 0.08-0.82, p = 0.021); without affecting chronic GVHD or graft versus leukemia effect, since cumulative incidence of relapse, event free survival and overall survival rates are similar in both groups of patients

Host Genetic Analysis Should Be Mandatory for Proper Classification of COVID-19 Reinfections

3 páginas, 1 figura, 1 tabla.This work was supported by Instituto de Salud Carlos III (Ref COV20/00140: SeqCOVID—Consorcio para la epidemiología genómica de SARSCoV-2 en España) and by Consejo Superior de Investigaciones Científicas (CSIC; PTI Salud Global). L.P.L. has a Miguel Servet Contract (CPII20/00001).Peer reviewe

Different Within-Host Viral Evolution Dynamics in Severely Immunosuppressed Cases with Persistent SARS-CoV-2

A successful Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) variant, B.1.1.7, has recently been reported in the UK, causing global alarm. Most likely, the new variant emerged in a persistently infected patient, justifying a special focus on these cases. Our aim in this study was to explore certain clinical profiles involving severe immunosuppression that may help explain the prolonged persistence of viable viruses. We present three severely immunosuppressed cases (A, B, and C) with a history of lymphoma and prolonged SARS-CoV-2 shedding (2, 4, and 6 months), two of whom finally died. Whole-genome sequencing of 9 and 10 specimens from Cases A and B revealed extensive within-patient acquisition of diversity, 12 and 28 new single nucleotide polymorphisms, respectively, which suggests ongoing SARS-CoV-2 replication. This diversity was not observed for Case C after analysing 5 sequential nasopharyngeal specimens and one plasma specimen, and was only observed in one bronchoaspirate specimen, although viral viability was still considered based on constant low Ct values throughout the disease and recovery of the virus in cell cultures. The acquired viral diversity in Cases A and B followed different dynamics. For Case A, new single nucleotide polymorphisms were quickly fixed (13–15 days) after emerging as minority variants, while for Case B, higher diversity was observed at a slower emergence: fixation pace (1–2 months). Slower SARS-CoV-2 evolutionary pace was observed for Case A following the administration of hyperimmune plasma. This work adds knowledge on SARS-CoV-2 prolonged shedding in severely immunocompromised patients and demonstrates viral viability, noteworthy acquired intra-patient diversity, and different SARS-CoV-2 evolutionary dynamics in persistent cases

Systematic Genomic and Clinical Analysis of Severe Acute Respiratory Syndrome Coronavirus 2 Reinfections and Recurrences Involving the Same Strain

10 páginas, 2 figuras, 3 tablasEstimates of the burden of severe acute respiratory syndrome coronavirus 2 reinfections are limited by the scarcity of population-level studies incorporating genomic support. We conducted a systematic study of reinfections in Madrid, Spain, supported by genomic viral analysis and host genetic analysis, to cleanse laboratory errors and to discriminate between reinfections and recurrences involving the same strain. Among the 41,195 cases diagnosed (March 2020-March 2021), 93 (0.23%) had 2 positive reverse transcription PCR tests (55-346 days apart). After eliminating cases with specimens not stored, of suboptimal sequence quality, or belonging to different persons, we obtained valid data from 22 cases. Of those, 4 (0.01%) cases were recurrences involving the same strain; case-patients were 39-93 years of age, and 3 were immunosuppressed. Eighteen (0.04%) cases were reinfections; patients were 19-84 years of age, and most had no relevant clinical history. The second episode was more severe in 8 cases.This work was supported by the Instituto de Salud Carlos III (Ref COV20/00140: SeqCOVID—Consorcio para la epidemiología genómica de SARS-CoV-2 en España) and by Consejo Superior de Investigaciones Científicas (CSIC) (PTI Salud Global). L.P.L. is the recipient of a Miguel Servet Research contract (CPII20/00001) from the Instituto de Salud Carlos III.Peer reviewe

Personalized monitoring of circulating tumor DNA with a specific signature of trackable mutations after chimeric antigen receptor T-cell therapy in follicular lymphoma patients

BackgroundCART therapy has produced a paradigm shift in the treatment of relapsing FL patients. Strategies to optimize disease surveillance after these therapies are increasingly necessary. This study explores the potential value of ctDNA monitoring with an innovative signature of personalized trackable mutations.MethodEleven FL patients treated with anti-CD19 CAR T-cell therapy were included. One did not respond and was excluded. Genomic profiling was performed before starting lymphodepleting chemotherapy to identify somatic mutations suitable for LiqBio-MRD monitoring. The dynamics of the baseline mutations (4.5 per patient) were further analyzed on 59 cfDNA follow-up samples. PET/CT examinations were performed on days +90, +180, +365, and every six months until disease progression or death.ResultsAfter a median follow-up of 36 months, all patients achieved a CR as the best response. Two patients progressed. The most frequently mutated genes were CREBBP, KMT2D and EP300. Simultaneous analysis of ctDNA and PET/CT was available for 18 time-points. When PET/CT was positive, two out of four ctDNA samples were LiqBio-MRD negative. These two negative samples corresponded to women with a unique mesenteric mass in two evaluations and never relapsed. Meanwhile, 14 PET/CT negative images were mutation-free based on our LiqBio-MRD analysis (100%). None of the patients had a negative LiqBio-MRD test by day +7. Interestingly, all durably responding patients had undetectable ctDNA at or around three months after infusion. Two patients presented discordant results by PET/CT and ctDNA levels. No progression was confirmed in these cases. All the progressing patients were LiqBio-MRD positive before progression.ConclusionThis is a proof-of-principle for using ctDNA to monitor response to CAR T-cell therapy in FL. Our results confirm that a non-invasive liquid biopsy MRD analysis may correlate with response and could be used to monitor response. Harmonized definitions of ctDNA molecular response and pinpointing the optimal timing for assessing ctDNA responses are necessary for this setting. If using ctDNA analysis, we suggest restricting follow-up PET/CT in CR patients to a clinical suspicion of relapse, to avoid false-positive results

Estudio de la infiltración del sistema nervioso central en niños con leucemia linfoblástica aguda y papel de BMP4

Tesis doctoral inédita leída en la Universidad Autónoma de Madrid. Facultad de Medicina, Departamento de Pediatría. Fecha de lectura: 19 de Diciembre de 2011

Indole-3-carbinol synergizes with and restores fludarabine sensitivity in chronic lymphocytic leukemia cells irrespective of p53 activity and treatment resistances

[Purpose]: Chronic lymphocytic leukemia (CLL) still is lacking a cure. Relapse and development of refractoriness to current treatments are common. New therapies are needed to improve patient prognosis and survival. [Experimental design]: Indole-3-carbinol (I3C) is a natural product with antitumor properties already clinically tested. The effect of I3C, F-ara-A, and combinations of both drugs on CLL cells from patients representing different Rai stages, IGHV mutation status, cytogenetic alterations, p53 functionality, and treatment resistances was tested, as well as the toxicity of these treatments in mice. [Results]: I3C induces cytotoxicity in CLL cells but not in normal lymphocytes. I3C strongly synergized with F-ara-A in all CLL cells tested, including those with p53 deficiency and/or F-ara-A resistance. The mechanism of cell death involved p53-dependent and -independent apoptosis. The combination of I3C + F-ara-A was equally effective in CLL cells irrespective of IGHV mutation stage and patient refractoriness. Moreover, CLL survival and treatment resistance induced by co-culturing CLL cells on stroma cells were overcome by the combinatory I3C + F-ara-A treatment. No toxicity was associated with the combined I3C + fludarabine treatment in mice. [Conclusions]: I3C in combination with F-ara-A is highly cytotoxic in CLL cells from refractory patients and those with p53 deficiency. The striking dose reduction index for F-ara-A in combination with I3C would reduce fludarabine toxicity while having a similar or better anti-CLL effectiveness. Moreover, the low toxicity of I3C, already clinically tested, supports its use as adjuvant and combinatory therapy in CLL, particularly for patients with relapsed or refractory disease.This work was supported by grants from the Ministerio de Economia y Competitividad (PI12/01135 to J.M. Zapata, PI12/00494 to C. Muñoz-Calleja, and PI11/00708 to I. Buño) and from the Asociacion Española Contra el Cancer and Fundacion LAIR (to I. Buño). G. Perez-Chacon was the recipient of a JAE Doc contract from CSIC. The cost of this publication was paid in part by FEDER funds.Peer Reviewe

KV1.3 channel inhibition by indolic compounds in chronic lymphocytic leukemia cells

Resumen del trabajo presentado al 5th Symposium on Biomedical Research: "Advances and Perspectives In Pharmacology, Drug Toxicity and Pharmacogenetics", celebrado en Madrid del 15 al 16 de marzo de 2018.[Introduction]: Chronic lymphocytic leukemia (CLL) is the most common leukemia in western countries and it is based on B cell clonal expansion. This disease has no cure and the appearance of pharmacological resistance is very common. We have previously identified indole-3-carbinol (I3C) and its main metabolite, 3,3’-diindolylmethane (DIM), as active compounds with pharmacological activity against CLL. KV1.3 potassium channels are involved in B and T cells function controlling plasmatic membrane potential, Ca2+ entry and cellular proliferation. Therefore, these channels could be a new therapeutic target against CLL. Here, we have analysed if these indolic compounds can act, in part, by modulating the KV1.3 function.[Material and Methods]: we assessed the activity and effect of the indolic compounds on KV1.3 channels in CLL cells that are either sensitive or resistant to I3C cytotoxicity. Currents were registered by whole-cell patch-clamp. Statistical significance was determined by t-Student test or by nonparametric Mann-Whitney test.[Results]: The KV1.3 current magnitude on CLL cells correlated with their sensitivity to the cytotoxic effect of I3C; I3C resistant CLL (IR-CLL) cells exhibiting ≈2.5-fold higher KV1.3 current amplitude than sensitive (IS-CLL) cells. Both I3C and DIM inhibited KV1.3 current in CLL cells, DIM being ≈4-fold more potent than the parent compound. However, a non-cytotoxic compound, indole-3-carboxylic acid (I3CA), did not inhibit the KV1.3 current.[Conclusions]: IR-CLL cells exhibit greater KV1.3 current magnitude than IS-CLL cells, which can be due to the existence of different canalosomes in these cells. The KV1.3 inhibitory effect of the indolic compounds tested, correlates with their cytotoxic effect on CLL cells. Our results suggest that KV1.3 channel could be involved in CLL cells pharmacological resistance mechanisms and its inhibition could be part of the cytotoxic effect of I3C and DIM, which open new venues to the treatment of this disease.This study was supported by MINECO (SAF2013-45800-R, SAF2016-75021-R, RD12/0042/0019, CB/11/00222) and ISCIII (PI12/01135 and PI16/00895).Peer reviewe