The serological prevalence of SARS-CoV-2 infection in patients with chronic myeloid leukemia is similar to that in the general population.

BACKGROUND: Patients with hematological malignancies are at an increased risk of SARS-CoV-2 disease (COVID-19) and adverse outcome. However, a low mortality rate has been reported in patients with chronic myeloid leukemia (CML). Preclinical evidence suggests that tyrosine kinase inhibitors (TKIs) may have a protective role against severe COVID-19. METHODS: We conducted a cross-sectional study of 564 consecutive patients with CML who were tested for anti-SARS-CoV-2 IgG/IgM antibodies at their first outpatient visit between May and early November 2020 in five hematologic centers representative of three Italian regions. RESULTS: The estimated serological prevalence of SARS-CoV-2 infection in patients with CML after the first pandemic wave was similar to that in the general population (about 2%), both at national and regional levels. CML patients with positive anti-SARS-CoV-2 serology were more frequently male (p = 0.027) and active workers (p = 0.012), while there was no significant association with TKI treatment type. Only 3 out of 11 IgG-positive patients had previously received a molecular diagnosis of COVID-19, while the remainders were asymptomatic or with mild symptoms. CONCLUSIONS: Our data confirm that the course of SARS-CoV-2 infection in patients with CML is generally mild and reassure about the safety of continuing TKIs during the COVID-19 pandemic. Furthermore, we suggest that patients with CML succeed to mount an antibody response after exposure to SARS-CoV-2, similar to the general population.

[Autoreactive TCD8+ lymphocytes in patients with chronic myeloid leukemia in association with HLA and adenovirus infection]. / Linfocitos TCD8+ autorreactivos en pacientes con leucemia mieloide crónica en asociación con HLA e infección con adenovirus.

BACKGROUND: A possible interaction between a specific HLA type and Adenovirus has been postulated as a promoter in leukemia clonal evolution. The HLA-DRB1*14, specifically DRB1*14:21, 14:22, 14:45, 14:26, 14:33, 14:51, 14:35 subtypes was the most frequent in CML Venezuelan patients. OBJECTIVES: It is interesting to evaluate the molecular mimicry between the Adenovirus and the DRB1*14 subtypes which exhibit the same change in the amino acid position of the DR53 epitope. This mimicked segment has been identified as a LLERRRA polypeptide. MATERIAL AND METHOD: Experimental research conducted in the IHO Venezuela, in peripheral blood samples of patients with ALL, CML and healthy controls. Mixed culture, serology, lymphocyte proliferation and cytofluorometry were performed. RESULTS: DRB1*14 patient's lymphocytes reacted in 48 hours mixed culture against DRB1*14 promoters lymphocytes exhibiting increased CD8+T lymphocytes. CML patients show a different serological profile against Adenovirus. Only CML patients reacted to LLERRRA peptide, increasing CD8+ T cells. CONCLUSION: It is established that the relationship CML, HLADRB1* 14, autoreactive CD8+ T memory cell and CD8+T specific response from Adenovirus could be at the origin of the CML in Venezuelan patients.

Antecedentes: algunos adenovirus se han señalado como activadores clonales en leucemias. El alelo HLA-DRB1* 14 subtipos DRB1*14:21, 14:22, 14:45, 14:26, 14:33, 14:51, 14:35 se asociaron con leucemia mieloide crónica (LMC) en pacientes venezolanos. Objetivo: evaluar el mimetismo molecular entre el adenovirus y la estructura del antígeno HLA-DRB1*14 que exhiben el mismo cambio en la posición de aminoácido del epítopo DR53. Material y método: estudio experimental realizado en el IHO Banco de Sangre del Estado Zulia, Venezuela en muestras de sangre periférica de pacientes con LLA, LMC y controles sanos. Se realizaron cultivo mixto de linfocitos, serología, proliferación linfocitaria y citofluorometría. Resultados: los linfocitos DRB1*14 del paciente reaccionaron en 48 horas versus los linfocitos DRB1*14 estimuladores, que exhibieron aumento de los linfocitos T CD8+. Los pacientes con LMC tuvieron un perfil serológico diferente contra el adenovirus. Sólo pacientes con LMC reaccionaron frente al péptido secuencia LLERRRA con incremento de las células TCD8+. Conclusión: se estableció que la relación leucemia mieloide crónica, HLA-DRB1*14, células TCD8+ de memoria autorreactivas y TCD8+ en respuesta específica frente al adenovirus podría estar en el origen de la leucemia mieloide crónica de pacientes venezolanos.

Reactivation of resolved infection with the hepatitis B virus immune escape mutant G145R during dasatinib treatment for chronic myeloid leukemia.

Reactivation of hepatitis B virus (HBV) following immunosuppressive therapy or hematopoietic stem cell transplantation is a potentially fatal complication that may occur even in patients with prior resolution of HBV infection. Dasatinib is a small-molecule inhibitor of the tyrosine kinases SRC and ABL that has been approved for the treatment of chronic myeloid leukemia (CML) and Philadelphia chromosome-positive acute lymphoblastic leukemia. Here, we report the first case of reactivation of resolved infection with the HBV immune escape mutant G145R in a CML patient receiving dasatinib. Although dasatinib is not recognized as an immunosuppressant, our observations suggest that dasatinib may enhance HBV replication and induce its reactivation in immunocompetent patients, that HBV escape mutants may contribute to the pathogenesis of HBV reactivation, and that close monitoring of HBV status is advisable in patients with current or resolved HBV infection.

The V-val subtype Epstein-Barr virus nuclear antigen 1 promotes cell survival after serum withdrawal.

Epstein-Barr virus (EBV) can establish latent infection and has been associated with various human cancers. Epstein-Barr nuclear antigen 1 (EBNA1) is the only viral protein that is expressed in all EBV-associated malignant tissues. The N- and C-terminal domains of EBNA1, which are connected by internal glycine/alanine-rich short repeat sequences of various sizes, show sequence divergence across EBV strains isolated from around the world. At least five subtypes have been described, according to the amino acid at residue 487: P-ala, P-thr, V-val, V-pro, and V-leu. Whether the variations of EBNA-1 contribute to the pathogenesis of EBV or simply reflect the geographical distribution of EBV remain to be investigated. Furthermore, the cell effects conferred by EBNA1 subtypes that differ from that of the B95.8 prototype, which belongs to the P-ala subtype, remain to be elucidated. In this study, PCR was amplified with the full-length V-val EBNA1 gene from the CG3 cell line, an EBV-carrying lymphoblastoid cell line derived from a Taiwanese chronic myeloid leukemia patient. Plasmids expressing His-tagged EBNA1 fusion proteins in E. coli were constructed and used to raise antibodies in rabbit. The V-val EBNA1 gene was then cloned into a eukaryotic expression vector and successfully expressed in the transfected cultured cells. Expression of V-val EBNA1 rendered 293 cells able to undergo serum­independent cell proliferation, providing them with anti-apoptotic abilities, which are two characteristics of cancer cells. These data suggested that use of EBNA1 originally derived from tumor cells, rather than the more commonly utilized prototype, when investigating the potential role of EBNA1 in the oncogenesis of EBV-associated malignancies, is crucial.

CMV reactivation after allogeneic HCT and relapse risk: evidence for early protection in acute myeloid leukemia.

The association between cytomegalovirus (CMV) reactivation and relapse was evaluated in a large cohort of patients with acute myeloid leukemia (AML) (n = 761), acute lymphoblastic leukemia (ALL) (n = 322), chronic myeloid leukemia (CML) (n = 646), lymphoma (n = 254), and myelodysplastic syndrome (MDS) (n = 371) who underwent allogeneic hematopoietic cell transplantation (HCT) between 1995 and 2005. In multivariable models, CMV pp65 antigenemia was associated with a decreased risk of relapse by day 100 among patients with AML (hazard ratio [HR] = 0.56; 95% confidence interval [CI], 0.3-0.9) but not in patients with ALL, lymphoma, CML, or MDS. The effect appeared to be independent of CMV viral load, acute graft-versus-host disease, or ganciclovir-associated neutropenia. At 1 year after HCT, early CMV reactivation was associated with reduced risk of relapse in all patients, but this did not reach significance for any disease subgroup. Furthermore, CMV reactivation was associated with increased nonrelapse mortality (HR = 1.31; 95% CI, 1.1-1.6) and no difference in overall mortality (HR = 1.05; 95% CI, 0.9-1.3). This report demonstrates a modest reduction in early relapse risk after HCT associated with CMV reactivation in a large cohort of patients without a benefit in overall survival.

CMV reactivation is associated with a lower incidence of relapse after allo-SCT for CML.

Preemptive therapy at CMV reactivation has diminished post-transplant CMV mortality. Furthermore, recent studies suggest a favorable 'virus-versus-leukemia' effect from reactivating CMV, reducing relapse of AML after SCT. We studied the relationship of CMV reactivation with leukemic relapse in 110 patients with CML receiving HLA-identical sibling SCT between 1993 and 2008. Of these, 79 (72%) were in chronic phase, 5 in second chronic phase, 17 in accelerated phase and 9 in blast phase. A total of 97 patients (88%) received a myeloablative conditioning regimen, 97 received 4-log ex vivo T cell-depleted grafts and 13 received T-replete grafts. CMV reactivation before day 100 was observed in 72 patients (65.5%). At a median follow-up of 6.2 years, CMV reactivation < day 100 as a time-dependent covariate was an independent factor associated with decreased relapse. We conclude that CMV reactivation may contribute to a beneficial GVL effect in CML transplant recipients.

Dengue virus infection in a patient with chronic myeloid leukemia.

This is a case report of a patient with chronic myeloid leukemia (CML) undergoing imatinib treatment who became infected with dengue virus. The patient presented with classic dengue symptoms, along with early minor bleeding (blood-stained sputum) during the first 5 days of illness. Continuous inpatient imatinib treatment for CML was given without blood transfusion. The hemoglobin and white blood-cell count slowly improved over 30 days while recovering from the dengue viral infection. The patient recovered from the dengue virus infection without complication. Clinical monitoring of hematologic changes is needed in dengue patients undergoing anticancer treatment.

Human immunodeficiency virus infection and chronic myeloid leukemia.

CML (chronic myeloid leukaemia) in association with HIV (human immunodeficiency virus) infection (HIV-CML) is rarely described and is likely to be coincidental. The natural history and behaviour of HIV-CML is different, being more atypical and aggressive. Both conditions, and their respective treatments may cause myelosuppression. Concurrent treatment with cART (combination antiretroviral therapy) and the tyrosine kinase inhibitors (TKI's) can result in appropriate control of CML and HIV infection, as well as long term survival. However, drug interactions between ARV's and TKI's may require adjustment of treatment.

Hepatitis B virus reactivation in a chronic myeloid leukemia patient treated with imatinib mesylate.

Imatinib mesylate is a molecular targeted agent for treating chronic myeloid leukemia (CML) and gastrointestinal stromal tumor. Although imatinib mesylate is not regarded as an immunosuppressive agent, few studies have also shown that it may impair immune response. In this report, we present a case of transient hepatitis B virus (HBV) reactivation during imatinib mesylate treatment for CML.

Rapid and sustained increase of large granular lymphocytes and rare cytomegalovirus reactivation during dasatinib treatment in chronic myelogenous leukemia patients.

We retrospectively investigated increases in large granular lymphocytes (LGL) in peripheral blood during dasatinib treatment in 25 chronic myelogenous leukemia patients. Fifteen of 25 patients (60 %) showed an increase in LGL. All 15 of these patients also showed an increase in NK cells, and 11 showed an increase in CD8(+) T cells. High frequencies of clonal rearrangements of TCR-ß, -γ, and -δ genes were observed in LGL (+) patients, and at lower frequencies in LGL (-) patients as well. Clinical responses were favorable for all. With respect to their newly obtained complete molecular response after dasatinib treatment, LGL (+) patients showed higher response rates than did LGL (-) patients. In contrast, pleural effusions were more commonly observed in LGL (+) patients (60 %) than in LGL (-) patients (20 %). LGL counts significantly increased at 2 h after oral intake of dasatinib in all 25 patients. This was not observed in treatment with imatinib or nilotinib. Cytomegalovirus (CMV) C7-HRP tests were negative in all patients. Serum CMV-IgM antibodies were positive in only 2 of 25 patients without symptom of infection. Thus, LGL lymphocytosis during dasatinib treatment may be correlated with favorable molecular response, and with increased incidence of pleural effusions. In the clinical setting, CMV reactivation appears uncommon.

[Reactivation of chronic hepatitis B infection related to imatinib mesylate therapy in patients with chronic myeloid leukemia: two cases report and literatures review].

OBJECTIVE: To probe the cause for triggering HBV reactivation and possible management of the chronic hepatitis B individuals received imatinib. METHODS: This study presented two cases of transient hepatitis B virus (HBV) reactivation and hepatic dysfunction during oral imatinib for chronic myeloid leukemia (CML) and made a literatures review about the pathogenesis, possible prophylactic and therapeutic management of such chronic hepatitis B individuals receiving imatinib. RESULTS: Two CML patients, without prior liver dysfunction but with chronic HBV infection, suffered from transient HBV reactivation occurred during oral imatinib. Both of them finally obtained good outcome following the additional oral nucleotide antiviral therapy. CONCLUSION: It remained unclear whether imatinib induced the reactivation of HBV in patients with a latent HBV infection. From our study, all candidates receiving oral imatinib should be screened for HBsAg and anti-HBc antibodies prior to initiation of imatinib. Prophylactic antiviral therapy should be offered to HBV-infected individuals along with a close monitoring for signs of reactivation.

Mono/oligoclonal T and NK cells are common in chronic myeloid leukemia patients at diagnosis and expand during dasatinib therapy.

In a proportion of patients with chronic myeloid leukemia (CML) being treated with dasatinib, we recently observed large granular lymphocyte (LGL) expansions carrying clonal T-cell receptor (TCR) gamma/delta gene rearrangements. To assess the prevalence and role of clonal lymphocytes in CML, we collected samples from patients (n = 34) at the time of diagnosis and during imatinib and dasatinib therapies and analyzed lymphocyte clonality with a sensitive polymerase chain reaction-based method of TCR gamma and delta genes. Surprisingly, at CML diagnosis, 15 of 18 patients (83%) had a sizeable clonal, BCR-ABL1 negative lymphocyte population, which was uncommon in healthy persons (1 of 12; 8%). The same clone persisted at low levels in most imatinib-treated patients. In contrast, in a distinct population of dasatinib-treated patients, the diagnostic phase clone markedly expanded, resulting in absolute lymphocytosis in blood. Most patients with LGL expansions (90%) had TCR delta rearrangements, which were uncommon in patients without an LGL expansion (10%). The TCR delta clones were confined to gammadelta(+) T- or natural killer-cell compartments and the TCR gamma clones to CD4(+)/CD8(+) alphabeta(+) fractions. The functional importance of clonal lymphocytes as a part of leukemia immune surveillance and the putative anergy-reversing role of dasatinib require further evaluation.

Use of oncolytic viruses for the eradication of drug-resistant cancer cells.

Targeted therapy using small-molecule inhibitors is a promising new therapy approach against cancer, but drug-resistant mutants present an obstacle to success. Oncolytic virus therapy, where viruses replicate specifically in cancer cells and kill them, is another promising therapy approach against cancer. While encouraging results have been observed in clinical trials, consistent success has not been possible so far. Based on a computational framework, I report that even if oncolytic virus therapy fails to eradicate a cancer, it can have the potential to eradicate the sub-population of drug-resistant cancer cells. Once this has occurred, targeted drug therapy can be used to induce cancer remission. For this to work, a drug resistance mutation must confer a certain fitness cost to the cell, as has been documented in the literature. The reason for this finding is that in the presence of a shared virus, the faster growing (drug-sensitive) cell population produces an amount of virus that is too much for the slower growing (drug-resistant) cell population to survive. This is derived from a population dynamic principle known as apparent competition. Therefore, a sequential combination of oncolytic virus and targeted therapies can overcome major weaknesses of either approach alone.

Transcription of HERV-E and HERV-E-related sequences in malignant and non-malignant human haematopoietic cells.

Infection of a human T-cell leukaemia cell line (HSB-2) with HHV-6 led to the induction of exosome-like-particles attached to newly formed HHV-6 enveloped particles and to amplification of a 1642 bp molecule consisting of a partial human endogenous retrovirus (HERV)-E polymerase gene and repetitive sequences. We initiated an analysis of transcriptional patterns of predicted genes from HERV-E sequences in normal and malignant haematopoietic cells. Transcription patterns of regions corresponding to gag, pol and env genes at different chromosomal loci varied among cell types tested. Several specific transcripts were only observed in malignant haematopoietic cells and transcriptional activity varied among different malignant cell types. A transcript of 7.1 kb spanning the complete gag, pol and env gene region, originating from chromosome 8p23, was identified in normal peripheral blood cells and cells of the chronic myeloid leukaemia cell line K562. Our study describes new active HERV-E sequences and new loci throughout the human genome.