Efficacy and safety of mRNA1273 SARS-CoV-2 vaccination in hematopoietic stem cell transplant recipients: Single center experience

BACKGROUND

COVID-19 represents a worldwide pandemic and vaccination remains the most effective preventive strategy. Among hematological patients, COVID-19 has been associated with a high mortality rate. Vaccination against SARS-CoV-2 has shown high efficacy in reducing community transmission, hospitalization and deaths related to severe COVID-19 disease. However, patients with impaired immunity may have lower sero-responsiveness to vaccination.

METHODS

This study focuses on hematopoietic stem cell transplantation (HSCT) recipients. We performed a unicenter, prospective, observational study of a cohort of 31 allogeneic and 56 autologous-HSCT recipients monitored between March 2021 and May 2021 for serological response after COVID-19 vaccination with two doses of mRNA1273 vaccine (Moderna). In order to determine seroconversion, serological status before vaccination was studied.

RESULTS

At a median range of 75 days after the second vaccine dose, seroconversion rates were 84% and 85% for the autologous and allogeneic-HSCT groups, respectively. We confirmed some potential risk factors for a negative serological response, such as receiving anti-CD20 therapy in the previous year before vaccination, a low B-lymphocyte count and hypogammaglobulinemia. Neutralizing antibodies were quantified in 44 patients, with a good correlation with serological tests. Adverse events were minimal.

CONCLUSION

mRNA1273 vaccination is safe and effective in HSCT recipients, especially in those presenting recovered immunity.

HHV8 and EBV-negative primary effusion-based lymphoma: A case report of a new provisional entity and review of literature

Key Clinical Message

HHV8- and EBV-negative primary effusion lymphoma is an extremely rare neoplasm involving body cavities without detectable tumor mass. It usually presents in elderly patients without known immunodeficiency. Compared to primary effusion lymphoma, it has a better prognosis.

Primary effusion lymphoma (PEL) is a rare non-Hodgkin lymphoma confined exclusively to body cavities without detectable tumor masses. The term PEL-like is an entity similar to PEL in clinical presentation but without relation to human herpesvirus 8 (HHV8). We report a case of HHV8- and EBV-negative primary effusion-based lymphoma.

Erythrocyte Lysing Solutions Have a Detrimental Effect in Flow Cytometric Dendritic Cell Detection

Flow cytometry enumeration of Peripheral Blood Dendritic Cells (PBDCs) is a minimally invasive procedure extremely useful for immunological studies. Numbers of PBDCs vary depending on age, lifestyle, or in pathologies like cancer, leukemia or immunodeficiencies. Conventional methods for PBDC identification by flow cytometry involve red blood cell lysis using either formaldehyde or ammonium chloride based solutions. This specific procedure has been widely reported to cause a detrimental effect as well as an artifactual detection of target populations. Alternatively, minimal sample perturbation assays that avoid the use of erythrolytic solutions with centrifugation steps and preserve the native cellular state are simpler and more robust than conventional methods. In this study, we aimed to evaluate how conventional flow cytometry assays can alter dendritic cell counting when compared with minimal sample perturbation protocols, in terms of absolute cell counting, percentage and Stain Index (SI) of PBDC subsets. We evaluated the use of three different erythrolytic solutions (CyLyse™, OptiLyse C, and Pharm Lyse™) on a series of n = 20 peripheral blood specimens for conventional and plasmacytoid DCs detection as well as for leukocyte and basophil detection. Our results showed a significant reduction of leukocytes and, specifically, of DCs and basophils in terms of absolute number when using erythrolytic solutions. In conclusion, our study shows that PBDC counting is heavily affected when lysing solutions are used, indicating that these stellate-shaped populations appear to be more labile. This article is protected by copyright. All rights reserved.

Impact of red blood cell lysing on rare event analysis

The challenges associated with analyzing rare cells are dependent on a series of factors, which usually require large numbers of cells per sample for successful resolution. Among these is determining the minimum number of total events needed to be acquired as defined by the expected frequency of the target cell population. The choice of markers that identify the target population, as well as the event rate and the number of aborted events/second, will also determine the statistically significant detection of rare cell events. Sample preparation is another important but often overlooked factor in rare cell analysis, and in this study we examine Poisson theory and methods to determine the effect of sample manipulation on rare cell detection. After verifying the applicability of this theory, we have evaluated the potential impact of red cell lysis on rare cell analysis, and how cell rarity can be underestimated or overestimated based on erythrolytic sensitivity or resistance of healthy leukocytes and pathological rare cells. This article is protected by copyright. All rights reserved.

CD34+CD19-CD22+ B-cell progenitors may underlie phenotypic escape in patients treated with CD19-directed therapies

CD19-directed immunotherapies have revolutionized the treatment of advanced B-cell acute lymphoblastic leukemia (B-ALL). Despite initial impressive rates of complete remission (CR) many patients ultimately relapse. Patients with B-ALL successfully treated with CD19-directed T cells eventually relapse, which, coupled with the early onset of CD22 expression during B-cell development, suggests that preexisting CD34+CD22+CD19- (pre)-leukemic cells represent an "early progenitor origin-related" mechanism underlying phenotypic escape to CD19-directed immunotherapies. We demonstrate that CD22 expression precedes CD19 expression during B-cell development. CD34+CD19-CD22+ cells are found in diagnostic and relapsed bone marrow samples of ∼70% of patients with B-ALL, and their frequency increases twofold in patients with B-ALL in CR after CD19 CAR T-cell therapy. The median of CD34+CD19-CD22+ cells before treatment was threefold higher in patients in whom B-ALL relapsed after CD19-directed immunotherapy (median follow-up, 24 months). Fluorescence in situ hybridization analysis in flow-sorted cell populations and xenograft modeling revealed that CD34+CD19-CD22+ cells harbor the genetic abnormalities present at diagnosis and initiate leukemogenesis in vivo. Our data suggest that preleukemic CD34+CD19-CD22+ progenitors underlie phenotypic escape after CD19-directed immunotherapies and reinforce ongoing clinical studies aimed at CD19/CD22 dual targeting as a strategy for reducing CD19- relapses. The implementation of CD34/CD19/CD22 immunophenotyping in clinical laboratories for initial diagnosis and subsequent monitoring of patients with B-ALL during CD19-targeted therapy is encouraged.

Follicular lymphoma: an update on diagnosis, prognosis, and management

Follicular lymphoma, the most common indolent lymphoma, originates from germinal centre B-cells of the lymphoid follicle, and is characterized by t(14;18). Clinical manifestations include the presence of lymphadenopathy, sometimes accompanied by constitutional symptoms or cytopenia. Diagnosis is established through the identification of a B-cell proliferation of nodular pattern in the lymph node biopsy. Upon staging with PET-CT and bone marrow biopsy, a significant proportion of patients do not need immediate treatment. When therapy is indicated, commonly used regimens include anti-CD20 immunotherapy with or without chemotherapy. Although overall survival for most patients is prolonged, relapses are very frequent, and early relapse and transformation to an aggressive lymphoma portend a much worse prognosis. New therapies are under development, which will most likely change outcomes for FL patients in the near future.

R-COMP versus R-CHOP as first-line therapy for diffuse large B-cell lymphoma in patients ≥60 years: Results of a randomized phase 2 study from the Spanish GELTAMO group

The use of non-pegylated liposomal doxorubicin (Myocet^® ) in diffuse large B-cell lymphoma (DLBCL) has been investigated in retrospective and single-arm prospective studies. This was a prospective phase 2 trial of DLBCL patients ≥60 years old with left ventricular ejection fraction (LVEF) ≥55% randomized to standard R-CHOP or investigational R-COMP (with Myocet^® instead of conventional doxorubicin). The primary end point was to evaluate the differences in subclinical cardiotoxicity, defined as decrease in LVEF to <55% at the end of treatment. Secondary objectives were efficacy, safety, and variations of troponin and N-terminal pro-B-type natriuretic peptide (NT-proBNP) and LVEF along follow-up. Ninety patients were included, 45 in each group. No differences were observed in the percentage of patients with LVEF <55% at end of treatment (11% in R-CHOP arm vs. 7% in R-COMP arm, p = 0.697) or at 4 months (10% vs. 6%, respectively, p = 0.667) and 12 months (8% vs. 7%, respectively, p = 1). However, a higher percentage of R-CHOP compared with R-COMP patients showed increased troponin levels in cycle 6 (100% vs. 63%, p = 0.001) and at 1 month after treatment (88% vs. 56%, respectively, p = 0.015). Cardiovascular adverse events were seen in five R-CHOP patients (nine episodes, four grade ≥3) and in four R-COMP patients (five episodes, all grade 1-2). No significant differences in efficacy were observed. In conclusion, R-COMP is a feasible immunochemotherapy schedule for DLBCL patients ≥60 years, with similar efficacy to R-CHOP. However, the use of non-pegylated doxorubicin instead of conventional doxorubicin was not associated with less early cardiotoxicity, although some reduced cardiac safety signals were observed. Trial registration: ClinicalTrials.gov Identifier: NCT02012088.

Long-term outcome comparing histological grades of follicular lymphoma patients treated with immunochemotherapy as first-line therapy: A retrospective analysis from two institutions

OBJECTIVES

To clarify the impact of histological grades in follicular lymphoma.

METHODS

We retrospectively analysed 250 patients diagnosed with FL treated with chemoimmunotherapy: 188 patients were grades 1-2 and 62 grade 3A.

RESULTS

In our series, grade 3A FL patients were older, higher proportion of localised disease and lower bone marrow infiltration at diagnosis comparing grades 1-2 FL patients. Estimated six-year progression-free survival and time to progression showed no differences between both groups [grade 3A: 56% (95%CI: 39%-73%) and 51% (95%CI: 41%-61%) vs grades 1-2:55% (95%CI: 46%-63%) and 57% (95%CI: 49%-65%), P = .782 and P = .521, respectively]. Estimated six-year overall survival was lower, 76% (95%CI: 64%-88%) for the grade 3A group than grades 1-2 83% (95%CI: 77%-89%); P = .044. In addition to that, cumulative incidence curves of death not related to lymphoma at 10 years between groups were as follows: [0.26 (95%CI: 0.25-0.27) and 0.05 (95%CI: 0.04-0.06) for G3AFL and G1-2FL, respectively], P = .010. Grade 3A FL showed in PFS curve no relapses after 6 years. These results were absolutely reproduced in 199 patients receiving R-CHOP regimen as induction.

CONCLUSIONS

Our results indicate similar long-term outcomes in terms of progression-free survival and time to progression in grades 1-2 and 3A. No relapses were observed in G3AFL group after 6 years.

Highly variable mutational profile of ASXL1 in myelofibrosis

OBJECTIVE

Somatic mutations in ASXL1 seem to have a negative prognostic impact in patients with several myeloid neoplasms, including myelofibrosis (MF). The aim of this work was to determine the prevalence and profile of ASXL1 mutations in MF.

METHODS

We analyzed mutations in ASXL1 in 70 consecutive MF patients from 8 Spanish hospitals by means of Sanger sequencing, as well as JAK2, CALR, and MPL mutations.

RESULTS

ASXL1 mutations were found in 16/70 (23%) of cases, most commonly p.Gly646TrpfsX12 (5/16). Most mutations (13/16) were frameshift mutations. Of 54 ASXL1- wild-type patients, 32 (59%) had at least one single nucleotide polymorphism (SNP), 27 of them had g.78128C>T, g.79017A>C, and g.79085T>C [triple SNP (TSNP) patients]. The 5-yr overall survival probability of TSNP patients was 67% (95% CI, 43-91%) vs. 90% (95% CI, 77-100%) in ASXL1-WT patients (P = 0.152).

CONCLUSION

ASXL1 mutations were found in 23% of cases, p.Gly646TrpfsX12 being the most frequent. About 85% of mutations were found only in individual cases and 46% had not previously been reported, a pattern also seen in other series. Fifty percent of ASXL1-WT patients had a combination of three specific SNPs that might have a prognostic correlation that needs to be determined in larger series.