Infections in patients with chronic lymphocytic leukaemia: Mitigating risk in the era of targeted therapies

Severe infections in patients with chronic lymphocytic leukemia included in trials investigating BTK and BCL2 inhibitors

Bruton tyrosine kinase inhibitors (BTKi) and the BCL-2 inhibitor venetoclax have significantly improved the prognosis of patients with chronic lymphocytic leukemia (CLL). However, the incidence of severe infections in patients receiving these agents needs to be better understood. Our review aimed to provide an overview of grade ≥3 infections in patients with CLL who received BTKi and venetoclax-based therapy in prospective trials. Infection rates were influenced by the age of patients and the duration of follow-up. For treatment-naive (TN) patients receiving BTKi, infection rates ranged between 11.4 % and 27.4 % and were close to 30 % in relapsed/refractory (R/R) patients. TN and R/R patients receiving fixed-duration venetoclax-based treatments showed variable rates, with maximum values around 20 %. Opportunistic and fatal infections were uncommon. In conclusion, infections remain a concern in patients with CLL receiving targeted agents. A better definition of factors increasing infection vulnerability could help identify those patients who require infection prophylaxis.

IgG testing, immunoglobulin replacement therapy, and infection outcomes in patients with CLL or NHL: real-world evidence

ABSTRACT

Patients with chronic lymphocytic leukemia (CLL) and non-Hodgkin lymphoma (NHL) can develop hypogammaglobulinemia, a form of secondary immune deficiency (SID), from the disease and treatments. Patients with hypogammaglobulinemia with recurrent infections may benefit from immunoglobulin replacement therapy (IgRT). This study evaluated patterns of immunoglobulin G (IgG) testing and the effectiveness of IgRT in real-world patients with CLL or NHL. A retrospective, longitudinal study was conducted among adult patients diagnosed with CLL or NHL. Clinical data from the Massachusetts General Brigham Research Patient Data Registry were used. IgG testing, infections, and antimicrobial use were compared before vs 3, 6, and 12 months after IgRT initiation. Generalized estimating equation logistic regression models were used to estimate odds ratios, 95% confidence intervals, and P values. The study population included 17 192 patients (CLL: n = 3960; median age, 68 years; NHL: n = 13 232; median age, 64 years). In the CLL and NHL cohorts, 67% and 51.2% had IgG testing, and 6.5% and 4.7% received IgRT, respectively. After IgRT initiation, the proportion of patients with hypogammaglobulinemia, the odds of infections or severe infections, and associated antimicrobial use, decreased significantly. Increased frequency of IgG testing was associated with a significantly lower likelihood of severe infection. In conclusion, in real-world patients with CLL or NHL, IgRT was associated with significant reductions in hypogammaglobulinemia, infections, severe infections, and associated antimicrobials. Optimizing IgG testing and IgRT are warranted for the comprehensive management of SID in patients with CLL or NHL.

Optimization of In Vitro Th17 Polarization for Adoptive Cell Therapy in Chronic Lymphocytic Leukemia

Although preclinical investigations have shown notable efficacy in solid tumor models utilizing in vitro-differentiated Th17 cells for adoptive cell therapy (ACT), the potential benefits of this strategy in enhancing ACT efficacy in hematological malignancies, such as chronic lymphocytic leukemia (CLL), remain unexplored. CLL is a B-cell malignancy with a clinical challenge of increased resistance to targeted therapies. T-cell therapies, including chimeric antigen receptor (CAR) T cells, have demonstrated limited success in CLL, which is attributed to CLL-mediated T-cell dysfunction and skewing toward immunosuppressive phenotypes. Herein, we illustrate the feasibility of polarizing CD4+ T cells from the Eμ-TCL1 murine model, the most representative model for human CLL, into Th17 phenotype, employing a protocol of T-cell activation through the inducible co-stimulator (ICOS) alongside a polarizing cytokine mixture. We demonstrate augmented memory properties of in vitro-polarized IL-17-producing T cells, and preliminary in vivo persistence in leukemia-bearing mice. Our findings gain translational relevance through successful viral transduction of Eμ-TCL1 CD4+ T cells with a CD19-targeted CAR construct during in vitro Th17 polarization. Th17 CAR T cells exhibited remarkable persistence upon encountering antigen-expressing target cells. This study represents the first demonstration of the potential of in vitro-differentiated Th17 cells to enhance ACT efficacy in CLL.

Chronic Lymphocytic Leukemia: Management of Adverse Events in the Era of Targeted Agents

The treatment landscape for CLL has undergone a profound transformation with the advent of targeted agents (TAs) like Bruton's Tyrosine Kinase inhibitors (BTKis) and BCL-2 inhibitors (BCL-2is). These agents target crucial cellular pathways in CLL, offering superior efficacy over traditional chemo-immunotherapy, which has led to improved progression-free and overall survival rates. This advancement promises enhanced disease control and potentially normal life expectancy for many patients. However, the journey is not without challenges, as these TAs are associated with a range of adverse events (AEs) that can impact treatment efficacy and patient quality of life. This review focuses on detailing the various AEs related to TA management in CLL, evaluating their frequency and clinical impact. The aim is to present a comprehensive guide to the effective management of these AEs, ensuring optimal tolerability and efficacy of TAs. By reviewing the existing literature and consolidating findings, we provide insights into AE management, which is crucial for maximizing patient outcomes in CLL therapy.

Prevention and management of infectious complications in patients with chronic lymphocytic leukemia (CLL) treated with BTK and BCL-2 inhibitors, focus on current guidelines

CLL is associated with an increased risk of infectious complications. Treatment with BTK or BCL-2 inhibitors does not seem to increase significantly the risk of opportunistic infections, but the role of combination therapies including BTK and/or BCL-2 inhibitors remains to be established. Various infectious complications can be successfully prevented with appropriate risk management strategies. In this paper we reviewed the international guidelines on prevention and management of infectious complications in patients with CLL treated with BTK or BCL-2 inhibitors. Universal pharmacological anti-herpes, antibacterial or antifungal prophylaxis is not warranted. Reactivation of HBV should be prevented in HBsAg-positive subjects. For HBsAg-negative/HBcAb-positive patients recommendations differ, but in case of combination treatment should follow those for other, particularly anti-CD20, agent. Immunization should be provided preferably before the onset of treatment. Immunoglobulin therapy has favourable impact on morbidity but not mortality in patients with hypogammaglobulinemia and severe or recurrent infections. Lack of high-quality data and heterogeneity of patients or protocols included in the studies might explain differences among the main guidelines. Better data collection is warranted.

Prediction of severe infections in chronic lymphocytic leukemia: a simple risk score to stratify patients at diagnosis

Chronic Lymphocytic Leukemia (CLL) is well-known for increasing susceptibility to infections. Factors such as immune dysregulation, IGHV status, hypogammaglobulinemia, and patient comorbidity and treatment, contribute to higher infection rates and mortality. However, the impact of hypogammaglobulinemia on infection rates is controversial. We aimed to identify clinical and biological parameters linked to the risk of severe infectious events. Additionally, we set up a straightforward risk infection score to stratify CLL patients at diagnosis, thereby enabling the development of suitable infection prevention strategies. We retrospectively evaluated 210 unselected CLL patients diagnosed between 1988 and 2018. This evaluation encompassed demographics, Binet stage, immunoglobulin (Ig) levels, treatment history, comorbidities, and IGHV mutational status at diagnosis. The frequency and severity of infectious events were recorded. Analysis revealed that age, IGHV mutational status, Binet stage, and hypogammaglobulinemia were statistically associated with the Time to First Infection (TTFI) in univariate and multivariate analyses. Using hazard ratios from the multivariate analysis, we finally devised a risk scoring system that integrated age, IGHV mutational status, immunoglobulin levels, and Binet stage to stratify patients at diagnosis based on their specific infection risk. In our cohort, disease progression and infections were the leading cause of death. These findings pointed out the clinical need for a screening process strategic for defining infectious risk at the time of CLL diagnosis, with a significant enhancement in the clinical management of these patients.

Vaccinations in patients with chronic lymphocytic leukemia

Chronic lymphocytic leukemia (CLL) is characterized by immune dysfunction resulting in heightened susceptibility to infections and elevated rates of morbidity and mortality. A key strategy to mitigate infection-related complications has been immunization against common pathogens. However, the immunocompromised status of CLL patients poses challenges in eliciting an adequate humoral and cellular immune response to vaccination. Most CLL-directed therapy disproportionately impairs humoral immunity. Vaccine responsiveness also depends on the phase and type of immune response triggered by immunization. In this review, we discuss the immune dysfunction, vaccine responsiveness, and considerations for optimizing vaccine response in patients with CLL.

Pathogenesis and management of immune dysfunction secondary to B cell haematological malignancies

Malignancies of the B-lymphocyte lineage are among the most diagnosed haematological malignancies in clinical practice. In our community, multiple myeloma (MM) and its precursor condition monoclonal gammopathy of undetermined significance are the commonest, accounting for ~12% of diagnoses, followed by chronic lymphocytic leukaemia (CLL) and its precursor condition monoclonal B lymphocytosis, ~9%. Along with diffuse large B cell lymphoma, follicular lymphoma and marginal zone lymphoma, these conditions comprise around a third of all haematological malignancies diagnosed. Infection remains an important cause of mortality and morbidity in the management of patients with these conditions. This is in part treatment-related but also reflective of disease-related immune dysfunction. Infectious complications account for up to 50% of early mortality in patients with myeloma and up to 50% of all mortality in patients with CLL. A variety of strategies are available to decrease the morbidity and mortality of infectious complications; however, practices vary between countries and often between treating physicians. Treatment options have evolved significantly over the last decade, with the introduction of monoclonal antibodies, small molecule inhibitors, second- and third-generation immunomodulatory agents and CAR-T cell therapy. Much of the data that inform clinical practice in infection management predates current therapeutic approaches. This is in part because of the rapid development of new therapies but also reflective of the long natural history of many of these diseases and the need for prolonged periods of observation. In this article, we review the aspects of disease and treatment that contribute to immune dysfunction in MM, CLL and B-cell non-Hodgkin lymphoma and review the current strategies used to manage immune dysfunction and infection.

Pierre F, Karmali R, Mi X, Boyer J, Nieves M, Ison MG, Winter JN, Gordon LI, Ma S. Humoral Immunity After COVID-19 Vaccination in Chronic Lymphocytic Leukemia and Other Indolent Lymphomas: A Single-Center Observational Study

BACKGROUND

Chronic lymphocytic leukemia (CLL) and other non-Hodgkin's lymphomas (NHLs) lead to broad immunosuppression, conferring a greater risk for morbidity and mortality from SARS-CoV-2. Our study analyzed antibody (Ab) seropositivity from SARS-CoV-2 vaccination in patients with these cancers.

METHODS

In the final analysis, 240 patients were involved, and seropositivity was defined as a positive total or spike protein Ab.

RESULTS

Seropositivity was 50% in CLL, 68% in WM, and 70% in the remaining NHLs. Moderna vaccination led to higher seropositivity compared to Pfizer vaccination across all cancers (64% vs. 49%; P = .022) and specifically CLL patients (59% vs. 43%; P = .029). This difference was not explainable by differences in treatment status or prior anti-CD20 monoclonal Ab therapy. In CLL patients, current or prior cancer therapy led to lower seropositivity compared to treatment-naïve patients (36% vs. 68%; P = .000019). CLL patients treated with Bruton's tyrosine kinase (BTK) inhibitors had better seropositivity after receiving the Moderna vaccination compared to Pfizer (50% vs. 23%; P = .015). Across all cancers, anti-CD20 agents within 1 year led to a lower Ab response compared to greater than one year (13% vs. 40%; P = .022), a difference which persisted after booster vaccination.

CONCLUSION

Antibody response is lower in patients with indolent lymphomas compared to the general population. Lower Ab seropositivity was found in patients with a history of anti-leukemic agent therapy or those immunized with Pfizer vaccine. This data suggests that Moderna vaccination may confer a greater degree of immunity against SARS-CoV-2 in patients with indolent lymphomas.

Significant reduction in the incidence of non-coronavirus infections in patients with chronic lymphocytic leukemia on ibrutinib and venetoclax treatment during the COVID-19 pandemic: An additional benefit of lockdown

Effective treatment and prevention of infections challenge management of patients with chronic lymphicytic leukemia (CLL). The COVID-19 pandemic resulted in the reduction of outpatient hospital visits as a part of non-pharmaceutical interventions that could affect the incidence of infectious complications. Study enrolled patients with CLL receiving ibrutinib or/and venetoclax who were observed at the Moscow City Centre of Hematology from 01 April 2017 to 31 March 2021. We found a reduction in the incidence of infectious episodes after the implementation of the lockdown in Moscow in 01 April 2020, when compared to data on the year prior to the lockdown (p < 0.0001), as well as when compared to the predictive model (p = 0.02), and based on individual infection profiles using cumulative sums (p < 0.0001). Bacterial infections had 4.44-fold decrease, bacterial in combination with undefined infections had 4.89-fold decrease, viral infections had unsignificant changes. The decrease in the number of outpatient visits coincides with the time of the lockdown could be a likely factor, explaining a decline in the incidence of infection. Patients were clustered according incidence and severity of infectious episodes for subgroup mortality assessment. No differences in overall survival due to COVID-19 were observed. Typical respiratory infections, bacterial and undefined, the transmission of which may be affected by patient-to-patient contact in the settings of out-patient health care visits were decreased, possibly due to SARS-CoV-2 restrictive measures. A positive correlation between outpatient visits and the incidence of bronchial and upper respiratory tract infection points at the role of hospital-acquired infection and attests to the necessity of reorganizing care for all patients with CLL.

Frequency of viral infections in adolescent and adult in-patient Ethiopians with acute leukemia at presentation to a tertiary care teaching hospital: a cross-sectional study

BACKGROUND

Leukemic patients are prone to infectious agents such as viruses due to dysregulated immune system resulting from infiltration of the bone marrow by malignant cells, chronic stimulation, reactivation of some viruses and viral pathogenicity as well as rarely from acquisition of a new infections leading to severe complications. However, the prevalence of these infections has not been systematically documented in resource-limited settings such as Ethiopia.

OBJECTIVE

To determine the prevalence of HBV, HCV, and HIV among adult and adolescent in-patients with acute leukemia before the administration of chemotherapy, at the Tikur Anbessa Specialized Hospital (TASH) in Addis Ababa, Ethiopia.

METHODS

A cross sectional study was conducted on 176 adult and adolescent inpatient Ethiopians, who were diagnosed with acute leukemia from April 2019 to June 2021. Socio-demographic characteristics and relevant clinical data were collected. Peripheral blood samples were collected and tested for HBV, HIV, and HCV using Enzyme-Linked Immunosorbent Assay (ELISA) and real-time PCR. Chi-square tests were used to assess associations between variables.

RESULTS

Of the 176 patients, 109(62%) were males. The median age was 25[IQR,18-35] yr, with a range from 13 to 76 year. The prevalence of HBV (positivity for HBsAg plus HBV DNA), HCV and HIV was 21.6%, 1.7%, and 1.7%, respectively. HBsAg was positive in 19 cases (10.8%). Among 157 HBsAg negative patients, 52(33.1%) were positive for Anti-HBcAg; of these seropositive cases, 47.5% were positive for HBV DNA. Most DNA positive, HBsAg negative cases (79.0%) had DNA concentrations below 200 IU/ml indicating true occult HBV infection (OBI). Of the 176 cases, 122 had a history of blood transfusions, but no statistically significant association was found between HBV infection and blood product transfusion history (P = 0.963).

CONCLUSIONS

The prevalence of HBV, HIV and HCV in patients with acute leukemia was similar to the national prevalence level of these infections. Given the HBsAg positivity and the high prevalence of occult hepatitis B infection in our study, these patients may be at increased risk for chemotherapy related hepatitis flares. Hence, clinicians caring these patients are strongly advised to screen their patients for HBV and also for HIV and HCV infections routinely.

A review of prophylactic regimens to prevent invasive fungal infections in hematology patients undergoing chemotherapy or stem cell transplantation

INTRODUCTION

The recent introduction of targeted therapies, including monoclonal antibodies, tyrosine-kinase inhibitors, and immunotherapies has improved the cure rate of hematologic patients. The implication of personalized treatment on primary antifungal prophylaxis will be discussed.

AREAS COVERED

We reviewed the literature for clinical trials reporting the rate of invasive fungal infections during targeted and cellular therapies and stem cell transplant, and the most recent international guidelines for primary antifungal prophylaxis.

EXPERT OPINION

As the use of personalized therapies is growing, the risk of invasive fungal infection has emerged in various clinical settings. Therefore, it is possible that the use of mold-active antifungal prophylaxis would spread in the next years and the risk of breakthrough infections would increase. The introduction of new antifungal agents in the clinical armamentarium is expected to reduce clinical unmet needs concerning the management of primary antifungal prophylaxis and improve outcome of patients.

Risk of Infections Secondary to the Use of Targeted Therapies in Hematological Malignancies

Concurrent infections in hematological malignancies (HM) are major contributors to adverse clinical outcomes, including prolonged hospitalization and reduced life expectancy. Individuals diagnosed with HM are particularly susceptible to infectious pathogens due to immunosuppression, which can either be inherent to the hematological disorder or induced by specific therapeutic strategies. Over the years, the treatment paradigm for HM has witnessed a tremendous shift, from broad-spectrum treatment approaches to more specific targeted therapies. At present, the therapeutic landscape of HM is constantly evolving due to the advent of novel targeted therapies and the enhanced utilization of these agents for treatment purposes. By initiating unique molecular pathways, these agents hinder the proliferation of malignant cells, consequently affecting innate and adaptive immunity, which increases the risk of infectious complications. Due to the complexity of novel targeted therapies and their associated risks of infection, it often becomes a daunting task for physicians to maintain updated knowledge in their clinical practice. The situation is further aggravated by the fact that most of the initial clinical trials on targeted therapies provide inadequate information to determine the associated risk of infection. In such a scenario, a cumulative body of evidence is paramount in guiding clinicians regarding the infectious complications that can arise following targeted therapies. In this review, I summarize the recent knowledge on infectious complications arising in the context of targeted therapies for HM.

High risk of infection in 'real-world' patients receiving ibrutinib, idelalisib or venetoclax for mature B-cell leukaemia/lymphoma

OBJECTIVE

The infection risk in patients receiving ibrutinib, idelalisib or venetoclax for chronic lymphocytic leukaemia (CLL) or B-cell lymphoma treated outside of clinical trials is incompletely defined. We sought to identify the severe infection rate and associated risk factors in a 'real-world' cohort.

METHODS

We conducted a retrospective cohort study of adult patients with CLL or lymphoma treated with ibrutinib, idelalisib or venetoclax.

RESULTS

Of 67 patients identified (ibrutinib n = 53, idelalisib n = 8 and venetoclax n = 6), 32 (48%) experienced severe infection. Severe infection occurred at a rate of 65 infections per 100 person-years, with a median of 17.8 months of therapy. Median time to first infection (IQR) was 5.4 months (1.4-15.9). Poor baseline Eastern Cooperative Oncology Group (ECOG) performance status and high Charlson Comorbidity Index (CCI) score associated with increased risk of severe infection [hazard ratios (95% CI) 1.57 (1.07-2.31, p = .018) and 1.3 (1.05-1.62, p = .016) respectively].

CONCLUSION

The severe infection rate for patients receiving ibrutinib, idelalisib or venetoclax for lymphoma and CLL exceeded those reported in clinical trials. Patients with poor ECOG or high CCI should be closely monitored for early signs of infection and prevention strategies actively pursued. Further prospective research is required to define optimal antimicrobial prophylaxis recommendations.

Management of secondary immunodeficiency in hematological malignancies in the era of modern oncology

Secondary immunodeficiency (SID) in patients with B-cell hematological malignancies is a common condition that presents with recurrent infection. SID is due to both the inherent immune defects due to the malignancy, as well as secondary to cancer therapies, many of which have B-cell depleting properties. The early diagnosis of SID and the optimization of intervention strategies are key to delivering the most effective cancer treatments and reducing infection-related morbidity and mortality. This review discusses current practice, recommendations, and challenges for SID diagnosis, based on the evaluation of clinical history and laboratory assessments, and the effectiveness of specific vaccines and immunoglobulin replacement therapy in reducing the frequency and recurrence of infections in patients with SID, and the healthcare system-associated costs.

B-cell malignancies treated with targeted drugs and SARS-CoV-2 infection: A European Hematology Association Survey (EPICOVIDEHA)

Patients with lymphoproliferative diseases (LPD) are vulnerable to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Here, we describe and analyze the outcome of 366 adult patients with chronic lymphocytic leukemia (CLL) or non-Hodgkin Lymphoma (NHL) treated with targeted drugs and laboratory-confirmed COVID-19 diagnosed between February 2020 and January 2022. Median follow-up was 70.5 days (IQR 0-609). Most used targeted drugs were Bruton-kinase inhibitors (BKIs) (N= 201, 55%), anti-CD20 other than rituximab (N=61, 16%), BCL2 inhibitors (N=33, 9%) and lenalidomide (N=28, 8%).Only 16.2% of the patients were vaccinated with 2 or more doses of vaccine at the onset of COVID-19. Mortality was 24% (89/366) on day 30 and 36%(134/366) on the last day of follow-up. Age >75 years (p<0.001, HR 1.036), active malignancy (p<0.001, HR 2.215), severe COVID-19 (p=0.017, HR 2.270) and admission to ICU (p<0.001, HR 5.751) were risk factors for mortality at last day of follow up. There was no difference in OS rates in NHL vs CLL patients (p=0.306), nor in patients treated with or without BKIs (p=0.151). Mortality in ICU was 66% (CLL 61%, NHL 76%). Overall mortality rate decreased according to vaccination status, being 39% in unvaccinated patients, 32% and 26% in those having received one or two doses, respectively, and 20% in patients with a booster dose (p=0.245). Overall mortality rate dropped from 41% during the first semester of 2020 to 25% at the last semester of 2021. These results show increased severity and mortality from COVID-19 in LPDs patients treated with targeted drugs.

Targeted therapies in CLL/SLL and the cumulative incidence of infection: A systematic review and meta-analysis

Background: Patients with chronic lymphocytic leukemia (CLL)/small lymphocytic lymphoma (SLL) are prone to infections.

Aims: Provide a pooled estimate of the cumulative incidence for infections that fulfilled the criteria associated with severe infectious adverse events for grade 3 or higher (including pneumonia, febrile neutropenia and sepsis) in patients who receive targeted therapies.

Methods: We searched PubMed and EMBASE for randomized controlled trials (RCT) that included patients with CLL/SLL who received targeted therapies and performed a random-effects meta-analysis to estimate the cumulative incidence of infections.

Results: Of 2,914 studies screened, we retrieved 31 which evaluated 11,660 patients. The pooled cumulative incidence of infections for patients who received treatment regimens based on a BTK inhibitors was 19.86%. For patients who received treatment based on rituximab and second generation anti-CD20 monoclonal antibodies, the pooled cumulative incidence of infections was 19.85 and 13.46%, respectively. Regarding PI3K inhibitor-based regimens the cumulative incidence of severe infections was 30.89%. BCL-2 inhibitors had a cumulative incidence of infections of 17.49% while lenalidomide and alemtuzumab had an incidence of 13.33 and 45.09%, respectively. The cumulative incidence of pneumonia ranged from 3.01 to 8.45% while febrile neutropenia ranged from 2.68 to 10.80%. Regarding sepsis, the cumulative incidence ranged from 0.9 to 4.48%.

Conclusion: Patients with CLL/SLL who receive targeted therapies may develop severe infections at significant rates that, in addition to disease stage and other complications, depend on the mechanism of action of the used drug. Surveillance for infections and development of effective prophylactic strategies are critical for patients with CLL/SLL who receive targeted therapies.

Systematic Review Registration: [https://systematicreview.gov/], identifier [registration number]

Effects of B-Cell Lymphoma on the Immune System and Immune Recovery after Treatment: The Paradigm of Targeted Therapy

B-cell lymphoma and lymphoproliferative diseases represent a heterogeneous and complex group of neoplasms that are accompanied by a broad range of immune regulatory disorder phenotypes. Clinical features of autoimmunity, hyperinflammation, immunodeficiency and infection can variously dominate, depending on the immune pathway most involved. Immunological imbalance can play a role in lymphomagenesis, also supporting the progression of the disease, while on the other hand, lymphoma acts on the immune system to weaken immunosurveillance and facilitate immunoevasion. Therefore, the modulation of immunity can have a profound effect on disease progression or resolution, which makes the immune system a critical target for new therapies. In the current therapeutic scenario enriched by chemo-free regimens, it is important to establish the effect of various drugs on the disease, as well as on the restoration of immune functions. In fact, treatment of B-cell lymphoma with passive immunotherapy that targets tumor cells or targets the tumor microenvironment, together with adoptive immunotherapy, is becoming more frequent. The aim of this review is to report relevant data on the evolution of the immune system during and after treatment with targeted therapy of B-cell lymphomas.

A Systematic Review on the Prevention and Control of Opportunistic Infections in Patients With Chronic Lymphocytic Leukemia Complicated by Richter's Transformation

Chronic lymphocytic leukemia (CLL) is one of the most commonly occurring types of leukemia among the elderly population, contributing to an increased vulnerability to infections that are especially prolific in the immunosuppressed and the risk of rapid progression of the disease into a more aggressive manifestation of large cell lymphoma, a process called Richter's Transformation (RT). CLL alone predisposes patients to develop infections; however, the additional complication of RT decreases survival and makes the prevention and control of infection for the CLL patient even more challenging. However, research that exists on preventing and controlling infection in CLL patients with RT is relatively limited. In most cases, studies have focused on the prevention of infection in CLL patients in general and with no reference to the progression of RT. Considering the dearth of research on infection prevention and control for patients with CLL complicated by RT specifically, the following review examines existing research in addressing the prevention and control of infection in CLL patients with RT and patients in general. The authors explored multiple databases such as PubMed, Google Scholar, and Science Direct. The ultimate focus of this study was to lay a fundamental understanding in preventing and controlling infection in CLL patients. After analyzing several studies, it can be concluded that identifying infections, even if rare, is a crucial aspect of managing CLL patients. A broad range of differential diagnoses should be sought in cases presenting with refractory CLL as well and management of infections before, during, or after CLL treatment should be considered.

A Specific CD44lo CD25lo Subpopulation of Regulatory T Cells Inhibits Anti-Leukemic Immune Response and Promotes the Progression in a Mouse Model of Chronic Lymphocytic Leukemia

Regulatory T cells (Tregs) are capable of inhibiting the proliferation, activation and function of T cells and play an important role in impeding the immune response to cancer. In chronic lymphocytic leukemia (CLL) a dysfunctional immune response and elevated percentage of effector-like phenotype Tregs have been described. In this study, using the Eµ-TCL1 mouse model of CLL, we evaluated the changes in the Tregs phenotype and their expansion at different stages of leukemia progression. Importantly, we show that Tregs depletion in DEREG mice triggered the expansion of new anti-leukemic cytotoxic T cell clones leading to leukemia eradication. In TCL1 leukemia-bearing mice we identified and characterized a specific Tregs subpopulation, the phenotype of which suggests its role in the formation of an immunosuppressive microenvironment, supportive for leukemia survival and proliferation. This observation was also confirmed by the gene expression profile analysis of these TCL1-specific Tregs. The obtained data on Tregs are consistent with those described so far, however, above all show that the changes in the Tregs phenotype described in CLL result from the formation of a specific, described in this study Tregs subpopulation. In addition, functional tests revealed the ability of Tregs to inhibit T cells that recognize model antigens expressed by leukemic cells. Moreover, inhibition of Tregs with a MALT1 inhibitor provided a therapeutic benefit, both as monotherapy and also when combined with an immune checkpoint inhibitor. Altogether, activation of Tregs appears to be crucial for CLL progression.

Consensus guidelines for antifungal prophylaxis in haematological malignancy and haemopoietic stem cell transplantation, 2021

Antifungal prophylaxis can reduce morbidity and mortality from invasive fungal disease (IFD). However, its use needs to be optimised and appropriately targeted to patients at highest risk to derive the most benefit. In addition to established risks for IFD, considerable recent progress in the treatment of malignancies has resulted in the development of new 'at-risk' groups. The changing epidemiology of IFD and emergence of drug resistance continue to impact choice of prophylaxis, highlighting the importance of active surveillance and knowledge of local epidemiology. These guidelines aim to highlight emerging risk groups and review the evidence and limitations around new formulations of established agents and new antifungal drugs. It provides recommendations around use and choice of antifungal prophylaxis, discusses the potential impact of the changing epidemiology of IFD and emergence of drug resistance, and future directions for risk stratification to assist optimal management of highly vulnerable patients.

Bruton's Tyrosine Kinase Inhibitors Impair FcγRIIA-Driven Platelet Responses to Bacteria in Chronic Lymphocytic Leukemia

Bacterial infections are a major cause of morbidity and mortality in chronic lymphocytic leukemia (CLL), and infection risk increases in patients treated with the Bruton’s tyrosine kinase (Btk) inhibitor, ibrutinib. Btk and related kinases (like Tec) are expressed in non-leukemic hematopoietic cells and can be targeted by ibrutinib. In platelets, ibrutinib therapy is associated with bleeding complications mostly due to off-target effects. But the ability of platelets to respond to bacteria in CLL, and the potential impact of ibrutinib on platelet innate immune functions remain unknown. FcγRIIA is a tyrosine kinase-dependent receptor critical for platelet activation in response to IgG-coated pathogens. Crosslinking of this receptor with monoclonal antibodies causes downstream activation of Btk and Tec in platelets, however, this has not been investigated in response to bacteria. We asked whether ibrutinib impacts on FcγRIIA-mediated activation of platelets derived from CLL patients and healthy donors after exposure to Staphylococcus aureus Newman and Escherichia coli RS218. Platelet aggregation, α-granule secretion and integrin αIIbβ3-dependent scavenging of bacteria were detected in CLL platelets but impaired in platelets from ibrutinib-treated patients and in healthy donor-derived platelets exposed to ibrutinib in vitro. While levels of surface FcγRIIA remained unaffected, CLL platelets had reduced expression of integrin αIIbβ3 and GPVI compared to controls regardless of therapy. In respect of intracellular signaling, bacteria induced Btk and Tec phosphorylation in both CLL and control platelets that was inhibited by ibrutinib. To address if Btk is essential for platelet activation in response to bacteria, platelets derived from X-linked agammaglobulinemia patients (lacking functional Btk) were exposed to S. aureus Newman and E. coli RS218, and FcγRIIA-dependent aggregation was observed. Our data suggest that ibrutinib impairment of FcγRIIA-mediated platelet activation by bacteria results from a combination of Btk and Tec inhibition, although off-target effects on additional kinases cannot be discarded. This is potentially relevant to control infection-risk in CLL patients and, thus, future studies should carefully evaluate the effects of CLL therapies, including Btk inhibitors with higher specificity for Btk, on platelet-mediated immune functions.

Invasive Fungal Infections and Targeted Therapies in Hematological Malignancies

The use of targeted biologic therapies for hematological malignancies has greatly expanded in recent years. These agents act upon specific molecular pathways in order to target malignant cells but frequently have broader effects involving both innate and adaptive immunity. Patients with hematological malignancies have unique risk factors for infection, including immune dysregulation related to their underlying disease and sequelae of prior treatment regimens. Determining the individual risk of infection related to any novel agent is challenging in this setting. Invasive fungal infections (IFIs) represent one of the most morbid infectious complications observed in hematological malignancy. In recent years, growing evidence suggests that certain small molecule inhibitors, such as BTK inhibitors and PI3K inhibitors, may cause an increased risk of IFI in certain patients. It is imperative to better understand the impact that novel targeted therapies might have on the development of IFIs in this high-risk patient population.

Risk factors for severe infections in secondary immunodeficiency: a retrospective US administrative claims study in patients with hematological malignancies

Real-world data are lacking to identify patients with secondary immunodeficiency (SID) who may benefit most from anti-infective interventions. This retrospective analysis used the IQVIA PharMetrics® Plus database to assess baseline characteristics associated with risk of severe infections post-SID diagnosis in patients with hematological malignancies. In 4066 patients included, the mean number of any and severe infections per patient in the one-year pre-SID diagnosis period was 9.5 and 0.7, respectively. Post-SID diagnosis, the mean annualized number of any and severe infections was 19.1 and 1.5, respectively. Receiver operating characteristic curve analysis identified a threshold (cutoff) of three bacterial infections at baseline as optimally predictive of severe infections post-SID diagnosis. Multivariate analysis indicated that hospitalizations, infections (≥3), or antibiotic use pre-SID diagnosis were predictive of severe infections post-SID diagnosis. Evaluation of these risk factors could inform clinical decisions regarding which patients may benefit from prophylactic anti-infective treatment, including immunoglobulin replacement if warranted.

Comparison of therapy with β-lactam/β-lactamase inhibitor combinations or carbapenems for bacteraemia of nonurinary source caused by ESBL-producing Escherichia coli or Klebsiella pneumoniae

Background

Extended-spectrum β-lactamase (ESBL)-producing Enterobacteriaceae has become a public health concern. This study aimed to compare the clinical outcomes of patients with nonurinary source bacteraemia caused by ESBL-producing Escherichia coli (E. coli) or Klebsiella pneumoniae (ESBL-producing EK) receiving β-lactam/β-lactamase inhibitor combinations (BLICs) versus carbapenem treatment and assess the risk factors of mortality with these two drugs.

Methods

We conducted a retrospective single-centre study of adult hospitalised patients with ESBL-producing EK bloodstream infection (BSI) from nonurinary source at our centre over a 4-year period. One hundred and eighty patients who received BLICs or carbapenems were included in the analysis. The outcome variables were 14-day treatment failure and 30-day mortality. For more reliable results, propensity score analysis was performed to compare the efficacy of the two drugs and analyse their risk factors for 30-day mortality.

Results

Out of 180 patients, 114 received BLICs, and 66 received carbapenem therapy. Compared to carbapenem-treated patients, those treated with BLICs were older and had higher age-adjusted Charlson comorbidity index, but they had shorter stay in the hospital. Additionally, their Pitt bacteraemia score, SOFA score, rate of leukaemia, and immune compromise were lower. After propensity score matching (PSM), the baseline characteristics of patients in the two treatment groups were balanced. BLICs were associated with a higher 14-day treatment failure rate (20.6%, 13/63) than carbapenems (16.3%, 7/43), although the difference was not significant in either univariate analysis (P = 0.429) or multivariate analysis (P = 0.122). And the 30-day mortality rate in BTG (11.1%, 7/63) and CTG (11.6%, 5/43) did not significantly differ (univariate analysis, P = 0.926; multivariate analysis, P = 0.420). In the multivariate analysis, after PSM, leukaemia was the only independent predictor of mortality in both BTG and CTG.

Conclusions

Our study showed that BLICs had higher 14-day treatment failure rate compared with carbapenems, although there were no statistically significant differences because of the small number of patients, therefore, further evaluation of the efficacy of BLICs is needed.

BCL-2 Inhibition as Treatment for Chronic Lymphocytic Leukemia

OPINION STATEMENT

At the end of the 1990s, with the advent of imatinib for chronic myeloid leukemia and rituximab for B cell lymphoproliferative diseases with CD20 expression, there was a great conceptual evolution in the treatment of onco-hematological diseases. Researchers from around the world and the pharmaceutical industry began to focus their efforts on the so-called target therapy used alone or associated with classic chemotherapeutic drugs. In chronic lymphocytic leukemia, the development of second-generation anti-CD20 antibodies, biosimilars, PI3K (phosphatidylinositol 3-kinases) inhibitors, BTK (Bruton's tyrosine kinase) inhibitors, and anti-bcl 2 drugs represented mainly by venetoclax brought new, broader, and more effective opportunities in the treatment of this disease. This breakthrough occurred mainly regarding patients with alteration in 17p or mutation of the p53 gene for whom selecting the new drugs that act on B cell signaling (BTK and PI3K inhibitors) in the first line is mandatory. In fit patients with immunoglobulin heavy chain mutation, it is still acceptable to use the chemotherapy regimen with fludarabine, cyclophosphamide, and rituximab (FCR) and, in those who do not fit or are not IgVH-mutated, bendamustine-rituximab regimen. However, the first-line use of ibrutinib or venetoclax associated with immunotherapy within the concepts of infinite (ibrutinib) or finite (venetoclax) treatment has been increasingly used. In the second line, venetoclax, ibrutinib, and idelalisib have become the preferred treatments. I believe that a process of instruction and decision shared with patients considering the risks-benefits-cost and access to treatments should guide the choices within these concepts. Another fundamental aspect to discuss is the objective of the treatment for chronic lymphocytic leukemia (CLL) for a specific patient: the increase progression-free survival and overall survival and/or the achievement of minimal residual disease. CLL is the most common leukemia in adults with a median age at diagnosis of 72 years. The clinical course is heterogeneous, and outcomes are influenced by individual clinical presentation and disease biology. Molecular and genomic factors, including fluorescence in situ hybridization (FISH) testing, karyotype, and immunoglobulin heavy chain variable region gene (IGHV) mutational status, are important to treatment decisions and to predict the clinical course. However, despite disease biology, the presence of active disease is the most important criteria to initiate treatment. In the past decade, target therapies that inhibit B cell receptor signaling pathways and, more recently, BCL2 antagonists have emerged as a new treatment paradigm: chemo-free with fixed duration therapy. Bruton's tyrosine kinase inhibitors (BTK) are a class of oral medications approved for frontline and relapsed disease, effective for achieving lasting response and disease control with a good safety profile. BTK inhibitors are an attractive option for high-risk patients who are not candidates for an intensive regimen. However, it is a continuous therapy, and drug resistance or severe adverse events could lead to treatment suspension. BCL2 antagonists are an attractive alternative to BTK inhibitors. Anti-apoptotic BCL2 is associated with tumor genesis and chemotherapy resistance. The BCl2, an anti-apoptotic protein located in the mitochondrial membrane, is a major contributor to the pathogenesis of lymphoid malignancies and is overexpressed in CLL cells promoting clonal cell survival. Venetoclax is a potent and selective member of the BH3 mimetic drugs and a physiologic antagonist of BCL2. Venetoclax has demonstrated quick and durable responses in naïve and relapsed or refractory CLL (r/r CLL) patients, including high-risk patients. Furthermore, it has shown deeper responses, achieving a higher incidence of negative minimal residual disease (MRD) with a fixed duration therapy. In the past decade, there was a remarkable progress in CLL treatment. However, neither of the new target therapies is considered curative or free of toxicity. This article will focus on the treatment approach of CLL patients with BCl2 antagonists. Treatment strategy (combined versus monotherapy; continuous versus limited duration therapy), toxicity profile, and future directions will be exposed in this review.

Targeting of the A2A adenosine receptor counteracts immunosuppression in vivo in a mouse model of chronic lymphocytic leukemia

Tumor immunosuppression is a major cause for treatment failure and disease relapse, both in solid tumors and leukemia. Local hypoxia is among the conditions that cause immunosuppression, acting at least in part through the upregulation of extracellular adenosine levels, which potently suppress T cell responses and skew macrophages towards an M2 phenotype. Hence, there is intense investigation to identify drugs that target this axis. By using the TCL1 adoptive transfer CLL mouse model, we show that adenosine production and signaling are upregulated in the hypoxic lymphoid niches, where intense colonization of leukemic cells occurs. This leads to a progressive remodeling of the immune system towards tolerance, with expansion of T regulatory cells (Tregs), loss of CD8+ T cell cytotoxicity and differentiation of murine macrophages towards the patrolling (M2-like) subset. In vivo administration of SCH58261, an inhibitor the A2A adenosine receptor, re-awakens T cell responses, while limiting Tregs expansion, and re-polarizes monocytes towards the inflammatory (M1-like) phenotype. These results show for the first time the in vivo contribution of adenosine signaling to immune tolerance in CLL, and the translational implication of drugs interrupting this pathway. Although the effects of SCH58261 on leukemic cells are limited, interfering with adenosine signaling may represent an appealing strategy for combination-based therapeutic approaches.

The PI3K∂-Selective Inhibitor Idelalisib Induces T- and NK-Cell Dysfunction Independently of B-Cell Malignancy-Associated Immunosuppression

B-cell receptors, multiple receptor tyrosine kinases, and downstream effectors are constitutively active in chronic lymphocytic leukemia (CLL) B cells. Activation of these pathways results in resistance to apoptosis and enhanced survival of the leukemic cells. Idelalisib is a highly selective inhibitor of the PI3K p110∂ isoform and is approved for the treatment of CLL in patients with relapsed/refractory disease or in those harboring 17p deletions or tp53 mutations. Despite the initial excitement centered around high response rates in clinical trials of idelalisib, its therapeutic success has been hindered by the incidence of severe opportunistic infections. To examine the potential contribution of idelalisib to the increased risk of infection, we investigated the effects of idelalisib on the immune cell compartments of healthy donors (HDs) and CLL patients. PI3K∂ blockade by idelalisib reduced the expression levels of inhibitory checkpoint molecules in T cells isolated from both HDs and CLL patients. In addition, the presence of idelalisib in cultures significantly decreased T-cell-mediated cytotoxicity and granzyme B secretion, as well as cytokine secretion levels in both cohorts. Furthermore, idelalisib reduced the proliferation and cytotoxicity of HD NK cells. Collectively, our data demonstrate that both human T and NK cells are highly sensitive to PI3K∂ inhibition. Idelalisib interfered with the functions of T and NK cell cells from both HDs and CLL patients. Therefore, idelalisib might contribute to an increased risk of infections regardless of the underlying B-cell malignancy.

Risk of infection associated with targeted therapies for solid organ and hematological malignancies

Higher risks of infection are associated with some targeted drugs used to treat solid organ and hematological malignancies, and an individual patient’s risk of infection is strongly influenced by underlying diseases and concomitant or prior treatments. This review focuses on risk levels and specific suggestions for management, analyzing groups of agents associated with a significant effect on the risk of infection. Due to limited clinical experience and ongoing advances in these therapies, recommendations may be revised in the near future. Bruton tyrosine kinase (BTK) inhibitors are associated with a higher rate of infections, including invasive fungal infection, especially in the first months of treatment and in patients with advanced, pretreated disease. Phosphatidylinositol 3-kinase (PI3K) inhibitors are associated with an increased risk of Pneumocystis pneumonia and cytomegalovirus (CMV) reactivation. Venetoclax is associated with cytopenias, respiratory infections, and fever and neutropenia. Janus kinase (JAK) inhibitors may predispose patients to opportunistic and fungal infections; need for prophylaxis should be assessed on an individual basis. Mammalian target of rapamycin (mTOR) inhibitors have been linked to a higher risk of general and opportunistic infections. Breakpoint cluster region-Abelson (BCR-ABL) inhibitors are associated with neutropenia, especially over the first months of treatment. Anti-CD20 agents may cause defects in the adaptative immune response, hypogammaglobulinemia, neutropenia, and hepatitis B reactivation. Alemtuzumab is associated with profound and long-lasting immunosuppression; screening is recommended for latent infections and prevention strategies against CMV, herpesvirus, and Pneumocystis infections. Checkpoint inhibitors (CIs) may cause immune-related adverse events for which prolonged treatment with corticosteroids is needed: prophylaxis against Pneumocystis is recommended.

Preventing and monitoring for tumor lysis syndrome and other toxicities of venetoclax during treatment of chronic lymphocytic leukemia

Recent developments in the management of chronic lymphocytic leukemia (CLL) have moved the standard of care away from chemoimmunotherapy to targeted agents such as oral kinase inhibitors or BCL-2 antagonists, alone or in combination with anti-CD20 antibodies. Two different treatment approaches have evolved: continuous, indefinite treatment and, more recently, fixed-duration combination treatment. With venetoclax-based treatment, there is a requirement to follow the established guidelines for close monitoring during initiation and ramp up, to reduce the risk of tumor lysis syndrome. The patient's risk should be assessed before the initiation of venetoclax. Appropriate management strategies should be used, including uricosuric agents, hydration, and routine laboratory monitoring, per guidelines. With early identification, immediate management, and dose adjustments, we suggest that tumor lysis syndrome and other toxicities, such as neutropenia and infections, with venetoclax-based treatment can be dealt with successfully.

Casting a wider protective net: Anti-infective vaccine strategies for patients with hematologic malignancy and blood and marrow transplantation

Patients who have hematologic malignancies are at high risk for infections but vaccinations may be effective prophylaxis. The increased infection risk derives from immune defects secondary to malignancy, the classic example being CLL, and chemotherapies and immunotherapy used to treat the malignancies. Therapy of hematologic malignancies is being revolutionized by introduction of novel targeted agents and immunomodulatory medications, improving the survival of patients. At the same time those agents uniquely change the infection risk and response to immunizations. This review will summarize current vaccine recommendations for patients with hematologic malignancies including patients who undergo hematopoietic cell transplant.

The chicken and the egg dilemma: A case of disseminated MAC with Hodgkin's lymphoma

Introduction

Mycobacterium avium complex (MAC) as a cause of disseminated disease has been well described in immunocompromised hosts. We report a case of disseminated MAC diagnosed in an otherwise healthy patient, one year before further testing and follow-up revealed a diagnosis of Hodgkin's lymphoma.

Case presentation

A 48-year-old woman with no significant medical history presented with new-onset fever, chills and night sweats. Chest imaging revealed large conglomerate mediastinal lymph nodes (LN). Endobronchial ultrasound-guided biopsy demonstrated caseating granulomatous inflammation and MAC on broth culture. She was started on guideline-based antibiotic therapy for disseminated MAC but showed no improvement after 6 months. An open mediastinal biopsy confirmed the findings of non-caseating granuloma. However, due to continued symptoms and widespread lymphadenopathy on additional full body imaging, an iliac lymph node core biopsy was performed which revealed abnormal CD30⁺ lymphoid infiltrate consistent with Hodgkin's lymphoma (HL). She was started on steroids and chemotherapy, whilst maintained on MAC treatment.

Discussion

Disseminated MAC is largely limited to immunocompromised hosts, signs and symptoms of which may overlap with lymphoma. Our case demonstrated that multiple initial LN biopsies were unrevealing except for MAC. As no clinical improvement was observed with guideline based MAC treatment, further diagnostic measures were aggressively pursued ultimately leading to a diagnosis of HL. It is unclear whether disseminated MAC preceded lymphoma, an early undiagnosed lymphoma led to MAC infection or an undefined systemic immune disorder was causative for both these processes.

Infections in patients with lymphoproliferative diseases treated with targeted agents: SEIFEM multicentric retrospective study

We describe the opportunistic infections occurring in 362 patients with lymphoproliferative disorders treated with ibrutinib and idelalisib in clinical practice. Overall, 108 of 362 patients (29·8%) developed infections, for a total of 152 events. Clinically defined infections (CDI) were 49·3% (75/152) and microbiologically defined infections (MDI) were 50·7% (77/152). Among 250 patients treated with ibrutinib, 28·8% (72/250) experienced one or more infections, for a total of 104 episodes. MDI were 49% (51/104). Bacterial infections were 66·7% (34/51), viral 19·6% (10/51) and invasive fungal diseases (IFD) 13·7% (7/51). Among the 112 patients treated with idelalisib, 32·1% (36/112) experienced one or more infections, for a total of 48 episodes. MDI were 54·2% (26/48). Bacterial infections were 34·6% (9/26), viral 61·5% (16/26) and IFD 3·8% (1/26). With ibrutinib, the rate of bacterial infections was significantly higher compared to idelalisib (66·7% vs. 34·6%; P = 0·007), while viral infections were most frequent in idelalisib (61·5% vs. 19·6%; P < 0·001). Although a higher rate of IFD was observed in patients treated with ibrutinib, the difference was not statistically significant (13·7% vs. 3·8% respectively; P = 0·18). Bacteria are the most frequent infections with ibrutinib, while viruses are most frequently involved with idelalisib.

Distinct immune composition in lymph node and peripheral blood of CLL patients is reshaped during venetoclax treatment

Morbidity and mortality due to immunosuppression remain among the foremost clinical challenges in chronic lymphocytic leukemia (CLL). Although immunosuppression is considered to originate within the lymph node (LN) microenvironment, alterations in T and natural killer (NK) cells have almost exclusively been studied in peripheral blood (PB). Whereas chemoimmunotherapy further deteriorates immune function, novel targeted agents like the B-cell lymphoma 2 inhibitor venetoclax potentially spare nonmalignant lymphocytes; however, the effects of venetoclax on nonleukemic cells have not been explored. We address these unresolved issues using a comprehensive analysis of nonmalignant lymphocytes in paired LN and PB samples from untreated CLL patients, and by analyzing the effects of venetoclax-based treatment regimens on the immune system in PB samples from previously untreated and relapsed/refractory patients. CLL-derived LNs contained twice the amount of suppressive regulatory T cells (T_regs) and CLL supportive follicular T helper (T_fh) cells compared with PB. This was accompanied by a low frequency of cytotoxic lymphocytes. The expression of PD-1 by CD8⁺ T cells was significantly higher in LN compared with PB. Venetoclax-based treatment led to deep responses in the majority of patients, but also to decreased absolute numbers of B, T, and NK cells. T_fh cell, T_reg, and PD-1⁺ CD8⁺ T cell numbers were reduced more than fivefold after venetoclax-based therapy, and overproduction of inflammatory cytokines was reduced. Furthermore, we observed restoration of NK cell function. These data support the notion that the immunosuppressive state in CLL is more prominent within the LN. Venetoclax-based regimens reduced the immunosuppressive footprint of CLL, suggesting immune recovery after the elimination of leukemic cells.

BTK Inhibition Impairs the Innate Response Against Fungal Infection in Patients With Chronic Lymphocytic Leukemia

Infections represent a cause of morbidity and mortality in patients affected by chronic lymphocytic leukemia (CLL). Introduction of new drugs in CLL clinical practice has showed impressive efficacy, in particular those targeting BTK. Among the consistent clinical data, an increasing number of reports describing the occurrence of unexpected opportunistic fungal infections has been reported during treatment with ibrutinib in the first 6 months of treatment. The reason underlying manifestations of invasive fungal infections in patients treated with ibrutinib is still under investigation. Our study aimed to understand the impact of BTK inhibition on immune response to fungal infection mediated by macrophages and CD14+ monocytic population obtained from CLL patients. Exposure to ibrutinib and acalabrutinib reduced signaling pathways activated by Aspergillus fumigatus determining an exacerbation of an immunosuppressive signature, a reduction of phagocytosis and a significant deficit in the secretion of inflammatory cytokines either in macrophages and monocytes isolated from CLL patients and healthy donors. These effects lead to a failure in completely counteracting conidia germination. In addition we investigated the biological effects of ibrutinib on monocyte counterpart in patients who were undergoing therapy. A significant impairment in cytokine secretion and a deficit of phagocytosis in circulating monocytes were detected after 3 months of treatment. Thus, our results uncover modifications in the innate response in CLL patients induced by ibrutinib that may impair the immunological response to fungal infection.

KEYPOINTS

•BTK inhibition affects a productive immune response of CLL-associated macrophages (NLC) during Aspergillus fumigatus infection.•Reduction of TNF-α secretion and phagocytosis are detected in monocytes isolated from CLL patients during ibrutinib therapy.

Targeted Therapy in Chronic Lymphocytic Leukemia

Despite a prevailing view that advances in cancer therapy will come through selective targeting of enzymes encoded by mutated oncogenes responsible for the neoplastic phenotype, recent advances in the treatment of patients with chronic lymphocytic leukemia (CLL) have instead exploited knowledge of its biology. Indeed, CLL cells depend on interactions with cells and soluble factors present in the tumor microenvironment for proliferation and survival. B-cell receptor signaling and chemokine-receptor signaling play prominent roles. Elucidation of these signaling pathways has defined physiologic targets for drugs, such as ibrutinib, which inhibit Bruton tyrosine kinase and are therapeutically effective. The characteristic high-level expression of BCL2 in CLL that can enhance leukemia-cell survival has now become an Achilles heel targeted by clinically effective drugs such as venetoclax. Here we discuss advances in such targeted therapy and highlight other disease attributes, such as the distinctive expression of ROR1, which may be targeted for clinical benefit, alone or in combination with other targeted therapies.

Clinical course and risk factors for mortality from COVID-19 in patients with haematological malignancies

BACKGROUND

The impact of coronavirus disease 2019 (COVID-19) in haematological patients (HP) has not been comprehensively reported.

METHODS

We analysed 39 patients with SARS-CoV-2 infection and haematological malignancies. Clinical characteristics and outcomes were compared to a matched control group of 53 non-cancer patients with COVID-19. Univariate and multivariate analyses were carried out to assess the risk factors associated with poor outcome.

RESULTS

The most frequent haematological diseases were lymphoma (30%) and multiple myeloma (30%). Eighty-seven % HP developed moderate or severe disease. Patients with haematological malignancies had a significantly higher mortality rate compared to non-cancer patients (35.9% vs 13.2%; P = .003 (odds ratio 6.652). The worst outcome was observed in chronic lymphocytic leukaemia patients. Only age >70 years and C reactive protein >10 mg/dl at admission were associated with higher risk of death (odds ratio 34.86, P = .003 and 13.56,P = .03). Persistent viral sheddind was detected in 5 HP. Active chemotherapy, viral load at diagnosis and COVID-19 therapy were not predictors of outcome.

CONCLUSION

Mortality of COVID-19 is significantly higher in patients with haematological malignancies compared to non-cancer patients. The impact of persistent viral shedding must be considered in order to re-start therapies and maintain infectious control measures.

How We Manage Patients With Chronic Lymphocytic Leukemia During the SARS-CoV-2 Pandemic

Infections are a major cause of morbidity and mortality in patients with chronic lymphocytic leukemia (CLL). These can be exacerbated by anti-leukemic treatments. In addition, the typical patients with CLL already have fragilities and background risk factors that apply to the general population for severe COVID-19. On these bases, patients with CLL may experience COVID-19 morbidity and mortality. Recurrent seasonal epidemics of SARS-CoV-2 are expected, and doctors taking care of patients with CLL must be prepared for the possibility of substantial resurgences of infection and adapt their approach to CLL management accordingly. In this Guideline Article, we aim at providing clinicians with a literature-informed expert opinion on the management of patients with CLL during SARS-CoV-2 epidemic.

Infectious Complications of Biological and Small Molecule Targeted Immunomodulatory Therapies

The past 2 decades have seen a revolution in our approach to therapeutic immunosuppression. We have moved from relying on broadly active traditional medications, such as prednisolone or methotrexate, toward more specific agents that often target a single receptor, cytokine, or cell type, using monoclonal antibodies, fusion proteins, or targeted small molecules. This change has transformed the treatment of many conditions, including rheumatoid arthritis, cancers, asthma, and inflammatory bowel disease, but along with the benefits have come risks. Contrary to the hope that these more specific agents would have minimal and predictable infectious sequelae, infectious complications have emerged as a major stumbling block for many of these agents. Furthermore, the growing number and complexity of available biologic agents makes it difficult for clinicians to maintain current knowledge, and most review articles focus on a particular target disease or class of agent. In this article, we review the current state of knowledge about infectious complications of biologic and small molecule immunomodulatory agents, aiming to create a single resource relevant to a broad range of clinicians and researchers. For each of 19 classes of agent, we discuss the mechanism of action, the risk and types of infectious complications, and recommendations for prevention of infection.

Response to the conjugate pneumococcal vaccine (PCV13) in patients with chronic lymphocytic leukemia (CLL)

Pneumococcal (PC) vaccination is recommended for patients with chronic lymphocytic leukemia (CLL). However, response to vaccines has been investigated in a small series of CLL patients. We analyzed the antibody response and outcomes of 112 CLL patients who received the 13-valent pneumococcal conjugate vaccine (PCV13). An immune response was defined by a twofold increase in the PC-IgG levels assessed by ELISA. The median age of patients was 68 years, 23.2% showed IgG levels ≤ 400 mg/L, 6.3% progressive disease, 52% unmutated IGHV. Twenty-two (19.6%) patients were treatment-naïve and 90 (80.4%) previously treated (40.2% front-line chemoimmunotherapy; ibrutinib first/advanced-line, 9.8%/21.4%; idelalisib advanced-line, 8.9%). Nine (8%) patients developed an immune response, eight treatment-naive, and one on front-line ibrutinib. No responses were observed in patients previously treated with chemoimmunotherapy. Age ≥ 60 years (p = 0.007), IgG levels < 400 mg/L (p < 0.0001), prior treatment (p < 0.0001), and signs of disease progression (p = 0.04) were associated with a lower response rate. Pneumonia-free survival was significantly shorter in patients with clinical signs of progressive disease (HR, 8.39), prior pneumonia (HR, 7.03), and TP53 disruption (HR, 2.91). In conclusion, our results suggest that vaccination should be offered at diagnosis to CLL patients with early stage and stable disease who have better resources for an effective immune response.

Immune Response Dysfunction in Chronic Lymphocytic Leukemia: Dissecting Molecular Mechanisms and Microenvironmental Conditions

Representing the major cause of morbidity and mortality for chronic lymphocytic leukemia (CLL) patients, immunosuppression is a common feature of the disease. Effectors of the innate and the adaptive immune response show marked dysfunction and skewing towards the generation of a tolerant environment that favors disease expansion. Major deregulations are found in the T lymphocyte compartment, with inhibition of CD8⁺ cytotoxic and CD4⁺ activated effector T cells, replaced by exhausted and more tolerogenic subsets. Likewise, differentiation of monocytes towards a suppressive M2-like phenotype is induced at the expense of pro-inflammatory sub-populations. Thanks to their B-regulatory phenotype, leukemic cells play a central role in driving immunosuppression, progressively inhibiting immune responses. A number of signaling cascades triggered by soluble mediators and cell–cell contacts contribute to immunomodulation in CLL, fostered also by local environmental conditions, such as hypoxia and derived metabolic acidosis. Specifically, molecular pathways modulating T-cell activity in CLL, spanning from the best known cytotoxic T lymphocyte antigen-4 (CTLA-4) and programmed cell death 1 (PD-1) to the emerging T cell immunoreceptor with immunoglobulin and immunoreceptor tyrosine-based inhibition motif domains (TIGIT)/CD155 axes, are attracting increasing research interest and therapeutic relevance also in the CLL field. On the other hand, in the microenvironment, the B cell receptor (BCR), which is undoubtedly the master regulator of leukemic cell behavior, plays an important role in orchestrating immune responses, as well. Lastly, local conditions of hypoxia, typical of the lymphoid niche, have major effects both on CLL cells and on non-leukemic immune cells, partly mediated through adenosine signaling, for which novel specific inhibitors are currently under development. In summary, this review will provide an overview of the molecular and microenvironmental mechanisms that modify innate and adaptive immune responses of CLL patients, focusing attention on those that may have therapeutic implications.

Immunomodulatory effect of ibrutinib: Reducing the barrier against fungal infections

The Bruton tyrosine kinase (BTK) inhibitor ibrutinib is increasingly used in the treatment of chronic lymphocytic leukemia (CLL). Moreover, very promising results have been reported in other B-cell malignancies, including primary central nervous system lymphoma (PCNSL). Although well-tolerated in the majority of patients, ibrutinib demonstrates in some cases troublesome toxicities, including invasive fungal infections (IFIs). In the present review, we summarize clinical manifestations of IFIs in patients treated with ibrutinib, generally characterized by an early onset, mild clinical manifestations, asymptomatic/low symptomatic pulmonary localization and high incidence of central nervous system (CNS) involvement. IFI risk appears particularly increased in patients receiving ibrutinib associated with other immune modulator agents, especially with steroids or immune-chemotherapy. Moreover, the immunomodulatory effect of ibrutinib is described, pointing the attention on the involvement of specific molecules targeted by ibrutinib in innate and adaptive response to fungal infection. Overall, the findings indicate the ibrutinib may rapidly impair innate immune cell functions, while concomitantly restoring an effective protective potential of adaptive immune compartment. A correct awareness, especially when other predisposing factors are present, is warranted about the potential risk of IFIs in ibrutinib-treated patients.

Bacterial Colonization in Patients with Chronic Lymphocytic Leukemia and Factors Associated with Infections and Colonization

Patients with chronic lymphocytic leukemia (CLL) have defects in both humoral and cellular immunity as a result of their underlying malignancy, as well as chemotherapy-related immune suppression. Upper respiratory tract (URT) colonization can be regarded as a major contributor to infection, so the relationship between carriage rates, disease incidence, or antibiotic resistance should be monitored. This prospective study included 50 newly diagnosed, previously untreated patients with CLL and 38 healthy volunteers. A total of 264 samples obtained from anterior nares and oropharynx were microbiologically examined. A significantly higher frequency of S. aureus and Gram-negative bacilli (GNB) colonization in CLL patients was observed in comparison to healthy volunteers. Information regarding baseline characteristics; the Rai staging system; hematological tests results; immunophenotype of basic lymphocyte subsets, including the expression of programmed cell death-1 protein (PD-1) and its ligand (PD-L1); as well as Epstein-Barr virus (EBV) status were determined to analyze risk factors for infections and bacterial colonization. The data represent the basic information for identification of further risk factors of infection and bacterial oropharyngeal colonization in CLL patients. The rate of disease progression within the time from the CLL diagnosis was significantly higher in patients colonized by GNB. This study highlights EBV infection and frequencies of PD-1 positive T CD3⁺ cells and B cells as risk factors in CLL patients.

A population-based analysis of invasive fungal disease in haematology-oncology patients using data linkage of state-wide registries and administrative databases: 2005 - 2016

BACKGROUND

Little is known about the morbidity and mortality of invasive fungal disease (IFD) at a population level. The aim of this study was to determine the incidence, trends and outcomes of IFD in all haematology-oncology patients by linking Victorian hospital data to state-based registries.

METHODS

Episodes of IFD complicating adult haematological malignancy (HM) and haematopoietic stem cell transplantation (HSCT) patients admitted to Victorian hospitals from 1st July 2005 to 30th June 2016 were extracted from the Victorian Admitted Episodes Dataset and linked to the date of HM diagnosis from the Victorian Cancer Registry and mortality from the Victorian Death Index. Descriptive analyses and regression modelling were used.

RESULTS

There were 619,702 inpatient-episodes among 32,815 HM and 1,765 HSCT-patients. IFD occurring twelve-months from HM-diagnosis was detected in 669 (2.04%) HM-patients and 111 (6.29%) HSCT-recipients, respectively. Median time to IFD-diagnosis was 3, 5, 15 and 22 months in acute myeloid leukaemia, acute lymphoblastic leukaemia, Hodgkin lymphoma and multiple myeloma, respectively. Median survival from IFD-diagnosis was 7, 7 and 3 months for invasive aspergillosis, invasive candidiasis and mucormycosis, respectively. From 2005-2016, IFD incidence decreased 0.28% per 1,000 bed-days. Fungal incidence coincided with spring peaks on time-series analysis.

CONCLUSIONS

Data linkage is an efficient means of evaluating the epidemiology of a rare disease, however the burden of IFD is likely underestimated, arguing for better quality hospital level surveillance data to improve management strategies.

Psoas Abscess Due to Mycobacterium avium in A Patient with Chronic Lymphocytic Leukemia－Case Report and Review

Infections may constitute a serious complication in patients with chronic lymphocytic leukemia (CLL). New treatment agents including obinutuzumab and ibrutinib have improved the progression-free survival in CLL, and data suggest a similar overall infection risk and a limited risk of opportunistic infections when compared to standard chemo-immunotherapy. Nevertheless, cases of opportunistic infections including non-tuberculous mycobacterial (NTM) in CLL patients have recently been published. We present a case of a 74-year old man with extensive prior CLL treatment history, including most recently obinutuzumab. He developed an abscess of the psoas muscle and inguinal lymphadenopathy. An inguinal node biopsy specimen showed infection with Mycobacterium avium, confirmed by broad-spectrum mycobacterial PCR, M. avium-specific PCR, and mycobacterial culture. This case and our literature review suggest that physicians should be aware of opportunistic infections in patients with CLL. Diagnostic differentiation from CLL disease progression, Richter's transformation to aggressive lymphoma, and secondary malignancy relies on histological and appropriate microbiological studies from biopsy material of affected organs. Infection prophylaxis in CLL should be considered, including vaccinations and intravenous immune globulin replacement.

Development and Applications of Prognostic Risk Models in the Management of Invasive Mold Disease

Prognostic models or risk scores are frequently used to aid individualize risk assessment for diseases with multiple, complex risk factors and diagnostic challenges. However, relatively little attention has been paid to the development of risk models for invasive mold diseases encountered in patients with hematological malignancies, despite a large body of epidemiological research. Herein we review recent studies that have described the development of prognostic models for mold disease, summarize our experience with the development and clinical use of one such model (BOSCORE), and discuss the potential impact of prognostic risk scores for individualized therapy, diagnostic and antifungal stewardship, as well as clinical and epidemiological research.