Viral infections are a natural part of our existence. They can affect us in many ways that are the result of the interaction between the viral pathogen and our immune system. Most times the resulting immune response is beneficial for the host. The pathogen gets cleared thus protecting our vital organs with no other consequences. Conversely, the reaction of our immune system against the pathogen can cause organ damage (immunopathology) or lead to autoimmune disease. To date, there are several mechanisms for virus-induced autoimmune disease, including molecular mimicry and bystander activation, in support of the “fertile field” hypothesis, terms defined in our review. On the flip side, viral infections have been associated with protection from autoimmunity through mechanisms that include Treg invigoration and immune deviation, in support of the “hygiene hypothesis”, also defined here. Infection with lymphocytic choriomeningitis virus (LCMV) is one of the prototypes showing that the interaction of our immune system with viruses can either accelerate or prevent autoimmunity. Studies using mouse models of LCMV have helped conceive and establish several concepts that we today know and explain how viruses can lead to autoimmune activation or induce tolerance. Some of the most important mechanisms established during the course LCMV are described in this short review.

Infection of hosts by morbilliviruses is facilitated by the interaction between viral hemagglutinin (H-protein) and the signaling lymphocytic activation molecule (SLAM). Recently, the functional importance of the N-terminal region of human SLAM as a measles virus receptor was demonstrated. However, the functional roles of this region in the infection process by other morbilliviruses and host range determination remain unknown partly because this region is highly flexible, which has hampered accurate structure determination of this region by X-ray crystallography. In this study, we analyzed the interaction between the H-protein from canine distemper virus (CDV-H) and SLAMs by a computational chemistry approach. Molecular dynamics simulations and fragment molecular orbital analysis demonstrated that the unique His28 in the N-terminal region of SLAM from Macaca is a key determinant that enables formation of a stable interaction with CDV-H, providing a basis for CDV infection in Macaca. The computational chemistry approach presented should enable determination of molecular interactions involving regions of proteins that are difficult to predict from crystal structures because of their high flexibility.

The lymphocyte function–associated antigen-1 (LFA-1) (also CD11a/CD18 and αLβ2), is just one of many integrins in the human body, but its significance derives from its exclusive presence in leukocytes. In this review, we summarize the studies relating LFA-1 and its major ligand ICAM-1 (CD54) with cancer, through the function of lymphocytes and myeloid cells on tumor cells. We consider how LFA-1 mediates the interaction of leukocytes with tumors and the role of ICAM-1 in tumor dynamics, which can be independent of its interaction with LFA-1. A more detailed examination of LFA’s role within B-cell chronic lymphocytic leukemia is made. Finally, we discuss the role of LFA-1-harboring exosomes in tumor growth and metastasis.

Ibrutinib, a first-in-class Bruton’s Tyrosine Kinase inhibitor (BTKi), is a commonly deployed therapeutic option for previously untreated, and relapsed/refractory (R/R) patients with chronic lymphocytic leukemia (CLL). The use of ibrutinib is, however, partially limited by significant off-target side effects. Zanubrutinib (zanu) is a second-generation BTKi with enhanced target selectivity and occupancy of the kinase binding site. The SEQUOIA study showed that zanu significantly prolonged progression-free survival (PFS) when compared to bendamustine–rituximab (BR) in treatment-naive CLL patients with an acceptable safety profile. More recently, data from the phase III ALPINE trial which directly compared zanu with ibrutinib has demonstrated that zanu’s advantages are both an improved safety profile and enhanced clinical efficacy. Based on the results of the SEQUOIA and ALPINE pivotal trials the Food and Drug Administration (FDA) and European Medicines Agency (EMA) licensed zanu for the treatment of patients with CLL or small lymphocytic lymphoma (SLL) in January 2023. The updated (v2.2023) National Comprehensive Cancer Network (NCCN) guidelines and newly released German CLL algorithm, suggest that zanu may replace first-generation BTKi as one of the preferred therapeutic options for patients with CLL/SLL due to its increased selectivity for the kinase binding site, improved therapeutic efficacy, and favorable toxicity profile.

Keywords: chronic lymphocytic leukemia; older patient, Bruton tyrosine kinase, BCL2, cost-effectiveness Bruton tyrosine kinase inhibitors (BTKi) and the BCL2 inhibitor venetoclax, with or without the anti CD20 monoclonal antibody Obinutuzumab, represent the preferred options for the first-line therapy of CLL because they are more effective and may improve quality of life. However, pa-tient’s inclusion criteria were heterogeneous across trials designed for older patients and the identification of CLL-specific parameters identifying unfit patients at risk of developing drug-specific adverse events are required to guide treatment choice. Due to inclusion/exclusion criteria in trials, higher discontinuation rates with BTKi were reported in real-world studies and registry analyses provided useful information on factors predicting for earlier discontinuation in a real-world setting. Though targeted agents were shown to be cost-effective treatments in high-income countries, the out-of-pocket expenses may limit accessibility to these drugs and the overall expenditure for new drugs in CLL is projected to increase substantially posing an issue for sustainability. This being said, the choice of a finite duration treatment based on venetoclax containing regimens or treatment until progression with BTKi is today possible in high- income countries and the therapy choice drivers are represented by coexisting medical conditions rather than age, by patient expectations, logistics and sustainability.

Chronic lymphocytic leukemia (CLL) is a hematologic malignancy characterized by progressive accumulation of a rare population of CD5+ B lymphocytes in peripheral blood, bone marrow and lymphoid tissues. CLL exhibits remarkable clinical heterogeneity, with some patients presenting with indolent disease and others progressing rapidly to aggressive CLL. The significant heterogeneity of CLL underscores the importance of identifying novel prognostic markers. Recently, the RAS-related gene RRAS2 has emerged as both a driver oncogene and a potential marker for CLL progression, with higher RRAS2 expression associated with poorer disease prognosis. Although missense somatic mutations in the coding sequence of RRAS2 have not been described in CLL, this study reports the frequent detection of three somatic mutations in the 3' untranslated region (3'UTR) affecting positions +26, +53, and +180 downstream of the stop codon in the mRNA. An inverse relationship was observed between these three somatic mutations and RRAS2 mRNA expression, which correlated with lower blood lymphocytosis and better prognosis. These findings highlight the importance of RRAS2 overexpression in CLL development and prognosis and point to somatic mutations in its 3'UTR as novel mechanistic clues. Our results may contribute to the development of targeted therapeutic strategies and improved risk stratification for CLL patients.

A 62-year-old male was diagnosed with B-CLL and treated with Fludarabine-containing regimen which maintained the disease in partial response. Nine years after diagnosis, a rapidly growing systemic lymphadenopathy was observed, and a biopsy specimen revealed the presence of typical Hodgkin/Reed–Sternberg (HRS) cells, surrounded by T-lymphocytes and CLL cells. Sequencing analysis of the germline CDR3 region of the IGH gene showed that the HRS cells were clonally unrelated to the preexisting CLL cells and the HRS cells were composed of five different clones, leading to the molecular diagnosis of de novo lymphocyte-rich classic Hodgkin LPDs with SLL. Because the initial treatment was neither effective for classic Hodgkin LPDs nor for SLL, Bendamustine, Rituximab (BR) was started and complete remission was achieved, which has continued for more than one year so far. BR may be a good therapeutic option for both entities without causing hematological toxicity.

Novel drugs profoundly changed the outcomes in CLL patients and traditional prognostic/predictive factors that were delineated in the era of chemo-immunotherapy need to be validated in the contest of these new targeted therapies. Currently, the most important prognostic genetic biomarkers are immunoglobulin heavy chain variable (IGHV) mutational status, genetic aberrations including del(17p)/TP53 abnormalities and the complex karyotype. In this review we discuss the prognostic/predictive role of these genetic markers in relation to novel treatments. Moreover, we present and discuss the new score systems that were elaborated and validated in the era of new drugs. Given the deeper responses obtained with small molecules, new prognostic/predictive markers, including measurable residual disease, and validated prognostic scores could possibly be incorporated into routine prognostic scores, to better identify “very-high” CLL patients, who will need more effective treatments.

B-cell chronic lymphocytic leukemia (B-CLL) is the most common type of leukemia in the Western world. Mutations in different genes, such as TP53 and ATM, and deletions in specific chromosomal regions, including 11q or 17p, have been associated with a worse prognosis for the disease. Recent research from our group has demonstrated that, contrary to the usual cancer development process through missense mutations, B-CLL is driven by the overexpression of the small GTPase RRAS2 in its wild-type form, without activating mutations. While some mouse models of this disease have been developed to date and are commonly used in B-CLL research, they come with various disadvantages, such as a long waiting period until the leukemia fully develops, the need for cell engraftment, or, in some cases, a failure to replicate the alterations found in human patients. We have recently introduced Rosa26-RRAS2fl/flxmb1-Cre as a new mouse model of B-CLL with full disease penetrance. In this work, we have validated this mouse model as a novel tool for the development of new therapies for B-CLL by testing two of the most widely applied targeted agents: ibrutinib and venetoclax. This also paves the way for the development of new targeted agents against R-RAS2 itself, an approach that has not yet been explored in clinical practice.

Chronic lymphocytic leukemia (CLL) is characterized by dysfunctional B cells. Immune checkpoint molecules such as cytotoxic T-lymphocyte-associated protein 4 (CTLA-4), and programmed death-1 (PD-1) are upregulated in patients with CLL and may correlate with prognostic markers such as beta-2 microglobulin (B2M). The aim of this study was to evaluate the levels of immune checkpoints on B-cell subsets and to further correlate them with B2M levels in patients with CLL. We recruited 21 patients with CLL and 12 controls. B cell subsets and the levels of immune checkpoint expression were determined using conventional multi-color flowcytometry. Basal levels of B2M in patients with CLL were measured using an Enzyme-linked immunosorbent assay. Patients with CLL had increased levels of activated B cells when compared to the control group, p< 0.001. The expression of PD-1 and CTLA-4 were increased on activated B cells and memory B cells, p< 0.05. There were no associations between B2M levels and the measured immune checkpoints on B cell subsets, after adjusting for sex and age. African patients with CLL express elevated levels of PD-1 and CTLA-4 immune checkpoints on activated and memory B cell subsets. However, there is no correlation between these immune checkpoint expressions and B2M levels.