Analysis of immunoregulatory CD5⁺CD19⁺ subpopulations in chronic lymphocytic leukemia and of the impact of ibrutinib therapy on these subpopulations

La leucémie lymphoïde chronique (LLC) est une hémopathie B qui se caractérise par une évolution clinique hétérogène et un dysfonctionnement du système immunitaire. Des travaux antérieurs du laboratoire ont mis en évidence l’existence de sous-populations lymphocytaires B CD5⁺/CD19⁺ qui sécrètent des facteurs solubles immuno-régulateurs, tels que l’IL10 et le TGFβ1 et, qui expriment le facteur de transcription FOXP3. Mon travail de thèse a consisté à poursuivre la caractérisation phénotypique et fonctionnelle de ces sous populations,et notamment celle sécrétant de l’IL10, tout en évaluant son évolution chez des patients en cours de traitement par ibrutinib, un inhibiteur de Btk. Sur le plan fonctionnel,mes travaux démontrent que les lymphocytes B de LLC ont la capacité d’inhiber la prolifération lymphocytaire T CD4⁺, d’induire une différenciation lymphocytaire T régulatrice et d’inhiber la différenciation Th1. Mes résultats démontrent également que la sous population IL10⁺ présente des caractéristiques phénotypiques et d’activation communes aux cellules de la fraction proliférative. De plus, la fréquence de la population IL10⁺, plus élevée chez les patients évolutifs, révèle que la capacité de sécrétion de l’IL10 par les cellules B de LLC est corrélée à la progression. Enfin, le traitement par ibrutinib induit une diminution rapide de la sous-population IL10+ qui se comporte comme celle de la sous-population CXCR4ˡᴼᵂ, un marqueur de la fraction proliférative. L’ensemble de ces données souligne l’importance des sous-populations immuno-régulatrices dans l’évolutivité de la LLC et apporte de nouveaux éléments sur les mécanismes d’action de l’ibrutinib.Chronic lymphocytic leukemia (CLL) is a chronic lymphoproliferative disorder characterized by a heterogeneous clinical evolution, with indolent and progressive forms, as well as by analtered immune system; the latter being consistently found during disease progression. Our laboratory has previously demonstrated the existence of clonal CD5⁺/CD19⁺ subpopulations that secrete soluble cytokines, such as IL10 and TGFβ1, and express the transcription factor FOXP3. Based on these results, my work aimed to further characterize phenotypically and functionally these subpopulations, and notably the IL10 secreting one and to by follow its evolution during therapy with ibrutinib, a Btk inhibitor. Functionally, my results demonstrate that CD5⁺ CD19⁺ B lymphocytes have the ability to inhibit CD4⁺ T cells proliferation, to induce regulatory T cells differentiation and to reduce Th1 differentiation. Moreover, we also evidenced that IL10 producing subpopulation shares common phenotypic and activation features with the CLL cells that are part of the proliferative fraction. Furthermore, the higher frequency of the IL-10⁺ found in progressive patients compared to the indolent ones reveals that IL10 secretion by CLL B cells is linked to disease progression. Finally, Ibrutinib therapy induced a rapid decrease of the absolute number of IL10⁺ cells, which behave like the cells expressing low levels of the CXCR4, a marker of the proliferative fraction. Altogether, our results highlight the crucial role of the immunoregulatory CD5⁺/CD19⁺ subpopulations in CLL progression, and provide new clues on the mechanisms underlying the therapeutic effects of ibrutinib

Anémie hémolytique auto-immune associée à la leucémie lymphoïde chronique : étude rétrospective et multicentrique de 48 observations

REIMS-BU Santé (514542104) / SudocSudocFranceF

Corneal in vivo confocal microscopy to detect belantamab mafodotin-induced ocular toxicity early and adjust the dose accordingly: a case report

International audienceBackground: New targeted antibody-drug conjugates (ADCs) against multiple myeloma are known to induce adverse effects that may lead to treatment discontinuation. Preclinical studies reported early severe ocular damage related to the use of belantamab mafodotin (belamaf), including ocular surface inflammation, severe dry eye, and a specific toxicity to the cornea, namely microcystic keratopathy. While belamaf-induced ocular changes have not been prospectively studied, a better understanding of mechanisms involved as well as kinetics may aid in anticipating dose adjustment rather than stopping the treatment once clinical ocular damage is too severe. Case presentation: A 61-year-old woman scheduled for belamaf as a fifth-line treatment against multiple myeloma was prospectively included. Clinical examinations were performed before and every 3 weeks afterward, together with in vivo confocal microscopy (IVCM) of the cornea. Visual acuity, symptoms, slit-lamp examination, and ultrastructural changes of the cornea were recorded according to the received dose of belamaf. More precisely, kinetics, shape, density, and location of the toxic corneal lesions have been followed and analyzed using IVCM. Also, specific lesions at the sub-basal nerve plexus layer were detected and characterized for the first time. This advanced approach allowed a better understanding of the belamaf-induced toxicity, further balancing the dose to maintain good vision and eye health while continuing the treatment. Conclusions: Systematic ultrastructural analysis and follow-up of the corneal state during ADCs treatment for multiple myeloma may open new avenues in the therapeutic approach. Early preclinical detection of ocular damage may accurately contribute to finding the correct dose for each patient and not stopping the treatment due to severe ocular adverse effects

Microenvironment Remodeling and Subsequent Clinical Implications in Diffuse Large B-Cell Histologic Variant of Richter Syndrome

International audienceIntroduction: Richter Syndrome (RS) is defined as the development of an aggressivelymphoma in the context of Chronic Lymphocytic Leukemia (CLL), with a Diffuse Large B-Cell Lymphoma (DLBCL) histology in 95% cases. RS genomic landscape shares only a few features with de novo DLBCLs and is marked by a wide spectrum of cytogenetic abnormalities. Little is known about RS microenvironment. Therapeutic options and efficacy are limited, leading to a 12 months median overall survival. The new targeted treatments usually effective in CLL fail to obtain long-term remissions in RS. Methods: We reviewed available PubMed literature about RS genomics, PD-1/PD-L1 (Programmed Death 1/Programmed Death Ligand 1) pathway triggering and subsequent new therapeutic options. Results: Data from about 207 patients from four landmark papers were compiled to build an overview of RS genomic lesions and point mutations. A number of these abnormalities may be involved in tumor microenvironment reshaping. T lymphocyte exhaustion through PD-L1 overexpression by tumor cells and subsequent PD-1/PD-L1 pathway triggering is frequently reported in solid cancers. This immune checkpoint inhibitor is also described in B lymphoid malignancies, particularly CLL: PD-1 expression is reported in a subset of prolymphocytes from the CLL lymph node proliferation centers. However, there is only few data about PD-1/PD-L1 pathway in RS. In RS, PD-1 expression is a hallmark of recently described « Regulatory B-cells », which interact with tumor microenvironment by producing inhibiting cytokines such as TGF-band IL-10, impairing T lymphocytes anti-tumoral function. Based upon the discovery of high PD-1 expression on tumoral Blymphocyte from RS, immune checkpoint blockade therapies such as anti-PD-1 antibodies have been tested on small RS cohorts and provided heterogeneous butencouraging results. Conclusion: RS genetic landscape and immune evasion mechanisms are being progressively unraveled. New protocols using targeted treatments such as checkpoint inhibitors as single agents or in combination with immunochemotherapy are currently being evaluated

Difficile examen direct par coloration de Gram : à propos d’un cas d’endocardite à Cardiobacterium hominis et revue de la littérature

International audienc

Enhanced immune-regulatory B cells function in progressive chronic lymphocytic leukemia patients.

International audienc

Th17/Treg ratio in human graft-versus-host disease.

International audienceTh17 cells have never been explored in human graft-versus-host disease (GVHD). We studied the correlation between the presence of Th17 cells with histologic and clinical parameters. We first analyzed a cohort of 40 patients with GVHD of the gastrointestinal tract. Tumor necrosis factor (TNF), TNF receptors, and Fas expression, and apoptotic cells, CD4(+)IL-17(+) cells (Th17), and CD4(+)Foxp3(+) cells (Treg) were quantified. A Th17/Treg ratio less than 1 correlated both with the clinical diagnosis (P < .001) and more than 2 pathologic grades (P < .001). A Th17/Treg ratio less than 1 also correlated with the intensity of apoptosis of epithelial cells (P = .03), Fas expression in the cellular infiltrate (P = .003), TNF, and TNF receptor expression (P < .001). We then assessed Th17/Treg ratio in 2 other independent cohorts; a second cohort of 30 patients and confirmed that Th17/Treg ratio less than 1 correlated with the pathologic grade of GI GVHD. Finally, 15 patients with skin GVHD and 11 patients with skin rash but without pathologic GVHD were studied. Results in this third cohort of patients with skin disease confirmed those found in patients with GI GVHD. These analyses in 96 patients suggest that Th17/Treg ratio could be a sensitive and specific pathologic in situ biomarker of GVHD