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Chimeric antigen receptor T‐cells (CAR‐T) are widely used for the treatment of relapsed/refractory diffuse large B cell lymphoma (DLBCL). The data for CAR‐T cell therapy in patients with extra‐nodal (EN) lymphoma is restricted. We included 126 consecutive patients with DLBCL treated with commercially available CAR‐T cells (tisagenlecleucel, n = 100, 79.4% and axicabtagene ciloleucel, n = 26, 20.6%). At lymphodepletion, 72 of 126 (57%) patients had EN disease, 42 of 126 (33%) patients had nodal disease (ND)‐only and 12 of 126 (10%) showed no disease assessed by PET‐CT. There were no significant differences in CAR‐T related toxicities and in the median Progression free survival (PFS) between EN patients and ND (10.76 [95% CI: 7.8–13.6] vs. 14.1 [95% CI: 10–18.1] months, p =.126). Similarly, median overall survival (OS) was not significantly different (15.36 [95% CI 12.5–18.2] vs. 18.4 [95% CI 14.8–22.1] months, p =.100). Subgroup analysis according to the number of EN involved sites showed that median PFS and OS were significantly higher in patients with <3 EN sites (12.3 months [95% CI 9–15.5] vs. 4.28 months [95% CI 0.6–7.9], p =.010) compared to patients with >2 EN sites, respectively (16.5 months [95% CI 13.4–19.6] vs. 8.7 months [95% CI 4.6–12.8], p =.05). In multivariate cox regression analysis, increased number sites of EN disease and high lactate dehydrogenase (LDH) at lymphodepletion negatively impacted PFS (p =.021 and <.001, respectively), while sex, type of product administered, age and performance status did not predict PFS and OS. Of note, all the patients with involvement of gastrointestinal tract (n = 9), urinary tract (n = 9), or pharynx (n = 3) at lymphodepletion, progressed or had an early relapse. In conclusions, patients with >2 EN sites at lymphodepletion have significantly worse clinical outcomes compared to patients with <3 EN sites. Patients with specific sites of EN disease may demonstrate grim prognosis. [ABSTRACT FROM AUTHOR]

In chronic lymphocytic leukemia (CLL), the immune system is skewed towards a suppressive milieu. Levels of thrombopoietin (TPO), promoting cellular immune regulatory activity in immune thrombocytopenic purpura, were shown to be elevated in CLL patients. This study explored TPO as a potential immunomodulator, supporting CLL progression. We evaluated CLL cell‐induced expression of TPO receptor (TPO‐R) on T‐cells and effects of its activation on T‐cell responses. CLL cell involvement in TPO generation was also assessed. Baseline TPO‐R expression on CD4 + T‐cells was found to be higher in CLL patients than in healthy controls (HC). Exposure of HC‐T‐cells to B‐cells, especially to CLL‐B‐cells stimulated with B‐cell activating molecules, resulted in enhanced TPO‐R expression on T‐cells. CLL‐T‐cell stimulation with TPO reduced their proliferation and expanded the regulatory T‐cell (Treg) population. At baseline, phosphorylation of STAT5, known to impact the Treg phenotype, was elevated in CLL‐T‐cells relative to those of HC. Exposure to TPO further enhanced STAT5 phosphorylation in CLL‐T‐cells, possibly driving the observed Treg expansion. The CLL immune milieu is involved in promotion of inhibitory features in T‐cells through increased TPO‐R levels and TPO‐induced intracellular signaling. TPO and its signaling pathway could potentially support immunosuppression in CLL, and may emerge as novel therapeutic targets. [ABSTRACT FROM AUTHOR]

Polatuzumab (Pola)-based regimens and chimeric antigen receptor T (CAR T) cells provide superior outcome compared to conventional chemoimmunotherapy in patients with relapsed/refractory diffuse large B cell lymphoma (R/R DLBCL). Choosing between these strategies remains controversial. The efficacy of CAR T versus Pola-rituximab(R) /Pola-bendamustine(B)-R in R/R DLBCL patients after failing ≥2 lines of treatment was compared in a retrospective, 'real-world' study. Propensity score matching, for age, lymphoma category (de-novo/transformed), number of prior lines, Eastern Cooperative Oncology Group performance status and lactate dehydrogenase level, was applied to control for differences in patients' characteristics. Response rate, progression-free survival (PFS) and overall survival (OS) were analyzed. A total of 82 patients, treated with CAR T (n=41) or Pola-based regimens (n=41), were included. No treatment-related deaths occurred with CAR T vs. 3 (7.3%) with Pola. The overall and complete response rates were 83% and 58% with CAR T vs. 66% and 44% with Pola-based-regimens (p=0.077 and p=0.18, respectively). At a median follow-up of 9 months (range 1-19.2) and 16 months (range 0.7-25.3) for the CAR T and Pola arm respectively, the median PFS has not been reached for CAR T vs. 5.6 months for Pola (95% CI 3.6-7.6, p=0.014). Median OS has not been reached for CAR T vs. 10.8 months (95% CI 2.2-19.4) for Pola (p=0.026). To conclude, in a real-world setting, treatment with CAR T achieved superior PFS and OS compared to Pola-based regimens in patients with R/R DLBCL. [ABSTRACT FROM AUTHOR]

Circulating chronic lymphocytic leukemia (CLL) cells share phenotypic features with certain subsets of regulatory B-cells (Bregs). The latter cells have been reported to negatively regulate immune cell responses, mostly by provision of IL-10. The purpose of the current study was to identify and delineate Breg properties of CLL cells. B-cells and T-cells were obtained from the peripheral blood of untreated CLL patients diagnosed according to the 2008 Guidelines of the International Workshop on Chronic Lymphocytic Leukemia. Co-culture assays were used to examine the ability of CLL cells to suppress autologous T-cell immune responses. IL-10 potency of CLL cells was assessed following stimulation with activators of the toll-like receptor 9 (TLR9) or CD40 and was correlated with the inhibitory activity of the cells. TLR9-activated CLL cells were found to increase the frequency of CD4+CD25hiFOXp3+ regulatory T-cells (Tregs) and to inhibit autologous CD4+ T-cell proliferation. This signaling cascade proved to control IL-10 generation in CLL cells, which in turn promoted the inhibition of T-cell proliferation by CLL cells. However, CD40 activation of CLL cells, while exhibiting a similar ability to augment Treg frequency, did not either affect IL-10 generation or T-cell proliferation. In conclusion, CLL cells demonstrate a unique clonal quality of adopting Breg properties which promote modulation of T-cell characteristics. TLR9 appears to be a potent activator of regulatory abilities in CLL cells, possibly contributing to preferential immune escape of TLR9-responsive cells. [ABSTRACT FROM AUTHOR]