CD8 + T Cells Exhibit an Exhausted Phenotype in Hemophagocytic Lymphohistiocytosis

Comprehensive evaluation of immune dysregulation in secondary hemophagocytic lymphohistiocytosis

Host immune dysfunction plays a crucial role in the onset, progression, and outcome of hemophagocytic lymphohistiocytosis (HLH). This study aimed to comprehensively evaluate the peripheral immune profiles in patients with newly diagnosed secondary hemophagocytic lymphohistiocytosis (sHLH), and explore their predictive value for patient prognosis. A total of 77 patients with sHLH were enrolled in this study, with 31 of them experiencing mortality. Flow cytometry was used to assess the percentages, absolute numbers, and phenotypes of lymphocyte subsets. Simultaneously, cytokine levels and routine laboratory indicators were also collected. In sHLH patients, lymphocyte subset absolute numbers were significantly impaired, accompanied by T cell hyperactivation, B cell hyperactivation, and increased plasmablast proliferation. Prognostic analysis revealed that lower CD8+ T cell percentages, elevated APTT, IL-6, IL-10 levels, and increased CD4+CD28null T cell proportions were associated with poor patient outcomes. The study demonstrates dysregulation in the counts and phenotypes of lymphocyte subsets in sHLH patients. Several key factors, including IL-6, IL-10, APTT, and various T cell percentages, have potential as prognostic markers and therapeutic targets in sHLH.

Severe lympho-depletion, abrogated thymopoiesis and systemic EBV positive T-cell lymphoma of childhood, a case

Epstein-Barr virus (EBV) associated T-cell and NK-cell lymphoproliferative diseases are lethal and extremely rare in Caucasians. We expand on the clinical, immunological and histogenetic characteristics associated with this second European case (19 years old, previously healthy, Caucasian boy) of systemic EBV positive T-cell lymphoma of childhood. We report, as novel findings, severe lympho-depletion and abrogation of thymopoiesis secondary to severe EBV activation and excessive immune activation. Similar to the first European case, we also detected a somatic missense variant in the proto-oncogene FYN. In the first European patient however, the FYN variant allele frequency (VAF) was 10% and the patient only experienced moderate leukopenia, whereas in our case, the VAF was 48% and the patient experienced severe leukopenia and lymphopenia. This could suggest a pathogenic role of these FYN variants in driving excessive T cell activation. If confirmed, FYN might become target in future treatments of this fatal disorder.

The signature and predictive value of immune parameters in patients with secondary hemophagocytic lymphohistiocytosis

BACKGROUND

Secondary hemophagocytic lymphohistiocytosis (sHLH) is a rare but fatal clinical syndrome, characterized by severe immune dysfunction and overwhelming inflammatory response. However, the host immune signature and also its role in predicting the clinical outcome are not fully described.

OBJECTIVE

The present study aims to investigate the host immune status of sHLH patients in the early stage of the disease, including lymphocyte subsets, phenotypes and cytokines, and also to explore its clinical value in prognosis.

METHODS

Sixty-four patients with sHLH admitted to a tertiary hospital in central China between 2018 and 2022 were enrolled, of which 21 were deceased. The subsets and phenotypes of lymphocytes, and the levels of cytokines in serum were analyzed.

RESULTS

In patients with sHLH, the percentages of total T cells, CD8+ T cells, HLA-DR+ T cells, HLA-DR+CD8+ T cells, CD45RO+CD4+ T cells, and the levels of IL-1β, IL-2R, IL-6, IL-8, IL-10 and TNF-α were significantly increased, while the percentages of CD4+ T cells, NK cells, CD45RA+CD4+ T cells, CD45RA+ regulatory T (Treg) cells, the counts of total T cells, total B cells, CD4+ T cells, CD8+ T cells, NK cells, and the ratio of CD4+ T/CD8+ T cells were significantly decreased, compared with healthy controls (HC). In addition, dysregulation of host immune response and high inflammatory status were more obvious in deceased patients than that of survivors. Kaplan-Meier survival analysis and multivariate logistic regression analysis demonstrated that lower levels of CD4+ T cells count and CD28+CD4+ T cells percentage, but higher levels of NK cells percentage and IL-1β were poor prognostic indicators of sHLH.

CONCLUSION

The evaluation of immunological markers has critical value for selecting prognostic markers and potential treatment target among adults with sHLH.

Obesity-induced thymic involution and cancer risk

Declining thymic functions associated either with old age (i.e., age-related thymic involution), or with acute involution as a result of stress, infectious disease, or cytoreductive therapies (e.g., chemotherapy/radiotherapy), have been associated with cancer development. A key mechanism underlying such increased cancer risk is the thymus-dependent debilitation of adaptive immunity, which is responsible for orchestrating immunoediting mechanisms and tumor immune surveillance. In the past few years, a blooming set of evidence has intriguingly linked obesity with cancer development and progression. The majority of such studies has focused on obesity-driven chronic inflammation, steroid/sex hormone and adipokine production, and hyperinsulinemia, as principal factors affecting the tumor microenvironment and driving the development of primary malignancy. However, experimental observations about the negative impact of obesity on T cell development and maturation have existed for more than half a century. Here, we critically discuss the molecular and cellular mechanisms of obesity-driven thymic involution as a previously underrepresented intermediary pathology leading to cancer development and progression. This knowledge could be especially relevant in the context of childhood obesity, because impaired thymic function in young individuals leads to immune system abnormalities, and predisposes to various pediatric cancers. A thorough understanding behind the molecular and cellular circuitries governing obesity-induced thymic involution could therefore help towards the rationalized development of targeted thymic regeneration strategies for obese individuals at high risk of cancer development.

The emerging role of anti-PD-1 antibody-based regimens in the treatment of extranodal NK/T-cell lymphoma-associated hemophagocytic lymphohistiocytosis

PURPOSE

Anti-PD-1 antibody (anti-PD-1 mAb) showed favorable outcomes in some patients with relapsed/refractory (r/r) extranodal NK/T-cell lymphoma (ENKTL). However, the role of anti-PD-1 antibody in NK/T-cell lymphoma-associated hemophagocytic lymphohistiocytosis (NK/T-LAHS) remains unclear. Here, we evaluated the efficacy and toxicity of anti-PD-1 antibody-based treatment in NK/T-LAHS patients.

METHODS

The clinical data of 98 patients diagnosed with NK/T-LAHS at Sun Yat-sen University Cancer Center and the First Affiliated Hospital of Guangdong Pharmaceutical University from May 2014 to November 2021 were retrospectively analyzed. All patients received anti-HLH [HLH-2004 (etoposide, dexamethasone, cyclosporine A) or DEP-based (liposomal doxorubicin, etoposide, methylprednisolone)] regimen and sequential anti-ENKTL chemotherapy (ChT) combined with anti-PD-1 antibody or not.

RESULTS

The overall response rate (ORR) of the anti-PD-1 mAb plus ChT regimens was higher than that of the ChT regimens (73.3% vs. 45.5%, P = 0.041). The toxicity of the anti-PD-1 mAb plus ChT regimens was tolerable. Except for higher rate of neutropenia, no significant difference in adverse events (AEs) was observed between the two groups. When the optimal response to anti-ENKTL was achieved, the median EBV DNA levels in patients who received anti-PD-1 mAb plus ChT were significantly lower than patients who received ChT only (878 copies/mL vs. 18,600 copies/mL, P = 0.001). With a median follow-up of 26.6 months (range 0-65.9 months), the median overall survival (mOS) was 3.5 months (95% CI：2.3-4.7 months). Patients treated with anti-PD-1 mAb plus ChT experienced a longer mOS than those who received ChT only [5.2 months (95% CI: 2.5-7.8 months) vs. 1.5 months (95% CI: 0.5-2.6 months), P = 0.002]. Cox multivariate analysis found that anti-PD-1 mAb was an independent prognostic factor for all NK/T-LAHS patients.

CONCLUSION

In conclusion, anti-PD-1 mAb combined with ChT regimens seemed to be associated with prolonged survival in NK/T-LAHS patients and may represent a potentially promising treatment strategy for this population.

Adoptive T cell therapy cures mice from active hemophagocytic lymphohistiocytosis (HLH)

Primary hemophagocytic lymphohistiocytosis (HLH) is a hyperinflammatory syndrome caused by impaired lymphocyte cytotoxicity. First-line therapeutic regimens directed against activated immune cells or secreted cytokines show limited efficacy since they do not target the underlying immunological problem: defective lymphocyte cytotoxicity causing prolonged immune stimulation. A potential rescue strategy would be the adoptive transfer of ex vivo gene-corrected autologous T cells. However, transfusion of cytotoxicity-competent T cells under conditions of hyperinflammation may cause more harm than benefit. As a proof-of-concept for adoptive T cell therapy (ATCT) under hyperinflammatory conditions, we transferred syngeneic, cytotoxicity-competent T cells into mice with virally triggered active primary HLH. ATCT with functional syngeneic trigger-specific T cells cured Jinx mice from active HLH without life-threatening side effects and protected Perforin-deficient mice from lethal HLH progression by reconstituting cytotoxicity. Cured mice were protected long-term from HLH relapses. A threshold frequency of transferred T cells with functional differentiation was identified as a predictive biomarker for long-term survival. This study is the first proof-of-concept for ATCT in active HLH.