Therapeutic potential of natural killer cells in neuroimmunological diseases

Natural killer (NK) cells, a major component of the innate immune system, have prominent immunoregulatory, antitumor proliferation, and antiviral activities. NK cells act as a double-edged sword with therapeutic potential in neurological autoimmunity. Emerging evidence has identified NK cells are involved in the development and progression of neuroimmunological diseases such as multiple sclerosis, neuromyelitis optica spectrum disorders, autoimmune encephalitis, Guillain-Barré Syndrome, chronic inflammatory demyelinating polyneuropathy, myasthenia gravis, and idiopathic inflammatory myopathy. However, the regulatory mechanisms and functional roles of NK cells are highly variable in different clinical states of neuroimmunological diseases and need to be further determined. In this review, we summarize the evidence for the heterogenic involvement of NK cells in the above conditions. Further, we describe cutting-edge NK-cell-based immunotherapy for neuroimmunological diseases in preclinical and clinical development and highlight challenges that must be overcome to fully realize the therapeutic potential of NK cells.

Safety evaluation of immune-cell therapy for malignant tumor in the Cancer Immune-cell Therapy Evaluation Group (CITEG)

BACKGROUND AIMS

With the aim of strengthening the scientific evidence of immune-cell therapy for cancer and further examining its safety, in October 2015, our hospital jointly established the Cancer Immune-Cell Therapy Evaluation Group (CITEG) with 39 medical facilities nationwide.

METHODS

Medical information, such as patients' background characteristics, clinical efficacy and therapeutic cell types obtained from each facility, has been accumulated, analyzed and evaluated by CITEG. In this prospective study, we analyzed the adverse events associated with immune-cell therapy until the end of September 2022, and we presented our interim safety evaluation.

RESULTS

A total of 3839 patients with malignant tumor were treated with immune-cell therapy, with a median age of 64 years (range, 13-97 years) and a male-to-female ratio of 1:1.08 (1846:1993). Most patients' performance status was 0 or 1 (86.8%) at the first visit, and 3234 cases (84.2%) were advanced or recurrent cases, which accounted for the majority. The total number of administrations reported in CITEG was 31890, of which 960 (3.0%) showed adverse events. The numbers of adverse events caused by treatment were 363 (1.8%) of 19661 administrations of αβT cell therapy, 9 of 845 administrations of γδT-cell therapy (1.1%) and 10 of 626 administrations of natural killer cell therapy (1.6%). The number of adverse events caused by dendritic cell (DC) vaccine therapy was 578 of 10748 administrations (5.4%), which was significantly larger than those for other treatments. Multivariate analysis revealed that αβT cell therapy had a significantly greater risk of adverse events at performance status 1 or higher, and patients younger than 64 years, women or adjuvant immune-cell therapy had a greater risk of adverse events in DC vaccine therapy. Injection-site reactions were the most frequently reported adverse events, with 449 events, the majority of which were associated with DC vaccine therapy. Among all other adverse events, fever (228 events), fatigue (141 events) and itching (131 events) were frequently reported. In contrast, three patients had adverse events (fever, abdominal pain and interstitial pneumonia) that required hospitalization, although they were weakly related to this therapy; rather, it was considered to be the effect of treatment for the primary disease.

CONCLUSIONS

Immune-cell therapy for cancer was considered to be a safe treatment without serious adverse events.

An Interleukin-15 Superagonist Enables Antitumor Efficacy of Natural Killer Cells Against All Molecular Variants of SCLC

INTRODUCTION

SCLC is a highly aggressive tumor with a 5-year survival rate of less than 6%. A heterogeneous disease, SCLC is classified into four subtypes that include tumors with neuroendocrine and non-neuroendocrine features. Immune checkpoint blockade has been recently added for the frontline treatment of SCLC; however, this therapy has only led to modest clinical improvements. The lack of clinical benefit in a cancer type known to have a high tumor mutational burden has been attributed to poor T-cell infiltration and low expression of MHC-class I in most SCLC tumors. In an attempt to devise a more effective immunotherapeutic regimen, this study investigated an alternate approach on the basis of the use of the clinical-stage interleukin-15 superagonist, N-803.

METHODS

Preclinical models of SCLC spanning all molecular subtypes were used to evaluate the susceptibility of SCLC to natural killer (NK)-mediated lysis in vitro, including NK cells activated by N-803. Antitumor activity of N-803 was evaluated in vivo with a xenograft model of SCLC.

RESULTS

In vitro and in vivo data revealed differences in susceptibility of SCLC subtypes to lysis by NK cells and that NK cells activated by N-803 effectively lyse SCLC tumor cells across all variant subtypes, regardless of their expression of MHC-class I.

CONCLUSIONS

These findings highlight the potential of a novel immune-based intervention using a cytokine-based therapeutic option for the treatment of SCLC. We hypothesize that N-803 may provide benefit to most patients with SCLC, including those with immunologically cold tumors lacking MHC expression.

Advances in immune therapies in hematological malignancies

Immunotherapy in cancer takes advantage of the exquisite specificity, potency, and flexibility of the immune system to eliminate alien tumor cells. It involves strategies to activate the entire immune defense, by unlocking mechanisms developed by tumor cells to escape from surrounding immune cells, as well as engineered antibody and cellular therapies. What is important to note is that these are therapeutics with curative potential. The earliest example of immune therapy is allogeneic stem cell transplantation, introduced in 1957, which is still an important modality in hematology, most notably in myeloid malignancies. In this review, we discuss developmental trends of immunotherapy in hematological malignancies, focusing on some of the strategies that we believe will have the most impact on future clinical practice in this field. In particular, we delineate novel developments for therapies that have already been introduced into the clinic, such as immune checkpoint inhibition and chimeric antigen receptor T-cell therapies. Finally, we discuss the therapeutic potential of emerging strategies based on T-cell receptors and adoptive transfer of allogeneic natural killer cells.

CD48-expressing non-small-cell lung cancer cells are susceptible to natural killer cell-mediated cytotoxicity

The susceptibility of cancer cells to natural killer (NK) cell-mediated cytotoxicity depends on the balance of activating and inhibitory ligands expressed on their surface. Although many types of cancer cells are killed by NK cells, non-small-cell lung cancer (NSCLC) cells are relatively resistant to NK cell-mediated cytotoxicity. In this study, we showed that several NSCLC cell lines have differential sensitivity to NK cell-mediated cytotoxicity: NCI-H522 cells were highly sensitive, but A549, NCI-H23, NCI-H1915, and NCI-H1299 were resistant. Among activating ligands such as CD48, HLA-A/B/G, ICAM-1, MICA/B, and ULBPs, only CD48 rendered NCI-H522 cells susceptible to NK cell-mediated cytotoxicity, which was proved by using CD48 siRNA and neutralizing antibody. CD48-positive NCI-H522 cells established a more stable contact with NK cells than did CD48-negative A549 and CD48 siRNA cell-transfected NCI-H522 cells. Taken together, these data demonstrate that CD48-positive NSCLC cells might be susceptible to NK cell-mediated cytotoxicity, which provide information on how to stratify NSCLC patients potentially responsive to NK-cell therapy.