Polymorphic KIR3DL3 expression modulates tissue-resident and innate-like T cells

The Importance of HHLA2 in Solid Tumors-A Review of the Literature

Cancer immunotherapy is a rapidly developing field of medicine that aims to use the host's immune mechanisms to inhibit and eliminate cancer cells. Antibodies targeting CTLA-4, PD-1, and its ligand PD-L1 are used in various cancer therapies. However, the most thoroughly researched pathway targeting PD-1/PD-L1 has many limitations, and multiple malignancies resist its effects. Human endogenous retrovirus-H Long repeat-associating 2 (HHLA2, known as B7H5/B7H7/B7y) is the youngest known molecule from the B7 family. HHLA2/TMIGD2/KIRD3DL3 is one of the critical pathways in modulating the immune response. Recent studies have demonstrated that HHLA2 has a double effect in modulating the immune system. The connection of HHLA2 with TMIGD2 induces T cell growth and cytokine production via an AKT-dependent signaling cascade. On the other hand, the binding of HHLA2 and KIR3DL3 leads to the inhibition of T cells and mediates tumor resistance against NK cells. This review aimed to summarize novel information about HHLA2, focusing on immunological mechanisms and clinical features of the HHLA2/KIR3DL3/TMIGD2 pathway in the context of potential strategies for malignancy treatment.

Down-regulated HHLA2 enhances neoadjuvant immunotherapy efficacy in patients with non-small cell lung cancer (NSCLC) with chronic obstructive pulmonary disease (COPD)

BACKGROUND

Emerging data suggested a favorable outcome in advanced non-small cell lung cancer (NSCLC) with chronic obstructive pulmonary disease (COPD) patients treated by immunotherapy. The objective of this study was to investigate the effectiveness of neoadjuvant immunotherapy among NSCLC with COPD versus NSCLC without COPD and explore the potential mechanistic links.

PATIENTS AND METHODS

Patients with NSCLC receiving neoadjuvant immunotherapy and surgery at Shanghai Pulmonary Hospital between November 2020 and January 2023 were reviewed. The assessment of neoadjuvant immunotherapy's effectiveness was conducted based on the major pathologic response (MPR). The gene expression profile was investigated by RNA sequencing data. Immune cell proportions were examined using flow cytometry. The association between gene expression, immune cells, and pathologic response was validated by immunohistochemistry and single-cell data.

RESULTS

A total of 230 NSCLC patients who received neoadjuvant immunotherapy were analyzed, including 60 (26.1%) with COPD. Multivariate logistic regression demonstrated that COPD was a predictor for MPR after neoadjuvant immunotherapy [odds ratio (OR), 2.490; 95% confidence interval (CI), 1.295-4.912; P = 0.007]. NSCLC with COPD showed a down-regulation of HERV-H LTR-associating protein 2 (HHLA2), which was an immune checkpoint molecule, and the HHLA2low group demonstrated the enrichment of CD8+CD103+ tissue-resident memory T cells (TRM) compared to the HHLA2high group (11.9% vs. 4.2%, P = 0.013). Single-cell analysis revealed TRM enrichment in the MPR group. Similarly, NSCLC with COPD exhibited a higher proportion of CD8+CD103+TRM compared to NSCLC without COPD (11.9% vs. 4.6%, P = 0.040).

CONCLUSIONS

The study identified NSCLC with COPD as a favorable lung cancer type for neoadjuvant immunotherapy, offering a new perspective on the multimodality treatment of this patient population. Down-regulated HHLA2 in NSCLC with COPD might improve the MPR rate to neoadjuvant immunotherapy owing to the enrichment of CD8+CD103+TRM.

TRIAL REGISTRATION

Approval for the collection and utilization of clinical samples was granted by the Ethics Committee of Shanghai Pulmonary Hospital (Approval number: K23-228).

Exceptional diversity of KIR and HLA class I in Egypt

Genetically determined variation of killer cell immunoglobulin like receptors (KIR) and their HLA class I ligands affects multiple aspects of human health. Their extreme diversity is generated through complex interplay of natural selection for pathogen resistance and reproductive health, combined with demographic structure and dispersal. Despite significant importance to multiple health conditions of differential effect across populations, the nature and extent of immunogenetic diversity is under-studied for many geographic regions. Here, we describe the first high-resolution analysis of KIR and HLA class I combinatorial diversity in Northern Africa. Analysis of 125 healthy unrelated individuals from Cairo in Egypt yielded 186 KIR alleles arranged in 146 distinct centromeric and 79 distinct telomeric haplotypes. The most frequent haplotypes observed were KIR-A, encoding two inhibitory receptors specific for HLA-C, two that are specific for HLA-A and -B, and no activating receptors. Together with 141 alleles of HLA class I, 75 of which encode a KIR ligand, we identified a mean of six distinct interacting pairs of inhibitory KIR and HLA allotypes per individual. We additionally characterize 16 KIR alleles newly identified in the study population. Our findings place Egyptians as one of the most highly diverse populations worldwide, with important implications for transplant matching and studies of immune-mediated diseases.

Underrepresentation of activating KIR gene expression in single-cell RNA-seq data is due to KIR gene misassignment

Standard single-cell RNA-sequencing alignment pipelines exhibit a propensity for misassigning killer immunoglobulin-like receptor (KIR) transcripts, thereby giving rise to inaccuracies in quantifying KIR expression. Alves et al. elucidated that these default workflows frequently misclassify activating KIR transcripts as inhibitory KIR expression, resulting in a skewed representation of the KIR repertoire.