CD8A, also known as cluster of differentiation 8 alpha, is a crucial gene associated with the T cytotoxic pathway. It plays a significant role in immune cell infiltration and is linked to immunotherapeutic response. CD8A is expressed in certain T cells, and its products are involved in the immune response processes, which are of great importance in maintaining immune homeostasis and fighting against diseases [1,3,4].

In various diseases, CD8A shows distinct associations. In bladder cancer, it's a novel protective gene, and low expression is related to immunotherapeutic failure and poor survival, while its expression is correlated with tumor mutation burden and immune checkpoint genes, predicting immunotherapy response. A radiomics signature can preoperatively predict its expression [1]. In clear cell renal cell carcinomas, enrichment of CD8A+ tissue-resident T cells is observed in patients responsive to immune checkpoint blockade [2]. In bronchopulmonary dysplasia, CD8A expression is down-regulated and is closely associated with immune cell infiltration, especially T cells CD8 and neutrophil [3]. In breast cancer, CD8A is down-regulated in metastatic lesions, and its high expression is correlated with improved survival and infiltration of CD8+ T cells [4]. Polymorphisms in the CD8A gene are associated with severity factors in chronic rhinosinusitis [5], and it may serve as a potential molecular biomarker for sepsis [6]. Also, [64Cu]NOTA-CD8a PET imaging can detect treatment-induced changes in CD8a+ infiltration in murine colon tumors following combined treatment, showing good prognostic and predictive value [7].

In conclusion, CD8A is essential in immune-related biological functions. Its study through various disease models reveals its significance in immunotherapy response, immune cell infiltration, and prognosis in diseases such as bladder cancer, renal cell carcinomas, bronchopulmonary dysplasia, breast cancer, chronic rhinosinusitis, and sepsis. Understanding CD8A provides insights into disease mechanisms and potential therapeutic strategies.

References:

1. Zheng, Zongtai, Guo, Yadong, Huang, Xiongsheng, Qiu, Xiaofu, Liu, Shenghua. 2022. CD8A as a Prognostic and Immunotherapy Predictive Biomarker Can Be Evaluated by MRI Radiomics Features in Bladder Cancer. In Cancers, 14, . doi:10.3390/cancers14194866. https://pubmed.ncbi.nlm.nih.gov/36230788/

2. Krishna, Chirag, DiNatale, Renzo G, Kuo, Fengshen, Chan, Timothy A, Hakimi, A Ari. 2021. Single-cell sequencing links multiregional immune landscapes and tissue-resident T cells in ccRCC to tumor topology and therapy efficacy. In Cancer cell, 39, 662-677.e6. doi:10.1016/j.ccell.2021.03.007. https://pubmed.ncbi.nlm.nih.gov/33861994/

3. Du, Yiting, Zuo, Limin, Xiong, Ying, Zou, Jun, Xu, Hong. 2023. CD8A is a Promising Biomarker Associated with Immunocytes Infiltration in Hyperoxia-Induced Bronchopulmonary Dysplasia. In Journal of inflammation research, 16, 1653-1669. doi:10.2147/JIR.S397491. https://pubmed.ncbi.nlm.nih.gov/37092130/

4. Chu, Jian, Tang, Shan, Li, Tangya, Fan, Huiwen. . The Role of CD8A in the Immune Microenvironment of Breast Cancer. In Frontiers in bioscience (Landmark edition), 29, 73. doi:10.31083/j.fbl2902073. https://pubmed.ncbi.nlm.nih.gov/38420798/

5. Alromaih, Saud, Mfuna-Endam, Leandra, Bosse, Yohan, Filali-Mouhim, Abdelali, Desrosiers, Martin. 2013. CD8A gene polymorphisms predict severity factors in chronic rhinosinusitis. In International forum of allergy & rhinology, 3, 605-11. doi:10.1002/alr.21174. https://pubmed.ncbi.nlm.nih.gov/23640800/

6. Li, Jin, Wang, Lantao, Yu, Bin, Su, Jie, Dong, Shimin. 2024. IL7R, GZMA and CD8A serve as potential molecular biomarkers for sepsis based on bioinformatics analysis. In Frontiers in immunology, 15, 1445858. doi:10.3389/fimmu.2024.1445858. https://pubmed.ncbi.nlm.nih.gov/39654893/

7. Kristensen, Lotte K, Christensen, Camilla, Alfsen, Maria Z, Nielsen, Carsten H, Kjaer, Andreas. . Monitoring CD8a+ T Cell Responses to Radiotherapy and CTLA-4 Blockade Using [64Cu]NOTA-CD8a PET Imaging. In Molecular imaging and biology, 22, 1021-1030. doi:10.1007/s11307-020-01481-0. https://pubmed.ncbi.nlm.nih.gov/32086762/