Molecular Classification of Primary Immunodeficiencies of T Lymphocytes

Precise CRISPR-Cas9 gene repair in autologous memory T cells to treat familial hemophagocytic lymphohistiocytosis

Familial hemophagocytic lymphohistiocytosis (FHL) is an inherited, often fatal immune deficiency characterized by severe systemic hyperinflammation. Although allogeneic bone marrow transplantation can be curative, more effective therapies are urgently needed. FHL is caused by inactivating mutations in proteins that regulate cellular immunity. Here, we used an adeno-associated virus-based CRISPR-Cas9 system with an inhibitor of nonhomologous end joining to repair such mutations in potentially long-lived T cells ex vivo. Repaired CD8 memory T cells efficiently cured lethal hyperinflammation in a mouse model of Epstein-Barr virus-triggered FHL2, a subtype caused by perforin-1 (Prf1) deficiency. Furthermore, repair of PRF1 and Munc13-4 (UNC13D)-whose deficiency causes the FHL subtype FHL3-in mutant memory T cells from two critically ill patients with FHL restored T cell cytotoxicity. These results provide a starting point for the treatment of genetic T cell immune dysregulation syndromes with repaired autologous T cells.

Genomics Driving Diagnosis and Treatment of Inborn Errors of Immunity With Cancer Predisposition

Inborn errors of immunity (IEI) are genetically and clinically heterogeneous disorders that, in addition to infection susceptibility and immune dysregulation, can have an enhanced cancer predisposition. The increasing availability of upfront next-generation sequencing diagnostics in immunology and oncology have uncovered substantial overlap of germline and somatic genetic conditions that can result in immunodeficiency and cancer. However, broad application of unbiased genetics in these neighboring disciplines still needs to be deployed, and joined therapeutic strategies guided by germline and somatic genetic risk factors are lacking. We illustrate the current difficulties encountered in clinical practice, summarize the historical development of pathophysiological concepts of cancer predisposition, and review select genetic, molecular, and cellular mechanisms of well-defined and illustrative disease entities such as DNA repair defects, combined immunodeficiencies with Epstein-Barr virus susceptibility, autoimmune lymphoproliferative syndromes, regulatory T-cell disorders, and defects in cell intrinsic immunity. We review genetic variants that, when present in the germline, cause IEI with cancer predisposition but, when arising as somatic variants, behave as oncogenes and cause specific cancer entities. We finally give examples of small molecular compounds that are developed and studied to target genetically defined cancers but might also proof useful to treat IEI.

Resilience in Long-Term Viral Infection: Genetic Determinants and Interactions

Virus-induced neurological sequelae resulting from infection by Theiler's murine encephalomyelitis virus (TMEV) are used for studying human conditions ranging from epileptic seizures to demyelinating disease. Mouse strains are typically considered susceptible or resistant to TMEV infection based on viral persistence and extreme phenotypes, such as demyelination. We have identified a broader spectrum of phenotypic outcomes by infecting strains of the genetically diverse Collaborative Cross (CC) mouse resource. We evaluated the chronic-infection gene expression profiles of hippocampi and thoracic spinal cords for 19 CC strains in relation to phenotypic severity and TMEV persistence. Strains were clustered based on similar phenotypic profiles and TMEV levels at 90 days post-infection, and we categorized distinct TMEV response profiles. The three most common profiles included "resistant" and "susceptible," as before, as well as a "resilient" TMEV response group which experienced both TMEV persistence and mild neurological phenotypes even at 90 days post-infection. Each profile had a distinct gene expression signature, allowing the identification of pathways and networks specific to each TMEV response group. CC founder haplotypes for genes involved in these pathways/networks revealed candidate response-specific alleles. These alleles demonstrated pleiotropy and epigenetic (miRNA) regulation in long-term TMEV infection, with particular relevance for resilient mouse strains.

Combined immunodeficiencies

OBJECTIVES

Inborn Errors of Immunity (IEI), also known as primary immunodeficiencies, correspond to a heterogeneous group of congenital diseases that primarily affect immune response components. The main clinical manifestations comprise increased susceptibility to infections, autoimmunity, inflammation, allergies and malignancies. The aim of this article is to review the literature on combined immunodeficiencies (CIDs) focusing on the diagnosis and treatment and the particularities of the clinical management of these patients.

SOURCE OF DATA

Critical integrative review, aimed to present articles related to primary immunodeficiencies combined with a searchin the PubMed and SciELO databases, with evaluation of publications from the last twenty years that were essential for the construction of knowledge on this group of diseases.

SUMMARY OF DATA

We highlight the main characteristics of CIDs, dividing them according to their pathophysiological mechanisms, such as defects in the development of T cells, TCR signaling, co-stimulatory pathways, cytokine signaling, adhesion, migration and organization of the cytoskeleton, apoptosis pathways, DNA replication and repair and metabolic pathways. In CIDs, clinical manifestations vary widely, from sinopulmonary bacterial infections and diarrhea to opportunistic infections, caused by mycobacteria and fungi. Neonatal screening makes it possible to suspect these diseases before clinical manifestations appear.

CONCLUSIONS

The CIDs or IEI constitute a complex group of genetic diseases with T-cell involvement. Neonatal screening for these diseases has improved the prognosis of these patients, especially in severe ones, known as SCIDs.

Heterogeneity in combined immunodeficiencies with associated or syndromic features (Review)

Primary immunodeficiencies are genetic diseases, mainly monogenic, that affect various components of the immune system and stages of the immune response. The category of combined immunodeficiencies with associated or syndromic features comprises over 70 clinical entities, characterized by heterogeneity of clinical presentation, mode of transmission, molecular, biological, mutational and immunological aspects. The mutational spectrum is wide, ranging from structural chromosomal abnormalities to gene mutations. The impact on the function of the proteins encoded by the genes involved is different; loss of function is most common, but situations with gain of function are also described. Most proteins have multiple functions and are components of several protein interaction networks. The pathophysiological mechanisms mainly involve: Missing enzymes, absent or non-functional proteins, abnormal DNA repair pathways, altered signal transduction, developmental arrest in immune differentiation, impairment of cell-to-cell and intracellular communications. Allelic heterogeneity, reduced penetrance and variable expressivity are genetic phenomena that cause diagnostic difficulties, especially since most are rare/very rare diseases, which is equivalent to delaying proper case management. Most primary immunodeficiencies are Mendelian diseases with X-linked or recessive inheritance, and molecular diagnosis allows the identification of family members at risk and the application of appropriate primary and secondary prevention measures in addition to the specific curative ones. In conclusion, recognizing heterogeneity and its sources is extremely important for current medical practice, but also for the theoretical value of improving biological and biomedical applications.

Exploration and validation of the effects of robust co-expressed immune-related genes on immune infiltration patterns and prognosis in laryngeal cancer

OBJECTIVES

Laryngeal cancer is a common malignant tumor that originates from the larynx, yet its molecular mechanisms have not been thoroughly explored. The purpose of this study was to identify and evaluate immune-related genes in laryngeal cancer through gene co-expression networks, which may serve as biomarkers for its immunotherapy.

METHODS

We applied ESTIMATE to evaluate the immune-infiltration landscape of tumor microenvironment. The co-expression networks were constructed by weighted gene co expression network analysis (WGCNA) and compared with the existing human immune related genes (IRGs) to determine the co-expressed IRGs. GSVA combined with CIBERSORT and ssGSEA illustrated the correlation of hub genes and immune infiltration patterns. TIDE algorithm and Subclass mapping evaluated the function of hub genes in predicting immune function and immunotherapeutic sensitivity. The pRRophetic was employed in the sensitivity prediction of chemotherapeutic drugs.

RESULTS

A total of 23 co-expressed IRGs were identified and showed robust expression characteristics. These genes were significantly related to immune infiltration patterns, immune function and sensitivity prediction of immunotherapy and chemotherapeutic drugs for laryngeal cancer patients. Genetic alteration in somatic mutation level and related pathways were also revealed.

CONCLUSION

The 23 co-expressed IRGs may act as immunotherapeutic biomarkers and potential therapeutic targets for laryngeal cancer with certain expression robustness. The molecular mechanisms deserve further investigation, which will guide clinical treatment in the future.

Multiple actin networks coordinate mechanotransduction at the immunological synapse

Activation of naive T cells by antigen-presenting cells (APCs) is an essential step in mounting an adaptive immune response. It is known that antigen recognition and T cell receptor (TCR) signaling depend on forces applied by the T cell actin cytoskeleton, but until recently, the underlying mechanisms have been poorly defined. Here, we review recent advances in the field, which show that specific actin-dependent structures contribute to the process in distinct ways. In essence, T cell priming involves a tug-of-war between the cytoskeletons of the T cell and the APC, where the actin cytoskeleton serves as a mechanical intermediate that integrates force-dependent signals. We consider each of the relevant actin-rich T cell structures separately and address how they work together at the topologically and temporally complex cell-cell interface. In addition, we address how this mechanobiology can be incorporated into canonical immunological models to improve how these models explain T cell sensitivity and antigenic specificity.