Monogenic forms of common variable immunodeficiency and implications on target therapeutic approaches

PURPOSE OF REVIEW

Common variable immunodeficiency (CVID) is the most common symptomatic inborn error of immunity. The disorder is characterized by variable clinical and immunological manifestations, and, in a small minority of patients, a monogenic cause may be identified. In this review, we focalized on three different monogenic forms of CVID-like disease.

RECENT FINDINGS

Activated phosphoinositide 3-kinase delta syndrome (APDS) is a rare disorder characterized by hyperactivated class I phosphatidylinositol-3 kinase (PI3K) pathway. Affected patients present with respiratory infectious episodes, impaired viral clearance and lymphoproliferation. Recently, a direct PI3K inhibitor has been approved and it showed encouraging results both in controlling clinical and immunological manifestations of the disease. On the other hand, patients with defects in CTLA-4 or LRBA gene present with life-threatening immune dysregulation, autoimmunity and lymphocytic infiltration of multiple organs. Abatacept, a soluble cytotoxic T lymphocyte antigen 4 (CTLA-4) fusion protein that acts as a costimulation modulator, has been widely implemented for affected patients with good results as bridge treatment.

SUMMARY

Understanding the biological basis of CVID is important not only for enriching our knowledge of the human immune system, but also for setting the basis for potential targeted treatments in this disorder.

The current management and biomarkers of immunotherapy in advanced gastric cancer

BACKGROUND

Gastric carcinoma (GC) is the fourth most common cause of cancer-related death worldwide. Most patients are diagnosed at later stage, because of few treatment options, the prognosis is poor. In recent years, however, Immune checkpoint inhibitors(ICIs), such as anti- programmed death-1 (PD-1), anti-PD-L1, and anti-cytotoxic T lymphocyte antigen 4, have emerged as promising therapeutic agents in GC. Here, we summary the current treatment and advances of immune checkpoint inhibitors in the advanced stage of GC.

METHODS

WANFANG MED ONLINE, CNKI, NCBI PUBMED and clinicaltrials.gov were used to search literature spanning from 2000 to 2021, and all literatures about "advanced gastric or gastro-oesophageal junction cancer, Immune checkpoint inhibitors, PD-1, PD-L1, Cytotoxic T lymphocyte antigen 4, immune therapy" with detailed data were included.

RESULTS

Nivolumab and pembrolizumab have been recommended for the third line or subsequent therapy in advanced GC. Nivolumab plus chemotherapy has been recommended for the first line treatment in advanced GC in China. Many other ICIs have been demonstrating encouraging efficacy. PD-L1, MSI-H, Epstein Barr virus, and tumor mutational burden (TMB) status maybe potential biomarkers for response to clinical outcomes for ICIs in GC.

CONCLUSION

ICIs have shown encouraging treatment efficacy and manageable safety profile in GC. Some biomarkers including PD-L1, MSI-H, EBV, and TMB status could evaluate the efficacy of ICIs in GC.

Correlative analysis between cytotoxic T lymphocyte antigen 4 genetic polymorphisms and head and neck cancer susceptibility: A protocol for systematic review and meta-analysis

BACKGROUND

Previous published studies have reported the association of cytotoxic T lymphocyte antigen 4 (CTLA-4) genetic polymorphisms with the susceptibility to head and neck cancer, but the results remain controversial. We therefore will conduct a meta-analysis to investigate the relationship between CTLA-4 genetic polymorphisms and head and neck cancer susceptibility.

METHODS

We will systematically search case-control studies for potential eligible studies from Cochrane Library, EMBASE, Google Scholar, PubMed, China Biomedical Database, WanFang database, and China National Knowledge Infrastructure (CNKI). Additionally, we will also examine other sources to avoid missing potential trials. Two authors will independently collect and perform the study selection, data extraction, and study methodological quality. Statistical analyses were utilized using STATA 12.0 and RevMan 5.3, and the odds ratios (ORs) with 95% confidence intervals (95% CI) were used to estimate the strength of the association of CTLA-4 genetic polymorphisms with the susceptibility to head and neck cancer.

RESULTS

This protocol study will assess the relationship between CTLA-4 genetic polymorphisms and head and neck cancer susceptibility.

CONCLUSION

The findings of this study will provide systematic evidence for future guidance developing and clinical decision making in patients with head and neck cancer.

ETHICS AND DISSEMINATION

Ethical approval will not be required as this study is a systematic review.

PROTOCOL REGISTRATION NUMBER

DOI 10.17605/OSF.IO/BFJTZ (https://osf.io/bfjtz/).

Therapeutic effect of cytotoxic T lymphocyte antigen 4/immunoglobulin on a murine model of primary biliary cirrhosis

Collectively, the data in both humans and murine models of human primary biliary cirrhosis (PBC) suggest that activated T cells, particularly CD8 T cells, play a critical role in biliary cell destruction. Under physiological conditions, T-cell activation involves two critical signals that involve the major histocompatibility complex and a set of costimulatory molecules, which include a receptor on T cells termed cytotoxic T lymphocyte antigen 4 (CTLA-4). Germane to the studies reported herein, signaling by CTLA-4 has the potential to modulate costimulation and induce inhibitory signals. In this study, we have taken advantage of our well-defined murine model of PBC, in which mice are immunized with 2-octynoic acid coupled to bovine serum albumin (2OA-BSA), leading to the production of high-titer antimitochondrial autoantibodies (AMAs) and portal cellular infiltrates. To investigate the potential of CTLA-4-Ig (immunoglobulin) as an immunotherapeutic agent, we treated mice both before and after induction of autoimmune cholangitis. First, we demonstrate that CTLA-4-Ig treatment, begun 1 day before 2OA-BSA immunization, completely inhibits the manifestations of cholangitis, including AMA production, intrahepatic T-cell infiltrates, and bile duct damage. However, and more critically, treatment with CTLA-4-Ig, initiated after the development of autoimmune cholangitis in previously immunized mice, also resulted in significant therapeutic benefit, including reduced intrahepatic T-cell infiltrates and biliary cell damage, although AMA levels were not altered.

CONCLUSION

These data suggest that an optimized regimen with CTLA-4-Ig has the potential to serve as an investigative therapeutic tool in patients with PBC.

Polymorphisms in the T cell regulatory gene cytotoxic T lymphocyte antigen 4 influence the rate of acute rejection after liver transplantation

BACKGROUND

The cytotoxic T lymphocyte antigen 4 (CTLA-4) gene encodes for a membrane bound (mCTLA-4) and a soluble (sCTLA-4) isoform, which are both involved in regulation of T cell function. The CTLA-4 +49A/G single nucleotide polymorphism (SNP) influences expression of mCTLA-4; +6230G/A SNP affects the production of sCTLA-4.

AIM

To examine whether these functional SNPs influence the rate of rejection after liver transplantation.

PATIENTS AND METHODS

Liver graft recipients (n = 483) were genotyped for both SNPs, and haplotypes were reconstructed. Association with rejection was tested by the log rank test using the Kaplan-Meier method with time to the first acute rejection episode as outcome. Multiple analysis of SNPs together with demographic factors was performed by Cox regression.

RESULTS

Three haplotypes were observed in the cohort: +49A/+6230A, +49A/+6230G, and +49G/+6230G. The +49A/+6230G haplotype was significantly and dose dependently associated with acute rejection (p = 0.01). Of the demographic factors tested, only underlying liver disease was significantly associated with rejection. Adjusted for underlying liver disease, each additional +49A/+6230G haplotype allele resulted in a significantly higher risk of acute rejection (risk ratio 1.34 (95% confidence interval 1.04-1.72); p = 0.02). Patients who lacked this haplotype had the lowest, carriers an intermediate, and homozygotes the highest risk of acute rejection.

CONCLUSION

The CTLA-4 +49A/+6230G haplotype, which encodes for normal mCTLA-4 expression but reduced sCTLA-4 production, is a co-dominant risk allele for acute rejection after clinical liver transplantation. This implies that even under immunosuppression, CTLA-4 is critically involved in the regulation of the human immune response to allogeneic grafts.

B7-1 engagement of cytotoxic T lymphocyte antigen 4 inhibits T cell activation in the absence of CD28

Ligation of cytotoxic T lymphocyte antigen 4 (CTLA4) appears to inhibit T cell responses. Four mechanisms have been proposed to explain the inhibitory activity of CTLA4: competition for B7-1 and B7-2 binding by CD28; sequestration of signaling molecules away from CD28 via endocytosis; delivery of a signal that antagonizes a CD28 signal; and delivery of a signal that antagonizes a T cell receptor (TCR) signal. As three of these potential mechanisms involve functional antagonism of CD28, an experimental model was designed to determine whether CTLA4 could inhibit T cell function in the absence of CD28. TCR transgenic/recombinase activating gene 2-deficient/CD28-wild-type or CD28-deficient mice were generated and immunized with an antigen-expressing tumor. Primed T cells from both types of mice produced cytokines and proliferated in response to stimulator cells lacking B7 expression. However, whereas the response of CD28+/+ T cells was augmented by costimulation with B7-1, the response of the CD28-/- T cells was strongly inhibited. This inhibition was reversed by monoclonal antibody against B7-1 or CTLA4. Thus, CTLA4 can potently inhibit T cell activation in the absence of CD28, indicating that antagonism of a TCR-mediated signal is sufficient to explain the inhibitory effect of CTLA4.

Cytotoxic T lymphocyte antigen 4 (CTLA4) blockade accelerates the acute rejection of cardiac allografts in CD28-deficient mice: CTLA4 can function independently of CD28

Cytotoxic T lymphocyte antigen 4 (CTLA4) appears to negatively regulate T cell activation. One mechanism by which CTLA4 might antagonize T cell function is through inhibition of CD28 signaling by competing for their shared ligands B7-1 and B7-2. In addition, CTLA4 ligation could initiate a signaling cascade that inhibits T cell activation. To address whether CTLA4 could inhibit immune responses in the absence of CD28, rejection of heart allografts was studied in CD28-deficient mice. H-2(q) hearts were transplanted into allogeneic wild-type or CD28-deficient mice (H-2(b)). Graft rejection was delayed in CD28-deficient compared with wild-type mice. Treatment of wild-type recipients with CTLA4-immunoglobulin (Ig), or with anti-B7-1 plus anti-B7-2 mAbs significantly prolonged allograft survival. In contrast, treatment of CD28-deficient mice with CTLA4-Ig, anti-B7-1 plus anti-B7-2 mAbs, or a blocking anti-CTLA4 mAb induced acceleration of allograft rejection. This increased rate of graft rejection was associated with more severe mononuclear cell infiltration and enhanced levels of IFN-gamma and IL-6 transcripts in donor hearts of untreated wild-type and CTLA4-Ig- or anti-CTLA4 mAb-treated CD28-deficient mice. Thus, the negative regulatory role of CTLA4 extends beyond its potential ability to prevent CD28 activation through ligand competition. Even in the absence of CD28, CTLA4 plays an inhibitory role in the regulation of allograft rejection.