Lack of an association of PD-1 and its ligand genes with Behcet's disease in a Chinese Han population

The potential for immune checkpoint modulators in cerebrovascular injury and inflammation

Introduction: Neuroinflammation has been linked to poor neurologic and functional outcomes in many cerebrovascular disorders. Immune checkpoints are upregulated in the setting of traumatic brain injury, intracerebral hemorrhage, ischemic stroke, central nervous systems vasculitis, and post-hemorrhagic vasospasm, and are potential mediators of pathologic inflammation. Burgeoning evidence suggests that immune checkpoint modulation is a promising treatment strategy to decrease immune cell recruitment, cytokine secretion, brain edema, and neurodegeneration.Areas covered: This review discusses the role of immune checkpoints in neuroinflammation, and the potential for therapeutic immune checkpoint modulation in inflammatory cerebrovascular disorders. A search of Pubmed and clinicaltrials.gov was performed to find relevant literature published within the last 50 years.Expert opinion: The clinical success of immune-activating checkpoint modulators in human cancers has shown the immense clinical potential of checkpoint-based immunotherapy. Given that checkpoint blockade can also precipitate a pathologic pro-inflammatory or autoimmune response, it is plausible that these pathways may also be targeted to quell aberrant inflammation. A limited but growing number of studies suggest that immune checkpoints play a critical role in regulating the immune response in the central nervous system in a variety of contexts, and that immune-deactivating checkpoint modulators may be a promising treatment strategy for acute and chronic neuroinflammation in cerebrovascular disorders.

Delicate Role of PD-L1/PD-1 Axis in Blood Vessel Inflammatory Diseases: Current Insight and Future Significance

Immune checkpoint molecules are the antigen-independent generator of secondary signals that aid in maintaining the homeostasis of the immune system. The programmed death ligand-1 (PD-L1)/PD-1 axis is one among the most extensively studied immune-inhibitory checkpoint molecules, which delivers a negative signal for T cell activation by binding to the PD-1 receptor. The general attributes of PD-L1's immune-suppressive qualities and novel mechanisms on the barrier functions of vascular endothelium to regulate blood vessel-related inflammatory diseases are concisely reviewed. Though targeting the PD-1/PD-L1 axis has received immense recognition-the Nobel Prize in clinical oncology was awarded in the year 2018 for this discovery-the use of therapeutic modulating strategies for the PD-L1/PD-1 pathway in chronic inflammatory blood vessel diseases is still limited to experimental models. However, studies using clinical specimens that support the role of PD-1 and PD-L1 in patients with underlying atherosclerosis are also detailed. Of note, delicate balances in the expression levels of PD-L1 that are needed to preserve T cell immunity and to curtail acute as well as chronic infections in underlying blood vessel diseases are discussed. A significant link exists between altered lipid and glucose metabolism in different cells and the expression of PD-1/PD-L1 molecules, and its possible implications on vascular inflammation are justified. This review summarizes the most recent insights concerning the role of the PD-L1/PD-1 axis in vascular inflammation and, in addition, provides an overview exploring the novel therapeutic approaches and challenges of manipulating these immune checkpoint proteins, PD-1 and PD-L1, for suppressing blood vessel inflammation.

The PD-1/PD-L pathway in rheumatic diseases

BACKGROUND/PURPOSE

Autoimmune diseases are diseases in which the body produces an abnormal immune response to self-antigens and damages its own tissues. Programmed death-1 (PD-1) and its ligands (PD-Ls) have been discovered to be important negative regulators of the immune system, playing crucial roles in autoimmunity.

METHODS

We analyzed the existing scientific literature dealing with this issue. In this review, the PD-1/PD-L pathway in the genetic susceptibility to and pathogenesis of rheumatic diseases is discussed. The PD-1/PD-L pathway might be helpful for diagnosing, evaluating the disease activity of and treating rheumatic diseases.

RESULTS

PD-1/PD-L gene polymorphisms are associated with a genetic predisposition to rheumatic disorders, which can provide reference information for diagnosis and disease activity. The conclusion of the crucial role of the PD-1/PD-L pathway in the pathogenesis of rheumatic diseases is consistent, but the details remain controversial. In some animal models, manipulating the PD-1/PD-L pathway could decrease disease severity. PD-1/PD-Ls may enable us to develop new therapeutics for patients with rheumatic diseases in the future.

CONCLUSION

The PD-1/PD-L pathway plays crucial roles in rheumatic disease. More work is needed to provide a better mechanistic understanding of the PD-1/PD-L pathway and to facilitate the precise therapeutic manipulation of this pathway.

Exploring the role of programmed cell death protein 1 and its ligand 1 in eye diseases

Programmed death receptor-1 (PD-1) and its ligand, PD-L1, as negative co-stimulatory molecules, are indispensable for regulating both physiological and pathological immune responses. The PD-1/PD-L1-mediated signaling pathway has been studied extensively in cancer research and has become a hotspot for biopharmaceuticals and immunotherapy. Furthermore, monoclonal antibodies to PD-1 have just been approved by the US Food and Drug Administration to treat certain types of malignancies. Recent research has unveiled a close association between the PD-1/PD-L1 system and eye diseases. This review describes the expression and physiological functions of PD-1 and its ligand in ocular tissues and summarizes the pathogenic, regulatory, and therapeutic roles of PD-1/PD-L1 system in eye diseases, including uveal melanoma, autoimmune uveitis, autoimmune dry eye, sympathetic ophthalmia, Graves' ophthalmopathy, diabetic retinopathy, herpes simplex keratitis, and trachoma, with the intent of highlighting the potential of PD-1/PD-L1 as novel therapeutic targets or biomarkers for these ocular diseases.

PD-1 Polymorphisms Are Associated with Susceptibility of Acute Anterior Uveitis in Chinese Population

Acute anterior uveitis (AAU) is an ordinary type of uveitis, which is an autoimmune disease produced by T cells. Programmed apoptosis protein 1 (PD-1) is a vital negative regulatory protein of immune tolerance. We detect the single nucleotide polymorphisms (SNPs) rs41386349, rs10204525, and rs2227982 of PD-1 to investigate the correlation between PD-1 polymorphisms and AAU. A total of 166 AAU patients and 263 controls were recruited in this case-control study. Compared with controls, the frequencies of the GG genotypes were higher in rs10204525 in AAU patients (p = 0.012). There were obvious increases in frequencies of the TT genotypes in rs2227982 and the GG genotypes in rs10204525 in human leukocyte antigen (HLA)-B27-negative AAU patients compared with controls (p = 0.03; p = 0.015, respectively). There were also increases in frequencies of TT genotypes in rs2227982 and the GG genotypes in rs10204525 in the patients without ankylosing spondylitis (AS) when compared with controls (p = 0.021; p = 0.003, respectively). Furthermore, the frequencies of TT genotypes in rs2227982 were higher in female patients diagnosed with AAU than with control group (p = 0.033). Our results showed that SNPs rs2227982 and rs10204525 were interrelated to AAU; the influence on AAU could be related with gender, HLA-B27, and AS status.

Vasculitis associated with immune checkpoint inhibitors-a systematic review

Recent experimental and genetic studies have implicated the role of programmed cell death protein 1 (PD-1), programmed cell death protein-ligand 1 (PDL-1), and cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) in the pathogenesis of medium and large vessel vasculitis. This study sought to evaluate the occurrence and nature of vasculitis associated with cancer treatment using immune checkpoint inhibition (anti-PD-1, anti-PDL-1, and anti-CTLA4). A systematic review of the medical literature was conducted by searching all available clinical data up to February 2018 in several databases and search engines including Cochrane Library, Embase, Google Scholar, Medline, Scopus, Web of Science, and Clinicaltrials.gov . Searches included the following FDA-approved anti-PD1 (nivolumab and pembrolizumab), anti-PDL1 (atezolizumab, avelumab, and durvalumab), and anti-CTLA4 (ipilimumab). The vasculitis cases were compiled and classified based on the 2012 revised Chapel Hill Consensus Conference nomenclature. The clinical feature of the vasculitis cases and their relationship to immune checkpoint inhibition was assessed. There were 53 cases of vasculitis of which 20 were confirmed. The main reported type of vasculitis was large vessel vasculitis and vasculitis of the central and peripheral nervous system. All cases resolved with either holding the immune checkpoint inhibitors and/or administering glucocorticoids. No death related to vasculitis was reported. Vasculitis, namely large vessel and vasculitis of the nervous system, is associated with immune checkpoint inhibition. Results of this study add to the growing evidence regarding the relationship between immune checkpoints and vasculitis and suggest that the pathway may be a therapeutic target.

Investigation of the role of interleukin-1 receptor antagonist VNTR variant on the Behçet's disease

Objective

Behçet's disease (BD), a chronic multisystem inflammatory disorder, is mainly characterized by relapsing periods of a wide range of clinical symptoms. Several cytokine genes may play important roles in the pathogenesis of BD. Therefore, interleukin-1 receptor antagonist (IL-1Ra) gene 86bp variable number tandem repeat (VNTR) variant was investigated in patients with BD in a Turkish population.

Methods

One hundred nine patients (60 females, 49 males; the mean age±standard deviation [SD] was 36.56±9.571 years) with BD and one hundred healthy individuals (54 females, 46 males; the mean age±SD was 36.64±2.294 years) were examined in the study. For genotyping, polymerase chain reaction-restriction fragment length polymorphism analysis was employed. Data were analyzed using Statistical Package for Social Sciences (SPSS) 22.0 (IBM Corp.; Armonk, NY, USA) (p<0.05).

Results

The genotype distribution and allele frequencies of the IL-1Ra VNTR variant did not differ significantly between the patients and the controls (p>0.05). The frequency of the a1/a1, a1/a2 genotypes and a1, a2 alleles were the most common both in patients and healthy controls (p=0.37, p=0.26, and p=0.53, respectively). Also, no statistically significant difference was found between the IL-1Ra VNTR variant genotypes and clinical characteristics (p>0.05).

Conclusion

The results of this study do not support an association between the IL-1Ra VNTR variant and the risk of BD in a Turkish population. However, further studies of this variant with larger sample sizes and different ethnicities are required for confirmation.

PD-L1 gene polymorphisms and low serum level of PD-L1 protein are associated to type 1 diabetes in Chile

INTRODUCTION

Type 1 diabetes (T1D) has a complex etiology in which genetic and environmental factors are involved, whose interactions have not yet been completely clarified. In this context, the role in PD-1 pathway and its ligands 1 and 2 (PD-L1 and PD-L2) have been proposed as candidates in several autoimmune diseases. The aim of this work was to determine the allele and haplotype frequency of six gene polymorphisms of PD-ligands (PD-L1 and PD-L2) in Chilean T1D patients and their effect on serum levels of PD-L1 and autoantibody profile (GAD65 and IA2).

METHODS

This study cohort comprised 205 T1D patients and 205 normal children. We performed genotypic analysis of PD-L1 and PD-L2 genes by TaqMan method. Determination of anti-GAD65 and anti-IA-2 autoantibodies was performed by ELISA. The PD-L1 serum levels were measured.

RESULTS

The allelic distribution of PD-L1 variants (rs2297137 and rs4143815) showed differences between T1D patients and controls (p = 0.035 and p = 0.022, respectively). No differences were detected among the PD-L2 polymorphisms, and only the rs16923189 showed genetic variation. T1D patients showed decreased serum levels of PD-L1 compared to controls: 1.42 [0.23-7.45] ng/mL versus 3.35 [0.49-5.89] ng/mL (p < 0.025). In addition, the CGG haplotype in PD-L1 associated with T1D (constructed from rs822342, rs2297137 and rs4143815 polymorphisms) showed an OR = 1.44 [1.08 to 1.93]. Finally, no association of these genetic variants was observed with serum concentrations of PD ligands or auto-antibody profile, although a correlation between PD-L1 ligand serum concentration and the age at disease onset was detected.

CONCLUSION

Two polymorphism of PD-L1 are presented in different allelic variants between T1D and healthy subjects, also PDL-1 serum levels are significantly lowered in diabetics patients. Moreover, the age of onset of the disease determine differences between serum ligand levels in diabetics, being lower in younger. These results points to a possible establishment of PDL-1 as a genetic and biochemical marker for T1D onset, at least in Chilean population.

The roles of genetic factors in uveitis and their clinical significance

BACKGROUND

Uveitis is a diverse group of intraocular inflammatory disease and is a significant cause of visual loss worldwide. Recent studies have identified various endogenous immune mechanisms and genetic factors that are involved in the pathogenesis of uveitis. This review provides an overview on the role of genetics in the development and clinical course of uveitis.

METHODS

PUBMED was used for literature search, and articles published from 1970 to 2012 that evaluated the genetic associations and mechanisms involved in the development and clinical features of uveitis were included.

RESULTS

Studies have demonstrated associations between various genetic factors and the development and clinical course of intraocular inflammatory conditions. Genes involved included genes expressing interleukins, chemokines, chemokine receptors, and tumor necrosis factor and genes involved in complement system, oxidation, and other intracellular molecular pathways.

CONCLUSION

Multiple genetic factors play important roles in the pathogenesis of uveitis and may influence the clinical course of uveitis. Further studies to investigate the genetic mechanisms of uveitis might identify additional genetic associations and might have the potential for identifying novel therapeutic targets in the treatment of intraocular inflammation.