Exclusion of PD-1 from the immune synapse: A novel strategy to modulate T cell function.

Targeting immune checkpoint receptors on T cells is a common cancer treatment strategy. Frequently, this is accomplished through antibodies targeting the ligand of inhibitory co-receptors. Blocking the immune checkpoint PD-1 binding to its ligands PD-L1 and PD-L2 prevents downstream signaling and enhances anti-tumor T cell responses. This approach improves cancer patients' outcomes. However, only one-third of the patients respond to these treatments. To better understand the mechanism of anti-PD-1 antibodies, we explored the location of PD-1 within the immune synapse. Surprisingly, we discovered that anti-PD-1 antibodies, besides blocking the interaction between PD-1 and its ligands, also removed PD-1 from the synapse. We demonstrated a correlation between removing PD-1 from the synapse by anti-PD-1 antibodies and the extent of T cell activation. Interestingly, a short version of the anti-PD-1 antibody, F(ab')2, failed to remove PD-1 from the synapse and activate T cells. Using the syngeneic tumor model, we showed a superior anti-tumor effect of the anti-PD-1 antibody over the shorter version of the same antibody. Our data indicate that anti-PD-1 antibodies activate T cells by removing PD-1 from the synapse, and changing the location of PD-1 or other immune receptors within the immune synapse could serve as an alternative, efficient approach to treat cancer.

Inhibition of IL-25/IL-17RA improves immune-related adverse events of checkpoint inhibitors and reveals antitumor activity.

BACKGROUND: Immune checkpoint inhibitors (ICIs) have improved outcomes and extended patient survival in several tumor types. However, ICIs often induce immune-related adverse events (irAEs) that warrant therapy cessation, thereby limiting the overall effectiveness of this class of therapeutic agents. Currently, available therapies used to treat irAEs might also blunt the antitumor activity of the ICI themselves. Therefore, there is an urgent need to identify treatments that have the potential to be administered alongside ICI to optimize their use. METHODS: Using a translationally relevant murine model of anti-PD-1 and anti-CTLA-4 antibodies-induced irAEs, we compared the safety and efficacy of prednisolone, anti-IL-6, anti-TNFɑ, anti-IL-25 (IL-17E), and anti-IL-17RA (the receptor for IL-25) administration to prevent irAEs and to reduce tumor size. RESULTS: While all interventions were adequate to inhibit the onset of irAEs pneumonitis and hepatitis, treatment with anti-IL-25 or anti-IL-17RA antibodies also exerted additional antitumor activity. Mechanistically, IL-25/IL-17RA blockade reduced the number of organ-infiltrating lymphocytes. CONCLUSION: These findings suggest that IL-25/IL-17RA may serve as an additional target when treating ICI-responsive tumors, allowing for better tumor control while suppressing immune-related toxicities.

Exclusion of PD-1 from the immune synapse: a novel strategy to modulate T cell function.

Targeting immune checkpoint receptors on T cells is a common cancer treatment strategy. Frequently, this is accomplished through antibodies targeting the ligand of inhibitory co-receptors. Blocking the immune checkpoint PD-1 binding to its ligands PD-L1 and PD-L2 prevents downstream signaling and enhances anti-tumor T cell responses. This approach improved cancer patients' outcome. However, only one-third of the patients respond to these treatments. To better understand the mechanism of anti-PD-1 antibodies, we explored the location of PD-1 within the immune synapse. Surprisingly, we discovered that anti-PD-1 antibodies, besides blocking the interaction between PD-1 and its ligands, also removed PD-1 from the synapse. We demonstrated a correlation between removing PD-1 from the synapse by anti-PD-1 antibodies and the extent of T cell activation. Interestingly, a short version of the anti-PD-1 antibody, F(ab') 2 , failed to remove PD-1 from the synapse and activate T cells. Using syngeneic tumor model, we showed a superior anti-tumor effect to anti-PD-1 antibody over the shorter version of the antibody. Our data indicates that anti-PD-1 antibodies activate T cells by removing PD-1 away from the synapse and changing the location of PD-1 or other immune receptors within immune synapse could serve as an alternative, efficient approach to treat cancer.

A de novo 921 Kb microdeletion at 11q13.1 including neurexin 2 in a boy with developmental delay, deficits in speech and language without autistic behaviors.

Microdeletions at 11q13.1 are very rare. At present only two patients with 11q13.1 deletion involving neurexin 2 (NRXN2) have been reported. Both patients exhibited autistic features, which supported the role of NRXN2 in autism pathogenicity. It is currently unknown whether heterozygous deletion of NRXN2 is of high penetrance or if it is sufficient to result in autism behaviors. Here we reported a 2-year-9-month old boy with developmental delay, short stature, significant language delay and other congenital anomalies. In contrast to previously reported cases, the boy did not present with autistic behaviors and did not meet the clinical diagnosis of autism. A de novo 921 kb microdeletion at 11q13.1 was detected by chromosomal microarray analysis (CMA). Whole Exome Sequencing (WES) was also employed for our patient. The deletion was confirmed and no additional pathogenic variants were detected. We compared our patient's genomic information and clinical features with those of two previously reported individuals. Three patients shared similar deleted intervals and had similar clinical features except for autistic behaviors. This study suggested that NRXN2 gene had incomplete penetrance for autistic behavioral phenotype. The finding is of interest for genetic counseling and clinical management to patients with NRXN2 defects.

A de novo 1.6Mb microdeletion at 19q13.2 in a boy with Diamond-Blackfan anemia, global developmental delay and multiple congenital anomalies.

BACKGROUD: Microdeletions at 19q13.2 are very rare. Only two cases have been previously described. Here we report a 2-year-2-month old boy with Diamond-Blackfan anemia, global developmental delay, cognitive impairments, distinctive facial features, behavior problems, skeletal and genital dysplasia. CASE PRESENTATION: A de novo 1.6 Mb microdeletion at 19q13.2q13.31 was detected by chromosomal microarray analysis. Haploinsufficiency of the RPS19 gene is known to cause Diamond-Blackfan anemia, other features in this patient are likely due to the deletion of other candidate genes such as PAFAH1B3, ERF, LIPE and GSK3A. CONCLUSION: The deletion detected in our patient overlapped and was significantly smaller than the ones previously reported, which offered the opportunity to further define the critical region for this proposed contiguous gene deletion syndrome.

FGFR3 gene mutation plus GRB10 gene duplication in a patient with achondroplasia plus growth delay with prenatal onset.

BACKGROUND: Achondroplasia is a well-defined and common bone dysplasia. Genotype- and phenotype-level correlations have been found between the clinical symptoms of achondroplasia and achondroplasia-specific FGFR3 mutations. RESULT: A 2-year-old boy with clinical features consistent with achondroplasia and Silver-Russell syndrome-like symptoms was found to carry a mutation in the fibroblast growth factor receptor-3 (FGFR3) gene at c.1138G > A (p.Gly380Arg) and a de novo 574 kb duplication at chromosome 7p12.1 that involved the entire growth-factor receptor bound protein 10 (GRB10) gene. Using quantitative real-time PCR analysis, GRB10 was over-expressed, and, using enzyme-linked immunosorbent assays for IGF1 and IGF-binding protein-3 (IGFBP3), we found that IGF1 and IGFBP3 were low-expressed in this patient. CONCLUSIONS: We demonstrate that a combination of uncommon, rare and exceptional molecular defects related to the molecular bases of particular birth defects can be analyzed and diagnosed to potentially explain the observed variability in the combination of molecular defects.

Paternal Uniparental Disomy of Chromosome 14 with Hypospadias.

Paternal uniparental disomy 14 (patUPD14) is a distinct, clinically recognizable syndrome. Using a clinical SNP microarray, we identified patUPD14 in a boy with a normal karyotype presenting cardiomyopathy and facial anomalies, a specific configuration of the thoracic ribs ('coat hanger sign'), and hypospadias. Analyses of polymorphic microsatellites confirmed the diagnosis of patUPD14. We discuss the functions of the genes included in the rearrangement and their involvement in the pathogenesis of these disorders, especially hypospadias. ESR2 single nucleotide polymorphisms (rs944050; 2681-4A>G) have been associated with an increased risk of hypospadias in previous studies. The patient's ESR2 (rs944050) genotype is GG, whereas the parents both exhibit an AG genotype. This report sheds light on the genetic phenomenon in which the combination of a polymorphism and UPD can lead to new phenotypes, such as hypospadias.