Using cfRNA as a tool to evaluate clinical treatment outcomes in patients with metastatic lung cancers and other tumors.

Aim: We report an exploratory analysis of cfRNA as a biomarker to monitor clinical responses in non-small cell lung cancer (NSCLC), breast cancer, and colorectal cancer (CRC). An analysis of cfRNA as a method for measuring PD-L1 expression with comparison to clinical responses was also performed in the NSCLC cohort. Methods: Blood samples were collected from 127 patients with metastatic disease that were undergoing therapy, 52 with NSCLC, 50 with breast cancer, and 25 with CRC. cfRNA was purified from fractionated plasma, and following reverse transcription (RT), total cfRNA and gene expression of PD-L1were analyzed by real-time polymerase chain reaction (qPCR) using beta-actin expression as a surrogate for relative amounts of cfDNA and cfRNA. For the concordance study of liquid biopsies and tissue biopsies, the isolated RNA was analyzed by RNAseq for the expressions of 13 genes. We had to close the study early due to a lack of follow-up during the Covid-19 pandemic. Results: We collected a total of 373 blood samples. Mean cfRNA PCR signals after RT were about 50-fold higher than those of cfDNA. cfRNA was detected in all patients, while cfDNA was detected in 88% of them. A high concordance was found for the expression levels of 13 genes between blood and solid tumor tissue. Changes in cfRNA levels followed over the course of treatments were associated with response to therapy, increasing in progressive disease (PD) and falling when a partial response (PR) occurred. The expression of PD-L1 over time in patients treated with immunotherapy decreased with PR but increased with PD. Pre-treatment levels of PD-L1 were predictive of response in patients treated with immunotherapy. Conclusion: Changes in cfRNA correlate with clinical response to the therapy. Total cfRNA may be useful in predicting clinical outcomes. PD-L1 gene expression may provide a biomarker to predict response to PD-L1 inhibition.

Trastuzumab deruxtecan (T-DXd) + durvalumab (D) as first-line (1L) treatment for unresectable locally advanced/metastatic hormone receptor-negative (HR-), HER2-low breast cancer: updated results from BEGONIA, a phase 1b/2 study

Background: Patients with HR- advanced/metastatic breast cancer (a/mBC) with a low level of HER2 (immunohistochemistry [IHC] score 1+ or IHC 2+ and negative in situ hybridization [ISH]) have poor prognosis. Combining 1L chemotherapy with immune checkpoint inhibitors can modestly improve outcomes vs chemotherapy alone, but treatment benefit is largely seen in patients with PD-L1+ disease. BEGONIA (NCT03742102) is an ongoing 2-part, open-label platform study, evaluating safety and efficacy of D, an anti-PD-L1 antibody, combined with other novel therapies in 1L triple-negative a/mBC, including HR-, HER2-low disease. T-DXd is a trastuzumab-topoisomerase I inhibitor antibody-drug conjugate that improves survival in patients with previously treated HR-, HER2-low mBC (NCT03734029;Modi NEJM 2022). Here, we report updated results of the T-DXd + D combination from BEGONIA. Method(s): Patients with unresectable HR-, HER2-low (per local testing, IHC 2+/ISH-, IHC 1+/ISH-, or IHC 1+/ISH untested) a/mBC were enrolled in the T-DXd + D arm. Patients eligible for 1L treatment, regardless of PD-L1 status, received intravenous T-DXd 5.4 mg/kg + D 1120 mg every 3 weeks until progression or unacceptable toxicity. PD-L1, assessed using the VENTANA PD-L1 (SP263) Assay, was defined as high if >= 5% of the tumor area was populated by PDL1-expressing tumor or immune cells. Primary endpoints were safety and tolerability. Secondary endpoints included investigator-assessed objective response rate (ORR;RECIST v1.1);progressionfree survival [PFS];and response duration. Patients included in the efficacy analysis had >= 2 ontreatment disease assessments, progressed, died, or withdrew from the study. Result(s): As of April 8, 2022, 56 patients received T-DXd + D (34 ongoing) and 46 were included in the efficacy analysis. Median (range) follow-up was 10.1 (0-22) months. Median age was 53.5 years, 71% had received prior treatment for early stage BC, and 64% had visceral metastases at baseline. Confirmed ORR was 26/46 (57% 95% CI, 41-71) and unconfirmed ORR was 33/54 (61% 95% CI, 47-74);1/46 patients (2%) had complete and 25/46 (54%) had partial responses. Confirmed response occurred irrespective of PD-L1 expression (PD-L1 high ORR, 5/7 [71%];PD-L1 low, 13/21 [62%];PD-L1 missing, 8/18 [44%]). Median duration of response was not reached;however, 64% of patients remained in response at 12 month follow-up and 73% had an ongoing response at data cutoff. Median PFS was 12.6 months (95% CI, 8-not reached). Adverse events (AEs) were consistent with the agents' known safety, with treatment-related AEs occurring in 49 patients (88%), any Grade 3/4 AEs in 18 patients (32%), and any serious AEs in 10 patients (18%). The most common all-Grade AEs were nausea (41 [73%]), fatigue (26 [46%]), and vomiting (17 [30%]). Adjudicated treatment-related interstitial lung disease/pneumonitis occurred for 5 patients (9%), which were mostly Grade 1 or 2 and 1 case of Grade 5 associated with COVID pneumonia. Seven patients (13%) and 21 patients (38%) had T-DXd dose reduction and dose delay, respectively;22 (39%) had D dose delay. Seven patients (13%) discontinued treatment due to AEs. Conclusion(s): For patients with HR-, HER2-low a/mBC, T-DXd in combination with D in the 1L setting shows manageable safety and promising efficacy including durable responses and an encouraging PFS. Although subgroups were small, responses were observed irrespective of PD-L1 expression. Analysis of additional translational data is ongoing. Funding(s): AstraZeneca/Daiichi Sankyo.

Optimal First-Line Therapy for Metastatic Adenocarcinoma of the Esophagus.

OPINION STATEMENT: Treatment strategies for esophageal adenocarcinoma patients continue to advance with the generation of more data from clinical trials that are permitting us to refine the use of immunotherapy in combination with other treatment modalities. While the frontline therapy for metastatic esophageal adenocarcinoma has become more complicated with the approval of combination regimens, it is also yielding better outcomes. These treatment strategies can now be individualized to fit patient circumstances and goals as well as the biomarker profile of their individual tumors leading to an increased likelihood of treatment related remissions and extended median survivals. Comprehensive genomic profiling at diagnosis should now be standard to allow the management team to customize each patient's treatment plan based on the genetic abnormalities discovered in their tumor. By refining these targeted approaches, we will see decreased toxicities and increased survival.

Atezolizumab for the treatment of advanced recurrent basal cell carcinoma and urothelial carcinoma of bladder: a case report.

BACKGROUND: The use of checkpoint inhibitors has become increasingly important in the treatment of different cancers, including advanced muscle-invasive urothelial cancer and even in basal cell carcinoma. We present the case of a patient with advanced basal cell carcinoma and metastatic muscle-invasive urothelial cancer, who was treated with the programmed death-ligand 1 inhibitor, atezolizumab for both cancers. CASE PRESENTATION: A 72-year-old Caucasian female patient, with a history of smoking without any comorbidities developed periocular basal cell carcinoma, which was surgically removed but relapsed 4 years later. Surgical excision was carried out twice, but with positive margins, therefore definitive radiotherapy was given. Subsequently, the patient developed non-muscle-invasive papillary urothelial carcinoma, which was removed by transurethral resection. Follow-up was irregular owing to the patient's inadequate compliance, and within 2 years, the patient's cancer relapsed and histology confirmed muscle-invasive urothelial carcinoma. Definitive radiochemotherapy was not accepted by the patient. Meanwhile, the patient's basal cell carcinoma had also progressed, despite receiving vismodegib therapy. Therefore, the patient was administered epirubicin-cisplatin. Having reached the maximum cumulative dose of epirubicin, treatment with this chemotherapeutic agent could not be continued. The patient developed bladder cancer metastasis in her left suprainguinal lymph nodes. Owing to the presence of both types of tumors, programmed death-ligand 1 inhibitor atezolizumab treatment was chosen. In just over 1 year, the patient received 17 cycles of atezolizumab altogether, which was tolerated well without any adverse or side effects. Follow-up imaging scans indicated complete remission of the metastatic bladder cancer and stable disease of the basal cell carcinoma. The patient subsequently passed away in hospital due to a complication of COVID-19 infection. CONCLUSIONS: Our patient attained stable disease in advanced basal cell carcinoma and complete remission in metastatic muscle-invasive urothelial cancer after receiving programmed death-ligand 1 inhibitor, atezolizumab, therapy. To our knowledge, this is the first paper to report the use of programmed death-ligand 1 inhibitor, atezolizumab, as treatment for advanced basal cell carcinoma. This case may also be of interest for clinicians when treating patients with two synchronous cancers.

Upregulation of PD-L1 by SARS-CoV-2 promotes immune evasion.

Patients with severe COVID-19 often suffer from lymphopenia, which is linked to T-cell sequestration, cytokine storm, and mortality. However, it remains largely unknown how severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) induces lymphopenia. Here, we studied the transcriptomic profile and epigenomic alterations involved in cytokine production by SARS-CoV-2-infected cells. We adopted a reverse time-order gene coexpression network approach to analyze time-series RNA-sequencing data, revealing epigenetic modifications at the late stage of viral egress. Furthermore, we identified SARS-CoV-2-activated nuclear factor-κB (NF-κB) and interferon regulatory factor 1 (IRF1) pathways contributing to viral infection and COVID-19 severity through epigenetic analysis of H3K4me3 chromatin immunoprecipitation sequencing. Cross-referencing our transcriptomic and epigenomic data sets revealed that coupling NF-κB and IRF1 pathways mediate programmed death ligand-1 (PD-L1) immunosuppressive programs. Interestingly, we observed higher PD-L1 expression in Omicron-infected cells than SARS-CoV-2 infected cells. Blocking PD-L1 at an early stage of virally-infected AAV-hACE2 mice significantly recovered lymphocyte counts and lowered inflammatory cytokine levels. Our findings indicate that targeting the SARS-CoV-2-mediated NF-κB and IRF1-PD-L1 axis may represent an alternative strategy to reduce COVID-19 severity.

Digital Pathology Training Effectiveness for the Evaluation of Pd-L1 Expression in Multiple Tumor Indications

Background In-person pathologist trainings during the COVID- 19 pandemic became impossible, necessitating a shift to remote-digital whole slide image (WSI) training. High concordance between WSI and glass slide scores from the same specimens stained with PD-L1 IHC 22C3 pharmDx (SK006) across multiple tumor indications supported the validity of digital training.1 However, in-person microscope (glass-slide) training versus remote-digital (WSI) training effectiveness must be assessed. Collated testing data on specimens (SK006 stained) spanning multiple indications scored by external pathologists during Agilent led training and testing (T&T) sessions via glass slides were compared to sessions utilizing WSIs. Methods Stained slides (30 unique specimens per tumor indication) were scanned on an Aperio AT2 scanner to generate WSIs for digital T&T. Remote T&T sessions used WebEx and PathcoreScholar's online platform to discuss scoring guidelines and WSI training cases. Subsequently, external pathologists evaluated WSIs in PathcoreScholar for PD-L1 expression using either Tumor Proportion Score (TPS) or Combined Positive Score (CPS) scoring algorithms and interpreted these scores at predefined cutoffs (figure 1). In both glass and WSI scoring test modalities, passing is defined as inter and intra-observer overall agreement (OA) >=85%. Training effectiveness pass rates from glass slide data (2018-2020) and WSI data (2021- 2022) spanning multiple indications and scoring algorithms were calculated and then compared using the Fisher-Freeman- Halton test, with a significance threshold of 0.05. Only data from initial pathologist tests were included in the pass rate calculation;data from re-tests executed after initial test failure were excluded. Results The differences between pass rates for microscope (glass slide) and digital (WSI) testing were not statistically significant (p-value > 0.05) (tables 1 and 2). Testing pass rates for indications scored with TPS or CPS using microscope glass slide vs digital WSI T&T was not statistically significant (pvalue > 0.05) (table 3). Conclusions No statistically significant differences in pathologist training effectiveness for PD-L1 were observed between remote and in-person trainings across multiple tumor indications, scoring algorithms, and cutoffs. These results demonstrate the effectiveness and equivalency of remote-digital pathologist trainings for evaluation of PD-L1 expression as detected by PD-L1 IHC 22C3 pharmDx in multiple tumor indications when compared to in-person-microscope glass slide T&T. Use of digital training and scoring proficiency testing can provide pathologists around the world with access to high-quality, interactive training from leading experts in PD-L1 expression evaluation.

Immunotherapeutic strategies to induce inflection in the immune response: therapy for cancer and COVID-19.

Cancer has agonized the human race for millions of years. The present decade witnesses biological therapeutics to combat cancer effectively. Cancer Immunotherapy involves the use of therapeutics for manipulation of the immune system by immune agents like cytokines, vaccines, and transfection agents. Recently, this therapeutic approach has got vast attention due to the current pandemic COVID-19 and has been very effective. Concerning cancer, immunotherapy is based on the activation of the host's antitumor response by enhancing effector cell number and the production of soluble mediators, thereby reducing the host's suppressor mechanisms by induction of a tumour killing environment and by modulating immune checkpoints. In the present era, immunotherapies have gained traction and momentum as a pedestal of cancer treatment, improving the prognosis of many patients with a wide variety of haematological and solid malignancies. Food supplements, natural immunomodulatory drugs, and phytochemicals, with recent developments, have shown positive trends in cancer treatment by improving the immune system. The current review presents the systematic studies on major immunotherapeutics and their development for the effective treatment of cancers as well as in COVID-19. The focus of the review is to highlight comparative analytics of existing and novel immunotherapies in cancers, concerning immunomodulatory drugs and natural immunosuppressants, including immunotherapy in COVID-19 patients.

Role of the PD-1 and PD-L1 axis in COVID-19.

Tweetable abstract Severe COVID-19 patients display dysregulated expression of checkpoint molecules PD-1 and its ligand PD-L1, suggesting that these checkpoint molecules could be considered as prognostic markers and therapeutic targets in severe cases of COVID-19.

Robust Preanalytical Performance of Soluble PD-1, PD-L1 and PD-L2 Assessed by Sensitive ELISAs in Blood.

The interaction between programmed death-1 receptor PD-1 and its ligands PD-L1 and PD-L2 is involved in self-tolerance, immune escape of cancer, cardiovascular diseases, and COVID-19. As blood-based protein markers they bear great potential to improve oncoimmunology research and monitoring of anti-cancer immunotherapy. A variety of preanalytical conditions were tested to assure high quality plasma sample measurements: (i) different time intervals and storage temperatures before and after blood centrifugation; (ii) fresh samples and repeated freeze-thaw-cycles; (iii) different conditions of sample preparation before measurement. Concerning short-term stability, acceptable recoveries for PD-1 between 80 and 120% were obtained when samples were kept up to 24 h at 4 and 25 °C before and after blood centrifugation. Similarly, recoveries for PD-L2 were acceptable for 24 h at 4 °C and 6 h at 25 °C before blood centrifugation and up to 24 h at 4 and 25 °C after centrifugation. Variations for PD-L1 were somewhat higher, however, at very low signal levels. Sample concentrations (ng/mL) were neither affected by the freezing process nor by repeated freeze-thaw cycles with coefficients of variation for PD-1: 9.1%, PD-L1 6.8%, and PD-L2 4.8%. All three biomarkers showed good stability regarding preanalytic conditions of sample handling enabling reliable and reproducible quantification in oncoimmunology research and clinical settings of anti-cancer immunotherapy.

Navigating the cellular landscape in tissue: Recent advances in defining the pathogenesis of human disease.

Over the past decade, our understanding of human diseases has rapidly grown from the rise of single-cell spatial biology. While conventional tissue imaging has focused on visualizing morphological features, the development of multiplex tissue imaging from fluorescence-based methods to DNA- and mass cytometry-based methods has allowed visualization of over 60 markers on a single tissue section. The advancement of spatial biology with a single-cell resolution has enabled the visualization of cell-cell interactions and the tissue microenvironment, a crucial part to understanding the mechanisms underlying pathogenesis. Alongside the development of extensive marker panels which can distinguish distinct cell phenotypes, multiplex tissue imaging has facilitated the analysis of high dimensional data to identify novel biomarkers and therapeutic targets, while considering the spatial context of the cellular environment. This mini-review provides an overview of the recent advancements in multiplex imaging technologies and examines how these methods have been used in exploring pathogenesis and biomarker discovery in cancer, autoimmune and infectious diseases.

A Dramatic Response to Toripalimab With Chemotherapy and Antiangiogenic Agent Followed by Surgery in a Stage IIIB Lung Adenocarcinoma Patient With an Uncommon EGFR Mutation: A Case Report.

Lung cancer patients with high programmed cell death-ligand 1 (PD-L1) expression in tumor cells and epidermal growth factor receptor (EGFR) mutations are rare, but there is no clinical standard for which treatment such patients should receive. Here, we report a 52-year-old male smoker who was diagnosed with stage IIIB lung adenocarcinoma. A rare EGFR G719A mutation was detected in the lymph node samples by next-generation sequencing (NGS), and a high PD-L1 expression was found by immunohistochemistry (IHC). After 10 cycles of induction therapy (toripalimab plus pemetrexed plus nedaplatin plus apatinib), surgery was successfully performed, followed by 2 cycles of consolidation therapy (toripalimab plus pemetrexed) and 4 cycles of maintenance therapy (toripalimab). A progression-free survival (PFS) of 7 months was achieved. In this case, we showed that the programmed cell death protein 1 (PD-1) inhibitor toripalimab plus chemotherapy and apatinib was effective and tolerable in a locally advanced EGFR-mutant non-small cell lung cancer (NSCLC) patient with a positive PD-L1 expression.

Chemokines, soluble PD-L1, and immune cell hyporesponsiveness are distinct features of SARS-CoV-2 critical illness.

Critically ill patients manifest many of the same immune features seen in coronavirus disease 2019 (COVID-19), including both "cytokine storm" and "immune suppression." However, direct comparisons of molecular and cellular profiles between contemporaneously enrolled critically ill patients with and without severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) are limited. We sought to identify immune signatures specifically enriched in critically ill patients with COVID-19 compared with patients without COVID-19. We enrolled a multisite prospective cohort of patients admitted under suspicion for COVID-19, who were then determined to be SARS-CoV-2-positive (n = 204) or -negative (n = 122). SARS-CoV-2-positive patients had higher plasma levels of CXCL10, sPD-L1, IFN-γ, CCL26, C-reactive protein (CRP), and TNF-α relative to SARS-CoV-2-negative patients adjusting for demographics and severity of illness (Bonferroni P value < 0.05). In contrast, the levels of IL-6, IL-8, IL-10, and IL-17A were not significantly different between the two groups. In SARS-CoV-2-positive patients, higher plasma levels of sPD-L1 and TNF-α were associated with fewer ventilator-free days (VFDs) and higher mortality rates (Bonferroni P value < 0.05). Lymphocyte chemoattractants such as CCL17 were associated with more severe respiratory failure in SARS-CoV-2-positive patients, but less severe respiratory failure in SARS-CoV-2-negative patients (P value for interaction < 0.01). Circulating T cells and monocytes from SARS-CoV-2-positive subjects were hyporesponsive to in vitro stimulation compared with SARS-CoV-2-negative subjects. Critically ill SARS-CoV-2-positive patients exhibit an immune signature of high interferon-induced lymphocyte chemoattractants (e.g., CXCL10 and CCL17) and immune cell hyporesponsiveness when directly compared with SARS-CoV-2-negative patients. This suggests a specific role for T-cell migration coupled with an immune-checkpoint regulatory response in COVID-19-related critical illness.

Construction of a Large Size Human Immunoglobulin Heavy Chain Variable (VH) Domain Library, Isolation and Characterization of Novel Human Antibody VH Domains Targeting PD-L1 and CD22.

Phage display is a well-established technology for in vitro selection of monoclonal antibodies (mAb), and more than 12 antibodies isolated from phage displayed libraries of different formats have been approved for therapy. We have constructed a large size (10^11) human antibody VH domain library based on thermo-stable, aggregation-resistant scaffolds. This diversity was obtained by grafting naturally occurring CDR2s and CDR3s from healthy donors with optimized primers into the VH library. This phage-displayed library was used for bio-panning against various antigens. So far, panels of binders have been isolated against different viral and tumor targets, including the SARS-CoV-2 RBD, HIV-1 ENV protein, mesothelin and FLT3. In the present study, we discuss domain library construction, characterize novel VH binders against human CD22 and PD-L1, and define our design process for antibody domain drug conjugation (DDC) as tumoricidal reagents. Our study provides examples for the potential applications of antibody domains derived from library screens in therapeutics and provides key information for large size human antibody domain library construction.

Intermediate Monocytes with PD-L1 and CD62L Expression as a Possible Player in Active SARS-CoV-2 Infection.

Monocytes play a role in viral biology, but little is known about the monocyte subpopulation in the course of COVID-19 disease. The aim of the study was the analysis of classical, intermediate and non-classical monocytes with expression of PD-L1 and CD62L, TIM-3 and CD86 molecules in peripheral blood (PB) to distinguish patients with SARS-CoV-2 infection from convalescent patients. The study group consisted of 55 patients with SARS-CoV-2 infection and 51 convalescent patients. The cells were analyzed by flow cytometry. The number and proportion of monocytes were lower in patients with COVID-19 than convalescent patients. We observed a lower proportion of non-classical monocytes in COVID-19 patients than convalescent ones. There was a higher proportion of PDL-1-positive intermediate monocytes in COVID-19 patients than convalescent ones. We noticed a higher geometric mean fluorescence intensity (GeoMean) of PD-L1 on intermediate monocytes in COVID-19 patients than convalescent patients, and a higher proportion of CD62L-positive monocytes in COVID-19 patients in comparison with convalescent ones. We found a higher GeoMean of CD62L on monocytes in COVID-19 patients than convalescent ones. Assessment of PD-L1- and CD62L-positive monocyte subsets may identify patients with a possible predisposition for rapid recovery. The monitoring of monocyte subsets in PB might be a useful test in COVID-19 patients.

IFN-γ Induces PD-L1 Expression in Primed Human Basophils.

Programmed death-ligand 1 (PD-L1) plays a key role in maintaining immune tolerance and also in immune evasion of cancers and pathogens. Though the identity of stimuli that induce PD-L1 in various human innate cells and their function are relatively well studied, data on the basophils remain scarce. In this study, we have identified one of the factors, such as IFN-γ, that induces PD-L1 expression in human basophils. Interestingly, we found that basophil priming by IL-3 is indispensable for IFN-γ-induced PD-L1 expression in human basophils. However, priming by other cytokines including granulocyte-macrophage colony-stimulating factor (GM-CSF) and thymic stromal lymphopoietin (TSLP) was dispensable. Analyses of a published microarray data set on IL-3-treated basophils indicated that IL-3 enhances IFNGR2, one of the chains of the IFNGR heterodimer complex, and CD274, thus providing a mechanistic insight into the role of IL-3 priming in IFN-γ-induced PD-L1 expression in human basophils.

Vitamin D can reduce severity in COVID-19 through regulation of PD-L1.

COVID-19 is a highly contagious viral infection that has killed millions of people around the world. The most important diagnostic feature of COVID-19 is lymphocyte depletion, particularly the depletion of T cells. In COVID-19 infections, there is a link between destruction of T cells and increased expression of inhibitory immune checkpoint molecules (PD-1/PD-L1) on T cell surfaces. It was shown that PD-1/PD-L1 levels increase in severely COVID-19 infected individuals. Higher proinflammatory cytokine levels cause increased PD-1/PD-L1 expression. In severe COVID-19, higher proinflammatory cytokine levels may increase PD-1/PD-L1. Vitamin-D is an important immune regulator. It is known that the numbers of CD4+ and CD8+ T lymphocytes decrease in vitamin D deficiency while vitamin D supplementation increases CD + 4 lymphocytes. Vitamin D can increase regulatory T cell (Treg) activity. Vitamin D also has a diminishing effect on proinflammatory cytokines. In severe COVID-19 cases, vitamin D supplementation may inhibit the increase of PD-L1 expression through reducing proinflammatory cytokine levels. Thus, vitamin D supplementation could eliminate the suppressive effect of PD-L1 on CD4+ and CD8+ T cells, preventing lymphopenia and reducing disease severity and mortality in patients infected with COVID-19. Besides, vitamin D supplementation can reduce inflammation by increasing Treg activity. The aim of this letter is to discuss the functions of inhibitory immune checkpoint molecules and their effects on dysfunction and depletion of T-cells as well as to explain the possible modulatory effect of vitamin D on these checkpoints and T cells.

Platelets modulate CD4+ T-cell function in COVID-19 through a PD-L1 dependent mechanism.

Severe COVID-19 is associated with a systemic inflammatory response and progressive CD4+ T-cell lymphopenia and dysfunction. We evaluated whether platelets might contribute to CD4+ T-cell dysfunction in COVID-19. We observed a high frequency of CD4+ T cell-platelet aggregates in COVID-19 inpatients that inversely correlated with lymphocyte counts. Platelets from COVID-19 inpatients but not from healthy donors (HD) inhibited the upregulation of CD25 expression and tumour necrosis factor (TNF)-α production by CD4+ T cells. In addition, interferon (IFN)-γ production was increased by platelets from HD but not from COVID-19 inpatients. A high expression of PD-L1 was found in platelets from COVID-19 patients to be inversely correlated with IFN-γ production by activated CD4+ T cells cocultured with platelets. We also found that a PD-L1-blocking antibody significantly restored platelets' ability to stimulate IFN-γ production by CD4+ T cells. Our study suggests that platelets might contribute to disease progression in COVID-19 not only by promoting thrombotic and inflammatory events, but also by affecting CD4+ T cells functionality.

Analysis of the humoral and cellular immune response after a full course of BNT162b2 anti-SARS-CoV-2 vaccine in cancer patients treated with PD-1/PD-L1 inhibitors with or without chemotherapy: an update after 6 months of follow-up.

BACKGROUND: The durability of immunogenicity of SARS-CoV-2 vaccination in cancer patients remains to be elucidated. We prospectively evaluated the immunogenicity of the vaccine in triggering both the humoral and the cell-mediated immune response in cancer patients treated with anti-programmed cell death protein 1/programmed death-ligand 1 with or without chemotherapy 6 months after BNT162b2 vaccine. PATIENTS AND METHODS: In the previous study, 88 patients were enrolled, whereas the analyses below refer to the 60 patients still on immunotherapy at the time of the follow-up. According to previous SARS-CoV-2 exposure, patients were classified as SARS-CoV-2-naive (without previous SARS-CoV-2 exposure) and SARS-CoV-2-experienced (with previous SARS-CoV-2 infection). Neutralizing antibody (NT Ab) titer against the B.1.1 strain and total anti-spike immunoglobulin G concentration were quantified in serum samples. The enzyme-linked immunosorbent spot assay was used for quantification of anti-spike interferon-γ (IFN-γ)-producing cells/106 peripheral blood mononuclear cells. Fifty patients (83.0%) were on immunotherapy alone, whereas 10 patients (7%) were on chemo-immunotherapy. We analyzed separately patients on immunotherapy and patients on chemo-immunotherapy. RESULTS: The median T-cell response at 6 months was significantly lower than that measured at 3 weeks after vaccination [50 interquartile range (IQR) 20-118.8 versus 175 IQR 67.5-371.3 IFN-γ-producing cells/106 peripheral blood mononuclear cells; P < 0.0001]. The median reduction of immunoglobulin G concentration was 88% in SARS-CoV-2-naive subjects and 2.1% in SARS-CoV-2-experienced subjects. SARS-CoV-2 NT Ab titer was maintained in SARS-CoV-2-experienced subjects, whereas a significant decrease was observed in SARS-CoV-2-naive subjects (from median 1 : 160, IQR 1 : 40-1 : 640 to median 1 : 20, IQR 1 : 10-1 : 40; P < 0.0001). A weak correlation was observed between SARS-CoV-2 NT Ab titer and spike-specific IFN-γ-producing cells at both 6 months and 3 weeks after vaccination (r = 0.467; P = 0.0002 and r = 0.428; P = 0.0006, respectively). CONCLUSIONS: Our work highlights a reduction in the immune response in cancer patients, particularly in SARS-CoV-2-naive subjects. Our data support administering a third dose of COVID-19 vaccine to cancer patients treated with programmed cell death protein 1/programmed death-ligand 1 inhibitors.