Staining For CD3 Research Articles

T cell costimulatory blockade ameliorates induction of experimental membranous nephropathy potentially through T-helper 17 cell suppression in the kidney.

Recent advances in membranous nephropathy treatment have focused on B cell depletion, which is incompletely effective, potentially due to persistent autoantibody-producing plasma cells or alternative pathways of injury. T cell costimulatory blockade (cytotoxic-T-lymphocyte-associated antigen 4 (CTLA4)-Ig) to prevent T cell-dependent B cell activation and short-course proteasome inhibition (bortezomib) to deplete plasma cells may represent a complementary form of treatment. Lewis rats were immunized with Fx1A and complete Freund's adjuvant (CFA) to induce experimental membranous nephropathy (Heymann nephritis or HN) and treated with CTLA4-Ig alone or CTLA4-Ig plus a short-course of bortezomib. Serum creatinine, proteinuria, kidney histology, serum anti-Fx1A levels, kidney and spleen messenger RNA expression, and flow cytometry on splenocytes were evaluated at 12 weeks. CTLA4-Ig-treated and CTLA4-Ig plus bortezomib-treated rats had significant and similar reductions in serum creatinine and proteinuria, with less histological kidney injury compared to untreated HN rats. Glomerular IgG deposition was reduced in CTLA4-Ig-treated and CTLA4-Ig plus bortezomib-treated rats compared to untreated HN rats but there were no significant differences in serum anti-Fx1A levels. CTLA4-Ig-treated and CTLA4-Ig plus bortezomib-treated rats exhibited significantly reduced T helper (Th)-17 cell cytokines (interleukin (IL)-6, IL-17, IL-21) and regulatory T cell (Foxp3, TGF-β) expression in the kidney but not the spleen. Immunohistochemical staining of CD4+ and intracellular STAT3+ cells were reduced in CTLA4-Ig plus bortezomib-treated and CTLA4-Ig-treated compared to untreated HN rats. On flow cytometry, CTLA4-Ig reduced B cells and plasma cells but not T cell subsets. CTLA4-Ig ameliorated induction of experimental membranous nephropathy, potentially through suppression of Th17 cells in the kidney and may represent an effective adjunct treatment in membranous nephropathy.

A comprehensive analysis of molecular characteristics of hot and cold tumor of gastric cancer

BackgroundThe advent of immunotherapy has revolutionized the treatment paradigm for gastric cancer (GC), offering unprecedented clinical benefits. However, a detailed molecular characterization of the tumor immune microenvironment in GC is essential to further optimize these therapies and enhance their efficacy.MethodsConsensus clustering was utilized to classify GC patients into distinct immune states, followed by an in-depth analysis of differences in mutation profiles, copy number variations, and DNA methylation patterns. Weighted gene co-expression network analysis (WGCNA) and correlation analysis were applied to identify gene modules underlying the classification of immune “hot” and “cold” tumors. Subsequently, 101 machine learning algorithm combinations were employed to construct a prognostic model based on the identified gene modules. Single-cell analysis was conducted to investigate cellular interactions associated with the immune-determinant gene module. Finally, immunofluorescence staining for CD8, CD45, and CXCR4 was performed on human GC tissue samples.ResultsA total of 1,298 GC patients were included in this comprehensive analysis. For the first time, we identified and characterized immune “hot” and “cold” tumors in GC patients, revealing distinct molecular features associated with these tumor types. Immune “hot” tumor-related genes were identified, and their functional roles were validated through biological behavior analysis. A prognostic signature, termed the hot tumor top regulators (HTTR), was developed using 101 machine learning algorithm combinations. The HTTR signature emerged as an independent prognostic factor, effectively stratifying patients into low- and high-risk groups with significant differences in overall survival. High-risk groups demonstrated strong associations with immune checkpoint regulation, antigen presentation, and inhibitory pathways. Notably, single-cell analysis revealed that HTTR genes were highly active in CD8 + T cells, with the CXCL12-CXCR4 axis playing a critical role in mediating interactions between CD8 + T cells and endothelial cells.ConclusionIn conclusion, the HTTR signature served as a robust prognostic biomarker for GC patients and effectively identified those with immune “hot” tumors. This finding provided valuable insights into the molecular mechanisms of tumor immunity in GC, offering potential avenues for targeted therapeutic interventions.

CD3/CD20/CD45 negative leukemia cutis.

A 56-year-old male presented to the clinic with complaints of multiple skin lesions. A complete blood count (CBC) was not available. No constitutional symptoms were present, and physical examination revealed tender skin lesions of the back, arms, legs, and scalp. A skin punch biopsy showed fragments of skin with extensive lymphoid infiltrates. The initial lymphoma workup by immunohistochemistry demonstrated negative staining for CD45, CD3, and CD20. Additional stains were performed which revealed the atypical lymphoid infiltrate to be positive for PAX5, TdT, CD10, CD34, CD79a, and CD99 and negative for CD4, CD8, Keratin, S100, CD56, CD138, and EMA. These histologic and immunophenotypic findings supported the diagnosis of skin involvement by B-lymphoblastic leukemia/lymphoma (B-ALL/LBL). Consequent peripheral blood and bone marrow biopsy evaluations supported this diagnosis. To avoid misdiagnosis, it is important to remember that B-ALL/LBL can rarely present as a skin lesion and can be negative for the most commonly used lymphoma immunohistochemical markers: CD45, CD3, and CD20. Additionally, skin involvement by B-ALL/LBL, although very uncommon, is most often reported in children or young adults, unlike this unique case occurring in an adult.

A novel approach to digital characterisation of Tertiary Lymphoid Structures in colorectal cancer

IntroductionTertiary Lymphoid Structures (TLS) in cancer tissue are potential sites for the organisation of immune responses to cancer, and correlate positively with improved clinical outcomes for patients including in colorectal cancer (CRC). However it has proven challenging to standardise assessment of TLS due to the highly variable appearances of circumscribed domains of TLS within tissue sections. A recent three-dimensional reconstruction of TLS in CRC tissue showed that TLS are often large, multi-lobular structures, suggesting that assessing TLS across whole sections may be necessary to provide an accurate view of TLS activity in a patient’s tumour.MethodsWe used whole-section scans of multiplexed immunofluorescence images to characterise TLS from 22 subjects with CRC. Multiplexed staining for CD20, CD3, CD8, Foxp3 and Ki-67 enabled us to identify B-cells, CD8+ T-cells, Foxp3– CD4 T-cells, and Foxp3+ CD4 Tcells in all sections, and quantify both the presence of these cell subsets in lymphocytic clusters and their degree of proliferation within those clusters.ResultsIn total we identified 524 lymphocytic clusters with morphology consistent with TLS. TLS domains varied substantially between samples in size, morphology, cellular constituents, count (from 4 to 100), and proportion of total section area they occupied (0.2%-7.8%). We quantified proliferation of B-cells and T-cell subsets within TLS domains across entire sections and compared data to the canonical approach of counting and phenotyping individual TLS domains. The whole-slide approach proved simpler, generating digital summaries that readily identified patients with strikingly different levels of immune activity within their TLS. Strong correlations were observed between the proliferation of B-cells and T-cell subsets. The presence of non-proliferating Foxp3+ CD4 T-cells within TLS showed no correlation with the level of proliferation of other lymphocyte subsets.DiscussionWhole-section digital quantification of immune cell activity within TLS has advantages over canonical approaches, and could accelerate research into correlations between TLS status and clinical outcomes, with potential to enable a standardised assay for clinical use.

Identification of cold tumor induction–related markers in pancreatic cancer and the clinical implication of PCDH7

PurposePancreatic ductal adenocarcinoma (PDAC) is considered a “cold” tumor because the tumor immune microenvironment (TIME) exhibits poor intratumoral T-cell infiltration. This study aimed to identify the marker genes associated with induction of cold TIME in PDAC cells.MethodsWe orthotopically transplanted 10 primary cultures of PDAC derived from KrasG12D/+; Trp53R172H/+; Pdx-1-Cre (KPC) mice into immunocompetent mice and evaluated TIME by immunohistochemistry (IHC) staining of CD8. We divided primary cultures into two groups: cold TIME group with low CD8+ T-cell infiltration and a hot TIME group with high infiltration. RNA sequencing was performed to identify specific genes in the cold TIME group, and single-cell RNA sequencing (scRNA-seq) data was used for validation. IHC was performed to evaluate expressions in human PDAC samples.ResultsWe identified six genes specific in PDAC cells to the cold TIME group by RNA sequencing; these were defined as “cold tumor induction–related genes”. Human PDAC scRNA-seq data revealed that cold tumor induction–related genes were significantly and negatively correlated with the number of CD8+ T-cells (p = 0.0341). These genes included protocadherin 7 (PCDH7). High expression of PCDH7 significantly and negatively correlated with the number of CD8+ T-cells in scRNA-seq (p = 0.0474) and IHC (p = 0.0110) data using human PDAC samples. PCDH7 was an independent factor for poor prognosis in PDAC (overall survival: hazard ratio = 2.07, p = 0.0367).ConclusionPCDH7 is a prognostic marker associated with CD8+ T-cell infiltration for PDAC patients.

Tumor-infiltrating plasma cells are a prognostic factor in penile squamous cell carcinoma.

Penile cancer (PeCa) is a rare disease with poor prognosis in the metastatic stage. Neither effective adjuvant nor palliative therapeutic options are available. Research efforts in this field have so far failed to establish robust predictors of survival. To identify prognostic targets in PeCa, the current project focused on characterizing the tumor microenvironment (TME). A study cohort of 93 men with PeCa was used for the construction of a tissue microarray and immunohistochemical staining for CD3, CD4, CD8, CD20, CD56, CD138, FoxP3, and PD-L1. The quantity and spatial distribution of tumor-infiltrating immune cells were analyzed using digital image analysis. PD-L1 staining of tumor and immune cells was manually scored (combined positivity score (CPS)). T cells, T helper cells, cytotoxic T cells (CTLs), and regulatory T cells were detected in > 90% of PeCa and B cells in 88%, plasma cells in 85%, and NK cells in 23%. Approximately 50% of the PeCa samples were PD-L1 positive. In the univariate survival analysis, high PD-L1 CPS, plasma cells, CTLs, and B cells were significantly associated with favorable overall survival (OS), and the latter two with adverse recurrence-free survival. In multivariate analysis, plasma cells remained a significant factor for favorable OS (p = 0.04). In this study, the immune cells in the TME, especially plasma cells, were favorably associated with patient survival compared to other established prognostic factors in PeCa. Contemporarily, plasma cells have been discussed in the light of contributing to responses to modern immunotherapies. The results of this study support this notion.

Genomic and Transcriptomic Profiling of Digital Papillary Adenocarcinomas Reveals Alterations in MatrixRemodeling and Metabolic Genes.

Digital papillary adenocarcinoma (DPAC) is a rare but aggressive cutaneous malignant sweat gland neoplasm that occurs on acral sites. Despite its clinical significance, the cellular and genetic characteristics of DPAC remain incompletely understood. We conducted a comprehensive genomic and transcriptomic analysis of DPAC (n = 14) using targeted next-generation DNA and RNA sequencing, along with gene expression profiling employing the Nanostring Technologies nCounter IO 360 Panel. Gene expression in DPAC was compared to that in hidradenoma (n = 10). Immunohistochemistry was employed to validate gene expression. Two out of eight DPACs showed fusion gene rearrangements (CRTC3::MAML2 and TRPS1::PLAG1). No uniform mutational signature was detected in DPAC. Comparative gene expression analysis revealed an enrichment of genes related to matrix remodeling, metabolism, and DNA damage repair. Hallmark pathway analysis demonstrated significant upregulation of E2F target genes in DPAC compared to hidradenoma (p = 0.00710). Human papillomavirus-42 was found to be positive in all of our tested DPAC cases. Immunohistochemistry confirmed increased protein expression of CD56, CDC20, and SOX10 in DPAC. Notably, most DPAC tumors also exhibited B-cell infiltration, as indicated by CD20 staining. Our findings reveal novel fusions and validate altered replication pathways related to HPV42 in DPAC.

The relationship between clinical prognostic factors, microvascular density, and tumor-infiltrating lymphocytes with CD47 and SIRPα expression in diffuse large B cell lymphomas.

CD47 interacts with signal regulatory protein alpha (SIRPα) on macrophages to deliver an anti-phagocytic signal, enabling tumor cells to evade immune destruction. This study explores the relationship between CD47 and SIRPα expression and key clinical prognostic factors, microvascular density (MVD), and tumor-infiltrating lymphocytes (TIL) in Diffuse Large B Cell Lymphoma (DLBCL) cases. We analyzed tissue samples from 122 DLBCL cases using tissue microarray (TMA) blocks and immunohistochemical staining for CD47, SIRPα, CD31, and CD3. CD47 expression was scored using the Allred scoring system, and SIRPα expression was quantified based on the percentage of positive membranous and cytoplasmic expression. Clinical data, including IPI scores, relapse rates, and gene expression profiles, were correlated with the immunohistochemical findings.CD47 expression score ≥ 6 was significantly associated with the DLBCL-ABC phenotype (p = 0.029), higher IPI scores (p = 0.020), and increased relapse rates (p = 0.021). High SIRPα expression (≥25 % staining) was also linked to the ABC phenotype (p = 0.022) and frequent relapses (p = 0.021). Notably, cases with high microvascular density exhibited lower SIRPα expression (p = 0.013). There was no significant relationship between MVD and CD47 or other clinical prognostic factors. Additionally, higher CD3-positive TIL percentages were inversely correlated with IPI scores (p = 0.005), although no significant association was found between CD3 and CD47-SIRPα. The study reveals that increased CD47-SIRPα expression is partially linked to adverse prognostic indicators and reduced MVD in DLBCL cases. These findings suggest that targeting the CD47-SIRPα axis could offer a novel therapeutic approach in DLBCL, particularly for patients with poor prognostic features.

Sustained immune activation and impaired epithelial barrier integrity in the ectocervix of women with chronic HIV infection.

Chronic systemic immune activation significantly influences human immunodeficiency virus (HIV) disease progression. Despite evidence of a pro-inflammatory environment in the genital tract of HIV-infected women, comprehensive investigations into cervical tissue from this region remain limited. Similarly, the consequences of chronic HIV infection on the integrity of the female genital epithelium are poorly understood, despite its importance in HIV transmission and replication. Ectocervical biopsies were obtained from HIV-seropositive (n = 14) and HIV-seronegative (n = 47) female Kenyan sex workers. RNA sequencing and bioimage analysis of epithelial junction proteins (E-cadherin, desmoglein-1, claudin-1, and zonula occludens-1) were conducted, along with CD4 staining. RNA sequencing revealed upregulation of immunoregulatory genes in HIV-seropositive women, primarily associated with heightened T cell activity and interferon signaling, which further correlated with plasma viral load. Transcription factor analysis confirmed the upregulation of pro-inflammatory transcription factors, such as RELA, NFKB1, and IKZF3, which facilitates HIV persistence in T cells. Conversely, genes and pathways associated with epithelial barrier function and structure were downregulated in the context of HIV. Digital bioimage analysis corroborated these findings, revealing significant disruption of various epithelial junction proteins in ectocervical tissues of the HIV-seropositive women. Thus, chronic HIV infection associated with ectocervical inflammation, characterized by induced T cell responses and interferon signaling, coupled with epithelial disruption. These alterations may influence HIV transmission and heighten susceptibility to other sexually transmitted infections. These findings prompt exploration of therapeutic interventions to address HIV-related complications and mitigate the risk of sexually transmitted infection transmission.

Abstract A001: Analytical validation of a novel multiomic metastatic breast cancer liquid biopsy test that combines ctDNA analysis with CTC HER2-ultralow and ER co-expression, as well as single-cell chromosomal instability

Abstract Background: Metastatic breast cancer (MBC) subtype characterization is critical for effective treatment. The DefineMBC™ multiomic blood biopsy clinical diagnostic combines ctDNA and circulating tumor cell (CTC) analyses to characterize MBC patients when a tissue biopsy is not feasible. Innovation in the DefineMBC 2.0 5-channel immunofluorescent (IF) CTC characterization assay now measures ultralow (UL) levels of HER2 protein expression, ER protein expression, and chromosomal instability (CI) as well as ERBB2 amplification via single- cell sequencing. Cell-level HER2/ER co-detection enables monitoring of receptor conversion during a patient’s MBC treatment journey. As trastuzumab-deruxtecan (T-DxD) has become standard of care for HER2-low disease, distinguishing HER2-UL from HER2[-] by DefineMBC’s liquid biopsy approach may identify additional patients who can benefit from such therapy. This addresses an unmet need given the known shortcomings of tissue biopsy IHC in the metastatic setting as recently noted by communications from NCCN, ASCO, and the College of American Pathologists. Methods: Assay development including analytical validation studies utilized biologically relevant cell lines of epithelial origin and known expression levels of HER2 and ER (MDA-MB-453: HER2[+] & ER[-]; MCF-7: HER2-low & ER[+]; and MCF-7/ERBB2 knockout: HER2[-]) that were spiked into healthy donor blood. Additionally, patients with various forms of MBC were characterized with the new assay. As with all samples, following red blood cell lysis, nucleated cells were deposited on glass slides at high density (∼3E6 WBC/slide). Slides underwent IF staining for cytokeratins (CK), CD31, CD45, HER2, ER, and Hoechst to localize nuclear DNA, followed by scanning and machine learning-based rare cell detection. CK[+], CD31[-]/CD45[-] cells were classified as CTC candidates and assessed for HER2/ER expression. Pathologist-selected CTCs were isolated for single-cell whole genome sequencing and analyzed using a proprietary CTC DNA copy number pipeline to detect CI and amplification at the ERBB2 locus. Results: Analytical validation studies demonstrated the limit of detection at 1 CTC per 12E6 WBC (∼1.6 mL of blood) with a linear range of 1- 300 CTCs per slide. Sensitivity, specificity, accuracy, and precision metrics of the HER2 and ER IF assays were 96%, 96%, 96%, 2% CV; 91%, 95%, 93%, 3% CV; respectively. CTC enumeration precision was validated at greater than 80% for enumeration bins of 0, 1-10, 11-50, and>50 CTCs per sample. During patient testing 7 patients previously called HER2[-] are now designated as consistent with HER2-low by the pathologist, suggesting improved test performance in future clinical validation studies is likely. Conclusions: Advancement of our comprehensive cancer profiling platform now includes ER/HER2-UL/CI co-detection on enumerated CTCs in MBC patients. Clinical studies currently in progress will reveal whether HER2-UL/HER2[+] detection on CTCs will identify patients better suited for T-DxD or trastuzumab, respectively. Citation Format: Raj Srikrishnan, Jordan Ritchie, Alessandra Cunsolo, Andrew Kunihiro, Brandon Guillory, Sara Tin, Zhuo Meng, Ernest T Lam, Bharat Annaldas, Evan Schwab, Nilesh Dharajiya, Timothy Pluard, Martin Blankfard, David Bourdon. Analytical validation of a novel multiomic metastatic breast cancer liquid biopsy test that combines ctDNA analysis with CTC HER2-ultralow and ER co-expression, as well as single-cell chromosomal instability [abstract]. In: Proceedings of the AACR Special Conference: Liquid Biopsy: From Discovery to Clinical Implementation; 2024 Nov 13-16; San Diego, CA. Philadelphia (PA): AACR; Clin Cancer Res 2024;30(21_Suppl):Abstract nr A001.

Thrombo-CARE-cardioembolic stroke etiology in cryptogenic stroke suggested by fibrin-/platelet-rich clot histology : Thrombo-CARE (configuration analysis to refine etiology).

Despite extensive diagnostic efforts, the etiology of stroke remains unclear in up to 30% of patients. Mechanical thrombectomy (MT) potentially enhances etiological determination by (immuno)histological analysis of retrieved thrombotic material. In this monocentric exploratory study, clots from 200 patients undergoing MT were investigated by hematoxylin and eosin, CD3, and CD45 staining. Semiquantitative and computer-based image analysis defined the histological composition and relative fractions of immunohistochemically stained areas. First, we correlated these results with strokes of known etiology. Subsequently, clots of unknown source were characterized with regard to their (immuno)histological profile to attempt etiological classification. Samples from 198 patients were accessible for analysis. Fibrin-/platelet-rich histology appeared in 45(23%), erythrocyte-rich in 18(9%), and mixed histology in 123 (62%) patients. Etiology was classified as cardioembolic in 87(44%), arterioembolic in 37(19%), and as cryptogenic stroke (CS) in 26(13%) cases. 20(23%) patients with cardioembolic stroke and 5(14%) patients with arterioembolic stroke had fibrin-/platelet-rich clots. 8(22%) patients with arterioembolic stroke and 1(1%) patient with cardioembolic stroke had erythrocyte-rich clots. In CS, cardioembolic clot features appeared more than twice as often as arterioembolic clot features. Whereas the association between histology and etiology was significant (p = 0.0057), CD3/CD45 staining did not correlate. Asignificant association between histology and etiology was observed, with the proportion of erythrocyte-rich thrombi being largest among arterioembolic strokes and the proportion of fibrin-/platelet-rich thrombi highest among cardioembolic strokes. Ahigh number of clots from CS presented histological features of cardioembolic clots. Thus, patients with CS and fibrin-/platelet-rich clots particularly require long-term cardiac rhythm monitoring and may benefit from oral anticoagulation.

Prognostic assessment of T-cells in primary colorectal cancer and paired synchronous or metachronous liver metastasis.

Prognostic value of T-cells between primary colorectal cancer (pCRC) and its paired synchronous and metachronous liver metastasis (LM) is underinvestigated and is the subject of the present study. We enrolled into this retrospective cohort study patients, who underwent resection of both pCRC and synchronous LM (N = 55) or metachronous LM (N = 44). After immunohistochemical staining for CD3+, CD8+, and CD45R0+ whole slides were scanned and T-cell densities were quantified using QuPath software in tumor center (TC), inner margin (IM), outer margin (OM), and peritumor zone (PT) of pCRC and LM. High densities of CD8+ T-cells in TC, OM and PT of synchronous LM were associated with longer disease-free survival (DFS). Greater densities of CD3+ T-cells in IM and PT and CD8+ T-cells in IM, OM and PT in synchronous LM over pCRC were associated with longer DFS. Greater densities of CD8+ T-cells in the TC and IM and CD3+ T-cells in the IM of pCRC were found in the metachronous over synchronous group. The first novel finding demonstrated that high density of CD8+ T cells in synchronous LM were associated with favorable outcome. The second finding of high CD8+ cell density in pCRC in metachronous over synchronous CRC may provide a mechanistic basis for the delay of metastatic spread. Both findings could be applied clinically with own reference values.

RGS5 balances macrophage vs vascular smooth muscle cell origin of foam cells in apoE-deficient plaques

Abstract Background G Protein Coupled Receptors and regulators of G-protein signalling (RGS), play a pivotal role in the signalling processes associated with atherosclerosis [1]. RGS5 is highly expressed in aortic tissue [2]. Development of atherosclerotic plaque is a complex process that involves foam cells originating from macrophages (Mϕ) and/or vascular smooth muscle cells (VSMCs). Differentiation of Mϕ and VSMC into various intermediary cells of varying inflammatory potency affects atherosclerotic plaque composition and vulnerability [3]. We hypothesize that RGS5 is involved in signalling of foam cell transition and thus, plaque biology. Purpose To evaluate the role of RGS5 on atherosclerotic plaque complexity and shifts of foam cell origin. Methods ApoE-/-RGS5+/+ and ApoE-/-RGS5-/- mice were fed a high fat Western Diet for 14 weeks. Cryosections bearing aortic valve cusps were used for staining. Lesion size was quantified on hematoxylin and eosin staining. Plaque composition was assessed by CD68, CD45, Oil red O and collagen staining. Triple staining was performed for CD45, CD68 and aSMA. Double immunofluorescent staining for CD45 and pro- and anti-inflammatory markers was carried out. Co-Localisation was analysed by Zeiss Zen. Data were analysed using Mann-Whitney-U test. Results Lesion size was significantly reduced in RGS5-deficient mice in comparison to control (in mm2: 0.398±0.02 vs 0.191±0.09, p=0.0001, n=15). Relative areas positive for Oil Red O and collagen did not differ between genotypes. Area positive for leukocyte marker CD45 increased significantly by 30.8% (p<0.0001, n=15), whereas area positive for CD68 was reduced by 10.3% (p=0.0292, n=15) in RGS5-deficient mice. Absence of RGS5 decreased co-localization of Mϕ-derived foam cells by 23% (p=0.03734, n=4-5) while leading to an 5.8% increase in aSMA-derived foam cells compared to control. Area positive for pro-inflammatory M1 Mϕ marker CD86 and iNOS increased by 36.3% and 36.8% after RGS5 knock-out (p<0.0001, n=15). No difference in M2 Mϕ positive area was observed when RGS5 was lacking. Conclusion RGS5 promotes plaque formation. The number of Mϕ-derived foam cells is increased by RGS5, while it reduces inflammatory M1 Mϕ. Interestingly, there were no differences in numbers of M2 Mϕ, indicating RGS5 inhibits VSMCs transition to M1 Mϕ resulting in an overall decrease of CD68-positive foam cells. Further study is required to determine molecular signalling of RGS5 that modulates the phenotype of Mϕ- and VSMC-derived cells. RGS5 could be useful as therapeutic target to suppress undesirable plaque phenotypes and to reduce acute cardiovascular events.

The Impact of Pre-biopsy Corticosteroids Use on CD20 Staining Pattern in B-cell Lymphomas

Abstract Introduction/Objective Diffuse large B-cell lymphomas, the most common Non-Hodgkin’s lymphoma are heterogeneous in terms of varied clinical presentation. The pathological work up these lymphomas is usually initiated with a CD20/CD3 immunohistochemical panel. Due to the aggressive nature of these lymphomas, pre-diagnosis corticosteroids are necessitated in some cases. However, the corticosteroids treatment can significantly alter the antigen staining of the lymphoma delaying the pathological diagnosis and subsequent treatment. This study investigates how pre-biopsy corticosteroids administration affects CD20 staining in B-cell lymphoma cells along with CD3 and PAX5, aiming to provide insights to the practicing pathologist for prompter diagnosis in these challenging cases. Methods/Case Report 14 biopsy cases of B-cell lymphoma pretreated with corticosteroids were included in this study. Clinicopathological parameters including corticosteroids usage are collected. H&E and immunohistochemistry slides were reviewed to analyze CD20, CD3 and PAX5 staining patterns. Results (if a Case Study enter NA) Of 14 cases, 10 cases showed cytoplasmic and granular staining with CD20, with extracellular spilling instead of the typical membranous pattern. This change was more frequent with intravenous dexamethasone (7/9) compared to oral prednisone (3/5), high dose (80%) compared to moderate and low dose (67%), short-term corticosteroids usage (86%) compared to intermediate-term and long-term (57%) usage and shorter dosing interval (100% in Q6H). The impact of prebiopsy corticosteroids was seen more on lymph node (5/7) compared to bone marrow (3/5). This cytoplasmic granularity was also observed in CD3 in the background non-neoplastic T lymphocytes in 25% of the cases. Though nuclear stains such as PAX5, Ki67, MUM1 and BCL6 also showed granularity in a significant number of cases, it was limited to the nucleus. Conclusion Pre-biopsy corticosteroids leads to alteration in CD20 staining pattern of the lymphoma cells leading to cytoplasmic granularity with extracellular spillage, which causes diagnostic challenge. This effect varies according to the type, route, dose, and duration of corticosteroids usage.

Impact of T Cell Ratios on Survival in Pleural Mesothelioma: Insights from Tumor Microenvironment Analysis

Background: Immunotherapy has significantly improved overall survival in patients with pleural mesothelioma, yet this benefit does not extend to those with the epithelioid subtype. Tumor growth is believed to be influenced by the immune response. This study aimed to analyze the tumor microenvironment to gain a better understanding of its influence on tumor growth. Methods: The tumor immune cell infiltration of 188 patients with pleural mesothelioma was characterized by multiplex immunofluorescence staining for CD3+ cells (CD3+), CD4+ cells (CD3+/CD4+), CD8+ cells (CD3+/CD8+), Treg (CD3+/CD4+/CD8-/CD163-/Foxp3+), PD1 cells (PD1+), and T helper cells (CD3+/CD4+/CD8-/CD163-/FoxP3-). The distribution of specific immune cells was correlated with clinical parameters. Results: A total of 188 patients with pleural mesothelioma (135 epithelioid, 9 sarcomatoid, 44 biphasic subtypes) were analyzed. The median age was 64.8 years. Overall survival was significantly longer in the epithelioid subtype than in the non-epithelioid subtype (p = 0.016). The presence of PD-L1 expression had a negative effect on overall survival (p = 0.041). A high ratio of CD4+ cells to regulatory T cells was associated with a significantly longer overall survival of more than 12 months (p = 0.015). The ratio of CD4+ cells to regulatory T cells retained its significant effect on overall survival in the multivariate analysis. Conclusions: Distinct differences in the T cell immune infiltrates in mesothelioma are strongly associated with overall survival. The tumor microenvironment could therefore serve as a source of prognostic biomarkers.

Aberrant CD45 Immunoreactivity in Neuroendocrine Neoplasms: A Diagnostic Pitfall-Report of 10 Specimens and Clinical Recommendations.

Leukocyte common antigen (LCA), or CD45, is classically thought of as a leukocyte-exclusive protein, and as such, CD45 immunohistochemistry (IHC) is often used as a key differentiator between non-Hodgkin lymphomas (NHLs) and morphologically similar neuroendocrine neoplasms (NENs). Herein, we report our experience regarding aberrant CD45 immunoreactivity in a series of NENs. A natural language search was used to retrieve desired archival patient files. All prior NENs which had a positive neuroendocrine diagnosis or IHC results (synaptophysin, chromogranin, CD56, and/or neuron-specific enolase), as well as CD45 staining performed, were reviewed for possible CD45 positivity (n = 686). Among these 686 NENs, 10 were aberrantly positive for CD45 staining. CD45 showed nuclear, cytoplasmic, and/or membranous staining in tumor cells. The significance of such staining is unclear. Albeit for a minority of patients, pathologists should be aware that NENs may aberrantly stain with CD45 and thereby pose a diagnostic pitfall. Therefore, broadening routine IHC panels is recommended to differentiate NENs more clearly from NHLs.

Investigation of the relationship of tissue-resident γδ T cells and IL-17 gene expression with the pathogenesis of autoimmune hepatitis.

Autoimmune hepatitis (AIH) is a chronic inflammatory liver disease. Elevated serum immunoglobulin G (IgG) levels, autoantibodies, and histopathological interface hepatitis are the hallmarks of AIH. Autoantibodies and pathological findings, clinical and biochemical features, typical immunoglobulin levels, and exclusion of other diseases are used to diagnose the condition. Gamma-delta (γδ) T cells are a unique population of unconventional T cells with γ and δ glycoprotein chains. γδ T cells have been shown to play a crucial role in autoimmune diseases by producing interleukin (IL)-17. However, its role in AIH remains to be further elucidated. In this study, we aimed to examine the role of γδ T cells and IL-17 in the pathogenesis of AIH, by working on biopsy samples. Paraffin blocks of 18 patients with type 1 AIH and 18 control liver tissues were analyzed. qRT-PCR assessed IL-17 gene expression. Immunofluorescence double staining of CD3+TCRγδ+ was performed to reveal tissue-resident γδ T cells' role in AIH. When comparing AIH to the control, there was a substantial increase in the ratio of CD3+TCRγδ+ cells in total inflammatory cells (p = 0.01). IL-17 gene expression was lowered in AIH when compared to the control (p = 0.01). This study provides evidence for the involvement of γδ T cells and IL-17 in the pathogenesis of AIH. The ratio of γδ T cells and IL-17 gene expression showed a significant difference in AIH suggesting a potential role for γδ T cells in driving liver inflammation in A fIH.

Cancer cell-specific PD-L1 expression is a predictor of poor outcome in patients with locally advanced oral cavity squamous cell carcinoma

BackgroundLocally advanced oral cavity squamous cell carcinoma (OCSCC) presents a significant clinical challenge despite being partially responsive to standard treatment modalities. This study investigates the prognostic implications of programmed death-ligand...

Expression of antigen-presenting cells in lung of postmortem SARS-CoV-2 cases.

Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) is a deadly pulmonary disease with impaired immunological response that causes significant tissue damage and organ failure. Postmortem examination of the lung is a useful tool for understanding the immunopathogenesis of this virus. Lung autopsy samples from seven dead SARS-CoV-2 patients were obtained and evaluated using hematoxylin and eosin stain to analyze the histopathological changes in those samples, on the other hand, Immunohistochemical (IHC) staining was used for detection of CD21, CD1a, CR1 (CD35), CD68, Myeloperoxidase (MPO), CD15, CD56, CD3, CD20, CD4, and CD8 cells markers. Histopathological examination revealed diffuse alveolar damage with extensive parenchymal architecture distortion, intravascular fibrin clot, deposition of collagen fibers, vascular congestions and blood vessels containing thrombi, pneumocyte type II with inflammatory cell infiltration. The IHC staining for the innate immune cells such as antigen-presenting cells (APCs) including dendritic cells, Macrophages, and neutrophils showed a strong positive staining, while CD56 Natural killer (NK) cells showed negative staining. On the other hand, the specific immune cells including; CD20 B cells, CD3 T cells, and CD4 helper T cells, showed positive staining while CD8 Cytotoxic T cells showed negative staining. The lung autopsy samples from patients with COVID-19 confirmed the presence of APCs through the positive staining of CD21, CD1a, CD35, CD68, MPO, and CD15 expressed the virus recognition, proinflammatory cytokine production, and adaptive immune cells activation through CD3, CD4, and CD20 positive staining and the role of APCs in the severity of pulmonary infection and pathogenesis of SARS-CoV-2 infection however the absence of the CD56 NK and CD8 cytotoxic T explains the worse infection status for the patients.

587. PD-L1 EXPRESSION AND CD8+ TUMOR-INFILTRATING LYMPHOCYTES CHANGES AFTER PREOPERATIVE CHEMORADIOTHERAPY IN ESOPHAGEAL SQUAMOUS CELL CARCINOMA

Abstract Background Neoadjuvant chemoradiotherapy (nCRT) has been established as a standard treatment for locally advanced esophageal squamous cell carcinoma (SqCC), but there are still insufficient research advances on the incorporation of immunologic agents. The aim of this study was to explore immune microenvironment changes before and after nCRT. Methods A total of 101 patients who underwent nCRT followed by radical surgery for esophageal SqCC in a single institution between 2005 and 2021 were analyzed. Pre-nCRT endoscopic biopsy and post-nCRT surgical specimen were evaluated using tissue microarray. Immunohistochemical staining for CD3, CD8, and PD-L1 were performed. Tumor-infiltrating lymphocytes (TIL) density were independently evaluated by blinded pathologist (total number of 2+ to 3+ cells/total area (mm2)). Results Compared to pre-nCRT biopsy, PD-L1 expression (8.7% vs. 14.0%, p<0.001) and TIL density (259.1 vs. 566.9, p<0.001) were significantly increased in surgical specimen after nCRT. When divided into groups according to nCRT response, post-nCRT TIL density (p=0.341), fold changes of TIL density (p=0.749), and PD-L1 expression (p=0.642) were not significantly different between ypCR (n=23) and non-ypCR group (n=78). In ypT0 group (n=36), post-nCRT TIL density was marginally higher than that of non-ypT0 group (404 vs. 259, p = 0.050). Conclusion Irrespective of clinical responses, PD-L1 expression and TIL density were both increased after nCRT. Our results could help the development of combination strategy of immunologic drugs and seek the possibility of an organ-saving strategy that will contribute to improving quality of life of patients.