Memory-T-cell-derived interferon-γ instructs potent innate cell activation for protective immunity.

Cells of the innate immune system are essential for host defenses against primary microbial pathogen infections, yet their involvement in effective memory responses of vaccinated individuals has been poorly investigated. Here we show that memory T cells instruct innate cells to become potent effector cells in a systemic and a mucosal model of infection. Memory T cells controlled phagocyte, dendritic cell, and NK or NK T cell mobilization and induction of a strong program of differentiation, which included their expression of effector cytokines and microbicidal pathways, all of which were delayed in nonvaccinated hosts. Disruption of IFN-γ signaling in Ly6C+ monocytes, dendritic cells, and macrophages impaired these processes and the control of pathogen growth. These results reveal how memory T cells, through rapid secretion of IFN-γ, orchestrate extensive modifications of host innate immune responses that are essential for effective protection of vaccinated hosts.

Artifacts and main lesions in fetal ocular histology.

Histological artifacts in fetal eyes can involve different tissues and can be related to mechanical or autolytic lesions, fixation, the cause of death or the cutting technique. Knowing the causes, effects and appearance of artifacts allow the minimization of the risk of avoidable artifacts and help distinguish them from "true" pathological lesions. We describe these different types of artifacts and specifically analyze their involvement in different tissue structures of the eye. We compare them with primary fetal ocular lesions. Given the wide variety of artifacts, the identification of lesions in fetal eyes must be done with caution, since differentiating true lesions from artifacts requires some experience and relies on both macroscopic examination and microscopic analyses, with ideally comparisons with references' images of normal tissues of the same gestational age.

Inflammatory monocytes activate memory CD8(+) T and innate NK lymphocytes independent of cognate antigen during microbial pathogen invasion.

Memory CD8(+) T cells induced upon immunization exhibit improved functional features that contribute to protection of immunized hosts. Although both cognate antigen recognition and inflammation are important for memory CD8(+) T cell reactivation, the relative contribution of these factors and the cell types providing these signals in vivo are poorly defined. Here, we show that Ly6C(+)CCR2(+) inflammatory monocytes, a subset of monocytes, largely orchestrate memory CD8(+) T and NK lymphocytes activation by differentiating into interleukin-18 (IL-18)- and IL-15-producing cells in an inflammasome and type I interferon-IRF3-dependent manner. Memory CD8(+) T cells became potent effector cells by sensing inflammation from monocytes independently of their cognate antigen. Like NK cells, they underwent rapid mobilization, upregulated intense and sustained effector functions during bacterial, viral, and parasitic infections, and contributed to innate responses and protection in vivo. Thus, inflammatory monocyte-derived IL-18 and IL-15 are critical to initiate memory CD8(+) T and NK lymphocytes differentiation into antimicrobial effector cells.

Ultrasound-guided fine-needle capillary cytology of parotid gland masses coupled with a rapid-on-site evaluation improves results.

OBJECTIVE OF THE STUDY: To test whether a direct-on-site microscopic examination of fresh, unstained puncture slides by the radiologist decreases the rate of false-negative cases on ultrasound-guided fine-needle cytology of parotid gland masses. PATIENTS: Thirty parotid gland masses from 28 patients were punctured under ultrasound guidance. The same group was used as its control group. METHODS: After one or two passes, the material was spread on slides and air-dried (control group, without microscopic examination). For the study group, it was thus analyzed unstained under the microscope. A sample was considered adequate if at least six clusters of parotid cells were found per slide on at least two slides. For the study group, new punctures were obtained and slides prepared until this condition was fulfilled. RESULTS: Of the 30 evaluated masses, 100% benefited from a cytological diagnosis after microscopy. Twenty-four were adequate in the control group, while 30 were adequate in the study group. The maximum number of punctures to obtain an adequate sample was six. On-site direct microscopy significantly increased the number of adequate specimens by 20% (P=0.03, CI [1.63-20%]). CONCLUSION: Direct and systematic examination of slides by a radiologist avoided the risk of false-negative results caused by having insufficient sample material.

Use of fluorescent in-situ hybridisation in salivary gland cytology: A powerful diagnostic tool.

OBJECTIVE: Salivary gland cytology is challenging because it includes a diversity of lesions and a wide spectra of tumours. Recently, it has been reported that many types of salivary gland tumours have specific molecular diagnostic signatures that could be identified by fluorescent in-situ hybridisation (FISH). The aim of the present study was to demonstrate the feasibility and efficiency of FISH on routine cytological salivary gland smears. METHODS: FISH was conducted on 37 cytological salivary gland smears from 34 patients. According to the cytological diagnosis suspected, MECT1/MAML2 gene fusion and rearrangements of PLAG1, MYB, or ETV6 were analysed. The presence and percentages of cells that had gene rearrangements were evaluated. Results were compared with the histological surgical samples, available from 26 patients. RESULTS: The PLAG1 rearrangement was observed in 12/20 (60%) cases of pleomorphic adenoma. MECT1/MAML2 gene fusion was observed in 1:2 mucoepidermoid carcinomas but was not observed in five other tumours (two pleomorphic adenomas, one Warthin's tumour, one mammary analogue secretory carcinoma [MASC] and one cystic tumour). MYB rearrangement was observed in 4/4 adenoid cystic carcinomas. ETV6-gene splitting identified one MASC. CONCLUSION: Overall, FISH had a specificity of 100% and a sensitivity of 66.7%. When FISH and cytological analyses were combined, the overall sensitivity was increased to 93.3%. It can thus be concluded that when the FISH analysis is positive, the extent of surgery could be determined with confidence pre-operatively without needing a diagnosis from a frozen section.

Immunocytochemical staining for p53 and Ki-67 helps to characterise urothelial cells in urine cytology.

OBJECTIVE: The presence of atypical cells in urine cytology is unsatisfactory for both cytologists and clinicians. The objective of this study was to test whether p53 and Ki-67 immunostaining could improve urothelial carcinoma (UC) detection on urinary cytology. METHODS: A total of 196 urine samples were analysed, 142 from the bladder, 41 from the upper tract and 13 from ileal bladder replacement. Cytology results were expressed as normal (N) (n = 81), atypia cannot exclude low-grade UC (ALG) (n = 25), suspicious for high-grade UC (SHG) (n = 39) and high-grade UC (HG) (n = 51). Actual diagnoses were confirmed by histopathological analysis, cystoscopic examination or follow-up for at least 1 year. Immunocytochemistry performed on CytoSpin™ slides allowed the determination of the percentage of positive cells with p53 and Ki-67. RESULTS: The median percentage values [first to third quartile] of p53 and Ki-67 were 0 [0-5] and 0 [0-1] for N cytology, 5 [0-40] and 2 [1-10] for ALG, 10 [0-30] and 6 [3-25] for SHG, and 30 [10-80] and 20 [10-30] for HG, respectively. Statistically higher values were observed for both tests (P < 0.001) in positive cytologies (ALG, SHG and HG). The optimal cut-offs were 5% for p53 and 3% for Ki-67. The sensitivity and specificity for the detection of all UC were 86.4% and 76.7% for cytology alone, 81.3% and 93.2% for cytology and p53, 75.7% and 88% for cytology and Ki-67, and 68.9% and 97.5% for cytology, p53 and Ki-67, respectively. CONCLUSION: Using p53 and/or Ki-67 in addition to cytology increases the specificity without penalising the sensitivity.

Guidelines for May-Grünwald-Giemsa staining in haematology and non-gynaecological cytopathology: recommendations of the French Society of Clinical Cytology (SFCC) and of the French Association for Quality Assurance in Anatomic and Cytologic Pathology (AFAQAP).

OBJECTIVE: Since the guidelines of the International Committee for Standardisation in Haematology (ICSH) in 1984 and those of the European Committee for External Quality Assessment Programmes in Laboratory Medicine (EQALM) in 2004, no leading organisation has published technical recommendations for the preparation of air-dried cytological specimens using May-Grünwald-Giemsa (MGG) staining. DATA SOURCES: Literature data were retrieved using reference books, baseline-published studies, articles extracted from PubMed/Medline and Google Scholar, and online-available industry datasheets. RATIONALE: The present review addresses all pre-analytical issues concerning the use of Romanowsky's stains (including MGG) in haematology and non-gynaecological cytopathology. It aims at serving as actualised, best practice recommendations for the proper handling of air-dried cytological specimens. It, therefore, appears complementary to the staining criteria of the non-gynaecological diagnostic cytology handbook edited by the United Kingdom National External Quality Assessment Service (UK-NEQAS) in February 2015.

Two-Phase Acto-Cytosolic Fluid Flow in a Moving Keratocyte: A 2D Continuum Model.

The F-actin network and cytosol in the lamellipodia of crawling cells flow in a centripetal pattern and spout-like form, respectively. We have numerically studied this two-phase flow in the realistic geometry of a moving keratocyte. Cytosol has been treated as a low viscosity Newtonian fluid flowing through the high viscosity porous medium of F-actin network. Other involved phenomena including myosin activity, adhesion friction, and interphase interaction are also discussed to provide an overall view of this problem. Adopting a two-phase coupled model by myosin concentration, we have found new accurate perspectives of acto-cytosolic flow and pressure fields, myosin distribution, as well as the distribution of effective forces across the lamellipodia of a keratocyte with stationary shape. The order of magnitude method is also used to determine the contribution of forces in the internal dynamics of lamellipodia.

Mechanisms of Memory T Cell Activation and Effective Immunity.

Effective immunization induces the development of populations of robust effector lymphocytes specific for the immunizing antigens. Amongst them are cytotoxic/CD8(+)T lymphocytes, which few will further differentiate into long-lived memory cells persisting in the host and exhibiting improved functional characteristics. The current model is that such memory cells can confer rapid host protection upon cognate antigen-mediated activation and direct killing of infected cells. In this chapter, we discuss work from our group and others that highlight the contribution of inflammatory cytokines to memory CD8(+) T cell activation and of cytolysis-independent mechanisms of host protection.

Inflammatory monocyte effector mechanisms.

Monocytes are blood-derived mononuclear phagocytic cells that traffic throughout the body and can provide rapid innate immune effector responses in response to microbial pathogen infections. Among blood monocytes, the most abundant subset in mice is represented by inflammatory Ly6C(+) CCR2(+) monocytes and is the functional equivalent of the CD14(+) monocytes in humans. Herein we focus on published evidence describing the exquisite functional plasticity of these cells, and we extend this overview to their multiples roles in vivo during host immune defenses against microbial pathogen infections, as antigen-presenting cells, inflammatory cells or Trojan horse cells.

Minimal tolerance to a tumor antigen encoded by a cancer-germline gene.

Central tolerance toward tissue-restricted Ags is considered to rely on ectopic expression in the thymus, which was also observed for tumor Ags encoded by cancer-germline genes. It is unknown whether endogenous expression shapes the T cell repertoire against the latter Ags and explains their weak immunogenicity. We addressed this question using mouse cancer-germline gene P1A, which encodes antigenic peptide P1A(35-43) presented by H-2L(d). We made P1A-knockout (P1A-KO) mice and asked whether their anti-P1A(35-43) immune responses were stronger than those of wild-type mice and whether P1A-KO mice responded to other P1A epitopes, against which wild-type mice were tolerized. We observed that both types of mice mounted similar P1A(35-43)-specific CD8 T cell responses, although the frequency of P1A(35-43)-specific CD8 T cells generated in response to P1A-expressing tumors was slightly higher in P1A-KO mice. This higher reactivity allowed naive P1A-KO mice to reject spontaneously P1A-expressing tumors, which progressed in wild-type mice. TCR-Vß usage of P1A(35-43)-specific CD8 cells was slightly modified in P1A-KO mice. Peptide P1A(35-43) remained the only P1A epitope recognized by CD8 T cells in both types of mice, which also displayed similar thymic selection of a transgenic TCR recognizing P1A(35-43). These results indicate the existence of a minimal tolerance to an Ag encoded by a cancer-germline gene and suggest that its endogenous expression only slightly affects diversification of the T cell repertoire against this Ag.

Analytical solutions of actin-retrograde-flow in a circular stationary cell: a mechanical point of view.

The network of actin filaments in the lamellipodium (LP) of stationary and migrating cells flows in a retrograde direction, from the membrane periphery toward the cell nucleus. We have theoretically studied this phenomenon in the circular stationary (fully spread) cells. Adopting a continuum view on the LP actin network, new closed-form solutions are provided for the actin-retrograde-flow (ARF) in a polar coordinate system. Due to discrepancy in the mechanical models of the actin network in the ARF regime, solutions are provided for both assumptions of solid and fluid behavior. Other involved phenomena, including polymerizing machine at the membrane periphery, cytosol drag, adhesion friction, and membrane tension, are also discussed to provide an overall quantitative view on this problem.

Improvement of the cytological diagnostic accuracy of follicular thyroid lesions by the use of the Ki-67 proliferative index in addition to cytokeratin-19 and HBME-1 immunomarkers: a study of 61 cases of liquid-based FNA cytology with histological controls.

OBJECTIVES: To evaluate HBME-1, cytokeratin-19 (CK-19) and Ki-67 immunomarkers in order to increase the diagnostic accuracy of preoperative thyroid fine needle aspiration (FNA) cytology. METHODS: Immunocytochemistry against HBME-1, CK-19 and Ki-67 was performed on 123 thyroid FNAs processed by liquid-based cytology (LBC). Statistical analysis was carried out on 61 cases with histological control and sufficient material for one or more of the three markers. The Bethesda System was used for cytological diagnosis. RESULTS: Taking into account all the cytological categories, with a cut-off of 30% of positive cells, HBME-1 (n = 47) and CK-19 (n = 53) showed a sensitivity for malignancy of 66.7% (95% confidence interval, 53.2-80.1) and 90.5% (82.6-98.4) and a specificity of 90.6% (82.3-99) and 75% (63.3-86.7), respectively. For Ki-67 (n = 54) with a cut-off of 1% of positive cells, the sensitivity was 85.0% (75.5-94.5) and the specificity 70.6% (58.4-82.7). In the follicular neoplasm/suspicious for follicular neoplasm (FN/SFN) category (n = 37), which was the focus of the study, papillary thyroid carcinomas (PTCs) were less numerous (four cases, three of which were the follicular variant), the positivity of the three immunomarkers combined showed an overall accuracy of 91% (21/23). The mean percentage of Ki-67-positive cells was increased in malignant lesions, with the exception of follicular variant PTCs: 16% ± 15.6% in two follicular carcinomas, 4.8% ± 3.2% in 13 classical PTCs, 1% ± 1.2% in five follicular variant PTCs and 0.5% ± 1.9% in 34 non-malignant lesions. CONCLUSIONS: Immunocytochemistry using HBME-1, CK-19 and the Ki-67 proliferative index increased the diagnostic accuracy of FNA in the FN/SFN category of the Bethesda System, which may help to distinguish lesions in this category with a low or high risk of malignancy. Thus, clinical management would be improved.

Repellent effect of alphacypermethrin-treated netting against Bemisia tabaci (Hemiptera: Aleyrodidae).

For > 20 yr, Bemisia tabaci Gennadius persists as a begomovirus vector and is a serious problem in tomato production in many parts of the world. In tropical countries, the use of netting to protect horticultural crops has proven to be an effective and sustainable tool against Lepidoptera but not against small insects. This study evaluated the repellent effect of AgroNet 0.9T, a 0.9-mm pore diameter and 40-mesh size netting treated with alphacypermethrin insecticide against B. tabaci. This pyrethroid insecticide is known to have toxic and repellent effects against mosquitoes and has been used for treatment of mosquito nets. Two nontreated netting materials were used as control: AgroNet 0.9NT with 0.9-mm pore diameter and 40-mesh size and AgroNet 0.4NT with 0.4-mm pore diameter and 80-mesh size. The behavior of B. tabaci and its parasitoid Encarsia formosa Gahan as they progressed through the treated netting was studied in the laboratory in choice and no-choice tests. The development of wild B. tabaci population on tomato plants protected by the same nets was followed in two field trials implemented in Njoro, Kenya. Results obtained with the no-choice tests showed a significant reduction of movement on the treated net with 40-mesh (19%) compared with nontreated netting (35 and 46% with 80- and 40-mesh, respectively). The mortality of B. tabaci was significantly higher (two-fold) in the test tube containing only the treated netting compared with the nontreated one. The repellent effect of the treated netting was also demonstrated against E. formosa, but it did not have this toxic effect. Unlike for B. tabaci, the treated and nontreated nets appeared to have a similar repellent effect on E. formosa in the choice test, which suggests a learning behavior of the parasitoid. In both field tests, B. tabaci population was significantly lower on tomato protected by the treated net compared with the same nontreated net. However there was no significant difference in B. tabaci population between the treated 0.9-pore diameter and the nontreated 0.4-pore diameter. We discussed these findings and their implications for the use of repellent netting in integrated pest management in horticulture and more specifically in vegetable production.

Dermatofibrosarcoma protuberans: margins reduction using slow-Mohs micrographic surgery. Experience with 35 patients.

INTRODUCTION: Dermatofibrosarcoma protuberans (DFSP) is a potentially malignant dermal mesenchymal tumour with a high risk of local recurrence. DFSP presents a sprawling appearance whose complete excision requires important margins. DFSP was initially resected with a 5cm excision margins, and more recently 3cm then 2cm margins were recommended. Mohs micrographic surgery (MMS) helps reduce these margins thanks to a 3-dimensional excision around the tumour, which is analysed in its entirety. We used the modified MMS called slow-MMS and tried every time it was possible to perform direct closure. METHODS: Thirty-five patients presenting a DFSP between 2004 and 2013 within the Plastic Surgery unit at Claudius Regaud Institute were included in this retrospective study. The patients were treated with slow-MMS using paraffin-embedded sections. RESULTS: One surgery was necessary for 72% of patients. For 17%, we had to perform a second surgery, and for 11% a third one. Our median clinical excision margins was 17mm (range 9.0:30.0). After a median follow-up of 46 months (range 35.2:60.2), we didn't observe any recurrence. Only one case required a local flap; for the others, the loss of substance was resolved with a direct closure. CONCLUSION: Slow-MMS enabled a local control of the margins without recurrence at 46 months in our series. Besides, it helps performing smaller margins than wide excision and thus preserving the tissues. In our opinion, this is the treatment of choice regarding DFSP for which tissue sparing is essential. It seems particularly appropriate near functional areas or on the face.

Cytopathological analysis of salivary gland cancer: REFCOR recommendations by the formal consensus method.

OBJECTIVE: To determine the indications for fine-needle cytology and the modalities of frozen section pathological analysis in the management of salivary gland cancer. MATERIAL AND METHODS: The French Network of Rare Head and Neck Tumors (REFCOR) formed a steering group who drafted a narrative review of the literature published on Medline and proposed recommendations. The level of adherence to the recommendations was then assessed by a rating group according to the formal consensus method. RESULTS: Fine-needle cytology is recommended as part of the diagnostic work-up for a major salivary gland tumor suspicious for malignancy. Fine-needle cytology should be performed after MRI to avoid artifacts. Frozen section analysis is recommended to confirm the malignant nature of the tumor, to adapt the extent of resection and to indicate neck dissection. Whenever possible, the entire tumor and adjacent salivary or periglandular tissue should be sent for frozen section analysis. CONCLUSION: Fine-needle cytology and frozen section analysis play an essential role in the management of salivary gland cancers.

Real-time and non-invasive acute lung rejection diagnosis using confocal LASER Endomicroscopy in lung transplant recipients: Results from the CELTICS study.

BACKGROUND AND OBJECTIVE: Traditionally, the diagnosis of acute rejection (AR) relies on invasive transbronchial biopsies (TBBs) to obtain histopathological samples. We aimed to evaluate the diagnostic yield of probe-based confocal laser endomicroscopy (pCLE) as a complementary and non-invasive tool for ACR screening, comparing its results with those obtained from TBBs. METHODS: Between January 2015 and April 2022, we conducted a retrospective study of all lung transplant recipients aged over 18 years at Toulouse University Hospital (France). All patients who underwent bronchoscopies with both TBBs and pCLE imaging were included. Two experienced interpreters (TV and MS) reviewed the pCLE images independently, blinded to all clinical information and pathology results. RESULTS: From 120 procedures in 85 patients, 34 abnormal histological samples were identified. Probe-based confocal laser endomicroscopy revealed significant associations between both alveolar (ALC) and perivascular (PVC) cellularities and abnormal histological samples (p<0.0001 and 0.003 respectively). Alveolar cellularity demonstrated a sensitivity (Se) of 85.3 %, specificity (Spe) of 43 %, positive predictive value (PPV) of 37.2 % and negative predictive value (NPV) of 88.1 %. For PVC, Se was 70.6 %, Spe 80.2 %, PPV 58.5 % and NPV 87.3 %. Intra-interpreter correlation (TV) was 88.3 % for the number of vessels (+/-1), 98.3 % for ALC and 90 % for PVC. Inter-interpreter correlation (TV and MS) was 80 % for vessels (+/-1), 97.5 % for ALC and 83.3 % for PVC. CONCLUSION: Our study demonstrates the feasibility of incorporating pCLE into clinical practice, demonstrating good diagnostic yield and reproducible outcomes in the screening of AR in lung transplant recipients.

Inflammatory monocytes and neutrophils are licensed to kill during memory responses in vivo.

Immunological memory is a hallmark of B and T lymphocytes that have undergone a previous encounter with a given antigen. It is assumed that memory cells mediate better protection of the host upon re-infection because of improved effector functions such as antibody production, cytotoxic activity and cytokine secretion. In contrast to cells of the adaptive immune system, innate immune cells are believed to exhibit a comparable functional effector response each time the same pathogen is encountered. Here, using mice infected by the intracellular bacterium Listeria monocytogenes, we show that during a recall bacterial infection, the chemokine CCL3 secreted by memory CD8+ T cells drives drastic modifications of the functional properties of several populations of phagocytes. We found that inflammatory ly6C+ monocytes and neutrophils largely mediated memory CD8+ T cell bacteriocidal activity by producing increased levels of reactive oxygen species (ROS), augmenting the pH of their phagosomes and inducing antimicrobial autophagy. These events allowed an extremely rapid control of bacterial growth in vivo and accounted for protective immunity. Therefore, our results provide evidence that cytotoxic memory CD8+ T cells can license distinct antimicrobial effector mechanisms of innate cells to efficiently clear pathogens.

Splenic CD8α⁺ dendritic cells undergo rapid programming by cytosolic bacteria and inflammation to induce protective CD8⁺ T-cell memory.

Memory CD8(+) T lymphocytes are critical effector cells of the adaptive immune system mediating long-lived pathogen-specific protective immunity. Three signals - antigen, costimulation and inflammation - orchestrate optimal CD8(+) T-cell priming and differentiation into effector and memory cells and shape T-cell functional fate and ability to protect against challenge infections. While among the conventional spleen DCs (cDCs), the CD8α(+) but not the CD8α(-) cDCs most efficiently mediate CD8(+) T-cell priming, it is unclear which subset, irrespective of their capacity to process MHC class I-associated antigens, is most efficient at inducing naïve CD8(+) T-cell differentiation into pathogen-specific protective memory cells in vivo. Moreover, the origin of the required signals is still unclear. Using mice infected with the intracellular bacterium Listeria monocytogenes, we show that splenic CD8α(+) cDCs become endowed with all functional features to optimally prime protective memory CD8(+) T cells in vivo within only a few hours post-immunization. Such programming requires both cytosolic signals resulting from bacterial invasion of the host cells and extracellular inflammatory mediators. Thus, these data designate these cells as the best candidates to facilitate the development of cell-based vaccine therapy.