Selective neuronal expression of progranulin is sufficient to provide neuroprotective and anti-inflammatory effects after traumatic brain injury.

Progranulin (PGRN), which is produced in neurons and microglia, is a neurotrophic and anti-inflammatory glycoprotein. Human loss-of-function mutations cause frontotemporal dementia, and PGRN knockout (KO) mice are a model for dementia. In addition, PGRN KO mice exhibit severe phenotypes in models of traumatic or ischemic central nervous system (CNS) disorders, including traumatic brain injury (TBI). It is unknown whether restoration of progranulin expression in neurons (and not in microglia) might be sufficient to prevent excessive TBI-evoked brain damage. To address this question, we generated mice with Nestin-Cre-driven murine PGRN expression in a PGRN KO line (PGRN-KONestinGrn) to rescue PGRN in neurons. PGRN expression analysis in primary CNS cell cultures from naïve mice and in (non-) injured brain tissue from PGRN-KONestinGrn revealed expression of PGRN in neurons but not in microglia. After experimental TBI, examination of the structural brain damage at 5 days post-injury (dpi) showed that the TBI-induced loss of brain tissue and hippocampal neurons was exacerbated in PGRN-KOGrnflfl mice (PGRN knockout with the mGrn fl-STOP-fl allele, Cre-negative), as expected, whereas the tissue damage in PGRN-KONestinGrn mice was similar to that in PGRN-WT mice. Analysis of CD68+ immunofluorescent microglia and Cd68 mRNA expression showed that excessive microglial activation was rescued in PGRN-KONestinGrn mice, and the correlation of brain injury with Cd68 expression suggested that Cd68 was a surrogate marker for excessive brain injury caused by PGRN deficiency. The results show that restoring neuronal PGRN expression was sufficient to rescue the exacerbated neuropathology of TBI caused by PGRN deficiency, even in the absence of microglial PGRN. Hence, endogenous microglial PGRN expression was not essential for the neuroprotective or anti-inflammatory effects of PGRN after TBI in this study.

Expression of CD68 and CD163 in malignant epithelial cells of oral squamous cell carcinoma: Phenotypic shift or mere cell fusion.

BACKGROUND / PURPOSE: The progression of epithelial to mesenchymal tissue (EMT) is a highly intricate process that facilitates the transformation of cancer cells, allowing them to changeover their characteristic epithelial properties to mesenchymal attributes. This notable change empowers the cells with enhanced mobility and the ability to migrate to distant locations. Furthermore, it is imperative to adopt the idea of macrophage tumor cell fusion to achieve comprehensive considerate of this phenomenon. Our primary objective was to conduct a thorough investigation of macrophage-restricted antigens expression, specifically CD68 and CD163, in malignant epithelial cells of oral cavity squamous cell carcinoma (OSCC) to elucidate aforementioned perceptions. MATERIALS AND METHODS: CD68 and CD163 immunohistochemical expression were assessed in oral squamous cell carcinoma (OSCC), encompassing both the neoplastic cells and the tumor-associated macrophages (TAMs). RESULTS: Both CD68 and CD163 antigens were revealed in OSCC malignant epithelial cells in a granular cell pattern, localized in membrane and cytoplasm of tumor cells respectively as well as in the infiltrating TAMs. CONCLUSION: The macrophage antigens were not limited to the infiltrating tumor-associated macrophages (TAMs), but were also observed in a substantial proportion of OSCC malignant epithelial cells within the tumor parenchyma. This particular expression pattern may represent a subset of tumor cells that have undergone an epithelial to a mesenchymal phenotypic transition. In addition, fusion of macrophages with tumor cells cannot be excluded; both might be associated with increased metastatic activity of OSCC.

Microglial TREM2 promotes phagocytic clearance of damaged neurons after status epilepticus.

In the central nervous system, triggering receptor expressed on myeloid cells 2 (TREM2) is exclusively expressed by microglia and is critical for microglial proliferation, migration, and phagocytosis. Microglial TREM2 plays an important role in neurodegenerative diseases, such as Alzheimer's disease and amyotrophic lateral sclerosis. However, little is known about how TREM2 affects microglial function within epileptogenesis. To investigate this, we utilized male TREM2 knockout (KO) mice within the murine intra-amygdala kainic acid seizure model. Electroencephalographic analysis, immunocytochemistry, and RNA sequencing revealed that TREM2 deficiency significantly promoted seizure-induced pathology. We found that TREM2 KO increased both the severity of acute status epilepticus and the number of spontaneous recurrent seizures characteristic of chronic focal epilepsy. Phagocytic clearance of damaged neurons by microglia was also impaired by TREM2 KO and reduced phagocytic activity correlated with increased spontaneous seizures. Analysis of human tissue from patients who underwent surgical resection for drug resistant temporal lobe epilepsy also showed a negative correlation between expression of the microglial phagocytic marker CD68 and focal to bilateral tonic-clonic generalized seizure history. These results indicate that microglial TREM2 and phagocytic activity are important to epileptogenic pathology.

CD68-Negative Histiocytoses with Cardiac Involvement, Associated with COVID-19.

Histiocytoses are rare diseases characterised by infiltration of affected organs by myeloid cells with a monocyte or dendritic cell phenotype. Symptoms can range from self-resolving localised forms to multisystemic lesions requiring specific treatment. To demonstrate extremely rare cases of CD68-negative cardiac histiocytosis with expression of SARS-CoV-2 antigen in infiltrate cells. We demonstrated a case of Erdheim-Chester disease in a 67-year-old man with pericardial involvement and positive dynamics with vemurafenib treatment, an autopsy case of xanthogranulomatous myopericarditis in a 63-year-old man, surgical material of xanthogranulomatous constrictive pericarditis in a 57-year-old man, and an autopsy case of xanthogranulomatosis in a 1-month-old girl. In all cases, xanthogranuloma cells expressed CD163, many of them spike protein SARS-CoV-2, while CD68 expression was detected only in single cells. In this article, we demonstrated four cases of extremely rare CD68-negative cardiac xanthogranulomatosis in three adults and one child with expression of the spike protein SARS-CoV-2 in M2 macrophages. This potential indirect association between COVID-19 and the development of histiocytosis in these patients warrants further investigation. To substantiate this hypothesis, more extensive research is needed.

Potential Impact of Omega 6/3 Ratio and CD68+ Macrophage Infiltration on Survival in NSCLC Patients Undergoing Pulmonary Resection.

Background: Lung cancer remains the leading cause of cancer-related mortality worldwide with non-small cell lung cancer (NSCLC) accounting for the majority of cases. The stage of detection significantly influences survival rates with early-stage diagnosis offering the best prognosis. This study investigates the prognostic impact of the omega-6/omega-3 ratio and tumor infiltration by CD8+ lymphocytes and CD68+ macrophages on overall survival (OS) and disease-free survival (DFS) in NSCLC patients undergoing pulmonary resection. Methods: We conducted a retrospective analysis of 53 patients with early-stage NSCLC who underwent pulmonary resection between September 2017 and January 2020. The omega-6/omega-3 ratio was quantified using gas chromatography and spectrometry. Tumor infiltration by CD8 and CD68 was assessed through immunohistochemistry. Survival outcomes were evaluated using Kaplan-Meier and Cox regression analyses. Results: An increased omega-6/omega-3 ratio and higher CD68+ macrophage infiltration were associated with a trend towards worse OS and DFS in NSCLC patients, though these results did not reach statistical significance. CD8+ T-cell infiltration was associated with improved survival outcomes, confirming its role as a favorable prognostic marker. Comparative analysis with existing datasets revealed similar demographic and clinical characteristics, reinforcing the generalizability of our findings. Conclusions: The omega-6/omega-3 ratio and CD68+ macrophage infiltration serve as important factors potentially influencing prognosis in NSCLC patients undergoing pulmonary resection. These findings highlight the need for further research to refine the prognostic utility of these biomarkers and to explore therapeutic strategies targeting inflammation and immune cell infiltration.

Characterization of giant endocrine cells in the fundic stomach of African catfish (Clarias gariepinus) demonstrated by histochemical, immunohistochemical and ultrastructure microscopy methods suggesting their role in immunity.

Endocrine cells in the fundic stomach of Clarias gariepinus were characterized in this work using transmission electron microscopy, immunohistochemistry, and histochemistry. Performic acid mixed with alcian blue pH2.5 and silver stain were among the histochemical stains used for endocrine cells. Endocrine cells can be found in the epithelium, lamina propria, submucosa, muscular layer, serosa, and the area between the stomach glands. Endocrine cells with one or more nuclei were found. Endocrine cells were studied using CD3, CD21, and CD68 in an immunohistochemistry analysis. The expression of the lymphocyte marker CD3 by endocrine cells is remarkable. In addition, they had a strong immunological response to CD21 and CD68, which are characteristics of phagocytic cells. Granules of varied sizes and electron densities are packed densely into the cytoplasm of the cells, as seen by transmission electron microscopy. We propose that endocrine cells play a crucial role in immune defense. The role of endocrine cells in the gut's immune system is an area that needs further investigation.

Rosai-Dorfman Disease in a Middle-Aged Man With Recurrent Pleural Effusions and Lymphadenopathy.

Rosai-Dorfman disease (RDD) is a rare benign condition that presents most commonly with lymphadenopathy and skin lesions and is characterized by infiltration of histiocytes into the skin and soft tissues. We present a case of RDD in an Afro-Caribbean male in his 50s who presented to our chest clinic with shortness of breath, cough, and weight loss of 15 kg over one year. CT scan showed evidence of right pleural effusion, mediastinal and hilar lymphadenopathy, and bony lesions in the spine. Cytology from multiple pleural effusions and endobronchial ultrasound-guided fine needle aspiration from lymph nodes did not show any malignancy. Left axillary excisional biopsy showed a pattern consistent with RDD. The patient was started on interferon therapy by the hematologist and pleurodesis after repeated pleural taps failed to relieve recurrent right pleural effusions. This case emphasizes the importance of tissue diagnosis to avoid misdiagnosis and unnecessary treatment.

Histopathological and Immunohistochemical Study of Acute Tubular Injury in Native Kidney Biopsy.

Background: Acute tubular injury (ATI) is a common diagnosis on renal biopsy. There are no accepted parameters to assess the severity of injury or predict recovery. An objective histologic grading system would be of immense value in clinical practice. The macrophage response to injury involves the MI phenotype which is proinflammatory and M2 which is prorepair. The study of these macrophages could aid in studying the severity and the recovery. Materials and Methods: A total of 58 native kidney biopsies with features of ATI and a minimum follow-up of 12 weeks were graded into mild, moderate and severe, using scores for simplification, sloughing, and mitosis. These scores and the density of macrophages stained with CD68, CD163, and HLA-DR were correlated with serum creatinine at presentation and with recovery. The effect of chronicity index as measured by glomerulosclerosis, tubular atrophy, and interstitial fibrosis and of co-morbidities of age, hypertension, and diabetes on the recovery pattern was also studied. Results: All three histologic scores and the grades of ATI showed positive correlation with the serum creatinine level. The densities of CD 68 + and CD163 + macrophages also showed a significant correlation with serum creatinine level. However, none of these these histological features nor the macrophage densities predicted clinical recovery. Age >60 years, hypertension, diabetes, and chronicity score on biopsy were indicators of partial and delayed recovery. Conclusion: The histopathological semiquantitative scoring system can be used routinely to grade ATI. However none of the studied parameters predicted recovery.

Unusual presentation of primary central xanthoma of the maxilla associated with impacted canine: An update on immunohistochemistry in the diagnosis.

A xanthoma is an extremely rare condition that affects the soft tissues and bones and is characterized by a predominance of lipid-rich foamy histiocytes. The onset of xanthomas is frequently accompanied by primary or secondary hyperlipidemia. Primary bone xanthomas are very uncommon benign bone lesions that are not linked to hyperlipidemia. Histopathologically, they are distinguished by histiocytes, an abundance of foam cells or xanthoma cells that contain lipids, and a paucity of multinucleated giant cells. There have only been four reports of primary maxillary xanthoma in the medical literature. We present a rare primary intrabony xanthoma of the anterior maxilla in a 23-year-old normolipidemic female patient with solitary radiolucency. Using CD68, S-100, and CD1a immunohistochemical staining, it is possible to distinguish between macrophage/non-Langerhans histiocytes and Langerhans histiocytes. Therefore, a diagnosis of a central xanthoma of the jaws must be made.

Integrated Analysis of Phagocytic and Immunomodulatory Markers in Cervical Cancer Reveals Constellations of Potential Prognostic Relevance.

Despite improvements in vaccination, screening, and treatment, cervical cancer (CC) remains a major healthcare problem on a global scale. The tumor microenvironment (TME) plays an important and controversial role in cancer development, and the mechanism of the tumor's escape from immunological surveillance is still not clearly defined. We aim to investigate the expression of CD68 and CD47 in patients with different histological variants of CC, tumor characteristics, and burden. This is a retrospective cohort study performed on paraffin-embedded tumor tissues from 191 patients diagnosed with CC between 2014 and 2021 at the Medical University Pleven, Bulgaria. Slides for immunohistochemical (IHC) evaluation were obtained, and the expression of CD68 was scored in intratumoral (IT) and stromal (ST) macrophages (CD68+cells) using a three-point scoring scale. The CD47 expression was reported as an H-score. All statistical analyses were performed using R v. 4.3.1 for Windows. Infiltration by CD68-IT cells in the tumor depended on histological type and the expression of CD47. Higher levels of the CD47 H-score were significantly more frequent among patients in the early stage. Higher levels of infiltration by CD68-ST cells were associated with worse prognosis, and the infiltration of CD68-IT cells was associated with reduced risk of death from neoplastic disease. TME is a complex ecosystem that has a major role in the growth and development of tumors. Macrophages are a major component of innate immunity and, when associated with a tumor process, are defined as TAM. Tumor cells try to escape immunological surveillance in three ways, and one of them is reducing immunogenicity by the overexpression of negative coreceptors by T-lymphocytes and their ligands on the surface of tumor cells. One such mechanism is the expression of CD47 in tumor cells, which sends a "don't eat me" signal to the macrophages and, thus, prevents phagocytosis. To our knowledge, this is the first study that has tried to establish the relationship between the CD47 and CD68 expression levels and some clinicopathologic features in CC. We found that the only clinicopathological feature implicating the level of CD68 infiltration was the histological variant of the tumor, and only for CD68-IT-high levels were these observed in SCC. High levels of CD47 expression were seen more frequently in pT1B than pT2A and pT2B in the FIGO I stage than in the FIGO II and III stages. Infiltration by large numbers of CD68-IT cells was much more common among patients with a high expression of CD47 in tumor cells. A high level of infiltration by CD68-ST cells was associated with a worse prognosis, and a high level of infiltration by CD68-ST cells was associated with a lower risk of death from cancer.

[Corrigendum] Macrophage­secreted IL­8 induces epithelial­mesen-chymal transition in hepatocellular carcinoma cells by activating the JAK2/STAT3/Snail pathway.

Subsequently to the publication of the above article, an interested reader drew to the authors' attention that a possible error had been identified in the selection of images in Figs. 1 and/or 7. After having consulted their original data, the authors realized that an erroneous image appeared on p. 593, in Fig. 7F [the 'Hep­G2 / IL­8 (5 ng/ml)' data panel], where part of this figure panel was overlapping with an image on p. 589 in Fig. 1C (the 'Hep­G2 Co­cultured' data panel). After a thorough review and verification of the data by all the authors, they have confirmed that the original data presented in the paper were accurate, and the error was solely due to the selection of an incorrect image during figure arrangement. The authors confirm that this mistake in image selection did not affect the overall conclusions reported in the article. A corrected version of Fig. 7, including the correct data for the 'Hep­G2 / IL­8 (5 ng/ml)' panel in Fig. 7F, is shown on the next page. The authors are grateful to the Editor of International Journal of Oncology for granting them the opportunity to publish this Corrigendum. All the authors agree to the publication of this Corrigendum, and apologize to the readership for any inconvenience caused. [International Journal of Oncology 46: 587­596, 2015; DOI: 10.3892/ijo.2014.2761].

TIM-3/CD68 double-high expression in Glioma: Prognostic characteristics and potential therapeutic approaches.

BACKGROUND: Immunotherapy has revolutionized the treatment of various types of tumors, but there has been no breakthrough in the treatment of gliomas. The aim of this study is to discover valuable immunotherapy target in glioma, analyze its expression in glioma and the related microenvironment, explore potential immunotherapy strategies, and propose new possibilities for the treatment of gliomas. METHODS: Immunohistochemistry (IHC) and multiplex fluorescence immunohistochemistry (mIHC) were used to analyze the expression of common immune markers and checkpoints in 187 glioma patients from Sun Yat-sen University Caner Center (SYSUCC). Bioinformatics analysis was used to examine the expression of TIM-3 in different macrophages using the Chinese Glioma Genome Atlas (CGGA) single-cell sequencing database. The Kaplan-Meier curve was used to predict the prognostic value of samples with high TIM-3 and CD68 expression. The R package was used to analyze the somatic mutation status and the sensitivity of small molecule inhibitors in TIM-3/CD68 double-high expression samples. RESULTS: TIM-3 is a relatively highly expressed immune checkpoint in glioma. Unlike other tumors, TIM-3 is mainly expressed on macrophages in the glioma microenvironment. TIM-3/CD68 double-high expression suggests poor survival in glioma and may be a new upgrade marker in both IDH-mutant glioma and IDH-wildtype low-grade glioma (LGG) glioma (P < 0.01). Exploring the combination of TIM-3 inhibitors and p38 MAPK inhibitor may be a potential treatment direction for TIM-3/CD68 double high expression gliomas in the future. CONCLUSIONS: The combination of TIM-3 and CD68 holds significant importance as a potential target for both prognosis and therapeutic intervention in glioma.

Modulation of the intestinal mucosal and cell-mediated response against natural helminth infection in the African catfish Clarias gariepinus.

Fish gut is a versatile organ serving as the primary pathway for invasion by pathogens, particularly parasites, playing a crucial role in modulating the intestinal adaptive immune response. This study aimed to investigate the cellular-mediated reaction, mucosal acidity, and the expression of proliferating cell nuclear antigen (PCNA), vascular endothelial growth factor (VEGF), and CD68 in the intestines of catfish, Clarias gariepinus, naturally infected with helminths. Forty catfish were collected from the Nile River and examined for intestinal parasites. The intestinal tissues of the control and infected fish were fixed for histochemical and immunohistochemical studies. Two groups of helminths were found: cestodes Tetracampos ciliotheca and Polyonchobothrium clarias, and nematodes Paracamallanus cyathopharynx, with a prevalence rate of 63.63%, 18.0%, and 18.0%, respectively. Our results showed that the infected fish had a statistically significant rise in the activity of immune cells, including mast cells, eosinophil granular cells, and dendritic cells. This correlated with upregulation in the expressions of PCNA, VEGF, and CD68. Histochemical analyses demonstrated a marked increase in acidic mucus production, Sudan black B, and bromophenol mercury blue. This study enriches our understanding of the evolution of vertebrate immunity in combating intestinal parasitic infections and the host's adaptive responses.

Immunohistochemical-properties of the dermal embryonic telocytes.

The current investigation aims to study the embryonic dermis formed in the early stages of development and identify the initial interstitial components of the dermis that serve as biological and structural scaffolds for the development of the dermal tissue. To investigate the dermal structure, the current study used morphological and immunological techniques. TCs identified by TEM. They had a cell body and unique podomeres and podoms. They formed a 3D network spread throughout the dermis. Homocellular contact established between them, as well as heterocellular contacts with other cells. Immunohistochemical techniques using specific markers for TCss CD34, CD117, and VEGF confirmed TC identification. TCs represent the major interstitial component in the dermal tissue. They established a 3D network, enclosing other cells and structures. Expression of VEGF by TC promotes angiogenesis. TCs establish cellular contact with sprouting endothelial cells. At the site of cell junction with TCs, cytoskeletal filaments identified and observed to form the pseudopodium core that projects from endothelial cells. TCs had proteolytic properties that expressed MMP-9, CD68, and CD21. Proteolytic activity aids in the removal of components of the extracellular matrix and the phagocytosis of degraded remnants to create spaces to facilitate the development of new dermal structures. In conclusion, TCs organized the scaffold for the development of future dermal structures, including fibrous components and skin appendages. Studying dermal TCs would be interested in the possibility of developing therapeutic strategies for treating different skin disorders and diseases.

Histomorphological Evidence of Complex Cannibalism-An Uncharted Territory in Oral Squamous Cell Carcinoma.

Complex cannibalism (CxC) is an emerging new seeming entity in oral squamous cell carcinoma (OSCC) embody as a prime metabolic event in determining the aggressive potential. Owing to paucity in literature regarding it, the aim of the present study to deciphering the occurrence of CxC in OSCC. Further, the expression of cluster of differentiation 68 (CD68) was studied in tumor cells and correlated with CxC to ascertain the biological behaviour of OSCC. 30 Hematoxylin and Eosin stained sections of various grades of OSCC were scanned for CxC and correlated with clinicopathological parameters. Immunohistochemical analysis using CD68 was performed. While observing CxC in OSCC, statistically significant in age (p-0.048) and histological grades (p-0.004). CD68 expression in tumor cells was statistically significant in histopathological grades (p < 0.001) whereas on correlating with CxC (p - 0.171) was non-significant. The analogous rise in CxC and CD68 with increasing histopathological grades could aid in recognising CxC as a precise histopathological parameter to assess the aggressive biological potential in OSCC.

The VISTA/VSIG3/PSGL-1 axis: crosstalk between immune effector cells and cancer cells in invasive ductal breast carcinoma.

A checkpoint protein called the V-domain Ig suppressor of T cell activation (VISTA) is important for controlling immune responses. Immune cells that interact with VISTA have molecules, or receptors, known as VISTA receptors. Immune system activity can be modified by the interaction between VISTA and its receptors. Since targeting VISTA or its receptors may be beneficial in certain conditions, VISTA has been studied in relation to immunotherapy for cancer and autoimmune illnesses. The purpose of this study was to examine the expression levels and interactions between VISTA and its receptors, VSIG3 and PSGL-1, in breast cancer tissues. IHC analysis revealed higher levels of proteins within the VISTA/VSIG3/PSGL-1 axis in cancer tissues than in the reference samples (mastopathies). VISTA was found in breast cancer cells and intratumoral immune cells, with membranous and cytoplasmic staining patterns. VISTA was also linked with pathological grade and VSIG3 and PSGL-1 levels. Furthermore, we discovered that the knockdown of one axis member boosted the expression of the other partners. This highlights the significance of VISTA/VSIG3/PSGL-1 in tumor stroma and microenvironment remodeling. Our findings indicate the importance of the VISTA/VSIG3/PSGL-1 axis in the molecular biology of cancer cells and the immune microenvironment.

In situ analysis of neuronal injury and neuroinflammation during HIV-1 infection.

BACKGROUND: Since the introduction of combination antiretroviral therapy (cART) the brain has become an important human immunodeficiency virus (HIV) reservoir due to the relatively low penetration of many drugs utilized in cART into the central nervous system (CNS). Given the inherent limitations of directly assessing acute HIV infection in the brains of people living with HIV (PLWH), animal models, such as humanized mouse models, offer the most effective means of studying the effects of different viral strains and their impact on HIV infection in the CNS. To evaluate CNS pathology during HIV-1 infection in the humanized bone marrow/liver/thymus (BLT) mouse model, a histological analysis was conducted on five CNS regions, including the frontal cortex, hippocampus, striatum, cerebellum, and spinal cord, to delineate the neuronal (MAP2ab, NeuN) and neuroinflammatory (GFAP, Iba-1) changes induced by two viral strains after 2 weeks and 8 weeks post-infection. RESULTS: Findings reveal HIV-infected human cells in the brain of HIV-infected BLT mice, demonstrating HIV neuroinvasion. Further, both viral strains, HIV-1JR-CSF and HIV-1CH040, induced neuronal injury and astrogliosis across all CNS regions following HIV infection at both time points, as demonstrated by decreases in MAP2ab and increases in GFAP fluorescence signal, respectively. Importantly, infection with HIV-1JR-CSF had more prominent effects on neuronal health in specific CNS regions compared to HIV-1CH040 infection, with decreasing number of NeuN+ neurons, specifically in the frontal cortex. On the other hand, infection with HIV-1CH040 demonstrated more prominent effects on neuroinflammation, assessed by an increase in GFAP signal and/or an increase in number of Iba-1+ microglia, across CNS regions. CONCLUSION: These findings demonstrate that CNS pathology is widespread during acute HIV infection. However, neuronal loss and the magnitude of neuroinflammation in the CNS is strain dependent indicating that strains of HIV cause differential CNS pathologies.

Profiling of Tumour-Infiltrating Lymphocytes and Tumour-Associated Macrophages in Ovarian Epithelial Cancer-Relation to Tumour Characteristics and Impact on Prognosis.

Early evidence suggests a strong impact of tumour-infiltrating lymphocytes (TILs) on both the prognosis and clinical behaviour of ovarian cancer. Proven associations, however, have not yet translated to successful immunotherapies and further work in the field is urgently needed. We aimed to analyse the tumour microenvironment of a well-characterised cohort of ovarian cancer samples. Tumour markers were selected owing to their comparative underrepresentation in the current literature. Paraffin-embedded, formalin-fixed tumour tissue blocks of 138 patients representative of the population and including early stage disease were identified, stained for CD3, CD20, CD68 and CD163 and analysed for both the stromal and intertumoral components. Data were statistically analysed in relation to clinical details, histological subtype, borderline vs. malignant status, survival and management received. Mean stromal CD3, total CD3 count, mean stromal CD20 and total CD20 count all correlated negatively with survival. Malignant ovarian tumours consistently demonstrated significantly higher infiltration of all analysed immune cells than borderline tumours. Assessment of the stromal compartment produced a considerably higher proportion of significant results when compared to the intra-tumoural infiltrates. Customary assessment of solely intra-tumoural cells in advanced stage disease patients undergoing primary debulking surgery should be challenged, with recommendations for future scoring systems provided.