Tissue-Resident Memory-Like CD8+ T Cells Exhibit Heterogeneous Characteristics in Tuberculous Pleural Effusion.

Tissue-resident memory T (TRM) cells are well known to play critical roles in peripheral tissues during virus infection and tumor immunology. Our previous studies indicated that CD69+CD4+ and CD69+CD8+ T cells in tuberculous pleural effusion (TPE) were antigen-specific memory T cells. However, the phenotypical and functional characteristics of CD8+ TRM cells in tuberculosis remain unknown. We found that CD103+CD8+ T cells were the predominant subset of CD103+ lymphocytes in TPE; both CD103 and CD69 expressed on memory CD8+ T cells from TPE were significantly increased compared with those from paired peripheral blood. Phenotypically, CD103+CD69+ and CD103+CD69-CD8+ T cells expressed higher levels of CD45RO than CD103-CD69+CD8+ T cells did; CD103+CD69-CD8+ T cells highly expressed CD27, CD127, and CD62L and some chemokine receptors. We further compared the functional differences among the four distinct CD45RO+CD8+ T subsets identified by CD103 and CD69 expression. In consist with our published results, CD69+CD8+ T cells, but not CD103+CD8+, produced high levels of IFN-γ after treatment with BCG in the presence of BFA. Nevertheless, CD103-CD69+ and CD103+CD69+ memory CD8+ T cells expressed higher levels of Granzyme B, while CD103+CD69- memory CD8+ T cells were characterized as a possibly immunosuppressive subset by highly expressing CTLA-4, CD25, and FoxP3. Furthermore, TGF-ß extremely increased CD103 expression but not CD69 in vitro. Together, CD103+CD8+ T cells form the predominant subset of CD103+ lymphocytes in TPE; CD103 and CD69 expression defines distinct CD8+ TRM-like subsets exhibiting phenotypical and functional heterogeneity. Our findings provide an important theoretical basis to optimize and evaluate new tuberculosis vaccines.

Genetic fate-mapping reveals surface accumulation but not deep organ invasion of pleural and peritoneal cavity macrophages following injury.

During injury, monocytes are recruited from the circulation to inflamed tissues and differentiate locally into mature macrophages, with prior reports showing that cavity macrophages of the peritoneum and pericardium invade deeply into the respective organs to promote repair. Here we report a dual recombinase-mediated genetic system designed to trace cavity macrophages in vivo by intersectional detection of two characteristic markers. Lineage tracing with this method shows accumulation of cavity macrophages during lung and liver injury on the surface of visceral organs without penetration into the parenchyma. Additional data suggest that these peritoneal or pleural cavity macrophages do not contribute to tissue repair and regeneration. Our in vivo genetic targeting approach thus provides a reliable method to identify and characterize cavity macrophages during their development and in tissue repair and regeneration, and distinguishes these cells from other lineages.

Purification and Immune Phenotyping of B-1 Cells from Body Cavities of Mice.

B-1 cells are fetal-origin B lymphocytes with unique developmental and functional characteristics that can generate natural, polyreactive antibodies with important functions in tissue homeostasis and immune defense. While B-1 cell frequencies in bone marrow and secondary lymphoid tissues are low, relative high frequencies exist within peritoneal and pleural cavities of mice, including both CD5+ and CD5- B-1 cells. These cells represent B-1 reservoirs that, when activated, migrate to lymphoid tissues to secrete antibodies and/or cytokines. Here, we outline efficient methods for the extraction and magnetic isolation of CD5+ B-1 cells from the peritoneal and pleural cavities as well as the separation and phenotypic characterization of CD5+ and CD5- B-1 cells by flow cytometry.

Glucocorticoid-induced leucine zipper modulates macrophage polarization and apoptotic cell clearance.

Macrophages are professional phagocytes that display remarkable plasticity, with a range of phenotypes that can be broadly characterized by the M1/M2 dichotomy. Glucocorticoid (GC)-induced leucine zipper (GILZ) is a protein known to mediate anti-inflammatory and some pro-resolving actions, including as neutrophil apoptosis. However, the role of GILZ in key macrophage function is not well understood. Here, we investigated the role of GILZ on macrophage reprogramming and efferocytosis. Using murine bone-marrow-derived macrophages (BMDMs), we found that GILZ was expressed in naive BMDMs and exhibited increased expression in M2-like macrophages (IL4-differentiated). M1-like macrophages (IFN/LPS-differentiated) from GILZ-/- mice showed higher expression of the M1 markers CD86, MHC class II, iNOS, IL-6 and TNF-α, associated with increased levels of phosphorylated STAT1 and lower IL-10 levels, compared to M1-differentiated cells from WT mice. There were no changes in the M2 markers CD206 and arginase-1 in macrophages from GILZ-/- mice differentiated with IL-4, compared to cells from WT animals. Treatment of M1-like macrophages with TAT-GILZ, a cell-permeable GILZ fusion protein, decreased the levels of CD86 and MHC class II in M1-like macrophages without modifying CD206 levels in M2-like macrophages. In line with the in vitro data, increased numbers of M1-like macrophages were found into the pleural cavity of GILZ-/- mice after LPS-injection, compared to WT mice. Moreover, efferocytosis was defective in the context of GILZ deficiency, both in vitro and in vivo. Conversely, treatment of LPS-injected mice with TAT-GILZ promoted inflammation resolution, associated with lower numbers of M1-like macrophages and increased efferocytosis. Collectively, these data indicate that GILZ is a regulator of important macrophage functions, contributing to macrophage reprogramming and efferocytosis, both key steps for the resolution of inflammation.

Transmembrane TNF and Partially TNFR1 Regulate TNFR2 Expression and Control Inflammation in Mycobacterial-Induced Pleurisy.

Pleural tuberculosis is one of the most frequent forms of extra-pulmonary tuberculosis observed in patients infected with Mycobacterium tuberculosis. Tumor Necrosis Factor (TNF) is a crucial cytokine needed to control tuberculosis infection that remains a leading cause of morbidity and mortality worldwide. TNF blockade compromises host immunity and may increase the risk of reactivation of latent infection resulting in overt pulmonary, pleural and extra-pulmonary tuberculosis. While TNF signaling is mainly considered pro-inflammatory, its requirement for the anti-inflammation process involved in the resolution of infection and tissue repair is less explored. Our study analyzes the role of TNF and TNF receptors in the control of the inflammatory process associated with Bacillus Calmette-Guérin (BCG)-induced pleurisy. This study shows that the absence of TNF causes exacerbated inflammation in the pleural cavity of BCG-infected mice which is controlled by the transmembrane TNF (tmTNF) expression. The lack of TNF is associated with an impaired cellular expression and shedding of TNFR2 in the pleural cavity. The presence of tmTNF restores the normal expression of TNFR2 on myeloid cells during BCG-induced pleurisy. We also show that absence of TNFR1 affects the expression of TNFR2 on pleural cells and inflammation in the pleural cavity of BCG-infected mice. In conclusion, tmTNF but not soluble TNF prevents pleural cavity inflammation leading to attenuation and the resolution of the inflammatory process caused by mycobacterial pleurisy in association with the expression of TNFR2 on myeloid cells.

The biology of serous cavity macrophages.

For decades, it has been known that the serous cavities, which include the peritoneal, pleural and pericardial cavities, harbour large numbers of macrophages. In particular, due to the ease of isolating these cells, the peritoneal cavity has been used as a convenient source of macrophages to examine many facets of macrophage biology over the last 50-60 years. Despite this, it is only recently that the true heterogeneity of serous cavity mononuclear phagocyte compartment, which includes macrophages and dendritic cells, has been revealed. Advances in technologies such as multi-parameter flow cytometry and the 'OMICs' revolution have uncovered the presence of distinct populations of mononuclear phagocytes in the serous cavities. Given that peritoneal macrophages have been implicated in many pathologies, including peritonitis, pancreatitis, endometriosis and acute liver injury, it is imperative to understand the biology of these cells. Here, we review the recent advances in understanding the identity, origin and function of discrete serous cavity mononuclear phagocyte subsets in homeostasis and how these may change when homeostasis is perturbed, focusing on peritoneal and pleural cavities and highlighting differences in the mononuclear phagocytes found in each.

Mutant KRAS promotes malignant pleural effusion formation.

Malignant pleural effusion (MPE) is the lethal consequence of various human cancers metastatic to the pleural cavity. However, the mechanisms responsible for the development of MPE are still obscure. Here we show that mutant KRAS is important for MPE induction in mice. Pleural disseminated, mutant KRAS bearing tumour cells upregulate and systemically release chemokine ligand 2 (CCL2) into the bloodstream to mobilize myeloid cells from the host bone marrow to the pleural space via the spleen. These cells promote MPE formation, as indicated by splenectomy and splenocyte restoration experiments. In addition, KRAS mutations are frequently detected in human MPE and cell lines isolated thereof, but are often lost during automated analyses, as indicated by manual versus automated examination of Sanger sequencing traces. Finally, the novel KRAS inhibitor deltarasin and a monoclonal antibody directed against CCL2 are equally effective against an experimental mouse model of MPE, a result that holds promise for future efficient therapies against the human condition.

Pleural effusion of malignant aetiology: cell block technique to establish the diagnosis.

We describe cases of two previously healthy women presenting with progressively worsening breathlessness for 1-2 months. In both cases, physical examination was suggestive of a left-sided pleural effusion, confirmed by chest X-ray. Analysis of aspirated fluid showed a lymphocytic exudate, but cytological analysis was negative for malignancy in both patients. CT scan revealed malignancies as the underlying cause of the effusions. Both patients were managed with intercostal drainage in order to collect a sufficient amount of pleural fluid to perform a new technique in our hospital: cell block. This proved to be extremely useful in assessing the definitive diagnosis and management of both women. We briefly discuss the approach to a malignant pleural effusion and the aid of this not-so-new technique.

[Value of Cell Block in the Diagnosis of Malignant Pleural Effusion].

Malignant pleural effusion (MPE ) is due tumor which arises from the mesothelium or metastases from tumor origniating other sites. In large, for undiagnosed unilateral pleural effusions, the most frequent and important diagnosis to be established or excluded is malignancy. Cell block is prepared from residual fluid which is centrifuged or is naturally sedimenting to obtain clots at the bottom of the container. The cell block technique is simple, relatively non-invasive, reproducible and has a high yield for malignant plerual effusion. It plays an important role in the diagnosis, guiding the treatment of maligant pleural effusion. Herein, we summarize the technologys which make the cell block, the differential diagnostic value when multiple sections of the cell block are processed for immunhistochemistry, advantages in the diagnosis of malignant pleural effusion, the clinical value of gene screening in cell block. The aim of this article is to discuss the value of cell block in diagnosis of maligant pleural effusion.

Modulatory effect of Senecio brasiliensis (Spreng) Less. in a murine model of inflammation induced by carrageenan into the pleural cavity.

ETHNOPHARMACOLOGICAL RELEVANCE: Senecio brasiliensis (Spreng) Less (S. brasiliensis), known as "Flor-das-almas", "Margaridinha" or "Maria mole", is used in folk medicine as an anti-inflammatory and to treat gastric ulcers and stomach pain. While the Senecio genus has been widely studied for its pharmacological activities to support its use in traditional medicine, few studies focus on the anti-inflammatory activities of the species. AIM OF THE STUDY: To investigate the anti-inflammatory activities of S. brasiliensis, a specie native to Brazil, using a murine model of pleurisy induced by carrageenan. MATERIAL AND METHODS: The flowers of S. brasiliensis were air-dried for 3 days and subjected to ethanol (96%) extraction for 7 days to obtain the crude extract (CE). The CE was subjected to acid-base extraction to obtain the alkaloid fraction (AF). The hexane (HEX), dichloromethane (DCM) and ethyl acetate (EtOAc) fractions were obtained by extracting from CE with different solvents. The alkaloids senecionine (Sen), integerrimine (Int) and senecionine N-oxide were obtained from AF by chromatographic fractionation and a mixture of 1,4-, 3,4-, 3,5- and 4,5-dicaffeoylquinic acids (DCQs) were obtained from the EtOAc fraction. The isolated alkaloids were identified through spectroscopic analysis of IR, NMR and LC-MS coupled with electrospray ionization mass spectrometry (ESI-MS), and the dicaffeoylquinic acids through the hierarchical key method. Swiss mice were used in the in vivo experiments. We evaluated the effect of the CE, its derived fractions (AF, HEX, DCM and EtOAc), and the isolated compounds (Sen, Int, N-oxide senecionine, and DCQs) on: leukocyte migration, exudate concentrations, myeloperoxidase (MPO) and adenosine-deaminase (ADA) activities, and tumor necrosis factor-α (TNF-α), interleukin 1ß (IL-1ß) and interleukin 17A levels in the fluid leakage from the pleural cavity using a mouse model of pleurisy induced by carrageenan. The effects of the isolated compounds, Sen, Int, N-oxide senecionine and DCQs, were also analyzed for their ability to inhibit p65 phosphorylation (p-p65) in the nuclear factor-kappa B (NF-κB) pathway in the lung tissue. MPO and ADA were analyzed by colorimetric assays, and the cytokines and protein p65 levels were determined using an enzyme immunoassay (EIA). RESULTS: The CE, its EtOAc and AF fractions, and its isolated compounds (Sen, Int and DCQs), significantly reduced leukocyte migration (P < 0.05), MPO and ADA activities (P < 0.01), and TNF-α (P < 0.05), and IL-17A levels (P < 0.01). The CE, the EtOAc and AF fractions, and the DCQs also decreased IL-1ß levels (P < 0.01). The isolated compounds, Sen, Int and the DCQs, inhibited p65 phosphorylation (NF-κB) (P < 0.05). CONCLUSION: This study demonstrated that S. brasiliensis has important anti-inflammatory properties that are capable of inhibiting activated leukocytes by decreasing neutrophil migration. This effect may be attributed to the inhibition of pro-inflammatory cytokines and the reduction of the NF-κB pathway. The compounds Sen, Int, and DCQs may be responsible for the anti-inflammatory actions of S. brasiliensis.

Purification and immune phenotyping of B-1 cells from body cavities of mice.

B-1 cells are innate-like lymphocytes that generate natural, polyreactive antibodies with important functions in tissue homeostasis and immune defense. While B-1-cell frequencies in secondary lymphoid tissues are low, relative high frequencies are found within peritoneal and pleural cavities of mice, including both CD5(+) B-1a and CD5(-) B-1b cells. They represent reservoirs of B-1 cells that can be activated for migration to lymphoid tissues to secrete antibodies and/or cytokines. Here, we outline efficient methods for the extraction and magnetic isolation of B-1a cells from the peritoneal and pleural cavities and the separation and phenotypic characterization of B-1a and B1-b cells by flow cytometry.

Immunological screening for tumor cells in serous body fluids has added value with the CELL-DYN Sapphire.

BACKGROUND: Conventional cytological examination has limited sensitivity for detecting tumor cells in serous body cavity effusions and therefore, adjuvant techniques are necessary for a reliable diagnosis. Flow cytometry has proven benefit in these circumstances. The aim of our study was to explore the feasibility of CELL-DYN Sapphire, an advanced hematology analyzer with flow cytometric capabilities, for detecting tumor cells in serous body fluids, using CD326 monoclonal antibodies, which are directed against the epithelial marker EpCAM. METHODS: One hundred and five serous fluids (39 peritoneal and 66 pleural effusions) were analyzed by the CELL-DYN Sapphire using monoclonal antibody combinations CD3/CD19 and CD45/CD326. Of all samples a cytospin preparation was made and microscopically examined; the pathology findings served as a reference. RESULTS: Using a threshold of 1% CD326+ cells, CELL-DYN Sapphire identified nine out of 12 cases with tumor cells in the serous effusions (sensitivity 75%), whereas routine cytology found eight cases (sensitivity 67%). The combination of immunophenotyping and cytology identified all 12 cases with tumor cells in the effusion fluid (sensitivity 100%). The specificities were 92% and 100%, respectively. CONCLUSIONS: We demonstrated that it is feasible to run an immunophenotypic assay on CELL-DYN Sapphire for detecting tumor cells in serous body fluids. In addition, this study confirmed that a combination of conventional cytology and flow cytometry had a very high diagnostic yield in cases of carcinomatous effusions.

ALDH(+)/CD44(+)/CD24(-) expression in cells from body cavity fluids.

BACKGROUND: Enhanced expression of aldehyde dehydrogenase 1 (ALDH1) and phenotypic markers (CD44(+)/CD24(-)) in stem cells from breast tumors has been reported. This study was undertaken to monitor expression of these markers in cells from body cavity fluids of female patients suspected to have a malignancy. METHODS: Cells from peritoneal and pleural fluids of 100 female patients were examined by diagnostic cytology and analyzed by laser flow cytometry for enhanced ALDH1 expression. Cells from 36 body cavity fluids with ALDH1(bright) fluorescence were then analyzed for the expression of CD44 and CD24 markers. RESULTS: In samples positive for malignancy, ALDH1(bright) cells with both SSC(low) and SSC(high) were seen. In 15 body cavity fluids positive for malignancy, the percentage of ALDH1(bright) cells ranged from 0.26 to 6.34% of the total cells. The percentage of ALDH1(bright) cells with CD44(+)/CD24(-) expression in these samples ranged from 0.02 to 3.66%. ALDH1(bright) cells with CD44(+)/CD24(-) expression were also present in body cavity fluids of patients in whom diagnostic cytology could not detect any malignancy. However, the percentage of ALDH1(bright) and CD44(+)/CD24(-) cells amongst the 21 body cavity fluids with negative cytology was lower than that of samples with malignancy. CONCLUSIONS: Expression of ALDH1(bright) and the CD44(+)/CD24(-) phenotype in body cavity fluids in which diagnostic cytology could not find any malignant cells suggests that this phenotype may not be restricted to the putative breast tumor stem cells. It is possible that only subsets of cells with this phenotype are the putative breast tumor stem cells.

Expression and regulation of epithelial Na+ channels by nucleotides in pleural mesothelial cells.

Pleural effusions are commonly clinical disorders, resulting from the imbalance between pleural fluid turnover and reabsorption. The mechanisms underlying pleural fluid clearance across the mesothelium remain to be elucidated. We hypothesized that epithelial Na(+) channel (ENaC) is expressed and forms the molecular basis of the amiloride-sensitive resistance in human mesothelial cells. Our RT-PCR results showed that three ENaC subunits, namely, alpha, beta, gamma, and two delta ENaC subunits, are expressed in human primary pleural mesothelial cells, a human mesothelioma cell line (M9K), and mouse pleural tissue. In addition, Western blotting and immunofluorescence microscopy studies revealed that alpha, beta, gamma, and delta ENaC subunits are expressed in primary human mesothelial cells and M9K cells at the protein level. An amiloride-inhibitable short-circuit current was detected in M9K monolayers and mouse pleural tissues when mounted in Ussing chambers. Whole-cell patch clamp recordings showed an ENaC-like channel with an amiloride concentration producing 50% inhibition of 12 microM in M9K cells. This cation channel has a high affinity for extracellular Na+ ions (K(m): 53 mM). The ion selectivity of this channel to cations follows the same order as ENaC: Li+ > Na+ > K+. The unitary Li(+) conductance was 15 pS in on-cell patches. Four ENaC subunits form a functional Na+ channel when coinjected into Xenopus oocytes. Furthermore, we found that both forskolin and cGMP increased the short-circuit currents in mouse pleural tissues. Taken together, our data demonstrate that the ENaC channels are biochemically and functionally expressed in human pleural mesothelial cells, and can be up-regulated by cyclic AMP and cyclic GMP.

Pleural cellular reaction to the filarial infection Litomosoides sigmodontis is determined by the moulting process, the worm alteration, and the host strain.

The filarial nematode Litomosoides sigmodontis model was used to decipher the complex in vivo relationships between filariae, granulomas and leukocytes in the host's pleural cavity. The study was performed from D5 p.i.: to D47 p.i. in resistant C57BL/6 mice, to D74 p.i. in susceptible BALB/c mice, and to D420 p.i. in permissive jirds. We showed that, during the first month, leukocytes only clustered as granulomas around shed cuticles (exuviae) and with eosinophils as the major constituents. In addition, carbohydrates residues became abundant on exuviae only, suggesting a glycan-dependent mechanism of eosinophil attachment. Neutrophils were absent from the pleural cavity of all rodents and from the murine granulomas, but they made up 25% of the granuloma cell population in jirds. After the first month of infection granulomas formed around developed adult worms and morphological evidence suggested that leukocytes preferentially clustered around altered, but still motile, worms. No carbohydrates were detected on these worms and neutrophils were abundant in those granulomas. Finally, a rare third type of granuloma was observed in the resistant mice only; they contained young newly moulted adult worms; typically these granulomas were attached to the lateral lines of the worm via eosinophils; this feature correlated with the persistence of carbohydrate residues on the worms' lateral lines. Neutrophils were always in low proportion in all granulomas from resistant mice, suggesting difference in their adhesive properties in these mice. In vitro neutrophil recruitment in resistant mice was similar to that observed in susceptible mice although they expressed less cell surface CD11b.

Cytology of body fluids from different sites: an approach for early diagnosis of malignancy.

Malignant effusions are a common presenting sign of malignancy and reflect dissemination. A retrospective study of all fluid samples accessioned at the Department of Pathology, TUTH from April 2000 to October 2002 were done. Over the study period, a total of 584 specimens were examined- 324 peritoneal fluid, 224 pleural fluid, 19 pericardial fluid, 9 knee joint effusion and 8 Cerebro-Spinal Fluid (CSF). One hundred and nine (18.66%) out of 584 cases were found to have malignancy, 57 were male and 52 were female. The age group of the adult male ranged from 42-78 years and female ranged from 43-62 years. Three patients were children with age ranging from 8-11 years. Adenocarcinoma was the commonest that comprised 89%, followed by Non Hodgkin's lymphoma 6.5% squamous cell carcinoma 2.7% and small cell carcinoma comprised 1.8 %. Exfoliative cytology is cheap, rapid and highly effective tool for the evaluation of body fluid and should be advised in all effusion cases.

Intraoperative pleural lavage: is it a valid prognostic factor in lung cancer?

BACKGROUND: In patients undergoing lung resection for non-small cell lung cancer (NSCLC), the primary TNM (tumor-regional lymph node-distant metastasis) staging system is the best prognostic factor. However, it is necessary to investigate other factors that could more accurately predict a patient's prognosis. In this study we evaluated the significance of positive intraoperative pre-resectional lavage in patients with NSCLC. METHODS: We enrolled 84 patients (79 men, 5 women) aged between 36 and 81 years (mean age, 64.8 years) undergoing a major lung resection for NSCLC, with no preoperative evidence of pleural effusions. Intraoperatively, the patients were given a pre-resectional pleural lavage with physiologic saline solution. The fluid was aspirated and sent to cytology. RESULTS: Pre-resectional pleural lavage was positive in 19 patients (22.6%). The lavage was positive in 7.3% in patients with early stage I disease (3/41) and 37.2% in patients with stage II/III disease. In the group of 16 patients with chest wall neoplastic involvement (T3), 9 had a positive lavage (56.2%; p = 0.05). No significant correlation was found between positive lavage and nodal status, visceral pleural involvement, or histologic findings. Patients with malignant cells in the pre-resectional lavage had a significantly shorter survival than patients with a negative lavage (p = 0.025). CONCLUSIONS: A positive cytology finding of intraoperative pre-resectional pleural lavage could be an important prognostic factor in patients undergoing major lung resection for NSCLC. Patients with a positive lavage should be upstaged. However, larger series are needed to define accurately the role of this technique in early stage lung cancer.

Significance of psammoma bodies in serous cavity fluid: a cytopathologic analysis.

BACKGROUND: Psammoma bodies (PBs) are encountered only rarely in body cavity fluids (BCF). Although to the authors' knowledge their presence in certain neoplasms (e.g., those of the thyroid, ovary, lung, brain, etc.) is established, their significance in BCF has not been well defined. METHODS: Diagnoses concerning 3335 BCF samples were reviewed from the cytopathology files for the presence of PBs over an 8-year period. Cytologic preparations included cytospin preparations and Millipore filters stained with the Papanicolaou stain. Clinicopathologic correlation was performed on any subsequent surgical studies. RESULTS: Of the 3335 BCF samples studies (2444 pleural samples, 688 peritoneal samples, and 203 pericardial samples), PBs were noted in 123 cases (3.7%). Of these 123 cases, 112 were the peritoneal fluid (91%), 10 were the pleural fluid (8.1%), and 1 was in the pericardial fluid (0.81%). All 11 cases of pleural and pericardial effusions with PBs were malignant (carcinomas of the thyroid, lung, and ovary) compared with 62 of 112 peritoneal fluid samples (55.4%) (carcinoma of the ovary and uterus and mesothelioma). Nine of the remaining 50 cases of cytologically benign peritoneal fluids with PBs detected on follow-up tissue biopsy demonstrated peritoneal metastases from ovarian or endometrial carcinoma. Therefore, 41 of 112 cases of peritoneal fluid with PBs remained benign even after clinical follow-up and/or tissue biopsy (36.6%) and demonstrated ovarian cystadenoma/cystadenofibroma, papillary mesothelial hyperplasia, endosalpingiosis, endometriosis, and other miscellaneous benign diagnoses. CONCLUSIONS: PBs in BCF is a rare finding. Although in the authors' experience their presence in pleural and pericardial effusions signifies carcinomatous involvement, in the current study, peritoneal fluids with PBs were found to be benign in a significant number of cases (36.6%). In the latter scenario and in the absence of an obvious malignancy, attempts should be made to rule out the above-mentioned benign lesions.

Factors secreted by peritoneal macrophages are cytotoxic for transformed rat pleural mesothelium and mesothelioma cells.

The report is devoted to the investigation of cytotoxic action of macrophages and asbestos on transformed mesothelium and mesothelioma cells, the characterization of its specificity, and the nature of the factors mediating it. The viability of different cells after asbestos exposure was studied in co-culture with macrophages. Mesothelioma cell lines obtained from tumors developed in vivo were the most sensitive to the cytotoxic action of macrophages and asbestos. Mesothelium cells of late passages and ras-transformed cell lines IAR2 and Rat1 were somewhat less sensitive, whereas untransformed cells of IAR2 and Rat1 lines and early passage mesothelium were low sensitive to that cytotoxic action. In experiments performed on Petri dishes with inserts that allowed treatment with asbestos of only one of two cell populations, it was shown that asbestos treatment of mesothelioma cells was necessary and sufficient for manifestation of cytotoxic effect (in the absence of macrophages asbestos caused very low cytotoxicity). The medium conditioned by macrophages was not cytototoxic by itself but it strongly enhanced cytotoxic action of asbestos on transformed mesothelium and mesothelioma cells but not on normal mesothelial cells and IAR2 and Rat1 cells (both normal and ras-transformed). The specificity of this augmenting effect for different toxicants was also investigated. It was shown that medium conditioned by macrophages enhanced cytotoxicity of hydrogen peroxide and sodium azide but not that of nonfibrous silicon dioxide, ethylmethanesulfonate, and sodium dodecylsulfate. The factor mediating this effect is thermolabile, non-dialyzable and protease-sensitive. Its m.w. is approximately 3-5 kD.