Immunophenotyping of mesothelial cells and carcinoma cells with monoclonal antibodies to cytokeratins, vimentin, CEA and EMA improves the cytodiagnosis of serous effusions

Transformed Mesothelial Cells in Patients on CAPD for Medium to Long Term Periods

Objective

To describe the characteristics of abnormal cells present in the peritoneal effluent of 4 continuous ambulatory peritoneal dialysis (CAPD) patients; the cells were accidentally detected in a longitudinal study of cell populations in 83 patients.

Design

Descriptive study.

Participants

Four stable CAPD patients (2 male, 2 female).

Interventions

Peritoneal cells were collected from nocturnal peritoneal effluent (NPE) by centrifugation.

Measurements

Light microscopy, ultrastructural, cytochemical, and immunohistochemical characteristics were studied.

Results

The abnormal cells were characterized by a flat appearance, large size (diameter 100 μm) -six to ten times larger than a normal macrophage, a broad acidophilic cytoplasm with rare granulations, and a low nucleus/cytoplasm ratio. The nucleus was pyknotic, with dense chromatin and sometimes appeared fragmented. Its number presented a considerable variability between the patients and was much higher in the 2 females. This number remained stable in each patient over time. These cells were negative for betaglucuronidase and positive for PAS stain with variable intensity. A very low number of flat cells were positive for vimentin with weak intensity, whereas cytokeratin and epithelial membrane antigen (EMA) were positive in a higher number of cells with medium to strong intensity. Ultrastructural studies showed numerous short surface microvilli, cytoplasm well-developed with intracytoplasmic lumina and abundant, dispersed intermediate filaments, scattered mitochondria, and stacks of rough endoplasmic reticulum were observed. Dispersed secretory vacuoles and isolated lipid vacuoles were present.

Conclusion

All these features imply that they are mesothelial in origin and are suggestive of a change known as peritoneal squamous metaplasia. To date, the clinical follow-up of our patients has shown a benign outcome; further studies are necessary to elucidate the significance of this peritoneal squamous metaplasia in CAPD patients.

Fibrocytes Regulate Wilms Tumor 1-Positive Cell Accumulation in Severe Fibrotic Lung Disease

Collagen-producing myofibroblast transdifferentiation is considered a crucial determinant in the formation of scar tissue in the lungs of patients with idiopathic pulmonary fibrosis. Multiple resident pulmonary cell types and bone marrow-derived fibrocytes have been implicated as contributors to fibrotic lesions because of the transdifferentiation potential of these cells into myofibroblasts. In this study, we assessed the expression of Wilms tumor 1 (WT1), a known marker of mesothelial cells, in various cell types in normal and fibrotic lungs. We demonstrate that WT1 is expressed by both mesothelial and mesenchymal cells in idiopathic pulmonary fibrosis lungs but has limited or no expression in normal human lungs. We also demonstrate that WT1(+) cells accumulate in fibrotic lung lesions, using two different mouse models of pulmonary fibrosis and WT1 promoter-driven fluorescent reporter mice. Reconstitution of bone marrow cells into a TGF-α transgenic mouse model demonstrated that fibrocytes do not transform into WT1(+) mesenchymal cells, but they do augment accumulation of WT1(+) cells in severe fibrotic lung disease. Importantly, the number of WT1(+) cells in fibrotic lesions was correlated with severity of lung disease as assessed by changes in lung function, histology, and hydroxyproline levels in mice. Finally, inhibition of WT1 expression was sufficient to attenuate collagen and other extracellular matrix gene production by mesenchymal cells from both murine and human fibrotic lungs. Thus, the results of this study demonstrate a novel association between fibrocyte-driven WT1(+) cell accumulation and severe fibrotic lung disease.

Usefulness of ploidy, AgNOR and immunocytochemistry for differentiating benign and malignant cells in serous effusions

OBJECTIVE

The objective of this study was to establish the value of different markers in differentiating reactive mesothelial cells from metastatic adenocarcinomatous cells in serous effusions (SE).

METHODS

Forty-five SE were processed for morphological examination (Papanicolaou stain), assessment of ploidy, AgNOR counting and immunocytochemical assay of carcinoembryonic antigen (CEA), epithelial membrane antigens (EMA), Ber-EP4 and Leu-M1. Ploidy was established in an image-analyser in smears stained by the Feulgen stain method. AgNOR dots were counted in the smears stained with the silver nitrate assay for non-histone proteins present in the nucleolar organizer region. CEA, EMA, Ber-EP4 and Leu-M1 were evaluated by immunocytochemistry using the streptavidin-biotin complex method.

RESULTS

All the smears with positive cytology were aneuploid. Three false negatives by morphological studies were aneuploid, with AgNOR values in two of them corresponding to the neoplastic group. CEA and Leu-M1 showed a low specificity; EMA and Ber-EP4 showed moderate sensitivity.

CONCLUSIONS

The assessment of ploidy and the study of AgNOR were better methods than immunocytochemistry for distinguishing between reactive mesothelial cells and adenocarcinomatous cells in serous fluid.

Evaluation of seven tumour markers in pleural fluid for the diagnosis of malignant effusions

Carcinoembryonic antigen (CEA), carbohydrate antigens 15-3, 19-9 and 72-4 (CA 15-3, CA 19-9 and CA 72-4), cytokeratin 19 fragments (CYFRA 21-1), neuron-specific enolase (NSE) and squamous cell carcinoma antigen (SCC) were evaluated in pleural fluid for the diagnosis of malignant effusions. With a specificity of 99%, determined in a series of 121 benign effusions, the best individual diagnostic sensitivities in the whole series of 215 malignant effusions or in the subgroup of adenocarcinomas were observed with CEA, CA 15-3 and CA 72-4. As expected, a high sensitivity was obtained with SCC in squamous cell carcinomas and with NSE in small-cell lung carcinomas. CYFRA and/or CA 15-3 were frequently increased in mesotheliomas. Discriminant analysis showed that the optimal combination for diagnosis of non-lymphomatous malignant effusions was CEA + CA 15-3 + CYFRA + NSE: sensitivity of 94.4% with an overall specificity of 95%. In malignant effusions with a negative cytology, 83.9% were diagnosed using this association. The association CYFRA + NSE + SCC was able to discriminate adenocarcinomas from small-cell lung cancers. Regarding their sensitivity and their complementarity, CEA, CA 15-3, CYFRA 21-1, NSE and SCC appear to be very useful to improve the diagnosis of malignant pleural effusions.

Evaluation of histochemical methods for the detection of intracytoplasmic mucin in serous effusions

We have studied 25 serous effusions containing definitive morphologic evidence of adenocarcinoma to evaluate the ability of two mucin stains (Mayer's mucicarmine, D-PAS) to detect intracytoplasmic mucin in both cytologic (cytospin) and corresponding histological (cell block) preparations. Mucicarmine stain was positive in six of 25 (24%) cytospins and 13 of 25 (52%) cell blocks. D-PAS was positive in 19 of 25 (76%) cytospins and 20 of 25 (80%) cell blocks. Eight cases were identified which showed mucicarmine positivity in the cell block but not the corresponding cytospin; prolonging incubation time resulted in a positive mucicarmine in cytospin preparations for seven of these cases. We conclude that: (i) D-PAS is a more sensitive stain for the detection of intracytoplasmic mucin in all preparations; (ii) mucicarmine shows preferential staining for cell blocks; (iii) alterations in the staining protocol may permit mucin detection by mucicarmine staining in cytologic preparations in a significant number of cases.

Immunohistochemical detection of cytotoxic lymphocytes in malignant serous effusions

The use of ancillary techniques to aid in the diagnosis of metastatic carcinoma in serous effusions has been the subject of numerous studies. In this article, we study 35 cases of malignant effusions (metastatic adenocarcinoma) and 20 benign effusions using a panel of immunohistochemical markers to determine whether changes in the subpopulations of accompanying lymphoid cells can be detected with this technique and whether such changes are associated with the presence of malignancy. We noted a significant increase in cytotoxic lymphocytes, defined as the percentage of all lymphoid cells staining with an antibody to TIA-1 (an antigen localized to the cytotoxic granule membranes of cytotoxic T cells and natural killer cells) in malignant compared with benign effusions (23% vs. 12%; P < 0.05). In addition, nearly all cases in which cytotoxic lymphocytes composed > 20% of the lymphoid cell population contained metastatic tumor. Thus, immunohistochemical staining for TIA-1 can reliably detect cytotoxic lymphocytes in cell blocks of serous effusions; in addition, a relative increase in their number is associated with the presence of malignancy.

Occurrence of intercellular spaces (windows) in metastatic adenocarcinoma in serous fluids: a cytomorphologic, histochemical, and ultrastructural study

The application of cytomorphologic criteria to the examination of serous effusions allows the reliable diagnosis of malignancy in the majority of cases. One feature observed in tissue fragments previously thought to be indicative of mesothelial origin is the presence of intercellular windows, presumably due to long surface microvilli. In this study, however, we examined cytologic preparations of 143 effusion and body-cavity washing specimens and noted distinct intercellular window formation within tissue fragments of adenocarcinoma in 13% of the cases studied. Stains for mucicarmine, Alcian blue with hyaluronidase pretreatment, and periodic acid-Schiff following diastase digestion on corresponding cell block material demonstrated that intercellular mucin contributes to such window formation in greater than half of these cases. Thus the presence of intercellular windows within tissue fragments does not, in isolation, preclude the diagnosis of malignancy in serous effusions.

Evaluation of alpha-fetoprotein assay in ascitic fluid for the diagnosis of hepatocellular carcinoma

Ascites and hepatocellular carcinoma are frequently associated. We evaluated the usefulness of alpha-fetoprotein assay in ascitic fluid versus the serum assay, for the diagnosis of hepatocellular carcinoma, in 125 patients with peritoneal effusions (31 patients with hepatocellular carcinoma, 14 with extra-hepatic malignancies and 80 with a benign effusion). Albumin and total protein were also assayed and cytological analysis of the ascitic fluid performed. Alpha-fetoprotein appeared to be lower in ascitic fluid than in serum. For a diagnostic specificity of 95%, the thresholds were 18.9 microg/l in serum and 4 microg/l in ascitic fluid and the diagnostic sensitivity of alpha-fetoprotein was identical in serum and ascitic fluid (67.7%). Various ratios between alpha-fetoprotein and albumin or total protein did not enhance the diagnostic performance. Thus alpha-fetoprotein concentration in ascitic fluid reflected the serum concentration and proved to be of similar value for the diagnosis of hepatocellular carcinoma, providing that the appropriate thresholds are considered.

Evaluation of pleural CYFRA 21-1 and carcinoembryonic antigen in the diagnosis of malignant pleural effusions

CYFRA 21-1 assay, measuring cytokeratin 19 fragments, was compared with carcinoembryonic antigen (CEA) assay, as an addition to cytological analysis for the diagnosis of malignant effusions. Both markers were determined with commercial enzyme immunoassays in pleural fluid from 196 patients. Cytological analysis and/or pleural biopsy confirmed the malignant origin of the effusion in 99 patients (76 carcinomas, nine pleural mesotheliomas and 14 non-epithelial malignancies). Effusions were confirmed as benign in 97 patients (33 cardiac failures, 39 infectious diseases--including 12 tuberculosis-- and 25 miscellaneous effusions). Both markers were significantly higher in malignant than in benign effusions. All the patients with non-epithelial malignancies presented CYFRA and CEA values lower than the 95% diagnostic specificity thresholds (100 and 6 ng ml(-1) respectively). The diagnostic sensitivity in the group of carcinomas and mesotheliomas was similar for CYFRA (58.8%) and CEA (64.7%). However, CEA had a significantly higher sensitivity in carcinomas (72.4% vs 55.3%), while CYFRA had a clearly higher sensitivity in mesotheliomas (89.9% vs 0%). Interestingly, 12 out of the 16 malignant effusions with a negative cytology were CEA and/or CYFRA positive. Regarding their high diagnostic sensitivity and their complementarity, CEA and CYFRA appear to be very useful for the diagnosis of malignant pleural effusions when cytology is negative.

Immunocytochemical staining of smears and corresponding cell blocks from serous effusions: a follow-up and comparative investigation

Recently, we have recommended immunocytochemistry on serous effusions with the monoclonal antibodies Ber-EP4 and EMA to be used as a routine procedure. In this study, our earlier defined immunocytochemical profiles were tested in daily diagnostic work for a period and the profiles were applicated on the corresponding cell blocks from the effusions, too. It is concluded that routine use of the benign, malignant epithelial, and malignant mesothelial immunocytochemical profiles is valuable and superior to cytomorphology alone. Additionally, immunocytochemical staining of smears proved slightly more sensitive than immunohistochemistry performed on sections from the cell blocks.

Immunocytological analysis of the Tn associated antigen 83D4 in serous effusions from patients with cancer: comparison with Tn soluble glycoprotein

AIMS

To determine whether the monoclonal antibody (MoAb) 83D4, previously shown to be highly specific for carcinoma cells, can be used as an immunocytological marker to discriminate between benign and malignant cells in serous effusions; and to test for a correlation between expression of the antigen reacting with MoAb 83D4 on effusion cells and the amount of soluble 83D4 antigen in effusion fluids.

METHODS

Thirty three pleural and 23 peritoneal effusions from 56 cancer patients with metastatic disease were tested for the presence of Tn associated 83D4 antigen by immunocytochemical staining, and for the presence of soluble antigen in supernatants. The patients had undergone various chemotherapy and radiation therapy protocols.

RESULTS

As a result of the various types of treatment, the cytological characteristics of the cells were often modified and the antigenic epitopes may have been altered. Positive staining for 83D4 MoAb was obtained in 36 (97%) of the 37 malignant effusions, eight (73%) of 11 suspect effusions, and three (38%) of the eight apparently benign effusions (free of malignant cells). In these latter cases, cytological reassessment showed a few suspect cells in two cases. 83D4 soluble antigen was detected in 30 of 37 malignant effusions (81%), five of 11 suspected infusions (46%), and five of eight apparently benign effusions (63%).

CONCLUSIONS

Immunocytochemical staining with anti-83D4 antibody is useful for differentiating reactive or atypical mesothelial cells from epithelial cells, especially in breast cancer effusions.

Antigen expression in normal and neoplastic canine tissues defined by a monoclonal antibody generated against canine mesothelioma cells

Monoclonal antibody (MAb) 3B5 generated against canine mesothelioma cells was applied to canine tumors and normal tissues via immunohistochemical and immunoblotting techniques to evaluate antigen binding. By use of an avidin-biotin immunoperoxidase complex (ABC) method, immunoreactivity was noted in reactive mesothelial cells and in normal tissues was observed primarily in mesothelial cell linings, endothelial cells, and smooth muscle of blood vessels and soft tissues; the reactivity was nearly equivalent in frozen or formalin-fixed, paraffin-embedded tissue sections. Use of the ABC method on formalin-fixed, paraffin-embedded tumors yielded moderate to strong cytoplasmic immunostaining of neoplastic cells in 10/11 (91%) mesotheliomas, 18/23 (78%) hemangiosarcomas, 4/10 (40%) intestinal and lung carcinomas, and < or = 20% of hemangiomas, leiomyosarcomas, leiomyomas, mammary carcinomas, and squamous cell carcinomas. No immunostaining of tumor cells was observed in fibrosarcomas, hemangiopericytomas, perianal gland carcinomas, and melanomas. Immunoblotting was performed on samples that demonstrated strong immunoreactivity with MAb 3B5 by the ABC method: mesothelioma, hemangiosarcoma, urinary bladder (smooth muscle), and lung (alveolar capillaries). These analyses showed that MAb 3B5 bound a major antigen of 78 kilodaltons (kd) and minor antigens at 56 and 54 kd in normal and neoplastic tissues. The preliminary immunohistochemical results suggest that MAb 3B5 may possess utility in diagnosis of mesotheliomas and hemangiosarcomas, discrimination of cell types in proliferative serosal lesions, and demonstration of vascularity or angiogenesis in neoplastic and inflammatory lesions.

Immunofluorescent staining of metastatic carcinoma cells in serious fluid with carcinoembryonic antibody, epithelial membrane antibody, AUA-1 and Ber-EP4

Using an indirect immunofluorescence technique, we assessed the accuracy and clinical usefulness of a panel of monoclonal and polyclonal antibodies. The panel consisted of carcinoembryonic antibody (CEA) and epithelial membrane antibody (EMA), AUA-1, and Ber-EP4 conjugated with fluorescein isothiocyanate. Twenty-six specimens from pleural, peritoneal or pericardial effusions known to contain carcinoma cells (adenocarcinoma or large cell anaplastic carcinoma) and 16 specimens without carcinoma were first examined. The sensitivity and specificity for each of the antibodies were as follows: CEA, 71% and 75%; EMA, 96% and 81%; AUA-1, 80% and 100%; and Ber-EP4, 85% and 100%, respectively. The panel of antibodies was then applied to a group of 14 'problematic' fluids. These had been identified as causing dilemmas in interpretation, either because the cells in the fluids were of equivocal appearance on light microscopy, or the cytological diagnosis was different from that expected in the light of the clinical condition of the patient. Insufficient cellular material was present in one specimen. In five (39%) of the cases the immunochemical staining supported the light microscopic diagnosis. In four (30%) cases, however, the results indicated that the original light microscopic report was incorrect. Two of these were examples of large cell carcinoma of the lung, in which false negative reports had been issued on pleural fluids. The other two were cases of benign ovarian tumours in which a false positive report had been issued. The immunostaining also clarified the final diagnosis in the three patients (23%) on whom 'suspicious' cytological reports had previously been issued. The remaining case, fluid from a patient with a high grade mixed Mullerian tumour of the ovary, was unresolved. We conclude that immunofluorescent staining by AUA-1, EMA and Ber-EP4 is an aid in the cytological interpretation of serous fluids. CEA is much less helpful.

Markers for metastatic adenocarcinoma in serous effusion specimens

A variety of stains have been proposed as useful adjuncts to the morphologic diagnosis of serous effusion specimens. This study evaluates the sensitivity and specificity of nine stains for the detection of metastatic adenocarcinoma in effusions. Mucin cytochemistry with the Periodic acid-Schiff reaction after diastase digestion (PASd) and the mucicarmine method, as well as immunochemical staining for five glycoprotein antigens, was undertaken on 153 effusion specimens with histological and/or clinically confirmed diagnoses. Immunochemical stains included three antibodies to CEA (Dako polyclonal, 4E7 and A5B7) and antibodies to HEA (Ber-EP4), TAG 72 (B72.3), CD15 (LeuM1) and Epithelial membrane antigen (EMA) were evaluated. The sensitivity of the stains for adenocarcinoma (102 cases) was: PASd 37%; mucicarmine 24%; polyclonal anti-CEA 69%; 4E7 52%; A5B7 21%; EMA 91%; B72.3 44%; Ber-EP4 32%; LeuM1 24%. With the exception of EMA, none of the stains reacted with any cases of benign mesothelial cells (11 cases), reactive mesothelial cells (34 cases), or with six cases of mesothelioma. However, EMA staining was present in two cases (6%) of reactive mesothelial cells and all cases of mesothelioma. The optimal combination of stains for use in a panel was polyclonal anti-CEA/B72.3/PASd. Combined results from these three stains yielded a sensitivity of 83% for adenocarcinoma with no false positive results. It is concluded that special staining may provide valuable information to assist in the classification of difficult effusion cases.

Immunocytochemical staining of serous effusions: an additional method in the routine cytology practice?

In a consecutive and prospective cytomorphologic and immunocytochemical study we have examined 100 serous fluids with a panel of antibodies. Three different immunocytochemical patterns of staining were recognized: (i) a benign profile showing no Ber-EP4 or CEA-positive cells; (ii) a malignant profile with Ber-EP4 and strongly EMA-positive epithelial cells; and (iii) a malignant profile in which mesothelial cells were strongly positive for EMA. By applying these profiles the number of malignant cases recognized increased from 19 to 38. All cytomorphologic malignant fluids showed a malignant profile, but in two cases a malignant epithelial profile was found in patients without otherwise proven malignant disease (false positive staining). Immunocytochemistry with anti-Ber-EP4 and anti-EMA can be recommended as a routine procedure, but the marker result should always be correlated with cytomorphology, eventual histologic data and clinical records.

Immunocytochemistry in diagnostic cytology

As the decision for immunocytochemistry is usually made on the basis of findings in Papanicolaou-stained smears and uncovering of the smears takes time, the immunocytochemical results are often reported with some delay. But they are of clinical interest only if reported within a short time. Therefore, immunocytochemistry on cytologic preparations must be carefully organized. The decision for immunocytochemistry must be made before the mounting medium has completely hardened to keep the time of uncovering short. The method of immunocytochemistry should fulfill the following prerequisites: 1. Cell sampling and fixation should be easy to handle for the clinician who sends the specimen to the laboratory. 2. Unspecific background staining, especially in cytologic preparations rich in blood and protein, should not occur. 3. The immunostaining method should be applicable to all kinds of cytologic material, fixed and stained smears included. 4. The nuclear structure of tumor cells should not be destroyed by the immunocytochemical procedure so that tumor cells after incubation are clearly distinguishable from normal cells showing a similar reaction as the tumor cells. There has hitherto been no such all-round method fulfilling all these prerequisites since the properties of the antigenic epitopes of the cells and of the antibodies recognizing them are too heterogeneous. Therefore several methods have to be considered and a variety of technical aspects such as fixation, storage of cytologic material, properties of tinctorial stains, of antibodies and of the antigenic epitopes must be studied to find out the two or three standard methods which meet the requirements in most cases. We recommend the ABC method for Papanicolaou-stained smears and the APAAP method for demonstration of lymphocyte markers. The indication of immunocytochemistry in diagnostic cytology is restricted by the limited number of specimens. Therefore, the following rules have to be observed: 1. The conventional light-microscopic examination must have priority over the immunocytochemical examination. 2. The cytologic specimens assigned for immunocytochemical examination must have been adequately fixed and stored. 3. As the number of smears is limited, the immunocytochemical examinations must be carefully planned and restricted to the absolutely necessary incubations. If possible, an informative smear has to be spared for documentation and future training of cytologists and cytotechnicians. 4. Immunocytochemical examinations in cytology are only justified if the diagnostic problem can be clearly defined. 5. The panel of antibodies should be selected carefully so that the results may give an answer to alternative questions. At least two antibodies should be applied.(ABSTRACT TRUNCATED AT 400 WORDS)

AUA1: new immunocytochemical marker for detecting epithelial cells in body cavity fluids

Further to detailed genetic and biochemical characterisation of AUA1 as a surface glycoprotein present on epithelial cells, the antibody against AUA1 was used as an immunocytochemical marker of epithelial cells in body cavity fluids in an attempt to improve the diagnosis made on routine staining. AUA1 was initially tested in 144 morphologically clear cut effusions. It was positive in 46 of 52 (88%) carcinomas and negative in 82 of 84 (98%) benign effusions, including technically inadequate or poorly cellular preparations. There were no false positive results. AUA1 was subsequently used more selectively--that is, in 42 of 175 (24%) of morphologically difficult fluids. AUA1 provided essential diagnostic information in 15 of 42 (36%) and confirmed diagnosis in 17 of 42 (40%), thus enabling accurate diagnosis in a further 32 of 42 (76%) of the difficult cases. The total diagnostic accuracy was therefore 94.3%. AUA1 is a reliable immunocytochemical marker for detecting epithelial cells in body fluids. Its use improves diagnostic accuracy of morphological assessment in difficult cases.

Immunocytochemical staining of serous effusions with the monoclonal antibody Ber-EP4

Cytospin preparations were made from 102 serous effusions for immunocytochemical staining using a panel of monoclonal antibodies including a new monoclonal antibody Ber-EP4. On cytological examination, 32 fluids were reported to contain tumour cells consistent with metastatic adenocarcinoma; 66 contained benign cells only and three were reported to contain cells suspicious of malignancy. One effusion contained tumour cells consistent with malignant mesothelioma. Positive staining of the tumour cells with Ber-EP4 was observed in the 32 effusions (100%) which contained adenocarcinoma cells. No staining of the mesothelial cells in these 32 specimens was observed. Carcinoembryonic antigen, epithelial membrane antigen Ca2 and CD15 staining of tumour cells was noted in 53%, 50%, 50% and 9% of these cases, respectively. None of the mesothelial cells in the benign effusions stained with Ber-EP4. Nor did the malignant mesothelial cells in the only case of malignant mesothelioma. These findings suggest that Ber-EP4 is a valuable addition to antibodies available for the differential diagnosis of mesothelial cells and adenocarcinoma cells in serous effusions.