Giant cell formation in sarcoidosis: cell fusion or proliferation with non-division?

Granulomas are inflammatory reactions featuring macrophages, epithelioid, T and multi-nucleated giant cells (MGC). Giant cells are present in a number of granulomatous reactions, but little is known about their formation and function, especially in man. We studied MGC in the granulomatous disorder sarcoidosis. In situ labelling of lymph nodes by means of [(3)H]-thymidine showed that proliferation and non-division of epithelioid cells leading towards giant cells was not observed in these granulomas. However, [(3)H]-uridine incorporation showed MGC with labelled as well as unlabelled nuclei in the same cell, pointing to a process of fusion of epithelioid cells to form giant cells. Apoptotic bodies were incidentally found in granulomas. A novel finding was that such bodies were statistically more often found in the close vicinity of MGC, but not within these cells. These apoptotic cells appeared to be CD4(+) lymphocytes or histiocytes. CD44 and CCR-5 involved in the process of fusion were expressed in MGC. In conclusion, MGC in sarcoidosis derive by cell fusion rather than by proliferation and non-division, and seem to play an active role in the induction of apoptosis in granulomas.

Biochemical parameters in BAL of sarcoisosis.

UNLABELLED: Sarcoidosis can be presented to the physician as an active or silent disorder, which may resolve or lead to pulmonary fibrosis. Various serum or bronchoalveolar lavage fluid (BAL) markers have been suggested when trying to find one marker or a combination of markers which could be representative of the disease. The aim of the study was to evaluate a number of biochemical markers in comparison to cellular parameters in BAL of 45 patients with active or inactive sarcoidosis, as well as in 44 patients with other disorders and of 10 healthy volunteers. Moreover, in order to get insight into ACE activity in different compartments, ACE values in BAL and serum were compared. In active sarcoidosis BAL-procollagen-III-peptide was significantly increased in contrast to the very low values in inactive disease. In healthy volunteers procollagen-III-peptide levels were below the detection limit. In BAL no significant differences were found for beta-2-microglobulin, hyaluronan or ACE. Laminin in BAL was not detectable. Serum ACE, significantly enhanced in sarcoidosis, was not discriminative between active and inactive disease. IN CONCLUSION: only procollagen-III-peptide in BAL was found to discriminate between active and inactive disease. Besides cell differentiation and T-helper/suppressor cell (CD4/CD8) ratio in BAL, no further biochemical parameters pointing to disease or activity of disease were found.

Identical expression of ELAM-1, VCAM-1, and ICAM-1 in sarcoidosis and usual interstitial pneumonitis.

Extravasation of leucocytes in tissues is mediated by leucocyte-endothelial cell interactions in which adhesion molecules play an important role. Until now, two pathways have been unravelled, i.e., the LFA-1/ICAM-1 and the VLA-4/VCAM-1 pathways. ELAM-1 has been shown to be involved in granulocyte accumulation and recently also in lymphocyte migration. The role of HECA-452 is under investigation. In this study we have investigated the expression of the above-mentioned adhesion molecules in lung tissue of patients with pulmonary sarcoidosis and usual interstitial pneumonitis (UIP), and in mediastinal lymph nodes of patients with sarcoidosis. ICAM-1 (CD54) was broadly distributed on the endothelium of all the vessels found in sarcoidosis and UIP. VCAM-1 was present on the endothelium of the venules, capillaries, and arterioles in both sarcoidosis and UIP. ELAM-1 reacted with endothelial cells lining venules and capillaries in chronic progressive sarcoidosis and in the active phase of UIP but not in the stationary phases of both diseases. HECA-452 activity could be detected only on high endothelial venules within sarcoid lymph nodes. In lung tissues, macrophages bearing the ICAM-1 antigen were present in sarcoid tissue but not in the interstitium and alveolar space of UIP. LFA-1 (CD11a/CD18) and VLA-4 (CD49d/CD29) were present on all leucocytes found but seemed to be more highly expressed on lymphocytes in sarcoidosis. These findings suggest that the LFA-1/ICAM-1 and VLA-4/VCAM-1 pathways are involved in leucocyte migration in both types of lung disease, while in the active phases of sarcoidosis and UIP, ELAM-1 is also involved.

Peripolesis in alveolar sarcoidosis.

We observed that in bronchoalveolar lavages (BAL) of patients with active sarcoidosis (SARC) a mononuclear cell infiltrate is present that often contains clusters consisting of lymphocytes adhering to a macrophage. In order to investigate what kind of cellular interactions are involved in such a process, cell suspensions obtained from BAL of patients with SARC or extrinsic allergic alveolitis (EAA) were cultured for 1 to 2 days, during which time lapse cinematography was applied. We were able to show that such clusters consist of lymphocytes gathered around a macrophage. This is known as peripolesis. Peripolesis, as observed in our BAL, could last for some minutes or for some hours during which time a number of lymphocytes were moving around a single alveolar macrophage, without losing contact with the macrophage. Short interactions were mostly observed in EAA, whereas SARC was characterized by long periods of lymphocyte-macrophage cooperation. We also found a correlation between the time-dependent peripolesis t > 30 min/t < 30 min and the CD4/CD8 ratio. Although the precise mechanisms of peripolesis are not well understood, some interactions between lymphocytes and macrophages have now become more comprehensive.

T lymphocytosis in a bronchoalveolar lavage of a pulmonary adenocarcinoma: case report.

We report the results of a bronchoalveolar lavage (BAL) in a patient suspected of interstitial lung disease and/or malignancy. The recovered cells from the lavage were characteristic of a high intensity alveolitis as seen in sarcoidosis. However, some adenocarcinoma cells were also found. The significance of these findings could be (a) that some immune response against this pulmonary malignancy may exist, and (b) that BAL can be used as a valuable tool to characterize the alveolitis of sarcoidosis, but carefully cytologic examination of BAL cells should be performed to exclude other causes of interstitial lung disease with an associated lymphocytic alveolitis.

Simultaneous enumeration of T-cell subsets and macrophages in bronchoalveolar lavage fluids by immunoenzyme double staining. Comparison with conventional immunofluorescence.

Bronchoalveolar lavage is a common research and clinical tool for the retrieval of cells from the lower respiratory tract. In addition to conventional morphologic study of these cells, the subtyping of T lymphocytes is often important for reaching a diagnosis of a disease or assessing its activity; subtyping is usually done by a standard immunofluorescence assay on cell suspensions requiring about 5 X 10(5) cells. Since the number of leukocytes in the lavage fluid from many patients is too small to obtain reliable information by this assay, a double immunoenzyme staining of T-lymphocyte subtypes on Cytospin preparations was utilized. This method, which requires a small number of cells, was compared with the standard immunofluorescence assay for the identification and quantitation of lymphocyte subtypes in the lavage fluids of patients with different disorders. Although the immunoenzyme double staining assay is somewhat more laborious, it provides important advantages: (1) simultaneous observation of two lymphocyte subsets and macrophages on the same slide; (2) a considerably smaller number of cells (2 X 10(4) instead of 5 X 10(5] is necessary; (3) the availability of permanent preparations; (4) the possibility of storing the Cytospin slides before staining; and (5) conventional light microscopy can be used. Since the reliability of both techniques appeared to be the same, the double staining assay for routine usage with bronchoalveolar lavage fluids appears to be preferable.