C R Taylor

Altered distribution of B and T lymphocytes in lymph-nodes from homosexual men with Kaposi's sarcoma.

Abstract Immunostaining of lymph-nodes from 10 homosexual men with Kaposis sarcoma by anti-B lymphocyte monoclonal antibodies revealed an abnormally exuberant follicular hyperplasia with erosion of the mantle zone and disruption of surrounding follicles. There were numerous IgD-positive and B-1-positive lymphocytes (B cells) in the interfollicular areas; these cells were uncommon at these sites in normal lymphoid tissue. In the interfollicular T zone of lymph-nodes from patients with Kaposis sarcoma the helper:suppressor ratio (0·9±0·3 SD) was significantly different from the value in controls (2·9±1·0). In nodes from Kaposis sarcoma patients there were numerous suppressor cells in the hyperplastic follicular centres and mantle regions; in normal lymphoid tissue suppressor cells were uncommon at these sites. These results implicate B lymphocyte proliferation in the pathogenesis of altered immunological status in homosexual men with Kaposis sarcoma.

Immunoperoxidase techniques applied to dermatopathology

Immunoperoxidase techniques provide the pathologist with the capability for staining a wide range of antigens in tissue sections. More than 100 different antigens have been successfully demonstrated in fixed paraffin sections; other antigens can only lie visualized in frozen sections. This latter group particularly includes lymphocyte surface antigens detectable by monoclonal antibodies. This review describes the current state of the art and provides several illustrations of the use of monoclonal antibodies for the identification of T‐lymphocyte phenotypes in fro/en section from cases of leprosy, mycosis fungoides, halo nevus, Kaposis sarcoma, lichen planus and atopic dermatitis. Technical details and potential applications arc discussed. The growing availability of commercial immunostaining kits makes these techniques more accessible to the surgical pathologist; indeed a whole new range of truly specific, special stains are available, as pathologists we must simply learn to use them.

The differentiation antigens of macrophages in human fetal liver

Macrophage populations from human fetal liver were examined for the sequential appearance of different antigenic determinant during maturation. Frozen sections of liver, from 12 to 21 weeks gestation were analyzed using a series of four monoclonal antibodies with known specificity. The macrophage monoclonal antibodies used were OKM-1, which defines monocytes, macrophages, and granulocytes; Leu M-3 and MO-2, which identify monocytes and macrophages; and 6B8, a new macrophage monoclonal antibody which binds to tissue macrophages. The staining pattern described by each of these monoclonal reagents was compared with the distribution of morphologically distinguishable tissue macrophages in fetal liver, based on the expression of surface and/or cytoplasmic antigens. The data indicate that the antigens defined by OKM-1 and 6B8 are present on large numbers of cells as early as 12 weeks gestation. In contrast, the antigenic determinants identified by Leu M-3 and MO-2 are present only on cells in 15 to 21 weeks of gestation; thus these antigens are mature differentiation antigens. Furthermore, double-staining studies confirmed that with the increase in fetal age unique macrophage populations can be identified based on the matrix of antigenic determinants. Thus, macrophage heterogeneity in the fetal liver may be a function of maturation.

Different localization of dendritic cell reservoirs in human immunodeficiency virus-1 subtype B versus subtype E-infected lymph nodes.

The presence of p24 protein was studied in lymph nodes from human immunodeficiency virus (HIV)-positive patients affected by persistent generalized lymphadenopathy. Paraffin-embedded lymph node sections from 50 HIV-1 subtype E-infected lymph nodes from patients in Thailand and 25 HIV-1 presumably subtype B-infected lymph nodes from patients in the United States were immunostained with p24 HIV major core and capsid monoclonal antibodies using the streptavidin-biotin immunoperoxidase technique. Positivity for HIV p24 protein was detected in 20 of 22 HIV-1 subtype B infected nodes in which lymphoid follicles were present, with p24 staining demonstrating a reticular pattern within the germinal centers. Interestingly, no case from 50 clade E-infected lymph nodes containing lymphoid follicles had such a reticular pattern in the germinal centers. This difference could be explained by differential infection of subsets of dendritic cells by the two HIV-1 clades, or perhaps by different routes of initial HIV-1 transmission.

Visualization of surface immunoglobulin of human B lymphocytes using microsphere—Immunoglobulin conjugate in Giemsa-stained preparations

Abstract In studies of normal and neoplastic lymphocytes it is important to correlate immunological findings with cell identification by cytological criteria. The demonstration of surface immunoglobulin (SIg) using direct immunoflourescence remains the principal method for the identification of B lymphocytes, but suffers from significant disadvantages in that preparations are not permanent and the morphological features of SIg-positive and -negative cells are not discernable. This paper describes the demonstration of lymphocyte SIg using a two-stage mixed antiglobulin procedure and polymeric microspheres coated with immunoglobulin. The labeling of cells by the immunoglobulin-coated microspheres can be assessed by light microscopy in Giemsa-stained preparations. Cytological detail is good and the method allows quantitation of the relative density of SIg of normal and neoplastic lymphoid cells.