title: Immunohistocytochemical correlation of DAP IV-CD 26 reactivity with immunologic markers of lymphocyte activation in human lymphoid tissues.
abstract: The topographic distribution of the dipeptidylaminopeptidase IV (DAP IV-CD 26) and II (DAP II) positive T-cell population in six reactive lymph nodes and seven follicular B-cell non-Hodgkin's lymphomas (NHL) was analysed with regard to the distribution of activated T-cells, as visualized by a panel of monoclonal antibodies including Tac-CD 25, HLA-DR, OKT 9-CD 71, ICAM-1-CD 54, LFA-1-CD 11a. For comparative studies serial frozen sections of the lymph nodes were tested by enzyme histochemistry and immunohistochemistry. In addition, cell suspensions obtained from 10 B-NHL and interleukin-2 (IL-2) activated T-cells were investigated by a combined cytochemical and immunological method for simultaneous visualization of DAP IV-CD 26 cytoplasmic activity and surface immunostaining for markers of lymphocyte activation. Both in reactive and lymphomatous lymph nodes the topographic distribution of DAP IV-CD 26+ and DAP II+ lymphocytes was rather similar to that of Tac-CD 25+ lymphocytes. On the contrary, the DAP IV-CD 26 and DAP II distribution pattern substantially differed from that of the other immunologic markers. In a cell suspension of IL-2 activated T-cells, more than 80% of the cells with a blastic morphology were DAP IV-CD 26+; DAP IV-CD 26+ cells coexpressing Tac-CD 25, OKT 9-CD 71, HLA-DR positivity, relative to the total number of DAP IV-CD 26 positive cells, were 90.5%, 70.5% and 87% respectively. Only small (not activated) lymphocytes expressed a focal cytoplasmic DAP II positivity. In cell suspensions from 10 cases of B-NHL the mean percentage of DAP IV-CD 26+ Tac-CD 25+ cells was 75.8. Only a small number of DAP IV-CD 26+ cells coexpressed HLA-DR, the mean percentage being 9.6. The results support the view that DAP IV-CD 26 may be considered as a marker of lymphocyte activation; this marker seems to be restricted to T lymphocytes that reside in the T dependent areas of reactive lymph nodes and to non malignant T-cells surrounding neoplastic follicles of follicular NHL.
authors.affiliation: Division of Pathology, Centro di Riferimento Oncologico, Aviano, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Cozzi
authors.forename: A
authors.initials: A
authors.lastname: Gloghini
authors.forename: R
authors.initials: R
authors.lastname: Volpe
authors.forename: A
authors.initials: A
authors.lastname: Carbone
mesh_terms: D015703:Antigens, CD / Q000032:analysis*; D018819:Dipeptidyl Peptidase 4; D004152:Dipeptidyl-Peptidases and Tripeptidyl-Peptidases / Q000276:immunology*; D006801:Humans; D006965:Hyperplasia / Q000276:immunology; D007150:Immunohistochemistry; D008198:Lymph Nodes / Q000276:immunology* / Q000473:pathology; D008213:Lymphocyte Activation / Q000276:immunology*; D008228:Lymphoma, Non-Hodgkin / Q000276:immunology* / Q000473:pathology; D013601:T-Lymphocytes / Q000276:immunology
chemical_list: D015703:Antigens, CD; D004152:Dipeptidyl-Peptidases and Tripeptidyl-Peptidases; C100151:dipeptidyl peptidase II; D018819:Dipeptidyl Peptidase 4