Abstract

The model of lymphocyte differentiation described for Lukes-Collins' classification of non-Hodgkin's lymphoma is related particularly to morphological alterations of nuclei of follicular center lymphocytes by antigenic stimulation. The authors carried out ultrastructural and morphometric studies to investigate morphological alterations during lymphocyte transformation on the nuclear profiles of follicular center, parafollicular and mantle zone lymphocytes in ten tonsillectomy cases of chronic hypertrophic tonsillitis. The nuclear parameters measured included nuclear area, contour index, frequency invagination and cleft, depth of invagination and nuclear diameters. Follicular centers contained a mixed population of lymphocytes consisting of untransformed (type 1), partially transformed (type 2) and fully transformed (type 3) lymphocytes. During lymphocyte transformation in both follicular, and parafollicular and mantle zones, the nuclei had a gradual and progressive increase in size. The nuclear contour index of type 2 nuclei of both follicular and parafollicular and mantle zones tended to be higher than those of type 1 and 3, indicating a greater degree of irregularity and variability of nuclear profiles. Invaginated and cleaved lymphocytes were not confined to me transformed lymphocytes. A considerable portion of lymphocytes had invaginations and clefts in parafollicular and mantle zone as well as follicular center. No difference on the depth of invagination was noted in type 1, type 2 and type 3 lymphocytes. The results indicate that some promise of the Lukes-Collins conepts of follicular center cells and the process of lymphocyte transformation in follicular centers may be necessary to revise

• Keywords: Lymphocyte;transformation;Follicular center;Ultrastructural and morphometric studies