title: Morphometry of normal human lymphoid tissues. Nuclear invaginations and clefts.
abstract: We performed morphometric analysis on samples of human lymphoid tissue involved by reactive hyperplasia to assess the basis for the concept of cleaved lymphocyte nuclei in current non-Hodgkin's lymphoma classification. Histologic sections from all regions of lymph node showed considerable variation (usually 9% to 16%) in the proportion of nuclear profiles, with invaginations of at least 0.4 micron. Invaginations sufficiently deep to label nuclear profiles as "cleaved" occurred in 2% or less of lymphocytes of all regions seen on 1-micron plastic-embedded sections. The majority of nuclear invaginations were less than 1.6 micron deep. Analysis of the morphometric data suggests that the nuclei of germinal center lymphocytes undergoing antigen-induced transformation do not progress through a specific phase in which they become increasingly cleft. With the increased angularity and irregularity of lymphocyte nuclear profiles in germinal centers, the "cleaved" appearance of these nuclei in paraffin-embedded sections seems to be due to linear creases and overlapping segments of the nucleus.
mesh_terms: D000293:Adolescent; D000328:Adult; D002467:Cell Nucleus / Q000648:ultrastructure*; D002648:Child; D005260:Female; D006801:Humans; D008198:Lymph Nodes / Q000166:cytology*; D008214:Lymphocytes / Q000166:cytology*; D008297:Male; D008875:Middle Aged; D014066:Palatine Tonsil / Q000166:cytology; D013154:Spleen / Q000166:cytology