Morphological Characteristic Subcapsular Area of Lymph Nodes in Immune Response

Abstract

Characteristics of the subcapsular region of lymph nodes (LN) with reactive hyperplasia in various types of immunomorphological reactions. The LN were obtained after surgery and diagnostic lymphadenectomy from 50 patients with various types of reactive hyperplasia, and researched. As a control, LN were obtained from 10 almost healthy persons who died from accidental causes (forensic autopsies). The subcapsular regions of LN were investigated with histological, immunohistochemical, electron microscopic, and morphometric methods at different variants of immunomorphological reactions: (1) hyperplasia of the paracortical zone with a high content of T cells; (2) hyperplasia of lymphoid follicles with the presence of reactive centers, a high content of B cells, and plasmatization of the cortical plateau and cords; (3) sinus histiocytosis with an increase in the number of macrophages in the LN; (4) the combination of the first three reactions. The subcapsular region, which includes the subcapsular sinus and the adjoining cortical zone, reacts to antigenic stimulation in any variant of immunomorphological reactions in case of reactive hyperplasia of the LN. The most expressed changes in this area are observed in cases with a predominance of B cell humoral immune response in the LN, which is morphologically represented by hyperplasia of lymphoid follicles, high B cell content, and plasmatization of cords. With this pattern of LN in the subcapsular sinus, the total number of CD45(+) lymphocytes, CD20(+) B cells, BLA-36(+) of their activated forms, and CD10(+) immunoblasts increased. Both in the subcapsular sinus and in the adjoining cortical zone, the proliferative activity of cells, determined by Ki-67 expression, increased. It also contained a large number of plasma cells (10.6 ± 1.09%), which significantly exceeded this value, in both the control and other observed groups. Their high antibody-forming ability was confirmed immunohistochemically by detecting the λ- and κ-chains of immunoglobulins, as well as by electron microscopy, which revealed expanded tanks of the granular endoplasmic reticulum in the cytoplasm of these cells. The subcapsular region of the LN is mainly a B-dependent region that is responsible for the humoral immune response in any type of reactive hyperplasia of LN, as well as a traditional B-dependent zones (lymphoid follicles and cords).