Immunohistochemical organization patterns of the follicular dendritic cells, myofibroblasts and macrophages in the human spleen--new considerations on the pathological diagnosis of splenectomy pieces

Abstract

There is reliable information about how changes in spleen histology are influenced by the relationship among B and T lymphocytes, macrophages, dendritic cells and myofibroblasts. Moreover, if it can be applied in the day-by-day pathology laboratory. This work intends to elucidate morpho-functional aspects of relationships of these cells in the different spleen compartments, how they are influenced by pathological conditions and how basic immunohistochemical techniques could optimize the histopathological diagnosis. We analyzed the usefulness of the monoclonal antibodies CD45RO, CD20, CD21, CD35, CD68, caldesmon, the smooth muscle alpha-actin type 1 (SMA-1) in 91 specimens. CD21(+) CD35(+) follicular dendritic cells were organized into three patterns in agreement with the immune condition of the lymphoid follicle. Smooth muscle alpha-actin type 1(+)and caldesmon(+)myofibroblasts draw two double rings: marginal-perifollicular and germinal-marginal. The latter is closely related to T-cells. CD68(+)red pulp macrophages had clear and linear configuration. The interruption of this CD68(+) linear pattern in splenic marginal zone lymphoma cases could be a criterion to differentiate it from reactive hyperplasia. CD45RO, CD20, CD21, CD68 and SMA-1 provide a basic and quality immunohistochemical battery for a better comprehension of the human spleen and could improve its histopathological diagnosis.

Keywords: Follicular dendritic cells; histopathology; immune system; immunohistochemical; macrophages; myofibroblasts; spleen.

Figure 1

A. Active secondary lymphoid follicle. SMZL and hyperplasia follicular area. Hematoxilin-eosin. B. FDCs pattern type 1. Primary lymphoid follicle. Follicular hyperplasia. CD21. C. FDCs pattern type 2. Small GC and wide MZ phase. Follicular hyperplasia. CD21. D. Follicle with small GC and wide MZ phase. Follicular hyperplasia. CD21. E. FDCs pattern type 3. SMZL. CD21. F. FDCs meshwork invaded by cells belonging to SMZL. SMZL. CD21.

Figure 2

G. Macrophage lineal drawing the red pulp sinuses. Hodgkin's lymphoma, hyperplasic area. CD68. H. Disturbance in macrophage lineal drawing. Spleen trauma, hyperplasic area. CD68. I. Myofibroblasts associated to red pulp. Follicular hyperplasia, active GC. SMA-1. J. Marginal-perifollicular myofibroblast double ring (MPDR). Follicular hyperplasia, large MZ. SMA-1. K. Germinal-marginal myofibroblast double-ring (GMDR). Large cells LNH B lymphoma, hyperplasia area. SMA-1. L. Germinal-marginal myofibroblast double-ring (GMDR). Follicular hyperplasia, large MZ. Caldesmon.

Figure 3

M. T-ring emerging from the T-cell meshwork associated to PALS. Follicular hyperplasia, large MZ.CD45RO. N. T-cell double-ring in a follicle with a small GC and wide MZ. Follicular hyperplasia, large MZ. CD45RO. O. Lymphoid follicles with T-cell double-ring in different moments of their organization next to PALS. Follicular hyperplasia, large MZ. CD45RO. P. Follicle with large GC (left). Follicle with small GC and wide MZ (right). Spleen trauma, follicular hyperplasia. CD45RO. Q. Secondary lymphoid follicle. Follicular hyperplasia, developed GC. CD20. R. Secondary lymphoid follicle (left) next to PALS (right). Follicular hyperplasia, large MZ. CD20.