Age-dependent histoarchitectural changes in human lymph nodes: an underestimated process with clinical relevance?

Abstract

Experimental evidence indicates that lymph nodes in humans undergo alterations during ageing. This is clinically important because of the crucial role of these organs in the immune system and their lymph reabsorption and drainage function. Although some age-related changes in lymph node histoarchitecture have been described, they are seldom taken into account in traditional depictions of lymph nodes. Recently introduced clinical procedures, such as intranodal vaccination or lymph node transplantation, have demonstrated the need for an accurate knowledge of these degenerative processes. In this study, superficial inguinal lymph nodes were obtained from 41 deceased patients between 17 and 98 years old. To minimize immunological influences, such as chronic diseases, specimens were only obtained from forensic pathology autopsies. An immunohistochemical analysis was carried out, on the basis of which lymph node degeneration was scored according to the numbers of lymphocytes and high endothelial venules, and degree of fibrosis and lipomatosis. We observed an age-dependent tendency towards the replacement of areas populated with diverse immune cells by connective tissue. Paradoxically, these changes were also detected in some of the nodes from younger age groups. In conclusion, lymph nodes can display degenerative changes that are mainly age-related and often diverge from the common description found in textbooks. These alterations should be taken into account when dealing with lymph nodes diagnostically and therapeutically in clinical practice.

Fig. 1

Human lymph node histology as traditionally depicted in textbooks. Under the subcapsular sinus of this J-shaped lymph node are active follicles with germinal centres separated by medullary cords. Haematoxylin and eosin staining.

Fig. 3

Upper row: CD20 staining (B-cells). Lower row: CD3 staining (T-cells). (A–D) Different sections of a lymph node with a low degeneration score (32-year-old male, fall from high building, score 1). (E and F) Different sections of a lymph node with a high degeneration score and high lipomatosis (77-year-old female, brain trauma, score 6). Note that B- and T-lymphocytes are found at the typical site in spite of degeneration.

Fig. 2

Histological examples of degeneration score. The upper row shows minimal scores (0) for low lymphocyte loss (A), low fibrosis (C) and low lipomatosis (E). The lower row shows examples of higher degeneration score (2) for lymphocyte depletion (B), advanced fibrosis (D) and advanced lipomatosis (F). Haematoxylin and eosin and Masson-Goldner staining.

Fig. 4

Human lymph node presenting degenerative features. Lipomatosis is intracapsular. Haematoxylin and eosin staining.

Fig. 5

Average degeneration score and SD according to each age group. A higher score corresponds to an increase in degenerative features.