Distribution of basement membrane laminin and type IV collagen in human reactive lymph nodes.

The location of two basement membrane components, laminin and the 7-S domain of type IV collagen, was studied in human lymph nodes using the peroxidase-antiperoxidase method. Basement membrane antigens were present on the walls of blood vessels and of marginal, trabecular and medullary sinuses. Thin, fragmented fibre-like staining was present also in parenchyma outside the germinal centres, in a pattern overlapping with reticular fibres as seen on conventional reticulin stains. This finding suggests that basement membrane components are a part of the reticular fibres of lymph nodes, or are closely associated with them.