Further notes about the morphostasis concept - split files

(59) Histology and immune cells.

Sometimes a glaringly obvious perspective has been staring us in the face for years without us acknowledging it. Ever since the invention of the microscope, it has been obvious that a host of different pathological conditions are accompanied by an infiltration of various immune cells. Infection, injury, neoplasms, degenerative diseases, "auto-immune" diseases, transplant rejection and, now, things like obesity and Alzheimer's disease are all associated, at some level, with the infiltration of lympho-monocytic cells and various other myeloid derived cells. Just pick up any histology textbook and the obvious cannot, justifiably, be ignored. But it is; and we still want to separate off infection as something that has a stranglehold on the immune system. Infection control remains, for most, the overriding purpose and evolutionary drive of our immune system. The latter is over-ridingly regarded as a system that chases and destroys invading organisms. Yet immune cell recruitment is common to virtually all disease. Just about any pathological condition you choose to examine shows some form of white cell infiltration and this is accompanied by an attempt to clear the debris then reconstruct the local architecture. Yes, infection may provoke an unusually intense lympho-monocytic invasion (inflammation followed by an adaptive immune amplification of the innate response) but it is far from unique in recruiting a histologically visible immune response. And the intensity of that inflammation is almost certainly a proportionate response to the damage inflicted by the infective agent on self tissue cells.