SPECIFIC AND NONSPECIFIC STRUCTURES DEVELOPING IN INFLAMMATORY RHEUMATIC DISEASES

The specific morphological substrate of rheumatic fever is the Aschoff's granuloma. However, the process may also take a purely exudative course, showing no morphological characteristics whatever. The clinical picture of primary chronic polyarthritis (PCP) is determined by the exudative processes taking place in the joints and in other mesodermic cavities. The inflammation is quite noncharacteristic from a morphological aspect. Contrary to this, necrotic foci with surrounding histiogenic palisade structure should be considered specific. The substrate of necrosis may be: tendon, synovial tissue, myocardium, or arterial wall. The special immunological conditions existing in such cases are marked by the rheumatic factor being always positive. Retrospectively, the muscle‐aggressive form of rheumatic fever again gains in significance: here, morphological and immunological parallels seem to exist between rheumatic fever and PCP, two diseases that otherwise are entirely different from an etiological point of view. In either case, an auto‐aggressive immuno‐mechanism leads to local necrosis and to subsequent environmental reaction of exactly histogenous but different nature. While being only one out of many possibilities for the origination of capillary affection and exudation, the immuno‐mechanism plays the leading part in the formation of primary tissue necrosis. This is why morphological specificity in similar immuno‐mechanisms is dependent on the structure of the substrate affected in each particular case: Capillary defect means nonspecific exudation, tissue defect means specific necrosis.