Degradation of amyloid A and serum amyloid A by red blood cell haemolysate in patients with familial mediterranean fever.

Enzymatic activity for the degradation of serum amyloid A (SAA) and amyloid A (AA) was detected in erythrolysates of normal subjects and patients with familial mediterranean fever. A significant difference between the activity of normal subjects and patients was not found. Serum inhibited the SAA (but not the AA) haemolysate proteolytic activity. Interindividual variation in the susceptibility of SAA to degradation by RBC haemolysates was shown. The original digestible fraction of SAA became gradually resistant to proteolytic cleavage over a 9 month period while the susceptibility of AA to degradation remained unchanged in this time period. These findings suggest that enzymatic degradation of SAA depends on the source of SAA, as well as inhibitory activity in serum.