The differential expression of heat shock proteins in rheumatic disease.

The concept of overexpression of endogenous heat shock proteins (hsps) is central to hypotheses in which hsps are implicated in the pathogenesis of autoimmune rheumatic disease. Hsps were quantitated in protein samples prepared from peripheral blood mononuclear cells (PBMC) of patients and controls by Western blotting and scanning densitometry. Evidence is presented for a specific pattern of overexpression of the 90 kDa hsp (hsp 90) and the highly inducible member of the 70 kDa hsp family (hsp 72) occurring overall in SLE relative to other diseases. Evidence is also presented for the differential expression of individual hsps in other autoimmune rheumatic diseases such as RA, primary SS and systemic sclerosis, and in other relevant conditions such as infectious diseases and multiple sclerosis. It is concluded that, while hsp 90 overexpression may have a specific role in, for example, SLE, overexpression of hsp 72 and underexpression of the constitutive member of the hsp 70 family (hsp 73) may be a more general reflection of ongoing disease states.