Differential heat shock protein overexpression and its clinical relevance in systemic lupus erythematosus

To determine which heat shock proteins (hsps) are overexpressed in systemic lupus erythematosus (SLE), and to examine the relevance of these findings to clinical disease activity.

Hsp levels in peripheral blood mononuclear cells (PBMC) of patients with SLE and normal controls were measured. Levels were analysed with respect to detailed clinical activity scores. Other hsps were also quantified in 30-50% of these samples.

There was significant increase of the 90 kilodalton heat shock protein (hsp90) in patients with SLE and active neuropsychiatric (p < 0.005) and cardiorespiratory (p < 0.01) disease. There was also significant increase of the inducible 72 kilodalton member (hsp72), but not the constitutive 73 kilodalton member (hsp73) of the hsp70 family, and no increase of the 60 kilodalton hsp (hsp60) was seen in patients compared with controls. There was no association of hsp72 with disease activity, and no correlation between hsp90 and hsp72 levels was seen in individual patients.

There may a specific role for hsp90 in distinct, clinically active subsets of patients with SLE.