Circulating antibodies to inducible heat shock protein 70 in patients with uveitis

Heat shock proteins with molecular weight 70 kDa (hsp70) are highly conserved immunogenic intracellular molecules. There are two main subtypes: one is expressed constitutively (hsc70), while the other is induced under stressful conditions (ihsp70). Using an ELISA directed against recombinant human ihsp70, antibody titers were determined in patients with defined ocular inflammatory conditions (Behcet's disease, Vogt-Koyanagi-Harada (VKH), pars planitis, and sarcoidosis) as well as in a group of age-matched normal volunteers. In comparison to healthy controls (n = 14, absorbance 0.269), levels were significantly elevated in Behcet's disease (n = 18; 0.412), sarcoidosis (n = 15; 0.432), and pars planitis (n = 13; 0.346), but not in VKH (n = 10; 0.263). A correlation was also noted for treatment versus no treatment in pars planitis (p = 0.028), but not in other inflammatory conditions. There was no correlation with the level of intraocular disease activity as defined by vitreous haze and vision drop. Since pars planitis is a purely ocular condition, circulating levels of ihsp antibodies likely reflect the extent of disease involvement within the eye.