EXPRESSION AND IMMUNE RECOGNITION OF STRESS PROTEINS IN SARCOIDOSIS AND OTHER CHRONIC INTERSTITIAL LUNG-DISEASES

Stress proteins (SP) are major immunogens in a number of microbial inf ections and have been implicated in some autoimmune diseases. The aeti ology of sarcoidosis, a non-caseating granulomatous disease, remains u nknown, but mycobacteria as well as autoimmunity have been considered. In the present study, patients diagnosed with sarcoidosis and other i nterstitial lung diseases (ILD), as well as healthy volunteers were st udied to determine: (i) the level of expression of SP in alveolar macr ophages and blood monocytes; (ii) the serum levels of antibodies speci fic for mycobacterial SP65 and SP70; and (iii) the reactivity of perip heral blood and alveolar lymphocytes to mycobacterial SP65. Our result s suggest that SP are expressed constitutively at high levels in alveo lar macrophages, retrieved by bronchoalveolar lavage, from all individ uals regardless of health status. In contrast, freshly isolated blood monocytes express low levels of SP, which are, however, readily upregu lated following exposure to IFN-gamma and TNF-alpha. Lymphocyte reacti vity and presence of antibodies against mycobacterial SP may reflect t he current state of in vivo. inflammation rather than the cause of inf lammation.