British Journal of Rheumatology 1994,33:508-519 ORIGINAL SCIENTIFIC PAPERS LAMELLAR BODIES IN SYNOVIOCYTES, MESOTHELIUM AND SPECIFIC EPITHELIA AS POSSIBLE SITE OF AUTO-ANTIGEN IN RHEUMATOID DISEASE

Intracytoplasmic lamellar organelles identical in ultrastnicture to surfactant-containing lamellar bodies found in type II pneumocytes, have been demonstrated in other tissues, in synoviocytes and mesothelial cells, in a distribution pattern which reflects the systemic expression of rheumatoid disease. Antibodies raised against surfactant protein A (SP-A), exhibit a ranking of tissue reactivity in area, intensity and density of cells which also parallels the frequency and degree of pathological involvement characteristic of rheumatoid disease, showing in ascending order of immunopositivity, lachrymal and salivary epithelia, pulmonary parenchyma, mesothelium and synoviocytes. Maximal tissue reactivity to anti-SP-A antibodies was found in the synovium of 55 rheumatoid patients exhibiting classical histopathological appearances of RA, in a pattern of immunostaining identical to that obtained with ML30, an antibody to mycobacterial heat shock protein 65kDa which, in turn, cross-reacted with SP-A in dot blot testing. KEY WORDS: Lamellar bodies, Anti-surfactant protein A antibody, Synoviocytes, Mesothelium, Anti-mycobacterial heat shock protein 65kDa antibody, Rheumatoid disease. ALTHOUGH synovium is the site of the major inflamma-tory process in RA, other tissues, especially serosa and lung, show a high frequency of significant pathological involvement, such that recognition of the true systemi