MULTIPLE CLINICAL AND BIOLOGICAL AUTOIMMUNE MANIFESTATIONS IN 50 WORKERS AFTER OCCUPATIONAL EXPOSURE TO SILICA

Objectives-A self referred group of four workers from a factory produc ing scouring powder with a high silica content showed a surprisingly h igh number of features compatible with a connective tissue disease. Fu rther subjects working at the same factory were subsequently studied t o evaluate the relation between this exposure and the development of a utoimmune processes. Methods-A total of 50 subjects (44 women, six men ; mean (SD) age 43.7 (5.5) years; mean duration of employment 6.1 year s) underwent a prospective study including clinical history and physic al examination, an immunobiological study, HLA typing, radiological an d functional oesophageal and respiratory examination, ophthalmological examination, and isotopic testing of salivary glands. Results-Symptom s of a systemic illness were present in 32 (64%) subjects: six with Sj ogren's syndrome; five with the criteria for systemic sclerosis; three with systemic lupus erythematosus (SLE); five with an 'overlap syndro me'; and 13 with undifferentiated findings not meeting the criteria fo r a defined disease. Antinuclear antibodies were present in 36 (72%) s ubjects; four had antibodies to native DNA, including two subjects wit h SLE, one with systemic sclerosis associated with secondary Sjogren's syndrome, and one with overlap syndrome. Anticentromere antibodies we re not detected. The frequency of HLA-DR3 was increased in the clinica lly affected subjects, but did not reach statistical significance. Con clusions-This descriptive study emphasises the high probability of wor kers occupationally exposed to silica developing a multiple spectrum o f clinical and serological autoimmune manifestations.