[Cell reactions to amber: amber lung in experimental animals]

Workers in the amber-processing industry are heavily exposed to amber dust during the cutting and grinding. Nothing is known about the effect on the lung of inhalation of amber dust. We studied the histological changes after subcutaneous injection of amber dust in man and the rat and after inhalation of amber dust in the rat.

1. The subcutaneous injection of amber dust led to acute inflammation and later to inflammation with large numbers of macrophages and giant cells, forming giant cell granulomas. 2. There was brisk phagocytosis of the amber dust by macrophages. Digestion of amber could not be identified with certainty. 3. Moderate inhalation of amber led to intraalveolar and intrabronchial phagocytosis, predominantly by macrophages. 4. After intense, repeated inhalation (4 and 6 1/2 months post-inhalation) peribronchiolar foreign body granulomas and fibroblasts were seen. In contrast to the findings in the skin (probably related to grinding paste), no epithelioid cell granulomas were found in the lung. The tissue reactions in man are similar to those in the rat. The inflammatory and fibrotic interstitial reactions observed in the rat lung after prolonged intense exposure to amber dust suggest that chronic pulmonary damage ("chronic amber lung") could occur as a result of occupational exposure to amber dust during cutting/polishing.