Histopathological findings in the iris of dapsone treated leprosy patients

From 43 Nepalese leprosy patients skin smear negative, and treated with dapsone (diamino diphenyl sulphone), and without any sign of active leprosy or iritis, specimens from iridectomy during cataract surgery were studied histopathologically. Of 49 iris specimens only six (12%) were found to be without any histopathological change. Atrophy of the iris stroma was seen in 63% and neovascularisation in 6% of all cases. In 16% in which the dilator muscle could be detected, it was atrophic, and in 11% the pigmented epithelium was thinned and atrophic. Cellular inflammatory infiltrations were seen in 88% of all specimens. They were mostly slight in eyes which before operation had been without posterior synechiae of the iris. In most of the eyes in which posterior synechiae had been present moderate or heavy inflammatory cell infiltrates composed of lymphocytes and plasma cells, often associated with macrophages, neutrophils, or eosinophils, were found. In five iris specimens acid fast bacilli were present. This raises the question whether these can survive systemically despite dapsone chemotherapy in the iris, thus leading to dapsone-resistant leprosy and to recurrent iritis.