Association of mycobacteria with Eales' disease

Eales' disease is an idiopathic disease resulting in retinal neovascularization, recurrent haemorrhages, with or without retinal detachment predominantly affecting healthy young males (97.6%) in the Indian subcontinent. Inspite of several studies, the aetiology of Eales' disease is not clear. The isolation of Mycobacterium fortuitum from the aqueous humour of a patient with classical Eales' disease, led us to hypothesize that rapid growing nontuberculous mycobacteria (RGNTM), particularly M. fortuitum and M. chelonae could be associated with Eales' disease. We therefore undertook this study to detect DNA of these RGNTM and also of M. tuberculosis in vitreous fluids (VFs) from patients with Eales' disease and non-Eales' disease.

We developed and optimized seminested polymerase chain reactions (SnPCRs) to detect DNAs of M. fortuitum and M. chelonae on archival ERMs (33) and VFs (19) of Eales' and control patients along with conventional mycobacteriological investigations.

In the retrospective study, 70 per cent ERM samples were positive for one or more Mycobacterium spp. tested by snPCR. M. fortuitum and M. chelonae were isolated from two VFs, which were also positive by sn PCR in the prospective study. Statistical evaluation of the results of both retrospective and prospective investigations showed a statistically significant association of Mycobacterium spp. with Eales' disease.

The results of the present study suggested the involvement of Mycobacterium spp. in the aetiopathogenesis of Eales' disease. Further studies on a larger sample will be required to confirm these findings.