Background
The definitive diagnosing of ocular tuberculosis (TB) is difficult; therefore, there is a need of better understanding of investigating TB DNA in presumed ocular TB patients. Objectives: The
Conclusion
Tubercular DNA detected from ocular fluids may possibly be due to bystander DNA and may not indicate primary ocular tubercular infection. Thus, caution must be exercised prior to labelling a case of uveitis as being tubercular based on the results of molecular assays on ocular fluids alone. The results of PCR on ocular fluids should be correlated with PCR on blood and systemic findings.
Methods
DNA was extracted from aqueous of cases of choroidal tuberculoma (group 1) and serpiginous choroiditis (group 2) and from vitreous of cases of vasculitis (group 3) and macular hole/retinal detachment (group 4). Gel-based PCR and real-time PCR amplification were performed using IS6110 primer on ocular fluids. The same was also performed on the blood samples of cases in which tubercular DNA was detected in the ocular fluids.
Results
Overall, 31 cases were analysed in our study. Tubercular DNA was detected in ocular fluids of seven cases: group 1, two cases (67%); group 2, one case (17%); group 3, four cases (27%); and no case of group 4. Blood samples of six of these seven patients were positive for tubercular DNA. Of these six patients, four had evidence of systemic TB and were on ATT. Two cases had no evidence of active systemic TB, yet PCR was positive from blood and ocular fluids.