The diagnostic value of intraocular fluid analysis by polymerase chain reaction in Thai patients with uveitis

Abstract

Uveitis is a major cause of severe visual impairment throughout the world and can be initiated by various infectious and non-infectious causes. Early recognition of specific infections is important as the treatment with antimicrobial agents might stop the progression or even cure the eye disease. To determine the infectious causes of uveitis in Thailand, intraocular fluid samples of 100 HIV-negative patients and 47 HIV-positive patients with uveitis were examined using real-time PCR analysis for herpes simplex virus, varicella zoster virus, cytomegalovirus and Toxoplasma gondii. Positive PCR results were found in 33/100 (33%) HIV-negative patients and in 33/47 (70%) HIV-positive patients with uveitis. In Thailand, cytomegalovirus was identified as the most frequent cause of infectious uveitis in both HIV-negative and HIV-positive patients (49 and 91%, respectively). PCR analysis of intraocular samples in uveitis was a valuable diagnostic assay. The pattern of uveitis observed in the Far East differs from that found in the West.

Aqueous humor polymerase chain reaction in uveitis – utility and safety

“…The presence of an infectious agent was also confirmed in two cases of suspected FUS found to be positive for the Herpes virus genome and who were treated accordingly . In our posterior uveitis patients, we observed a high prevalence of Toxoplasma gondii (10/45, 22.2 %) and lower rates of CMV, HSV and VZV positivity compared to Asian and US studies which reported CMV or CMV and HSV as leading infectious causes followed by Toxoplasma gondii [6, 19]. Previous systematic surveys on uveitis from Western Europe confirm Toxoplasmosis as the most common cause of infectious posterior uveitis which could be related to local customs of consumption of very rare meat and raw chopped steak [23–25].…”

“…Aqueous PCR analysis in uveitis has been previously reported [5–7, 15, 18, 19]. Harper et al reported a 20 % change in the management of patients with posterior uveitis following PCR results [6] and Rothova et al reported foreign DNA in 29 % of posterior uveitis patients with a change in management in 24 %.…”

Infectious causes of posterior uveitis and panuveitis in Thailand

“…Before extraction, 2,500-5,000 copies/ml of phocid herpes virus type 1 (PhHV-1) were added to each sample to monitor the quality of extraction and the amplification procedures [6]. Each focal pathogenic DNA was separately analyzed by real-time PCR with a repeated cycling program as previously described [7,8]. Briefly, 10 ll of the extracted nucleic acid was added to 15 ll of the real-time PCR mixture (DyNAmo TM Probe qPCR kit, New England Biolabs Inc., Keilaranta, Espoo, Finland), which contained specific primers and probes.…”

“…Briefly, 10 ll of the extracted nucleic acid was added to 15 ll of the real-time PCR mixture (DyNAmo TM Probe qPCR kit, New England Biolabs Inc., Keilaranta, Espoo, Finland), which contained specific primers and probes. Then, real-time PCR was performed in a Chromo4 TM -Realtime PCR Detector Machine (DNA Engine Ò , Bio-Rad, Hercules, CA, USA) [8].…”

Diagnostic issues in viral anterior uveitis

“…However, in certain parts of Asia a viral cause was found in 23-41% of AU in immunocompetent patients, of which CMV was the most common organism, being associated with 24-100% of cases [2,17]. Hence, the results of this paper may not be applicable in other populations.…”