Título

USEFULNESS OF LOW-VOLUME MULTIPLEX PCR FOR ETIOLOGICAL DIAGNOSIS OF INFECTIOUS UVEITIS

Objetivo

To analyze the usefulness of low-volume direct multiplex PCR of intraocular fluid for the etiological diagnosis of uveitis.

Método

Eighty-six patients with active uveitis were included in this study between July,21 and Nov,23. All patients had, at least, (2+) cells in anterior chamber or vitreous haze (SUN). All patients signed the informed consent form. Samples were obtained by anterior chamber paracentesis (81 samples) or pars plana vitrectomy (5 samples). Twenty µl of sample was analyzed using a direct multiplex qualitative polymerase chain reaction (PCR) assay, developed by Japanese researchers for uveitis diagnosis. It detects herpes simplex virus 1 and 2; varicella-zoster virus, cytomegalovirus, Epstein-Barr virus, human herpes virus 6, human T-lymphotropic virus, Treponema pallidum and Toxoplasma gondii (Figure 1). This multiplex PCR was validated mainly in Japan.

Resultado

Uveitis was anterior in 38 cases (44.2%) and posterior in 36 cases (41.9%). In 31 cases (36%), it was the first acute episode. Uveitis was classified, based on PCR analysis and 6-month follow-up, as infectious in 57 cases (66.3%). Overall positivity was 24.4% (21 positive detection; codetection of VZV and EBV in one sample). Considering only the infectious uveitis group, the positivity increased to 36.8%. The strip PCR result contributed to change the etiological diagnosis in 11 cases (12.8%). We could not detect differences in PCR results concerning inflammation grading, duration and treatment. Detailed results are shown in Table 1.

Conclusão

For uveitis etiological diagnosis, direct strip PCR was able to demonstrate the infectious agent in 36.8% of infectious uveitis samples, with the unique characteristics of using very small sample volume and of testing for multiple pathogens all together for rapid results. Also, we did not detect any influence of uveitis grading, uveitis duration and treatment on PCR results.