Purpose:
The results of real–time polymerase chain–reaction (PCR) and local specific IgG secretion against herpes viruses (HSV, VZV, CMV) performed in 146 aqueous humors were analysed.
Methods:
The detection of the viral genome of herpes viruses (HSV1–2, VZV, CMV) was performed by real–time polymerase chain–reaction (PCR) (sensitivity < 1 PFU/sample). Specific IgG of paired aqueous humor/serum samples were quantified by immunofluorescence and total IgG (g/l) by nephelemetry. The ratio (specific aqueous IgG / total aqueous IgG) / (specific serum IgG / total serum IgG) was determined and the local antibody secretion was considered as significant if the ratio was > 4 and negative if it was < 2 (grey zone : 2–4).
Results:
Results from 120 over the 146 aqueous specimens were not significant for both techniques. A total of 26 aqueous humors of patients with uveitis or acute retinal necrosis showed positive results for at least one technique (18%).
* ratio 2–4 in 7 cases
Delay between onset of clinical signs and aqueous sampling =
A : < 7 days for 11/13 patients
B : > 21 days for 5 patients ; 14 days for 2 patients
C : > 14 days for 4/6 patients
Conclusions:
Because of the reduced volume that can be obtained from the anterior chamber for laboratory testing, the delay between onset of clinical signs and aqueous sampling should orientate the choice of the biological tests aimed to detect viral genome and/or specific antibodies. PCR produces most of positive results in the first days after the onset of clinical signs. After two weeks of onset, the two techniques are complementary.
Keywords: clinical laboratory testing • anterior chamber • aqueous