Abstract
Purpose: :
Secretory phospholipase A2 (sPLA2) provides an innate defense against ocular infections. The purpose of this study is to compare the sPLA2 concentration of tears collected from patients with bacterial keratitis to tears collected from patients with nonbacterial keratitis, with both groups compared to the concentration of sPLA2 in tears from age-matched healthy controls.
Methods: :
The concentration of sPLA2 in tears was measured in 20 patients with keratitis and in 20 age-matched normal subjects. A nonstimulated tear sample of five microliters was collected from each suspected keratitis patient or healthy control subject using disposable capillaries. Tears were transferred to Eppendorf tubes and stored at -70ºC until analyzed. The concentration of sPLA2 in diluted tears was determined by the sPLA2 EIA kit (Cayman Chemical Company). Corneal scrapings from keratitis patients were collected for culture to determine the microbial etiology (bacterial, fungal, viral, parasitic).
Results: :
The sPLA2 concentration of tears collected from patients with keratitis was 152.5 ± 164.5 pg/ml and in age-matched normal subjects it was 34.2 ± 16.7 pg/ml (p=0.0001 95 CI). sPLA2 concentration of tears from patients with fungal keratitis, bacterial keratitis, viral keratitis, and Acanthamoeba keratitis were all significantly higher than the concentration of sPLA2 in control subjects (p=0.0034, p=0.0001, p=0.0052, p=0.0142 95 CI respectively). In addition, the concentration of sPLA2 in tears from bacterial keratitis patients was significantly higher than tears collected from patients with fungal, viral, and Acanthamoeba keratitis (p=0.0007, p=0.0005, p=0.0008 95 CI respectively).
Conclusions: :
The increase in the concentration of sPLA2 in tears collected from keratitis patients, particularly in patients with bacterial keratitis, is consistent with the function of this molecule as an innate host defensive factor.
Keywords: keratitis • cornea: tears/tear film/dry eye