PURPOSE OF THE STUDY.
To determine whether staphylococcal enterotoxin (SE) has a role in the pathogenesis of atopic keratoconjunctivitis (AKC) and corneal ulceration
Forty-five subjects were enrolled (18 with AKC, mean age 16.9 years; 9 with vernal keratoconjunctivitis [VKC], mean age 12.9 years; 10 with seasonal allergic conjunctivitis [SAC], mean age 21.9 years, and 8 healthy volunteers, mean age 21.6 years).
Upper tarsal conjunctiva, lower conjunctival sac, and upper lid margin skin were swabbed for bacterial cultures done once in all subjects. Culture material was used for detection of 8 superantigen genes (SEA, B, C, D, G, H, I, and tsst-1), staphylococcal coagulase gene, and protein A gene with amplification by polymerase chain reaction.
Among with 45 subjects (adolescents and older), Staphylococcus aureus was detected in 15 with AKC (83%), 3 with VKC (33%), 1 with SAC (10%), and 0 in healthy volunteers. S. aureus was detected in similar percentages from the various sites examined (24%–38%). Superantigen genes were detected in 7 subjects with AKC (39%) and 1 with VKC (11%). There were no significant differences in SE detection according to location. Corneal ulcers were observed in 7 AKC subjects (39%) and 3 VKC subjects (33%) but no in SAC subjects or healthy volunteers. Among 27 patients with AKC and VKC, SE was detected in 6 of 10 subjects (60%) with corneal ulcers and 2 of 17 subjects (12%) without corneal ulcers. Among 18 AKC subjects, SE was detected in 5 of 7 subjects (71%) with corneal ulcers and 2 or 11 subjects (18%) without corneal ulcers.
In patients with a severe type of ocular allergic disease (AKC), S. aureus and SE were detected more frequently compared with other patients and healthy volunteers. This was most notable in association with corneal ulceration, suggesting a role for SE.
This study suggests that SE has a pathogenic role in the development of ulcers in AKC. SE could produce tissue damage to the cornea by initiating an immune response or possible secondary to direct toxic effects, although SE is not a protease. The study supports the concept of prompt targeted immunomodulatory therapy to reduce morbidity from AKC, and additional studies are needed.
- Copyright © 2013 by the American Academy of Pediatrics