IL-8 may be a marker in Latinos for nonexudative AMD

An analysis of the levels of Interleukin-8 (IL-8) and C-Reactive Protein (CRP) in the blood of individuals with bilateral, high-risk, nonexudative age-related macular degeneration (AMD) suggests that IL-8 may play a novel role as a systemic inflammatory marker in certain patients. The study was conducted among participants in the Los Angeles Latino Eye Study (LALES), a population-based study of eye disease in Latinos aged 40 or more years.

Evidence accumulated over the past 10 years increasingly suggests that inflammation plays an important role in early and advanced AMD and that inflammatory markers such as IL-8, CRP, IL-6, and complement factor H are involved in AMD progression, said Michael Javaheri, MD, a resident at the Doheny Eye Institute, Keck School of Medicine, Los Angeles.

He and colleagues looked at the amounts of CRP and IL-8 in a subset of LALES patients who had soft, indistinct, or reticular drusen, indicating that they have a high incidence of progressing to advanced AMD. Fundus photographs were taken and graded, and blood specimens were evaluated for the two markers. Controls were matched on age, gender, body mass index, smoking status, hypertension, and cardiovascular status. There were 118 subjects and 118 controls.

Logistic regression analysis was performed, adjusted for previous history of chronic illnesses such as arthritis, asthma, stroke, and myocardial infarction. Univariate and multivariate analysis results showed that increased levels of IL-8 were significantly associated with a higher risk of developing early AMD, according to Dr. Javaheri. CRP was not associated with increased risk.

"Future studies are again needed to elucidate the exact role of IL-8 in early AMD and perhaps in progression," Dr. Javaheri concluded.