To evaluate the activation state of macrophage function in patientswith age-related macular degeneration (AMD) by quantifying the productionof the proinflammatory and angiogenic factor tumor necrosis factor α(TNF-α) and by correlating its expression with dry and wet AMD.
Circulating monocytes were obtained from the blood of patients withAMD or age-matched control subjects by gradient centrifugation. The monocyteswere then analyzed for either TNF-α release from cultured macrophagesin response to retinal pigment epithelium–derived blebs and cytokinesor TNF-α messenger RNA content by reverse transcriptase–polymerasechain reaction.
In human monocytes obtained from controls and AMD patients, TNF-αwas expressed by freshly isolated monocytes and produced by macrophages inculture after stimulation with retinal pigment epithelium–derived blebs.However, wide variability in TNF-α expression was observed among differentpatients. Patients with monocytes that expressed the greatest amount of TNF-αdemonstrated higher prevalence of choroidal neovascularization.
Both controls and AMD patients vary in the activation state (definedas TNF-α expression) of circulating monocytes. Partially active monocytes,defined as high TNF-α expression, may be a biomarker to identify patientsat risk for formation of choroidal neovascularization.
Early diagnostic testing may prove useful to detect those patients whowill progress to the more severe complications of the disease.