BLOOD-AQUEOUS BARRIER PERMEABILITY DETERMINATION IN HLA B27-POSITIVE ACUTE ANTERIOR UVEITIS PATIENTS

The blood-aqueous barrier (BAB) permeability was studied by fluorophot ometry in 17 healthy control subjects and in 27 eyes from 27 patients with HLA-B27-positive acute anterior uveitis (HLA-B27 AAU). Twenty of these patients had an associated spondyloarthropathy. BAB permeability was studied during the ocular inflammatory crisis and in the disease- free periods in the same patients. Anterior chamber fluorophotometric scans were performed before and 30 minutes after the intravenous injec tion of 14 mg/kg of sodium fluorescein. The diffusion coefficient (Kd) was obtained from the ratio between the fluorescein concentration in the anterior chamber and the NPBF. Data were analyzed using the Studen t's t test and analysis of variance. A statistically significant diffe rence (P < 0.001) was found between the Kd of active HLA-B27 AAU (61.4 +/- 16.8 x 10(-4) min(-1)) and the Kd of inactive HLA-B27 AAU (4.8 +/ - 1.6 x 10(-4) min(-1)). No statistically significant differences were found between the Kd of inactive HLA-B27 AAU and the Kd of the contro l subjects (4.3 +/- 1.0 x 10(-4) min(-1)). We also failed to detect si gnificant differences between patients with and without spondyloarthro pathy either during the acute attack or during the disease-free period . On the basis of these results we conclude that the permeability of t he BAB remains intact in inactive HLA-B27-positive AAU. The parallel f luorophotometric behaviour of HLA-B27-positive AAU with spondyloarthro pathy and without spondyloarthropathy suggests that both share a commo n pathogenetic mechanism.