Blood-aqueous barrier permeability determination in HLA B27-positive acute anterior uveitis patients.

The blood-aqueous barrier (BAB) permeability was studied by fluorophotometry 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 injection 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 Student's t test and analysis of variance. A statistically significant difference (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 control subjects (4.3 +/- 1.0 x 10(-4) min-1). We also failed to detect significant differences between patients with and without spondyloarthropathy either during the acute attack or during the disease-free period. On the basis of these results we conclude that the permeability of the BAB remains intact in inactive HLA-B27-positive AAU. The parallel fluorophotometric behaviour of HLA-B27-positive AAU with spondyloarthropathy and without spondyloarthropathy suggests that both share a common pathogenetic mechanism.