Immunohistochemical evaluation of the integrity of the blood-aqueous barrier in normal and rubeotic human eyes.

Abstract

The integrity of the blood-aqueous barrier (BAB) was analyzed using an immunohistochemical technique for the demonstration of albumin. Paraffin sections of 36 normal eyes obtained from eye banks or at autopsy (mean age 62.8 +/- 15.2 years) and 46 eyes with marked iris neovascularization (mean age 54.6 +/- 25.3 years) were formalin-fixed and examined using rabbit anti-human albumin. In normal eyes, albumin staining was found in the iris stroma inside and outside the iris vessels but was not detected across the anterior iris border; albumin was present in the anterior chamber in one eye, but not internal to the nonpigmented ciliary epithelium. In rubeotic eyes, albumin staining extended along the anterior iris in all 46 cases; albumin was demonstrated in the anterior chamber in 31 eyes and along to the nonpigmented ciliary epithelium in 13 eyes. Differences between normal and rubeotic eyes were significant for intensity of albumin staining in the iris stroma and for presence of albumin along the anterior iris, within the anterior chamber, and along the ciliary epithelium (P < 0.001, chi 2 test). Our findings indicate that the BAB may be less resistant to leakage in the iris stroma than at the ciliary epithelium. BAB breakdown in rubeotic eyes occurred mainly in the iris; the ciliary epithelium was much less involved. Immunohistochemical staining for albumin appears to be useful for evaluating the integrity of the BAB in human pathologic specimens.