Alpha 1-antitrypsin phenotypes in acute anterior uveitis.

The alpha 1-antitrypsin phenotype PiMZ has been reported to have a higher than normal incidence in patients with acute anterior uveitis, indicating an important role in the immunogenetics of this condition. We have determined the incidence of this phenotype in 72 patients with acute anterior uveitis. It was found to occur in four patients (5.6% of the total), with the highest incidence (3/34 or 8.8%, p less than 0.001) in patients negative for HLA B27 and without sacroiliac joint disease. The incidence in HLA B27 positive patients was normal. No correlation was found with the severity, bilaterality, or recurrence of uveitis. Although this increased incidence is statistically significant in comparison with the normal population incidence of 2.6%, its direct clinical significance is questionable; the most likely explanation for it includes possible linkage with other immunoregulatory genes. We also found a lower than expected incidence of the phenotype PiMS, and discuss the relevance of this finding.