Role of HLA-B27 Antigen in Acute Anterior Uveitis

Abstract

We studied the clinical features of 119 patients with HLA-B27 positive and 34 patients with HLA-B27 negative acute anterior uveitis. In the HLA-B27 positive group, a male preponderance (p＜0.05), a younger age of onset of uveitis (p＜0.005) and a more frequent recurrence were noted as compared with the HLA-B27 negative group. In both the HLA-B27 positive and negative groups, the ocular manifestation was mostly a serous iridocyclitis, and a more frequent presence of highly fibrinous exudates was noted in the HLA-B27 positive group. Mutton-fat keratic precipitates were only seen in the HLA-B27 negative group. The incidence of recurrence was 67.2% of patients in the HLA-B27 positive and 58.8% in the negative group. The average interval between recurrent attacks was longer than 1.5 years in 62.5% of the patients with a recurrence in the HLA-B27 positive group and in 75.0% in the HLA-B27 negative group. Except that simultaneous bilateral ocular inflammation happened in 3(8.8%) patients in the HLA-B27 negative group, all uveitis attacks involved a unilateral eye. In monthly distribution of uveitis attacks, a significant month to month variation with the highest incidence from December to March (p＜0.0001) was found in the HLA-B27 positive group but not in the HLA-B27 negative group. Among persistent ocular complications, posterior synechiae were the most common which presented in 31.5% of the diseased eyes in the HLA-B27 positive group and 10.4% in the HLA-B27 negative group (p＜0.01). Rubeosis iridis was found only in the HLA-B27 positive group (2.2%), and cystoid macular edema only in the HLA-B27 negative group (4.2%). A good visual prognosis was revealed in both HLA-B27 positive and negative groups. More than 90% of the diseased eyes in the HLA-B27 positive group and more than 75% in the HLA-B27 negative group had a visual acuity better than 0.5 with a uveitis duration within 6 years. Even with a uveitis duration of longer than 6 years, there were still 3/4 of diseased eyes in the HLA-B27 positive group and 2/3 in the HLA-B27 negative group having a visual acuity better than 0.5. In associated systemic illness, 75.6% of patients in the HLA-B27 positive group uniformly had an seronegative spondyloarthropathy. In contrast, 44.1% of patients in the HLA-B27 negative group had an association with systemic illness which, however, is diverse and non-specific. Serum levels of immunoglobulin (Ig)G, IgA, complement (C)3 and C4 of patients in the HLA-B27 positive group and IgA and C4 of patients in the HLA B27 negative group were statistically significantly increased as compared with the serum levels of normals, but no significant difference was revealed between the two groups. A significantly increased prevalence of positivity of C-reactive protein was also noted in the HLA-B27 positive group.