Tumour necrosis factor-alpha levels in aqueous humour and serum from patients with uveitis: the involvement of HLA-B27

OBJECTIVE: To study the local and systemic levels of the tumour necrosis factor-alpha in patients with active uveitis and to determine the implication of TNF-alpha in rheumatological uveitis and to observe if this relationship is more significant in the B27 positive patients. PATIENTS AND METHODS: Patients were selected on the basis of a diagnosis of uveitis of any aetiology. Data from 23 patients were stratified into two categories according to the presence or absence of systemic rheumatic disease. The first group comprised nine patients with rheumatic disease; the second group contained 14 patients without rheumatic disease. The patients were also sub-classified into those who were HLA-B27 positive (14 patients) and those who were not. TNF-alpha levels in serum and aqueous humour from a group of 16 patients with uncomplicated cataracts were analysed as a control group. RESULTS: In the control group (n = 16) the serum TNF-alpha concentration was 13.1 +/- 2.9 pg/ml and the aqueous humour concentration of TNF-alpha was 0.56 +/- 1.53 pg/ml. In uveitis patients (n = 23) the serum TNF-alpha concentration was 35.35 +/- 26.77 pg/ml and the aqueous humour concentration of TNF-alpha was 15.1 +/- 1.70 pg/ml (p < 0.01). In HLA-B27 positive patients (n = 9) the serum TNF-alpha concentration was 45.56 +/- 34.17 pg/ml and the aqueous humour concentration of TNF-alpha was 15.89 +/- 0.93 pg/ml. In HLA-B27 negative patients (n = 14) the serum TNF-alpha concentration was 28.79 +/- 19.38 pg/ml and aqueous humour concentration of TNF-alpha was 14.57 +/- 1.91 pg/ml (p < 0.01). CONCLUSIONS: The concentration of TNF-alpha in aqueous humour in patients who are HLA-B27 positive is significantly greater than in those who are B27 negative. No significant differences in the concentrations of TNF-alpha in serum or aqueous humour in patients with or without rheumatic diseases were detected. TNF-alpha is a cytokine that may participate actively in the pathogenesis of clinical uveitis.