The purpose of the study was to investigate interleukin-6 (IL-6) levels in the tear fluid and sera of patients with Sjögren syndrome (SS).
Twelve patients with primary SS and 12 normal control subjects participated.
Tear fluid and sera were obtained from the study and the control groups. Evaluation of tear fluid and sera IL-6 levels was done by using a quantitative enzyme-linked immunosorbent assay kit. All assays were carried out blindly with respect to diagnosis.
Tear fluid IL-6 levels were measured.
The mean concentration (+/- standard error) of IL-6 in the tears of patients with SS was elevated significantly compared to that of normal control subjects (88.6+/-16.2 vs. 42.1+/-10.6 pg/ml; P < 0.05). No significant differences were noted in the serum IL-6 levels between the two groups. A significant correlation (r = 0.742, P = 0.006) was found between tear fluid IL-6 levels and the focus score of lip biopsy specimens in patients with SS.
Tear fluid IL-6 levels may serve as an important marker for tear gland involvement in SS.