CIRCULATING IMMUNE COMPLEXES IN VARIOUS FORMS OF BEHÇET'S DISEASE

Abstract Background. The etiology of Behget's disease (BD) is uncertain but there is strong evidence that the immune system is implicated in its pathogenesis. Methods. We assessed circulating immune complexes (CIC) in peripheral blood of 34 patients with BD, forming eight clinical groups, using a laser nephelometer to obtain more insight in the pathogenesis of different clinical forms of bd. Twenty healthy controls and eight patients with recurrent oral ulcerations were also included in the study. Results. Levels of CIC were significantly higher in patients (1.83 ± 0.93 μg/mL) than in controls (0.84 ± 0.51 μg/mL; P < 0.001). High titers were found in the groups of patients with erythema nodosum (3.14 ± 0.44 μg/mL), neurologic manifestations (2.9 ± 0.58 μg/mL), and ocular manifestations (2.34 ± 0.93 μg/mL). Compared to patients with recurrent oral ulcerations (1.91 ± 0.77 μg/mL), the mean value of CIC in patients with BD did not differ significantly, but the groups of patients having erythema nodosum, positive pathergy, and neurologic manifestations had significantly higher levels (P < 0.05) and the group of patients at the mild end of the spectrum (group 8) had a significantly lower level (1.09 ± 0.41 μg/mL) (P < 0.05). Only the groups having erythema nodosum, positive pathergy, and neurologic manifestations had significantly higher levels of CIC when compared to other groups lacking these clinical features, whereas group 8 had a significantly lower level (P < 0.05) when compared to all other groups. Conclusion. Our results show that CIC may be involved in the pathogenesis of BD, especially in those clinical forms of the disease with erythema nodosum, neurologic manifestations, and ocular manifestations. Patients at the mild end of the BD spectrum do not show significant changes in CIC levels compared to healthy control subjects. We can, therefore, suggest that in BD CIC may be implicated more in the pathogenesis of some features than of others.