Expression of complement receptors (CR1 and CR3) and Fc gamma RIII on polymorphonuclears from patients with spondylarthropathies.

We assessed the expression of complement receptors (CR1 and CR3) and Fc gamma RIII on unstimulated and FMLP activated polymorphonuclears (PMNs) by indirect immunofluorescence and flow cytometry using CD35 (CR1), CD11b (CR3) and CD16 (Fc gamma RIII) monoclonal antibodies in 24 patients with spondylarthropathies (SpA) and in 18 healthy subjects. SpA patients were classified into 3 groups according to the severity of the disease (severe = asymmetrical peripheral joint involvement and permanent limitation of spine motion; moderate = one of the two items, mild = none of the items). CR1 and Fc gamma RIII expression were significantly decreased in patients with mild SpA, whereas CR1 and CR3 expression were significantly increased in patients with severe disease as compared to control subjects. In patients with mild disease, CR1 expression increased after FMLP activation, but remained significantly lower than in control subjects. The results were confirmed by immunoelectroblotting. These findings suggest that membrane and intracellular pools of CR1 and CR3 may contribute to the clinical modulation of the spondylarthropathies.