Peripheral blood monocytes from patients with systemic lupus erythematosus(SLE) were isolated and examind for the presence of surface bound immunoglobulins by immunofluorescence technic using FITC labelled F(ab)'(2) fragment against IgG, A, and M. In 8 out of 20 patients examined, when tested with anti-IgG, increase amount of fluorescent staining was demonstrated. On the other hand, the staining of IgA and IgM were minimal, and were not significantly different from those of monocytes from normal volunteers. Although the staining of IgG on monocytes surface seemed to be mostly from in vivo formed immune complexes, there were no correlations between the amount of IgG and the levels of serum complement nor the levels of circulating immune complexes. These results indicate the possibility that the monocytes from patients with SLE can interact with circulating immune complexes in vivo.
monocyte surface bound immunoglobulin
systemic lupus erythematosus