Immunofluorescence study of cutaneous blood vessels of 16 patients with systemic lupus erythematosus.

In 16 patients with systemic lupus erythematosus, blood vessels in the affected region of the skin were examined regarding localization of immune complexes. Deposition of IgG, IgA, IgM, IgE, beta 1C and fibrin in the vessel walls was more frequently observed in intramural and perivascular sites than in intimal sites. IgM and fibrin were usually detected in intramural sites only. In large caliber arteries of the skin the intima was the main site of deposition of immune reactants, whereas, in small-caliber vessels, including capillaries, immune reactants were more often found in intramural and perivascular sites.