RESUMO
INTRODUCTION: Mannose binding lectin (MBL) has been linked to predisposition to systemic lupus erythematosus (SLE) and to disease activity. Some studies found deposits of MBL in glomerular tissue of patients with lupus nephritis. There is no research about the deposition of MBL in skin. MATERIALS AND METHODS: Skin biopsies from lesional and non lesional skin of 4 discoid lupus erythematosus (DLE) and 10 SLE patients were submitted to immunofluorescence staining for IgG, IgA, IgM, C3, C4, C1q, C5b-9 and MBL. Charts were reviewed for demographic, clinical and serological data. Patients with SLE had disease activity measured by SLEDAI. RESULTS: MBL was found only in SLE lesional skin and its presence showed an association trend towards higher disease activity. Deposition of C5b-9 occurred in vessels only in patients with SLE (70%) and in the two patients with kidney involvement. CONCLUSIONS: MBL deposition was found in the lesional skin of SLE patients but not in SLE non lesional skin nor in DLE patients, and it seems to be less frequent and less strong than observed in the kidneys biopsies, suggesting that the complement participation in the pathophysiology of SLE process may not be the same in these two clinical manifestations.