Epidermal nuclear immunoglobulin deposition in connective tissue diseases

Epidermal nuclear deposition of immunoglobulins (in vivo ANA) was observed in 45 out of 252 skin biopsies (17.8%). It occurred in 19% of cases with systemic lupus erythematosus, in 32% of the mixed connective tissue disease, in 22% of the scleroderma, in 20% of the cutaneous vasculitis, in 18% of the polymyositis, in 33% of the Sjogren's syndrome, but it was absent in cases with rheumatoid arthritis. The in vivo ANA showed a significant association with serum antibodies to an extractable nuclear antigen (ENA), with speckled pattern of immunofluorescent antinuclear antibody (FANA) and with antibody to a fraction of ENA sensitive to ribonuclease termed ribonucleoprotein (RNP). Indirect evidence was obtained suggesting that the epidermal nuclear deposition of immunoglobulins is a true in vivo phenomenon: some patients with serum antibodies to ENA do not display in vivo ANA and contrariwise, no difference was detected between diseased and normal skin for the occurrence of in vivo ANA and also no association was observed between this phenomenon with immune deposits at dermoepidermal junction or in subepidermal vessels.