Clinicopathological evaluation of in vivo epidermal nuclear fluorescence.

BACKGROUND: Nuclear fluorescence in keratinocytes is an occasional phenomenon, often present in autoimmune diseases, especially in connective-tissue disease (CTD); however, its clinical significance remains unclear.

AIM: To investigate the profile of patients with positive nuclear staining on direct immunofluorescence (DIF) of skin samples.

METHODS: A retrospective analysis of 28 patient records from our immunodermatology laboratory was performed between May 2003 and June 2006. Inclusion criteria were the presence of autoantibodies (IgG, IgA or IgM) or complement (C3) binding keratinocyte nuclei on DIF.

RESULTS: The most prevalent diseases related to the nuclear keratinocyte DIF staining were systemic lupus erythematosus (n = 9), mixed CTD (n = 3), overlap syndrome (n = 3), Sjögren's syndrome (n = 1), and CREST (calcinosis, Raynaud's phenomenon, oesophageal dysmotility, sclerodactyly and telangiectasia) syndrome (n = 1). Serum antinuclear antibody (ANA) was positive in 20 of 28 patients, with titres varying from 1 : 160 to 1 : 1280. Of the 20 patients with positive anti-nuclear antibodies (ANA), 17 were positive for anti-extractable nuclear antigen antibodies, 12 had anti-SSA/Ro, 11 had anti-SSB/La and 8 had anti-ribonucleoprotein. Eight patients were negative for ANA. Positive predictive value of in vivo ANA for systemic CTDs was 75%.

CONCLUSION: The present data suggest that in vivo ANA evaluation is an additional and feasible auxiliary tool for diagnosing CTDs.