ANTINUCLEAR ANTIBODIES IN KERATINOCYTES OF THE SUN-EXPOSED AND SUN-PROTECTED NON-LESIONAL SKIN

Background: We have previously shown that the presence of antinuclear antibodies (ANA) in keratinocytes of sun-protected non-lesional (SPNL) skin may be useful in the diagnosis of mixed connective tissue diseases (MCTD) and in the prognosis of renal involvement, especially in patients with systemic lupus erythematosus (1).Objectives: This study was carried out to examine the importance of chronic sunlight exposure on in vivo ANA binding to keratinocyte nuclei.Methods: Skin specimens of sun-exposed non-lesional (SENL) and SPNL skin from the same patients with various CTD were analyzed by the standard direct immunofluorescence procedure in the period between 1995-2002.Results: Granular immune deposits, either continuous or discontinuous at the dermo-epidermal junction of SENL skin were found in 63 patients (group I) and intranuclear immunoglobulins in keratinocytes of SENL skin was observed in 18 patients (group II). There were no significant differences between these two groups in terms of sex and age.Analysis of SPNL skin of group I of patients revealed that no deposits of immunoreactants in DEJ were found in 29 patients (46%), and 16 patients (25.4%) had fewer immunoreactants and/or lower intensity of fluorescence along the DEJ. In the second group 13 patients (72.2%) had the same pattern of in vivo ANA in keratinocytes of both SENL and SPNL skin.Conclusion: We conclude that chronic sunlight exposure had significantly less influence on in vivo ANA binding to keratinocyte nuclei than on the formation of immune deposits at DEJ. Our finding is in agreement with results from in vitro experiments (2).1. Bukilica MN, Andrejevic SB, Bonaci-Nikolic BM, Nikolic MM. Speckled antinuclear antibodies in keratinocytes - What does it mean? Clin Exp Rheumatol. 20(4):499-504, 2002.; 2. Golan TD, Sigal D, Sabo E, Shemuel Z, Guedj D, Weinberger A. The penetrating potential of autoantibodies into live cells in vitro coincides with the in vivo staining of epidermal nuclei. Lupus 6:118-26, 1997.Citation: , volume , supplement , year 2003, page Session: Diagnostics and imaging procedures