Background and Design:
We have observed that tissuefixed deposits of immunoglobulin (Ig) are occasionally present in the cytoplasm (CYT) of epidermal keratinocytes. This study was conducted to examine the frequency, significance, and possible cause of this finding.
Direct immunofluorescence studies were performed on 302 sequential skin specimens obtained from patients with lupus erythematosus (n=98), bullous diseases (n=114), or other dermatoses (n=90). Abnormal epidermal CYT deposits were observed in 22 of the patients with lupus erythematosus (22.5%), four of those with bullous diseases (3.5%), and two of those with other dermatoses (2.2%). The deposits were more common in systemic than in discoid lupus erythematosus, and in skin lesions than in normal skin. By indirect immunofluorescence, circulating antibodies to epidermal upper CYT antigens were present in 100% of 12 patients with tissue-fixed CYT deposits (average antibody titer, 300) and in 21% of 19 individuals without CYT deposits (average titer, 43).
Ioannides D, Bystryn J. Association of Tissue-Fixed Cytoplasmic Deposits of Immunoglobulin in Epidermal Keratinocytes With Lupus Erythematosus. Arch Dermatol. 1993;129(9):1130–1135. doi:10.1001/archderm.1993.01680300058008