Epithelial immunoglobulin deposits and Langerhans cells in patients with primary Sjögren's syndrome

Abstract

(1a + 1b) The purpose of this study was initially to examine whether in vivo Ig deposits in unaffected skin are a feature of patients with primary and secondary SS. A novel deposition pattern of IgG in the intercellular epidermal area was found in 68% of the patients with primary SS, but in only 13% of the patients with secondary SS. DEJ Ig deposits were observed in none of the patients. (2) Different stratified squamous epithelia from patients with primary SS were examined for intraepithelial in vivo Ig deposits. In the total of 3 investigations, epidermal intercellularly located IgG was found in 57 of 84 (68%) patients with primary SS. Intraepithelial Ig deposits were also demonstrated in the oral labial and uterine cervical mucous membranes of patients with primary SS. (3) The underlying pathomechanism(s) of the intraepidermal in vivo IgG deposits was (were) examined by investigations of skin and sera from patients with primary SS. The intraepidermal IgG deposits were found located to cell surfaces of both LC and keratinocytes. Circulating IgG from patients with primary SS was shown to bind in vivo to the intercellular area of normal human epidermis, when examined in the athymic nude mouse/human skin model. However, no similar in vitro binding of circulating IgG to normal human epidermis was found. Based on these observations and on further IH skin examinations, it was hypothesized that IgG-containing IC, bound to Fc-receptors on LC and keratinocytes, may be responsible for the in vivo deposits in skin of patients with primary SS. (4) The diagnostic significance of the intraepidermal in vivo IgG deposits for primary SS was examined in studies including normal controls and patients with other CTD. Intraepidermal IgG deposits were found to be significantly more common in patients with primary SS than in normal controls (p less than 0.001), in patients with RA (p less than 0.001), in patients with SLE (p less than 0.001), in patients with SS secondary to RA and SLE (p less than 0.001) and in the total group of other well-defined CTD (p less than 0.001). The frequency of intraepidermal IgG deposits in the patients with manifest primary SS did not differ from that of patients with incipient primary SS (0.1 less than p less than 0.2), patients with Wegener's granulomatosis (0.1 less than p less than 0.2), or patients with ill-defined CTD (0.05 less than p less than 0.1).(ABSTRACT TRUNCATED AT 400 WORDS)