Altered cytokine balance in the tear fluid and conjunctiva of patients with Sjögren's syndrome keratoconjunctivitis sicca

Psoriasis is a common papulosquamous skin disease. The histopathology is characterized by epidermal hyperplasia and inflammation. Recent studies suggest that keratinocyte proliferation and inflammation in psoriasis are manifestations of the same underlying pathological process. Interleukin 6 (IL-6), a cytokine that is a major mediator of the host response to tissue injury and infection, is produced by both keratinocytes and leukocytes in culture. IL-6 expression was studied in psoriatic plaques by immunoperoxidase staining with two different polyclonal anti-recombinant IL-6 antisera and by in situ nucleic acid hybridization with IL-6 cRNA probes. Epidermal and dermal cells in active psoriatic plaques from 35 psoriasis patients stained heavily for IL-6 as compared with nonlesional skin and with plaques after treatment with antimetabolic and antiinflammatory agents. Absorption of the anti-recombinant IL-6 antisera with purified fibroblast-derived IL-6 or with recombinant IL-6, but not bovine serum albumin, removed the immunostaining. Increased levels of IL-6 were detected in the plasma of patients with active psoriasis (mean 3 ng/ml) by using two different bioassays. IL-6 production by proliferating keratinocytes was suggested by IL-6-specific immunostaining in cultured normal and psoriatic keratinocytes and by the detection of mRNA specific for IL-6 in psoriatic epidermis by in situ hybridization. IL-6 stimulated the proliferation of cultured, normal human keratinocytes as assessed by two different assays. Thus, IL-6 could directly contribute to the epidermal hyperplasia seen in psoriatic epithelium as well as affect the function of dermal inflammatory cells.

We modified the conventional impression cytology technique for conjunctival study by designing a 24-well Teflon sample holder, using cellulose acetate paper cut in an asymmetrical shape, and introducing Gill's modified Papanicolaou stain. Using this modified technique, we studied 35 normal subjects and 67 patients with various ocular surface disorders, 42 of whom were later found to have squamous metaplasia. Six different cytological stages were defined based on changes of goblet cell density, nucleus, and cytoplasm, encompassing three major steps: (1) loss of goblet cells, (2) increase of cellular stratification or enlargement of superficial cells, and (3) keratinization. This staging system allowed us to correlate pathological changes with clinical findings, and to investigate the action mechanism of squamous metaplasia of conjunctival epithelium. This modified impression cytology technique may help increase understanding of various ocular surface disorders.