SCIENTIFIC CORRESPONDENCE Conjunctival inflammation in the chronic phase of Stevens–Johnson syndrome

Aims—To understand the immunopathogenesis of the corneal conjunctivalisation in Stevens–Johnson syndrome. Methods—Conjunctivalised corneas from five patients with Stevens–Johnson syndrome were studied immunohistochemically for several cell surface antigens and two cytokines. Chemical injury specimens were also studied. Results—In all cases, immunohistochemistry revealed LFA-1, CD4, CD8, and CD68 on subepithelial infiltrating cells. Also, HLA-DR and ICAM-1 were found on the surfaces of epithelial cells, subepithelial infiltrating cells, subepithelial fibroblasts, and endothelial cells in blood vessels. IFN-ã was found in basal epithelial cells; subepithelial cells and subepithelial extracellular matrix CD19 and IL4 were not detected. Conclusions—The infiltrating cell population in the Stevens–Johnson syndrome samples includes macrophages, CD4 positive T cells, and CD8 positive T cells. The cytokine expression pattern suggests CD4 positive T cells are Th1 cells. The infiltrating cell population is similar in Stevens– Johnson syndrome and chemical injury conjunctivalised corneas. (Br J Ophthalmol 2000;84:1191–1193) Stevens–Johnson syndrome, first reported in 1922, is an acute inflammatory disease that predominantly aVects skin and mucosal membranes including the ocular surface. In the acute phase, ocular manifestations include corneal ulceration and severe pseudomembranous conjunctivitis. After the initial attack has passed, about half of the patients with severe systemic Stevens–Johnson syndrome continue to have ocular surface problems that include symblepharon, entropion, ectropion, trichiasis, dry eye, persistent conjunctival inflammation, conjunctival injection, and corneal opacification. 5 It is thought that the pathogenesis of Stevens–Johnson syndrome in the acute phase might be related to an immunological hypersensitivity to drugs or micro-organisms. However, little is known about the persistent inflammation during chronic phase Stevens– Johnson syndrome. To better understand the immunopathogenesis of the corneal conjunctivalisation that is seen in Stevens–Johnson syndrome, we examined tissue from five patients with Stevens–Johnson syndrome who presented at Kyoto Prefectural University of Medicine Hospital between March and July 1995. We similarly examined conjunctivalised corneas from three chemically injured eyes. Materials and methods Resected tissues specimens were frozen sectioned (6 μm thick) and placed on glass slides. Immunohistochemical studies were performed by the standard ABC method. Cold acetone was used as fixative for the detection of LFA-1, CD4, CD8, CD19, CD68, HLA-DR, and ICAM-1 and 4% paraformaldehyde was used as fixative for the detection of IFN-ã and IL-4. To eliminate non-specific immune staining, 5% normal goat serum was used. All specimens were incubated overnight with the following primary antibodies at 4°C at the stated dilution (all were raised in mouse and purchased from Dako Corp (Glostrup, Denmark)): LFA-1 (1:200), CD4 (1:20), CD8 (1:200), CD19 (1:100), CD68 (1:100), HLA-DR (1:100), ICAM-1 (1:50). Antihuman IFN-ã (50 mg/ml) was purchased from Endogen (Cambridge, MA, USA) and the anti-human IL-4 (5 mg/ml) from Genzyme (Cambridge, MA, USA). For negative controls, normal mouse IgG was used instead of the primary antibody. Biotinylated rabbit antimouse immunoglobulin (Dako) was used as the secondary antibody, and specimens were incubated in it for 1 hour at a dilution of 1/800, followed by the incubation in the avidin-biotinperoxidase complex (Vector Laboratories Inc, Burlingame, CA, USA) at room temperature for 30 minutes. In developing, DAB buVered with 0.05 M TRIS buVer was used. Finally, sections were counterstained with methyl green. Results and discussion Before surgery, no inflammation was noted in patients 2 and 5, whereas patients 1, 3, and 4 occasionally presented with mild inflammation. However, these mild inflammatory episodes invariably resolved without the administration of extra medication. On histological examination, conjunctivalised corneas from all patients with Stevens– Johnson syndrome were characterised by fairly Br J Ophthalmol 2000;84:1191–1193 1191 Department of Ophthalmology, Kyoto Prefectural University of Medicine, Kyoto, Japan S Kawasaki K Nishida C Sotozono A J Quantock S Kinoshita