MACULAR CORNEAL-DYSTROPHY IN SAUDI-ARABIA - A STUDY OF 56 CASES AND RECOGNITION OF A NEW IMMUNOPHENOTYPE

PURPOSE: To determine the immunophenotype or immunophenotypes of macul ar corneal dystrophy in Saudi Arabia. METHODS: We studied 56 cases of macular corneal dystrophy. Tissue from 60 corneal trans plant buttons was stained by the avidin-biotin complex method using an anti-keratan sulfate monoclonal antibody. The serum antigenic keratan sulfate was m easured in 23 of the 56 patients, four unaffected relatives, and 13 in dividuals with chronic actinic keratopathy. Serum and corneal tissue w ere studied in 17 of the 50 affected individuals with corneal transpla nt material. RESULTS: Thirty-five corneas (58.3%) of 29 of 50 patients did not react with anti-keratan sulfate monoclonal antibody. The stro ma and abnormal intracellular and extracellular corneal accumulations reacted with anti-keratan sulfate monoclonal antibody in seven corneas (11.7%). The stroma in the other 18 corneas (30.0%) from 15 patients did not react with the anti-keratan sulfate monoclonal antibody, but c orneal fibroblasts did. Twenty-one of the 23 patients with macular cor neal dystrophy had no detectable serum antigenic keratan sulfate (<9 n g/ml); two had values of 12 and 51 ng/ml, respectively, and their corn eal stroma and abnormal accumulations reacted with anti-keratan sulfat e monoclonal antibody. CONCLUSIONS: We detected macular corneal dystro phy type IA, a new immunophenotype characterized by the lack of detect able antigenic keratan sulfate in the serum (<9 ng/ml), and a corneal stroma that did not react: with the keratan sulfate monoclonal antibod y but in which corneal fibroblasts did react with keratan sulfate mono clonal antibody (in 15 of 50 patients).