Migration of acetylated hemicellulose from capillary hemodialyzer to blood, causing scleritis and/or iritis.

From November 1981 to early March 1982, an outbreak of scleritis and/or iritis occurred among patients treated with a Nipro brand NAC series cellulose acetate capillary dialyzer. The rate of incidence with dialyzers produced in 1982 was significantly higher than that with dialyzers produced in 1981. An extract obtained from the dialyzers caused iritis in rabbits after its infusion into an auricula vein. Glycerol, acetylated carbohydrate (AC) derivatives, urethane derivatives, and polypropyleneglycol were found in the extract. AC derivatives caused iritis in rabbits, whereas they caused hyperemia of the bulbar conjunctiva in dogs. The AC derivatives contained xylose and glucose units in a ratio of 1.6-2.3:1. The amounts of AC derivatives were significantly larger in the extracts from 1982 than from 1981 devices. Moreover, another brand, but the same type, of dialyzer, the Cordis Dow 4000, contained a slight amount of them. These facts show that AC derivatives derived from hemicellulose played a primary role in the outbreak.