Summary

This article discusses the first five Reports presented at the Symposium, those of Drs. Villarroel, Chenowith, Pearson and colleagues, and Henne and colleagues (two presentations). Although Dr. Villarroel Reported hypersensitivity reactions only during hollow‐fiber dialysis, this may have been due to the way the information was gathered rather than accurately reflect actual happenings. The Report of the largest number of cases, to date, originated in England and came from a center that used mostly plate dialyzers. Thus, it is probable that any dialyzer may cause the syndrome, although more severe ones may be much more common in hollow‐fiber dialyzers. Dr. Chenoweth observed that different membranes activate complement to differing extents but that all cellulosic membranes activate complement. Currently every patient experiences complement activation and neutropenia early in dialysis. It seems unlikely that a biological phenomenon that occurs in almost all dialyses is responsible for a reaction that occurs only in 35 of every 1,000,000 dialyses. Dr. Pearson and co‐workers Reported the presence of Limulus amebocyte lysate‐reactive material (LAL‐RM) in 15 dialyzers tested with three different lysates. All dialyzers with cellulose‐based membranes had positive tests with some, but not all, lysate reagents. Second, cell response tests indicative of pyrogenicity in humans were negative. At least two substances could be eluted from hollow‐fiber dialyzers. One had a molecular weight of 23,000, the other of 3,100. Both could be inactivated by cellulase. These findings suggest that the LAL‐RM is not an endotoxin. As the entire blood path of the dialyzer was rinsed, it is not possible to conclude whether or not the origin of LAL‐RM is the headers, casings, or actual fibers. Drs. Henne, Schulze, and co‐workers came to the same conclusion as Dr. Pearson; LAL‐RM is of cellulosic origin, not an endotoxin. However, in a review of the composition of cotton fiber, the starting material for many dialysis membranes, it is of interest to note that it contains 1.5% protein and 0.6% wax. Perhaps these compounds should be investigated as possible causes of the severe allergic reaction in the rare patient who has it. Drs. Henne, Dietrich, and co‐workers Reported on the difficulty of removing ethylene oxide from dialyzers. There are two first‐order removal curves. One is for the fibers from which ethylene oxide washes out easily. The second is for the headers and casing. Ethylene oxide seems to be more firmly held in the latter; however much time is spent removing it, ethylene oxide will still leach out during the entire dialysis process. It is difficult to explain “first use syndrome“ allergic reaction by ethylene oxide hypersensitivity. If ethylene oxide were the common cause, one would expect the peak of reactions to occur after the patient had already been sensitized by previous blood transfusions and/or by ethylene oxide‐cleaned equipment. Eosinophilia may be associated with the use of ethylene oxide. However, this symptom is not unique to first use syndrome but is a chronic problem with dialysis patients. Perhaps ethylene oxide is a cause of dialysis eosinophilia. This would explain why, in this author's experience, it is more common in hemodialysis patients, followed by continuous peritoneal dialysis (CCPD) patients, and finally by continuous ambulatory peritoneal dialysis patients, since the hemodialyzer exposes the patient to more ethylene oxide than in the tubing used in CCPD.