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Characterization of Limulus amoebocyte lysate-reactive material from hollow-fiber dialyzers
Abstract:
Hollow-fiber hemodialyzers containing cellulose-based membranes have been shown to produce positive results with the Limulus amoebocyte lysate test. This study was undertaken to determine whether endotoxin was causing the reaction. Rinses from 45 parallel-plate and hollow-fiber dialyzers from eight different manufacturers were tested before and after treatment with cellulase, using three lysates and four Limulus amoebocyte lysate methods. In addition, four in vitro cellular methods--human leukocytic pyrogen, lymphocytic activating factor, peritoneal macrophage, and arginase release--were used to evaluate endotoxin activity. The substance causing the reaction was identified by chromatographic methods. Results indicate that the Limulus amoebocyte lysate reactive material is cellulose derived and not pyrogenic.
Insights
Cellulose-derived material in hemodialyzers can trigger a positive Limulus amoebocyte lysate (LAL) test. This study confirms the reactive substance is cellulose, not harmful endotoxin, ensuring patient safety.
Area of Science:
- Biomaterials Science
- Medical Device Technology
- Clinical Chemistry
Background:
- Cellulose-based hemodialyzers are widely used in renal replacement therapy.
- Positive results in the Limulus amoebocyte lysate (LAL) test for dialyzer rinses have raised concerns about potential endotoxin contamination.
- Endotoxins are potent pyrogens that can cause adverse patient reactions during hemodialysis.
Purpose of the Study:
- To investigate the cause of positive LAL test reactions in cellulose-based hemodialyzers.
- To determine if the reactive substance is endotoxin or another component of the dialyzer membrane.
- To assess the pyrogenicity of the material causing the LAL reactivity.
Main Methods:
- Tested rinses from 45 parallel-plate and hollow-fiber hemodialyzers from eight manufacturers.
- Analyzed samples before and after cellulase treatment to differentiate cellulose from endotoxin.
- Employed three different LAL lysates and four distinct LAL testing methods.
- Utilized four in vitro cellular assays (human leukocytic pyrogen, lymphocytic activating factor, peritoneal macrophage, and arginase release) to evaluate endotoxin activity.
- Identified the reactive substance using chromatographic methods.
Main Results:
- The Limulus amoebocyte lysate reactive material was consistently detected in hemodialyzer rinses.
- Cellulase treatment effectively eliminated the LAL reactivity, indicating a cellulose-based origin.
- In vitro cellular assays did not show evidence of pyrogenic activity associated with the reactive material.
- Chromatographic analysis confirmed the substance was cellulose-derived.
Conclusions:
- The positive Limulus amoebocyte lysate test results in these hemodialyzers are due to cellulose components, not endotoxins.
- The cellulose-derived material is not pyrogenic, suggesting no inherent risk of fever induction during hemodialysis.
- This finding clarifies the source of LAL reactivity, reassuring the safety of cellulose-based hemodialyzer membranes.