title: Increased ethyl mercury load in protein a immunoadsorption.
abstract: Immunoadsorption is an adsorption technique for extracorporeal removal of circulating autoantibodies in autoimmune diseases. To prevent microbial growth during storage, the protein A columns are primed with thiomersal, which contains toxic ethyl mercury, which may be released during the procedure and potentially begin to accumulate and become toxic. To reduce the thiomersal-related mercury release during immunoadsorption treatment, we introduced a modified rinsing solution containing N-acetylcysteine, which is an avid mercury scavenger. Thirteen patients received 17 protein A immunoadsorption treatments and their venous blood samples were collected immediately before and after each session. The total blood mercury levels were measured by atomic absorption spectrometry, and the ethyl mercury levels by atomic fluorescence spectrometry. Following the manufacturer's recommendations, we used 600 mg of N-acetylcysteine to rinse the mercury from protein-loaded columns before each immunoadsorption treatment. After immunoadsorption, the ethyl mercury levels increased from 0.148 +/- 0.402 ng/g to 2.026 +/- 1.944 ng/g (P < 0.001), and the total blood mercury levels increased from 2.447 +/- 3.065 ng/g to 20.437 +/- 28.603 ng/g (P = 0.02). The post-treatment values of total blood mercury exceeded the upper safety level of 5 ng/g in all 17 immunoadsorption treatments, but no patient developed clinical signs of mercury toxicity. The results of our study showed an increase in total blood mercury and ethyl mercury levels during the immunoadsorption treatments, suggesting mercury release from thiomersal-primed columns despite the addition of N-acetylcysteine to the rinsing solution.
authors.affiliation: University Medical Center Ljubljana, Department of Nephrology, University of Ljubljana, Ljubljana, Slovenia. andreja.marn@kclj.si
authors.forename: Andreja
authors.initials: A
authors.lastname: Marn-Pernat
authors.forename: Jadranka
authors.initials: J
authors.lastname: Buturović-Ponikvar
authors.forename: Martina
authors.initials: M
authors.lastname: Logar
authors.forename: Milena
authors.initials: M
authors.lastname: Horvat
authors.forename: Rafael
authors.initials: R
authors.lastname: Ponikvar
mesh_terms: D000111:Acetylcysteine / Q000494:pharmacology*; D016736:Antiphospholipid Syndrome / Q000628:therapy; D005035:Ethylmercury Compounds / Q000097:blood; D005923:Glomerulosclerosis, Focal Segmental / Q000628:therapy; D006801:Humans; D007163:Immunosorbent Techniques; D007164:Immunosorbents / Q000627:therapeutic use*; D008628:Mercury / Q000097:blood / Q000737:chemistry; D008875:Middle Aged; D009157:Myasthenia Gravis / Q000628:therapy; D011310:Preservatives, Pharmaceutical / Q000737:chemistry*; D013050:Spectrometry, Fluorescence; D013054:Spectrophotometry, Atomic; D013205:Staphylococcal Protein A / Q000627:therapeutic use*; D013849:Thimerosal / Q000037:antagonists & inhibitors* / Q000737:chemistry
chemical_list: D005035:Ethylmercury Compounds; D007164:Immunosorbents; D011310:Preservatives, Pharmaceutical; D013205:Staphylococcal Protein A; D013849:Thimerosal; D008628:Mercury; D000111:Acetylcysteine