Chelation Therapy for Kidney Transplant Recipients With Lead Exposure

Abstract

We read with interest the article of Sotomayor et al.1Sotomayor C.G. Giubergia F. Groothof D. et al.Plasma lead concentration and risk of late kidney allograft failure: findings from the TransplantLines Biobank and Cohort Studies.Am J Kidney Dis. 2022; 80: 87-97.e1https://doi.org/10.1053/j.ajkd.2021.10.009Abstract Full Text Full Text PDF PubMed Scopus (3) Google Scholar According to the researchers, pretransplant plasma lead concentrations, which decrease after kidney transplantation, are associated with increased risk of late kidney allograft failure. The finding is useful and stimulating, as it carries the implication of potential chelation therapy for kidney transplant recipients with lead exposure. Nevertheless, there are several untapped issues associated with this observational study. First, plasma specimens were used in the study for evaluation of body exposure to lead, cadmium, and arsenic. Plasma samples are suboptimal, and instead whole blood samples should be collected for analysis. A previous study2Sommar J.N. Hedmer M. Lundh T. Nilsson L. Skerfving S. Bergdahl I.A. Investigation of lead concentrations in whole blood, plasma and urine as biomarkers for biological monitoring of lead exposure.J Expo Sci Environ Epidemiol. 2014; 24: 51-57https://doi.org/10.1038/jes.2013.4Crossref PubMed Scopus (50) Google Scholar confirmed that lead level in whole blood is the ideal marker to distinguish between patients with different mean levels. Sommar et al2Sommar J.N. Hedmer M. Lundh T. Nilsson L. Skerfving S. Bergdahl I.A. Investigation of lead concentrations in whole blood, plasma and urine as biomarkers for biological monitoring of lead exposure.J Expo Sci Environ Epidemiol. 2014; 24: 51-57https://doi.org/10.1038/jes.2013.4Crossref PubMed Scopus (50) Google Scholar found that plasma lead performed well in those with high exposure, such as lead workers, but at low exposures plasma lead was inaccurate. Second, apart from lead, cadmium, and arsenic, the body burden of mercury should also be examined, as excess of mercury is also correlated with poorer kidney outcomes.3Lin H.H. Chou S.A. Yang H.Y. et al.Association of blood lead and mercury with estimated GFR in herbalists after the ban of herbs containing aristolochic acids in Taiwan.Occup Environ Med. 2013; 70: 545-551https://doi.org/10.1136/oemed-2012-101066Crossref PubMed Scopus (8) Google Scholar Third, it is suggested newer hydrophilic dithiol chelators—for example, meso-2,3-dimercaptosuccinic acid (DMSA) or 2,3-dimercapto-propanesulphonate (DMPS)—be considered for kidney transplant recipients with confirmed lead exposure.4Aaseth J. Skaug M.A. Cao Y. Andersen O. Chelation in metal intoxication--principles and paradigms.J Trace Elem Med Biol. 2015; 31: 260-266https://doi.org/10.1016/j.jtemb.2014.10.001Crossref PubMed Scopus (114) Google Scholar In this regard, although a blood lead reference value of 10 μg/dL is commonly used in adults, no safe blood lead level has been recognized.5Shefa S.T. Heroux P. Both physiology and epidemiology support zero tolerable blood lead levels.Toxicol Lett. 2017; 280: 232-237https://doi.org/10.1016/j.toxlet.2017.08.015Crossref PubMed Scopus (40) Google Scholar Therefore, the harmful effects of lead at any detectible level should not be ignored. The authors declare that they have no relevant financial interests. Received August 19, 2022. Accepted August 29, 2022, after editorial review by an Associate Editor and a Deputy Editor.