Phlebotomy Treatment for Elimination of Perfluoroalkyl Acids in a Highly Exposed Family: A Retrospective Case-Series

<div><p>Background</p><p>Perfluoroalkyl acids (PFAAs) are a family of commonly used synthetic chemicals that have become widespread environmental contaminants. In human serum, perfluorohexane sulfonate (PFHxS), perflurooctane sulfonate (PFOS), and perfluorooctanoate (PFOA) are most frequently detected, in part owing to their long elimination half-lives of between 3.8 yrs (PFOA) and 8.5 yrs (PFHxS). These PFAAs also cross the placenta and have been associated with developmental toxicity, and some are considered likely human carcinogens. Interventions to eliminate PFAAs in highly contaminated individuals would reduce future health risks, but minimal research has been conducted on methods to facilitate accelerated human clearance of these persistent substances.</p><p>Methods</p><p>Six patients with elevated serum concentrations from a single family were treated by intermittent phlebotomy over a 4–5 year period at intervals similar to, or less frequent than what is done for routine blood donation at Canadian Blood Services. The apparent elimination half-life (HL_app) for PFHxS, PFOS, and PFOA in this treated population was calculated in each patient and compared to the intrinsic elimination half-lives (HL_in) from a literature reference population of untreated fluorochemical manufacturing plant retirees (n = 26, age >55 yrs).</p><p>Results</p><p>For all three PFAAs monitored during phlebotomy, HL_app in each of the family members (except the mother, who had a low rate of venesection) was significantly shorter than the geometric mean HL measured in the reference population, and in some cases were even shorter compared to the fastest eliminator in the reference population.</p><p>Conclusion</p><p>This study suggests significantly accelerated PFAA clearance with regular phlebotomy treatment, but the small sample size and the lack of controls in this clinical intervention precludes drawing firm conclusions. Given the minimal risks of intermittent phlebotomy, this may be an effective and safe clinical intervention to diminish the body burden of PFAAs in highly exposed people.</p></div

Demographic and related information about the study participants.

<p>Demographic and related information about the study participants.</p

Phlebotomy details about the phlebotomy program used in the family.

<p>*The maximum blood donation recommended by Canadian Blood Services is ∼500 ml every 56 days.</p><p>Phlebotomy details about the phlebotomy program used in the family.</p

PFAAs serum concentrations before and after the treatment by phlebotomy for each participant.

<p>For comparison, the 95th percentiles for PFHxS, PFOS and PFOA were 8.9, 18.0 and 5.0 ng/mL, respectively, among Canadians for the period 2009–2011 <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0114295#pone.0114295-Health1" target="_blank">[7]</a>.</p><p>PFAAs serum concentrations before and after the treatment by phlebotomy for each participant.</p

Serum PFHxS elimination in each family member.

<p>PFHxS elimination in family members undergoing phlebotomy (red) compared to a reference population of occupationally exposed retirees (blue). Red data points are measured PFHxS concentrations in the family members, and the red band is the calculated 95% CI of a fitted exponential decay model. The blue band represents the 95% confidence interval of the geometric mean PFHxS HL_in (5.8–9.2 yrs) for the reference population, while the blue line represents the fastest eliminator in the same reference population (HL_in = 2.2 yrs). Black hollow circles indicate a phlebotomy session where the serum sample was not analyzed, and therefore was not used in calcualtions.</p

Phlebotomy efficiency coefficients for PFHxS, PFOS and PFOA in the family.

<p>Black error bars represent the 95%CI of each calculated half-life.</p

Serum PFOA elimination in each family member.

<p>PFOA elimination in family members undergoing phlebotomy (red) compared to a reference population of occupationally exposed retirees (blue). Red data points are measured PFOA concentrations in the family members, and the red band is the calculated 95% CI of a fitted exponential decay model. The blue band represents the 95% confidence interval of the geometric mean PFOA HL_in (3.0–4.1 yrs) for the reference population, while the blue line represents the fastest eliminator of PFOA in the same reference population (HL_in = 1.5 yrs). Black hollow circles indicate a phlebotomy session where the serum sample was not analyzed, and therefore was not used in calcualtions.</p

Apparent elimination half-lives (HL_app) of PFHxS, PFOS and PFOA in the family.

<p>Calculated HL_app in the family members based on all measurements in the current study (red markers). Black markers are HL_in from the reference population of Olsen <i>et al</i>.: arithmetic mean, geometric mean, and shortest among all individuals. Black error bars are the associated 95% confidence intervals.</p