Polymer-Specific Quantification of Circulating Microplastics in Healthy and Immunocompromised Individuals

<title>Abstract</title> <bold>Background</bold> Microplastics (MPs) are emerging contaminants of global concern that have recently been identified in the human blood. However, their presence in immunocompromised people is still not much identified. This research offers the comparative evaluation of MP load in normal and immunocompromised patients. <bold>Methods</bold> Blood samples were collected from healthy individuals (n = 15) and immunocompromised patients (n = 20) by using non-plastic equipments. Samples were subjected to acid (1M HCl, 1M HNO3) and alkaline (1M NaOH, 1.8M KOH) digestion. Polymer identification was performed on 14 representative samples using ATR-FTIR spectroscopy. An updated quantifying technique that minus both blank and biological control residues enhanced a more precise way of quantification. <bold>Results</bold> All analyzed blood samples contained microplastics (MPs). The refined digestion method yielded MP between 0.2 and 7.0 gL-1 with a mean ±SD of 2.86 ±1.80 g L-1. The findings showed that MP load in the immunocompromised was higher (3.57±1.55 g L-1) compared to healthy controls (1.90 ±1.93 g L-1) but the difference was not statistically significant (unpaired t = 1.99, p = 0.073). Environmental and medical sources were represented by such dominant polymers as polyacrylamide (PAM 25%), polyaramid (PA 20%), and polybutylene terephthalate (PBT 14%). The maximum recovery and polymer integrity was obtained with HCl digestion. <bold>Conclusion</bold> This study found microplastics in both normal and immunocompromised blood samples but load was higher in immunocompromised patients probably due to clinical exposure to polymer and its minimal clearance. These findings highlight the need for standardized analytical protocols and further investigation into the biological implications of circulating microplastics.