Micro and Nanoparticles As Possible Causative-Prognostic Co-Factors Of Mixed Cryoglobulinemia Syndrome

Background/Purpose: We previously demonstrated that patients affected by membranoproliferative glomerulonephritis and mixed cryoglobulinemia syndrome (MCs) show the presence of circulating micro and nanoparticles (MPs and NPs) as possible causative/prognostic co-factors. This pilot study aimed to evaluate the possible role of occupational/environmental agents in the etiopathogenesis of MCs by investigating the patients’ exposure to both MPs and NPs. Methods: We investigated 20 consecutive HCV-positive MCs patients without renal involvement compared to 10 healthy, sex-/age-matched volunteers. All subjects completed a questionnaire concerning demographic data, dietary and smoking habits, prosthesis implants, air pollution, occupational and medical history. Environmental Scanning Electron Microscopy (ESEM) has been employed to detect inorganic MPs and NPs and to evaluate their presence in subjects with and without MCs. Energy Dispersive X-ray Spectroscopy (EDS) microanalysis was used to chemically characterize the elemental composition of the particles. Blood serum samples were spotted on metal free cover slips in a sterile environment. The complex of particles (MPs and NPs) was quantified using the number of spots (NS) containing inorganic particles in a fixed mapping area for each sample. Levels of NS were assessed statistically with Mann-Whitney U test. Results: Patients displayed higher serum levels of MPs/NPs particles (NS 36.6718.18, p0.0003), compared to controls (NS 5.626.25), independently of smoking habits. A direct correlation between the presence of particles and patients occupational exposure, environmental pollution and prosthesis implants was found. EDS microanalysis revealed that the particles have complex compositions, which includes several elements like Si, Fe, Al, Ti, Zn, Cu, Mn, and Ni. Conclusion: The ESEM analyses were a valuable tool to detect particulate matter in the serum samples. The complex of MPs/NPs particles was greater in MCs patients than in healthy subjects. These preliminary data suggest that, in addition to HCV infection, particulate complex might represent an environmental co-factor in the etiopathogenesis of MCs.