Prognostic significance of low serum levels of Clara cell phospholipid-binding protein in occupational aluminium neurotoxicity

The relationship between respiratory and neurological effects of exposure to aluminium (Al) was investigated in a group of foundry workers exposed to At at concentrations below the threshold limit value (TLV) binding in Poland (2.0 mg Al2O3 m(-3))Neurological and neurophysiological parameters indicated subclinical effects of At exposure on the nervous system. The measurement of serum anti-inflammatory Clara cell protein (CC16) was employed as a peripheral marker of the lung epithelium function. There was a strong inverse relationship between serum At (Al-S) and CC16 concentrations (p = 0.006). The lowest CC16 concentrations were found in serum of workers characterised by subjective symptoms of the central nervous system (CNS) and abnormal results of neurophysiological examinations (EEG and VEP). Low serum CC16 concentrations and enhanced At and iron (Fe) levels were also observed in the younger age group of workers with the subjective CNS symptoms and abnormal VEP results, which suggests that Fe is implicated in strengthening of the neurotoxic At potential. The results of our study support the hypothesis that subclinical neurological symptoms (especially abnormal VEP) are most likely associated with internalisation of At ions with lipid fractions of the lung epithelium, which in turn may help At ions overcome the blood-brain barrier. Low serum CC16 concentrations (< 10 mu g L-1) were noted in workers with the abnormal results of neurological (CNS) and neurophysiological (EEG and VEP) examinations as well as with At body burden manifested by urinary excretion (Al-U) below 60 mu g L-1 and Al-S concentration of 2 mu g L-1. This concentration may be considered as a threshold allowable biological concentration of aluminium. (c) 2005 Elsevier Inc. All rights reserved.