CHRONIC URTICARIA AND LEAD EXPOSURE: EVALUATION OF IMMUNOLOGICAL MARKERS

Chronic urticaria (CU) is a mast-cell-driven disorder involving inflammatory and autoimmune mechanisms. Lead can affect immune function, but its relationship with CU has been little studied.

To examine the association of blood lead levels (BLLs) with CU, active wheals at blood sampling, and selected immunological markers.

This single-center case-control study included 303 participants from Western Georgia: 211 patients with CU and 92 healthy controls. BLLs were measured by inductively coupled plasma mass spectrometry. Eosinophils, total IgE, histamine, anti-IgE autoantibodies, and FcεRIα autoantibodies were assessed. BLL ≥10 µg/dL was used as the predefined analytical threshold for higher lead exposure. Associations were evaluated using group comparisons, Spearman correlation, and age-adjusted regression analyses.

BLLs were higher in patients with CU than in healthy controls. BLL ≥10 µg/dL was present in 66.8% of patients and 33.7% of controls (OR 3.96; 95% CI 2.36-6.66; p<0.001), and the association remained significant after adjustment for age (aOR 4.07; 95% CI 2.38-6.96; p<0.001). Within the CU group, higher BLLs were associated with eosinophilia and higher histamine, anti-IgE, and FcεRIα autoantibody levels, but not with total IgE. BLL ≥10 µg/dL was also associated with active wheals at blood sampling after adjustment for age (aOR 3.36; 95% CI 1.75-6.45; p<0.001). In an exploratory analysis, the dual-positive anti-IgE/FcεRIα group had the highest frequencies of BLL ≥10 µg/dL (83.3%) and active wheals (92.4%). Compared with patients in whom neither autoantibody was elevated, the dual-positive group had the strongest age-adjusted association with BLL ≥10 µg/dL (aOR 5.49; 95% CI 2.38-12.70; p<0.001).

Patients with CU had higher BLLs than healthy controls. Within the CU group, higher BLLs were associated with eosinophilia, histamine, anti-IgE and FcεRIα autoantibodies, and active wheals, but not with total IgE. These associations require confirmation in prospective studies.