LRG1 downregulation in allergic airway disorders and its expression in peripheral blood and tissue cells

Increased leucine-rich α2-glycoprotein-1 (LRG1) has been observed in plasma of individuals with various diseases. However, the role of LRG1 in allergic airway disease has not been investigated.

To explore the involvement of LRG1 in allergy and its cell origins.

The expression levels of LRG1 and its receptor transforming growth factor-beta receptor II (TGFBR2) in patients with allergic rhinitis (AR) and asthma (AS) were examined by flow cytometry, and enzyme-linked immunosorbent assay (ELISA).

LRG1 and soluble TGFBR2 expression in plasma of patients with AR and AS were markedly lower than that of healthy control (HC) subjects. Large proportions of CD123 + HLA-DR-, CD16+, CD4+, CD8+, CD14+, and CD19+ cells expressed LRG1, although the percentages of LRG1+ cells in these cell populations were lower in AR and AS patients. Up to 89.8 and 15.5 % of dispersed mast cells expressed LRG1 and TGFBR2. Moreover, allergen extract exposure significantly reduced LRG1 and TGFBR2 expression in the plasma and leukocytes of patients with AR and AS.

Reduced LRG1 and TGFBR2 levels in patients with allergic airway disorders are likely caused by inhibitory actions of allergens in LRG1 producing cells. Thus, LRG1 may be a key regulatory factor of allergic responses.