Increased expression of ADAM33 protein in asthmatic patients as compared to non-asthmatic controls

BACKGROUND & OBJECTIVES ADAM33 is a member of a family of genes that encode membrane-anchored proteins with a disintegrin and a metalloprotease domain, primarily expressed in lung fibroblasts and bronchial smooth muscle cells. ADAM33 has been identified as a risk factor for asthma and is known as a gene associated with airway remodelling. The present study was conducted with the aims to investigate the expression of ADAM33 protein in patients of asthma and non-asthmatic controls, and to assess if the expression of ADAM33 protein relates with severity of asthma. METHODS A total of 35 subjects, including 27 patients with asthma and eight non-asthmatic controls were included using Global Initiative for Asthma guidelines 2005. Bronchial biopsy tissues were collected and paraffin sections were made to store all study samples. Immunohistochemistry was performed using standardized protocol. RESULTS An increase in expression of ADAM33 protein was observed in the epithelium, smooth muscle and mesenchymal cells of asthma cases when compared to controls but there was no relationship with severity of asthma. INTERPRETATION & CONCLUSIONS A higher expression of ADAM33 protein was seen in asthma patients compared to controls. Large prospective studies need to be done with adequate study design to confirm these preliminary finding.