Research

Expression of Toll-like Receptor 9 in nose, peripheral blood and bone marrow during symptomatic allergic rhinitis

Mattias Fransson¹ , Mikael Benson² , Jonas S Erjefält³ , Lennart Jansson⁴ , Rolf Uddman¹ , Sven Björnsson⁵ , Lars-Olaf Cardell¹ and Mikael Adner¹

¹  Laboratory of Clinical and Experimental Allergy Research, Department of Oto-Rhino-Laryngology, Malmö University Hospital, Lund University, Malmö, Sweden

²  Department of Pediatrics, Queen Silvia Children's Hospital, Sahlgrenska University Hospital, Gothenburg, Sweden

³  Department of Experimental Medical Science, Lund University Hospital, Lund University, Sweden

⁴  AstraZeneca R&D, Lund, Sweden

⁵  Department of Clinical Chemistry, Malmö University Hospital, Lund University, Malmö, Sweden

author email corresponding author email

Respiratory Research 2007, 8:17doi:10.1186/1465-9921-8-17

Published:	28 February 2007

Abstract

Background

Allergic rhinitis is an inflammatory disease of the upper airway mucosa that also affects leukocytes in bone marrow and peripheral blood. Toll-like receptor 9 (TLR9) is a receptor for unmethylated CpG dinucleotides found in bacterial and viral DNA. The present study was designed to examine the expression of TLR9 in the nasal mucosa and in leukocytes derived from different cellular compartments during symptomatic allergic rhinitis.

Methods

The study was based on 32 patients with seasonal allergic rhinitis and 18 healthy subjects, serving as controls. Nasal biopsies were obtained before and after allergen challenge. Bone marrow, peripheral blood and nasal lavage fluid were sampled outside and during pollen season. The expression of TLR9 in tissues and cells was analyzed using immunohistochemistry and flow cytometry, respectively.

Results

TLR9 was found in several cell types in the nasal mucosa and in different leukocyte subpopulations derived from bone marrow, peripheral blood and nasal lavage fluid. The leukocyte expression was generally higher in bone marrow than in peripheral blood, and not affected by symptomatic allergic rhinitis.

Conclusion

The widespread expression of TLR9 in the nasal mucosa along with its rich representation in leukocytes in different compartments, demonstrate the possibility for cells involved in allergic airway inflammation to directly interact with bacterial and viral DNA.