This study investigates the effects of anti-CD44 murine antibodies on allergic airway inflammation induced by transnasal instillation of purified Ascaris suum (Asc) antigen. Two antibodies were used—one that directly blocks hyaluronic acid binding to cells expressing CD44, and one that causes CD44 receptor to be shed from tissue surfaces.

The study showed that the total number of airway eosinophils and lymphocytes increased after challenge with Asc and both types of anti-CD44 antibody significantly suppressed cell levels (p<0.05). Asc induced increases in interleukin (IL)-4 and IL-5 levels in bronchoalveolar lavage fluid were reduced after use of anti-CD44 antibodies (p<0.05). Levels of eotaxin and TARC were also reduced (p<0.05). Airway hyperresponsiveness to methacholine was analysed; anti-CD44 antibodies significantly reduced the response in Asc treated mice compared with rat IgG (p<0.05). Hyperresponsiveness was also significantly decreased in mite (Dermatophagoides) allergen treated mice given anti-CD44 antibody (p<0.05)

These results show that CD44 may play an important role in allergic airway inflammation through its actions on leucocyte binding and stimulation of cytokine production. Further evaluation of the interactions between IL-4, IL-5, and CD44 may determine which factor is most influential in airway inflammation and clarify the role of the eosinophil in asthma.