Recombinant Fragment of Human Surfactant Protein D: A Hierarchical Regulator of Pulmonary Hypersensitivity

Several molecular and cellular mechanisms were implicated in the therapeutic effect of rfhSP-D in pulmonary hypersensitivity, including reduced availability of allergens (10), induction of apoptosis in activated eosinophils, increased clearance of apoptotic eosinophils by macrophages (11), significant inhibition of NO production in alveolar macrophages (12), inhibition of release of mediators such as eotaxin (13), and a marked shift from a T-helper cell type 2 (Th2) to Th1 response (9, 14). In this issue of the Journal, Qaseem and colleagues (pp. 15261534) report that rfhSP-D suppressed basophil activation and Th2 and B-cell responses ex vivo, using samples derived from in 27 patients with seasonal allergic rhinitis with elevated levels of grass pollen-specific IgE antibodies (16). The authors discover novel molecular mechanisms underlying the rfhSP-D-mediated alleviation of allergic immune responses. rfhSP-D was able to inhibit allergen-induced basophil activation, as measured by CD63, CD203c, and fluorochrome-labeled diamine oxidase, a novel marker for detecting intracellular histamine.