Linking surfactant protein SP-D and IL-13: Implications in asthma and allergy

Airway Surfactant Protein D Deficiency in Adults With Severe Asthma

“…Altered airway concentrations of SP-D could also leave the airways susceptible to opportunistic airway infection due to impaired bacterial clearance and enhance the IL-13-dependent allergic airway response. 9,15 An altered airway microbiome has been described in severe asthma, linked to neutrophilic airway inflammation and poorer lung function 4 ; both of these features were evident in patients with severe asthma included in the present study. Furthermore, the elevated levels of LPS present in the BAL sample of those with severe asthma, compared with those with milder asthma, is consistent with the presence of increased gram-negative bacteria within the airways.…”

“…5 In addition, SP-D enhances their chemotactic, phagocytic, and oxidative properties and interacts with phagocytic cells, such as macrophages and neutrophils. 6 SP-D also modifies allergic responses in that it reduces the activation of basophils, 7 mast cells, 8 and eosinophils 9 while regulating the release of transforming growth factor-b, 10 IL-10, 11 and IL-12 12 and reducing concentrations of IL-2. 13 In allergen challenge models, exogenous SP-D inhibits allergen-induced T lymphocyte proliferation and hypersensitivity, 12 inducing a shift from a type 2 to type 1 cytokine response, and decreases induced airway remodeling.…”

“…13 In allergen challenge models, exogenous SP-D inhibits allergen-induced T lymphocyte proliferation and hypersensitivity, 12 inducing a shift from a type 2 to type 1 cytokine response, and decreases induced airway remodeling. 9,14 Conversely, SP-Ddeficient mice exhibit an enhanced IL-13-dependent inflammatory allergic response within the airways. 15 The aim of the present study was to investigate airway luminal and serum SP-D concentrations in patients with mild and severe asthma compared with healthy control subjects and to examine the structural integrity of SP-D in these study groups.…”

The Biomarker Salivary SP-D May Indicate Small Airway Inflammation and Asthma Exacerbation

“…Allergen challenge increased SP-D levels in BALF, which correlated with the degree of allergic inflammation in asthmatic lungs [32]. Animal studies in transgenic mice have shown that IL-4 and IL-13 increase SP-D expression [33]. Haczku et al [34] reported that allergen exposure increased SP-D protein levels in an IL-4/IL-13-dependent manner, which in turn, prevented further activation of sensitized T cells.…”

Surfactant protein D induces immune quiescence and apoptosis of mitogen-activated peripheral blood mononuclear cells

“…Surfactant Protein D (SP-D) is an extensively studied collectin in the models of infection, allergy and inflammation. SP-D contains an Nterminal triple-helical collagen region and a homotrimeric CRD region which has been shown to interact with a range of viral, bacterial and fungal pathogens and bring about clearance mechanisms that include agglutination, enhanced phagocytosis and superoxidative burst (8,9). SP-D can also bind allergens, inhibit specific IgE binding and basophil degranulation (10).…”