SFTPD and lung disorder: Figure 2 illustrates the immunological mechanisms of allergen immunotherapy, which aligns with SP-D role in modulating allergic responses. Recent studies on non-infectious lung diseases and lung injuries suggest that SP-D levels in bronchoalveolar lavage fluid and serum can fluctuate and potentially serve as biomarkers for disease or injury (10, 65). Additionally, the polymorphisms of surfactant proteins (SPs) may lead to altered functions and affect susceptibility to or severity of lung diseases through different receptor interactions (18, 54).