Amino acid variants in Surfactant protein D are not associated with bronchial asthma

Abstract

Surfactant protein D (SFTPD) belongs to the family of collectins and is part of the innate immune system. Thereby it plays an important role in the defense of various pathogens. Besides it is involved in the development of acute and chronic inflammation of the lung. Levels of SFTPD are elevated in serum and alveolar lavage of asthmatic patients. As SFTPD binds and neutralizes common allergens like house dust mites it is especially important in allergic asthma. Three common amino acid variants have been identified in SFTPD and association of the first variant has been described to severe infection with respiratory syncytial virus. Furthermore the functional impact of all three amino acid variants has been demonstrated. Due to its function SFTPD represents an ideal candidate gene for bronchial asthma and we were interested whether the polymorphisms were in association with asthma in children. The three polymorphisms leading to amino acid exchanges (Met11Thr, Ala160Thr, and Ser270 Thr) were typed by restriction fragment length polymorphisms in 322 asthmatic children and 270 controls. Association analyses were performed by Armitage's trend test. In addition haplotypes were calculated by FASTEHPLUS and FAMHAP. None of the polymorphisms was in association with bronchial asthma. Haplotype analyses revealed four major haplotypes all of which were evenly distributed between the populations. We conclude from our data that functional amino acid variants in SFTPD do not play a major role in the genetic pre-disposition to bronchial asthma in children.

Surfactant protein D alters allergic lung responses in mice and human subjects

“…A recent German study concludes that none of the 3 known amino acid variants in SP-D are associated with bronchial asthma. 27 However, the German control population was randomly selected and did not exclude all control subjects with a history of asthma. 27 In the present study the control subjects were carefully selected but therefore more limited in number.…”

“…27 However, the German control population was randomly selected and did not exclude all control subjects with a history of asthma. 27 In the present study the control subjects were carefully selected but therefore more limited in number. Furthermore, the atopic status of some asthmatic patients was not available.…”

Surfactant protein A and surfactant protein D variation in pulmonary disease

“…The three polymorphisms leading to amino acid exchanges in SP-D (Table 2, rs721917, rs2243639, and rs3088308) were recently typed in 322 asthmatic children and 270 controls but none of the polymorphisms were found in association with bronchial asthma (Krueger et al, 2006). Nevertheless, the potential involvement of both SP-D and SP-A in the pathophysiology of airway allergy and bronchial asthma may be suggested because the levels of both SP-A and SP-D were demonstrated increased in alveolar lavage of asthmatic patients (Cheng et al, 2000).…”

SP-D Polymorphisms and the Risk of COPD

“…Each fragment was restricted by a specific restriction enzyme as described previously by Kreuger et al [28] ( Table 1). Briefly, the 115 base pair PCR product for rs3088308 was cleaved by MnI1 into 3 fragments (54, 42 and 19 base pairs) for the major allele and 2 fragments (96 and 19 base pairs) for the minor allele (Fig.…”

“…Relevant fragments of DNA were amplified by polymerase chain reaction using sets of primers as shown in Table 1 [28]. PCR was performed in a thermocycler (Eppendorf Mastercycler Personal, USA).…”