Promoter variants in tissue inhibitor of metalloproteinase-3 (TIMP-3) protect against susceptibility in pigeon breeders’ disease
- 1Centre for Respiratory Research, Department of Medicine, Royal Free and University College Medical School, The Rayne Institute, London WC1E 6JJ, UK
- 2Instituto Nacional de Enfermedades Respiratorias, Tlalpan 4502, Col Seccion XVI, México DF, CP 14080, México
- 3Facultad de Ciencias, UNAM, Coyoacan, México DF, 04000 México
- Correspondence to:
Dr M R Hill
Centre for Respiratory Research, Department of Medicine, Royal Free and University College Medical School, The Rayne Institute, 5 University Street, London WC1E 6JJ, UK;
- Received 9 July 2003
- Accepted 15 March 2004
Background: Tissue inhibitors of metalloproteinases (TIMPs) play a major role in extracellular matrix turnover in the lung. However, in chronic lung disorders such as idiopathic pulmonary fibrosis (IPF) and pigeon breeders’ disease (PBD), TIMPs may promote an adverse non-degradative environment. We hypothesised that polymorphisms in TIMP-3 could affect susceptibility to IPF and PBD.
Methods: Two promoter variants, −915A>G and −1296T>C, were genotyped in 323 healthy subjects, 94 subjects with IPF, 115 with PBD, and 90 exposed to avian antigen but without PBD. The severity of fibrosis in lung tissue and the clinical outcome after 1 year was determined in the PBD group.
Results: The variants did not influence susceptibility to IPF, but the rare alleles of both variants appeared to be protective against susceptibility to PBD (odds ratio (OR) for carriage of at least one rare allele from either variant 0.48, 95% CI 0.30 to 0.76, p = 0.002). Haplotype analysis of positions −915 and −1296 estimated four haplotypes: *A*T, *G*T, *A*C and *G*C, respectively. Their frequencies differed overall between subjects with PBD and healthy subjects (p = 0.0049) and this was attributable primarily to the *G*C haplotype (OR 0.53, 95% CI 0.36 to 0.77, p = 0.001). The severity of fibrosis correlated with poorer outcome in the PBD group (r = 0.73, p<0.01) but no relationship was seen between the *G*C haplotype and outcome or fibrosis. However, PBD subjects with the *G*C haplotype did have proportionally fewer lymphocytes in their bronchoalveolar fluid than those with the common *A*T haplotype (p = 0.029).
Conclusions: TIMP-3 variants appear to contribute to susceptibility to PBD. This may be through the inflammatory reaction rather than the fibrotic reaction.
- pigeon breeders’ disease
- tissue inhibitor of metalloproteinases (TIMPs)
- idiopathic pulmonary fibrosis
Supported by The Wellcome Trust grant 097/347 (MRH, LB) and by PUIS, UNAM (MS and AP).