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Background: High-producer TGFβ1 genotypes are associated with severe lung disease in cystic fibrosis (CF), but studies combining IL-8, TNFα-, and TGFβ1(+genotype) levels and their impact on CF lung disease are scarce.
Aim: Assessing the relationship between TGFβ1, IL-8, and TNF-α and lung disease in CF in an exacerbation-free interval.
Methods: Twenty four patients delta F508 homozygous (median age 20.5 y, Shwachman score 75, FEV1(%) 83) and 8 controls (median age 27.5 y) were examined. TGFβ1 was assessed in serum and induced sputum (IS) by ELISA, for IL-8 and TNF-α by chemiluminescence in IS and whole blood. Genotyping was performed for TGFβ1 C−509T and T+869C utilizing RFLP.
Results: TGFβ1 in IS (CF/controls median 76.5/59.1 pg/mL, P < 0.074) was higher in CF. There was a negative correlation between TGFβ1 in serum and lung function (LF) (FEV1 (r = −0.488, P = 0.025), MEF 25 (r = −0.425, P = 0.055), and VC (r = −0.572, P = 0.007)). Genotypes had no impact on TGFβ1 in IS, serum, and LF. In IS TGFβ1 correlated with IL-8 (r = 0.593, P < 0.007) and TNF-α (r = 0.536, P < 0.018) in patients colonized by bacteria with flagellin.
Conclusion: TGFβ1 in serum not in IS correlates with LF. In patients colonized by bacteria with flagellin, TGFβ1 correlates with IL-8 and TNF-α in IS.
Aims: We have provided evidence in former studies that cytokines (IL-8, TNF alpha, LBP, TGFß) measured in blood correlate negatively with lung function in deltaF508 homozygous patients. GAP junction proteins might be of importance for the influx of blood cells into the lung. Our aim was to assess the relationship between connexin genotypes and cytokines (IL-8, TNF-alpha, LBP, TGFß) in induced sputum and serum, and lung disease.
Methods: 36 patients homozygous for deltaF508 (median age 18 y, m/f 16/20, FEV1(%) 77) were examined. Sequence analysis was performed for genes encoding GAP junction protein alpha 1 (GJA1/connexin 43) and gap junction protein alpha 4 (GJA4/connexin 37). Cytokines were assessed in serum and induced sputum (IS) by chemiluminescence (DPC Biermann, Bad Homburg, Germany) as well as leukocyte counts.
Results: DNA analysis was performed in 35 patients. Whereas GJA1 showed only one rare heterozygous synonymous SNP (rs138386744) in one patient, four common SNPs were detected in GJA4. Two were synonymous changes, but the third variant (rs41266431) predicts an amino acid substitution (GTA → valine, ATA → isoleucine) as well as the fourth SNP (rs1764391: CCC→proline, TCC→serine). For rs41266431 patients with homozygosity for the G variant had higher IL-8 levels (median: 13.3/8.0 pg/ml, p=0.07) in serum as well as leukocytes in sputum (median: 2050/421 /µl p=0.041) than those showing heterozygosity (G/A). In individuals > 30 years lung function (FEV1 41.3/84.83 % predicted, p=0.07) was worse.
Conclusion: SNP rs41266431 seems a promising candidate for further investigations, suggesting GJA4 a potential disease modifying gene.