Bactericidal/Permeability-Increasing Fold-Containing Family B Member 4 May Be Associated with NSAID-Induced Enteropathy

Background: There is considerable individual variability in nonsteroidal anti-inflammatory drug (NSAID)-induced enteropathy. Aim: To identify the SNP that is most significantly involved with NSAID-induced enteropathy. Methods: One hundred fifty human subjects who were known to have a certain degree of loxoprofen- or celecoxib-induced small-intestinal damage from a previous study were enrolled. The subjects were divided into groups based on treatments and also on the increased number of small intestinal mucosal breaks. The candidate SNP was selected by an initial analysis of GWAS among the groups in various combinations. After the initial analysis, the gene including the specified SNP was analyzed in detail using GWAS and genotype imputation. Results: After analysis, 70 subjects receiving the loxoprofen treatment and 69 subjects receiving celecoxib treatment were determined to be eligible for the analysis. The minimum p value in GWAS was detected in the analysis of 16 cases with an increase of five or more mucosal breaks and 123 controls with zero to four mucosal breaks. In the GWAS, five SNPs in the bactericidal/permeability-increasing fold-containing family B member 4 (BPIFB4) gene showed the lowest p value (p = 2.69 × 10 ⁻⁷ with an odds ratio of 40.9). Of the five SNPs, four were nonsynonymous SNPs (rs2070325: V268I, rs2889732: T320N, rs11699009: F527L, rs11696307: T533I, and rs11696310: intronic). Furthermore, 23 SNPs in BPIFB4 detected by genotype imputation based on the GWAS data also showed suggestive associations (p < 1 × 10 ⁻⁶ ). Conclusion: The results indicate that SNPs in BPIFB4 were associated with NSAID-induced small intestinal mucosal injury (UMIN: 000007936).