BACKGROUND: Alpha-1-antitrypsin (A-1-AT) is an important protease inhibitor which provides approx. 90 % of the serum anti-protease activity. The majority of the population (∼ 90%) have the MM genotype (codominant inheritance). Classic A-1-AT deficiency occurs with the ZZ genotype and is rare. Some of the heterozygote genotypes are associated with relatively lower A-1-AT serum levels. We have previously found that the mean pre-procedure A-1-AT levels were lower in patients who developed post-ERCP pancreatitis. HYPOTHESIS: We postulated that the difference in the group means was related to differences in the prevalence of A-1-AT heterozygotes; the pancreatitis group having more. Alternatively, an acute phase reaction could be responsible for a relative increase in the group of patients who did not develop pancreatitis. METHODS: In a new prospective series A-1-AT phenotypes were determined by a reference laboratory in 295 consecutive patients undergoing ERCP for various indications. C-reactive protein, a marker for the acute phase reaction, and serum A-1-AT levels were determined locally. Pancreatitis was diagnosed as previously described (Gastrointest Endosc 1990:36:462) . Using the z-statistic it was estimated that a sample size of approx. 200 pts would be sufficient to detect a difference of 10% in the incidence of abnormal phenotypes (α=0.05 two-tailed, β=0.20). RESULTS: Pancreatitis No Pancreatitis p-value (two-tailed) n = 26 n = 269 (Fisher's Exact Test) A-1-AT(mg/dl] 186.4±50.1 202.5 ± 59.9 0.19 CRP [mg/dl] 0.23 ± 0.59 1.3 ± 3.38 0.11 Heterozygotes 2/26 (7.8%) 24/269 (8.9%) 0.59 CONCLUSION: This prospective study shows no difference in the incidence of abnormal A-1-AT phenotypes (heterozygotes) between patients who developed post-ERCP pancreatitis and those who did not. This data supports our prior observation that the group of patients without pancreatitis has higher A-1-AT levels. CRP levels are higher in the patients who did not develop pancreatitis. However, the p-values do not reach statistical significance. This is probably due to a type II error and the data will be reanalyzed after more patients have been enrolled. Higher CRP levels suggest that an acute phase reaction may have increased the A-1-AT levels, and this may confer some degree of protection against post-ERCP pancreatitis.
ASJC Scopus subject areas
- Radiology Nuclear Medicine and imaging