CTLA4 polymorphisms and COPD.

We read with interest the article by ZHU et al. [1] describing the association of two single nucleotide polymorphisms (SNPs; rs231775 and rs3087243) within the CTLA4 gene and chronic bronchitis. Both of these polymorphisms may be risk factors for autoimmunity [2], and are often referred to as A49G and CT60, respectively. As alluded to briefly by the authors in their discussion, there has been recent interest in a possible role for autoimmunity in chronic obstructive pulmonary disease (COPD), hence shared genetic susceptibility with other autoimmune diseases would support this hypothesis. Although the authors report their association in two independent cohorts, general acceptance of the importance of this locus would require further validation in other COPD populations. We would like to add support to their results, by reporting association of rs231775 in an a1-antitrypsin deficient (a1-ATD) cohort, which also tended to associate with the same feature in the 1958 birth cohort.