Genetic influences of chromosomes 5q31-q33 and 11q13 on specific IgE responsiveness to common inhaled allergens among African American families. Collaborative Study on the Genetics of Asthma (CSGA).

BACKGROUND

We have recently conducted a genome-wide screening for genes influencing Dermatophagoides pteronyssinus-specific IgE responsiveness as a part of the Collaborative Study on the Genetics of Asthma (CSGA), which showed evidence for linkage in some regions, including chromosomes 5131-q33 and 11q13 in African American families.

OBJECTIVES

To clarify relative contributions of these regions to atopy in the same African American population, we have conducted further genetic linkage studies of specific IgE responses toward common inhaled allergens.

METHODS

We studied 328 individuals in 58 African American families participating in the CSGA. Specific IgE responses toward Dermatophagoides farinae, cat, dog, American cockroach, rye grass, and Bermuda grass, as measured by skin tests, were used for multipoint linkage analysis with polymorphic markers on chromosomes 5q31-q33 and 11q13.

RESULTS

Specific IgE response toward American cockroach showed evidence for linkage to chromosomes 5q31-q33 (P = .0050) and 11q13 (P = .017). Specific IgE response toward dog showed evidence for linkage with chromosome 5q31-q33 (P = .0043). Evidence for linkage with chromosome 11q13 was obtained for specific IgE responses toward Dermatophagoides farinae (P = .012), cat (P = .035), and Bermuda grass (P = .017). The presence of a positive ST response for at least 1 of 30 common allergens showed evidence for linkage to chromosomes 5q31-q33 (P = .017) and 11q13 (P = .00058).

CONCLUSIONS

These data support that genes on both chromosomes 5q31-q33 and 11q13 confer susceptibility to upregulated IgE-mediated immune responses in this African American population. The putative genes on chromosomes 5q31-q33 and 11q13, however, showed contrasting effects on atopy, which may result from strong gene-environmental interactions.