GENETIC INFLUENCES OF CHROMOSOMES 5Q31-Q33 AND 11Q13 ON SPECIFIC IGE RESPONSIVENESS TO COMMON INHALED ALLERGENS AMONG AFRICAN-AMERICAN FAMILIES

Background: We have recently conducted a genome-wide screening for gen es influencing Dermatophagoides pteronyssinus-specific IgE responsiven ess as a part of the Collaborative Study on the Genetics of Asthma (CS GA), which showed evidence for linkage in some regions, including chro mosomes 5q31-q33 and 11q13 in African American families. Objectives: T o clarify relative contributions of these regions to atopy in the same African American population, we have conducted further genetic linkag e studies of specific IgE responses toward common inhaled allergens. M ethods: We studied 328 individuals in 58 African American families par ticipating 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 w ith polymorphic markers on chromosomes 5q31-q33 and 11q13. Results: Sp ecific IgE response toward American cockroach showed evidence for link age to chromosomes 5q31-q33 (P =.0050) and 11q13 (P =.017). Specific I gE response toward dog showed evidence for linkage with chromosome 5q3 1-q33 (P =.0043). Evidence for linkage with chromosome 11q13 was obtai ned for specific IgE responses toward Dermatophagoides farinae (P =.01 2), cat (P =.035), and Bermuda grass (P =.017). The presence of a posi tive 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-q3 3 and 11q13 confer susceptibility to upregulated IgE-mediated immune r esponses in this African American population. The putative genes on ch romosomes 5q31-q33 and 11q13, however, showed contrasting effects on a topy, which may result from strong gene-environmental interactions.