Association analysis of TIM-1 -232G > A and 5383_5397 insertion/deletion polymorphisms with childhood asthma and total serum immunoglobulin E levels in middle China.

BACKGROUND

One of the members of the T cell immunoglobulin (Ig) domain and mucin domain (TIM) gene family, TIM-1, located in the chromosome 5q31-33 region, has been associated with the development of T helper (T(H)) 2-biased immune responses and may be selectively expressed in T(H)2 cells. Previous studies have also shown an association between polymorphisms in the TIM-1 gene and asthma or asthma-related phenotypes.

OBJECTIVE

The aim of the present study was to analyze the association between the TIM-1 polymorphisms -232G > A and 5383_5397 insertion/deletion (ins/del) and susceptibility to asthma in a group of patients from middle China.

METHODS

Polymerase chain reaction (PCR)-restriction fragment length polymorphism analysis and PCR-polyacrylamide gel electrophoresis were used to detect -232G > A and 5383_5397 ins/del genotypes in 302 asthmatic children and 206 controls. Serum total IgE was measured by chemiluminescence and specific IgE to common aeroallergens by immunoblot analysis.

RESULTS

We found no association between the -232G > A polymorphism and asthma or total serum IgE levels or statistically significant differences between asthma and control subjects in terms of genotype and allele frequency for the 5383_5397 ins/del polymorphism.We did, however, detect a difference in total serum IgE levels for 5383_5397 ins/ins genotypes in individuals with atopic asthma (P < .05) in that they had higher IgE levels than those with del/del and del/ins genotypes.

CONCLUSION

Our results suggest that the 5383_5397 ins/ins genotype in the TIM-1 gene is associated with elevated serum total IgE levels, particularly in individuals with atopic asthma. Further studies are needed to confirm such an association.