Genetic predisposition to diffuse panbronchiolitis

ABSTRACT Diffuse panbronchiolitis is characterized by chronic inflammation in respiratory bronchioles and sinobronchial infection. The pathophysiology accompanying the persistent bacterial infection is noteworthy for the accumulation of lymphocytes and foamy macrophages around the small airways, for mucus hypersecretion, and for the number of neutrophils in the large airways. Until the establishment of long‐term macrolide therapy, the prognosis was generally poor. Case studies of diffuse panbronchiolitis in East Asians, including Japanese, Koreans and Chinese, have frequently been reported, and genetic predisposition to the disease has been assumed in Asians. Immunogenetic studies revealed a strong association with human leukocyte antigen (HLA)‐B54 in Japanese, whereas an association with HLA‐A11 was reported in Koreans. These findings imply that a major susceptibility gene may be located between the HLA‐A and HLA‐B loci on the short arm of human chromosome 6. We have recently cloned novel mucin‐like genes in this candidate region. In addition to accumulated knowledge of classical HLA genes and mucin genes, further analysis of newly identified genes may provide insights into the pathogenesis of the disease.