Two Series of Familial Cases With Unclassified Interstitial Pneumonia With Fibrosis

Lee, Eun; Seo, Ju-Hee; Kim, Hyoung-Young; Yu, Jinho; Song, Jin Woo; Park, Young Soo; Jang, Se-Jin; Do, Kyung-Hyun; Kwon, Jiwon; Park, Sung-woo; Park, Jeong-hwan; Hong, Soo-Jong

The association between interstitial pneumonia and genetic mutations in a family raised the question of whether genetic mutation could be responsible for the simultaneous development of this disease in family members of different ages. Although genetic susceptibility cannot be ruled out in these familial cases, the simultaneous development of interstitial pneumonia implies the involvement of exposure to common environmental factors or the presence of infection in each family member. Because all family members reside in an urban region with no history of contact with animals or dust, it is suggested that interstitial pneumonia may be associated with viral infections; however, more investigation is needed in the future. A nationwide pediatric surveillance study performed in 2006 and then again in 2008 demonstrated a geographical and seasonal pattern to the increased incidence of unclassified interstitial pneumonia with fibrosis in Korea. 3 Between February and June in both 2006 and 2008, an increase in the incidence of unclassified interstitial pneumonia with fibrosis was initially observed in the southern regions of the country, and this progressed gradually toward the northern regions. 2, 5 The spring timing of this interstitial pneumonia, its characteristic pattern of spread from the south to north, and the detection of various viruses (i.e., human corona virus, cytomegalovirus, and parainfluenza virus), when considered together with the findings of the present familial case series, provide evidence that viral infection may be associated with the development of unclassified interstitial pneumonia with fibrosis in Korea. Altered or exaggerated host defense mechanisms, or repair processes triggered by a viral infection, may be responsible for the lung damage and fibrosis observed in these patients.