Different host genetic factors causes imbalance in the immune response. The purpose of this study was to establish whether pathological findings in chest radiography are related to the various host-related immunological factors in nephropathia epidemica (NE). Chest radiography findings, human leukocyte antigen (HLA) alleles B8, DR3, B27, genotypes of the genes of tumour necrosis factor alpha (TNFalpha), interleukin -1alpha (IL-1alpha), IL1beta and IL-1 receptor antagonist (IL1RA) were analysed in 114 patients with serologically confirmed acute NE. Both the presence and severity of abnormal NE-related chest radiography findings associated with the B8, DR3 and TNF2 alleles are known to form a frequent extended HLA haplotype in European populations. Pleural effusion showed the strongest association with these genetic factors. Pathological findings in chest radiography are related to host genetic factors in NE. Pleural effusion is a sign of increased capillary permeability, an important feature in NE. Host genetic factors may contribute to increased capillary permeability observed in NE patients.