A renal biopsy study of lupus nephropathy in the United States and Korea.

A comparative study was made using renal biopsy specimens obtained from US and Korean patients with lupus nephropathy. Significant differences were observed in the morphologic distribution and activity of the disease. Korean patients exhibited a higher frequency of World Health Organization class IV lupus nephropathy (77.8%) than black (47.2%) or white (42.1%) US patients (P less than 0.025, P less than 0.05, respectively), and a higher inflammatory intensity index (P less than 0.045) than US patients. Korean patients also showed a significantly lower frequency of WHO class III nephropathy (P less than 0.05). No significant morphologic differences were seen between the US white and black patient populations. These data suggest that the Korean patients had a more active and potentially more fulminating disease than the US patients. Whether differences in genetic and external causative factors play a role in the observed differences in renal histopathology among these groups remains to be clarified.