Characterization of proteinuria in asymptomatic family members and household contacts of children with hepatitis B virus-associated membranous nephropathy

The biosocial background in which the hepatitis B virus (HBV) carrier state with membranous nephropathy (MN) develops was studied by evaluating HBV ca rriage and proteinuria among 195 family members and household contacts of 3 1 index HBV carrier children with MN. Unrelated individuals from the commun ities of these index cases who were negative for HBV served as controls (n = 123), HBV was determined by using third-generation enzyme-linked immunoso rbent assay, slot-blot hybridization, and nested polymerase chain reaction. Patterns of proteinuria were determined by using sodium dodecyl sulfate-po lyacrylamide gel electrophoresis; immunoglobulin G and haptoglobulin were s uggestive of MN, Seventy-two members (36.9%) of the study group (n = 195) w ere HBV carriers; 21 of these carriers (29.2%) had proteinuria. Twenty eigh t members (41.2%) of the study group who were HBV negative (n = 68) and 26. 8% of the controls showed proteinuria, This lack of association between HBV carriage and proteinuria remained when controlled for sex and family relat ionship. HBV was not protective against the development of proteinuria. Pro teinuria suggestive of MN was strongly associated with an abnormal protein- creatinine ratio (P = 0.001), but was not significantly different between s ubjects and controls (8.7% Versus 6.5%; P = 0.5). Genetic influences or env ironmental exposures in these subjects may be responsible for the proteinur ia, suggesting underlying glomerular basement membrane damage. Discordance between the HBV carrier state and patterns of proteinuria in the study grou p suggest that HBV and MN may not be causally related or may reflect except ional interaction between specifically Vulnerable individuals and HBV, (C) 2001 by the National Kidney Foundation, Inc.