Complement gene expression in hepatic and extrahepatic tissues of NZB and NZB x W (F1) mouse strains

To study the role of local production of complement proteins during the evolution of a naturally occurring immune complex disease, C3, C4, C2 and Factor B mRNA expression was assessed in several tissues of the inbred mouse strains NZB and (NZB x W) F1 hybrid. In the NZB/W F1 hybrid strain, coincident with the development of glomerulonephritis a marked increase in kidney C3 and C4 mRNA was observed; Factor B mRNA, which is expressed as a doublet in kidney and intestine, showed an increase in expression of the smaller transcript. This alteration of kidney C3, C4 and Factor B mRNA is identical to that noted in association with lupus nephritis in the MRL lpr/lpr strain and following in vivo administration of endotoxin to the BALB/c strain. The development of systemic lupus erythematosis (SLE) in the NZB/W F1 was not associated with a marked change in hepatic complement gene expression. These findings support the hypothesis that local production of complement may play a role in the pathogenesis of glomerulonephritis and other tissue injury in SLE.