IRF5+/− mice exhibited less severe end-organ disease in that IRF5+/− mice had lower serum BUN levels and a trend toward longer survival (median = 188 days in IRF5+/− MRL/lpr mice vs 155 days in IRF5+/+ MRL/lpr mice, p = 0.07), however the increase in survival was modest as compared with IRF5−/− littermates which lived to a median of 272 days (Fig. 5 and 6). The gene discussed is IRF5; the disease is glycogen storage disease VI.