DNASE1 and lupus nephritis: To analyze if the down-regulation of Dnase1 gene expression and corresponding Dnase1 enzyme activity observed in nephritic BW mice was also relevant in human lupus nephritis, Dnase1 immunostaining was performed on histologically normal human kidney biopsies (Figure 3D) and to biopsies from patients with mild (Patient A, Figure 3E) and membranoproliferative (Patient B, Figure 3F) lupus nephritis.