Decreased renal destruction and lymphocyte infiltration in B6.Sle1.Sle3 mice after inhibition of Btk signaling. (A) Inhibition of Btk by PCI-32765 reduced renal damage. Paraffin-embedded kidneys were sectioned and stained with H&E before being scored by a pathologist blinded to the sample identity. (B) Decreased number of renal lymphocytes in mice that received PCI-32765. Single cell suspensions were prepared from kidneys isolated from mice treated with PCI-32765 or vehicle. After staining with antibodies specific for the indicated cell populations, percentage cell numbers were multiplied by the total intra-renal cell number as determined by a Cellometer Auto M10 automated cell counter (Nexcelom Bioscience). Each data point represents one mouse. Line represents mean ± standard error of the mean. *P < 0.05, **P < 0.005. Data were compared by two-tailed Student's t-test with Welch's correction. (C) Histopathological signs of renal damage. Shown are representative photomicrographs of period acid Schiff (PAS)-stained kidney sections isolated from PCI-32765-treated (n = 9) or vehicle-treated (n = 6) mice. All images were taken at 200 × total magnification. GN, glomerular nephritis.