Results. Rituximab was well tolerated in this patient population, with most experiencing no significant adverse effects. Only 3 serious adverse events, which were thought to be unrelated to rituximab administration, were noted. A majority of patients (11 of 17) had profound B cell depletion (to <5 CD19؉ B cells/ l). In these patients, the SLAM score was significantly improved at 2 and 3 months compared with baseline (P ‫؍‬ 0.0016 and P ‫؍‬ 0.0022, respectively, by paired t-test). This improvement persisted for 12 months, despite the absence of a significant change in anti-doublestranded DNA antibody and complement levels. Six patients developed human antichimeric antibodies (HACAs) at a level >100 ng/ml. These HACA titers were associated with African American ancestry, higher baseline SLAM scores, reduced B cell depletion, and lower levels of rituximab at 2 months after initial infusion.Conclusion. Rituximab therapy appears to be safe for the treatment of SLE and holds significant therapeutic promise, at least for the majority of patients experiencing profound B cell depletion. Based on these results, controlled trials of rituximab appear to be warranted.

Bortezomib therapy: (1) provides effective treatment of AMR and ACR with minimal toxicity and (2) provides sustained reduction in iDSA and non-iDSA levels. Bortezomib represents the first effective antihumoral therapy with activity in humans that targets plasma cells.

No abstract

Proteasome inhibitor-based combination therapy provides a potential means for rapid DSA elimination in early acute AMR in renal transplant recipients.

Reducing luminal NaCl concentration in the macula densa region of the nephron stimulates renin secretion, and this response is blocked by a specific inhibitor of cyclooxygenase-2 (COX-2) (Traynor, T. R., Smart, A., Briggs, J. P., and Schnermann, J. (1999) Am. J. Physiol. Renal Physiol. 277, F706 -710). To study whether low NaCl activates COX-2 activity or expression we clonally derived a macula densa cell line (MMDD1 cells) from SV-40 transgenic mice using fluorescence-activated cell sorting of renal tubular cells labeled with segment-specific fluorescent lectins. MMDD1 cells express COX-2, bNOS, NKCC2, and ROMK, but not Tamm-Horsfall protein, and showed rapid 86 Rb ؉ uptake that was inhibited by a reduction in NaCl concentration and by bumetanide or furosemide. Isosmotic exposure of MMDD1 cells to low NaCl (60 mM) caused a prompt and time-dependent stimulation of prostaglandin E 2 (PGE 2 ) release that was prevented by the COX-2 specific inhibitor NS-398 (10 M). Reducing NaCl to 60 and 6 mM for 16 h increased COX-2 expression in a chloride-dependent fashion. Low NaCl phosphorylated p38 kinase within 30 min and ERK1/2 kinases within 15 min without changing total MAP kinase levels. Low NaCl-stimulated PGE 2 release and COX-2 expression was inhibited by SB 203580 and PD 98059 (10 M), inhibitors of p38 and ERK kinase pathways. We conclude that low chloride stimulates PGE 2 release and COX-2 expression in MMDD1 cells through activation of MAP kinases.