Inhibition of complement factor C5 protects against anti-myeloperoxidase antibody-mediated glomerulonephritis in mice.

In mice, administration of murine anti-myeloperoxidase (MPO) IgG induces pauci-immune necrotizing crescentic glomerulonephritis. Recent studies in this model indicate a crucial role for complement activation in disease induction. Here, we investigated the effect of pretreatment or intervention with a C5-inhibiting monoclonal antibody (BB5.1) in the mouse model of anti-MPO IgG-induced glomerulonephritis. Mice received BB5.1 8 h before or 1 day after disease induction with anti-MPO IgG and lipopolysaccharide. Mice were killed after 1 or 7 days. Control antibody-pretreated mice developed hematuria, leukocyturia and albuminuria, and glomerulonephritis with a mean of 21.0+/-8.8% glomerular crescents and 12.8+/-5.5% glomerular capillary necrosis. BB5.1 pretreatment prevented disease development, as evidenced by the absence of urinary abnormalities, a marked reduction in glomerular neutrophil influx at day 1 and normal renal morphology at day 7. Importantly, BB5.1 administration 1 day after disease induction also resulted in a marked attenuation of urinary abnormalities and a more than 80% reduction in glomerular crescent formation. In conclusion, inhibition of C5 activation attenuates disease development in a mouse model of anti-MPO IgG-induced glomerulonephritis. These results favor further investigations into the role of complement activation in human MPO-anti-neutrophil cytoplasmic autoantibody-mediated glomerulonephritis, and indicate that inhibition of C5 activation is a potential therapeutic approach in this disease.

Advantages and limitations of (non-)myeloablative allogeneic stem cell transplantation.

Allogeneic stem cell transplantation (allo-SCT) is the treatment of choice for a variety of malignant diseases, not only as a method to regain haematopoiesis after myeloablative therapy, but also for its apparent antitumour effect. However, treatment-related morbidity and mortality are considerable. A potential way to overcome this problem is by decreasing the intensity of chemotherapy and/or radiotherapy given prior to transplantation. This reduced-intensity conditioning regimen is the basis of non-myeloablative allo-SCT (also referred to as mini SCT), a new treatment modality that relies more heavily on the antitumour effect exerted by the donor cells than on the antitumour effect of the conditioning therapy. The aim of this article is to place the concept of non-myeloablative SCT in a historical context and to discuss the advantages and disadvantages of regular myeloablative SCT compared with non-myeloablative SCT. Furthermore, human trials regarding non-myeloablative SCT are reviewed, and several experimental techniques are discussed that aim to augment the antitumour effect of an allogeneic graft.

Non-myeloablative allogeneic stem cell transplantation in patients with solid tumours and patients with a haematological malignancy.

Allogeneic stem cell transplantation (allo-SCT) is a treatment option for several haematological tumours, not only to regain haematopoiesis after myeloablative chemotherapy and/or radiotherapy, but also for its apparent antitumour effect. This so-called graft-versus-tumour effect might not only be effective against haematological tumours, where it has best been proven, but also against solid tumours. To reduce morbidity and treatment-related mortality of allo-SCT, efforts are being made to establish engraftment of allogeneic stem cells after a non-myeloablative conditioning regimen and create a 'mini transplantation'. Such a therapy relies more heavily on the graft-versus-malignancy effect than on the antitumour effect exerted by the chemotherapy/radiotherapy. Here, we report the outcomes of 15 patients with haematological disease or solid tumours who underwent an SCT in the University Hospital Maastricht after a non-myeloablative fludarabine/cyclophosphamide conditioning regimen. Although results are promising, adjustments will be needed to ensure long-term stable engraftment and optimise the antitumour effect.