Monoclonal anti-erythrocyte autoantibodies derived from NZB mice cause autoimmune hemolytic anemia by two distinct pathogenic mechanisms

In vivo pathological manifestations of eight monoclonal anti-mouse red blood cell (MRBC) autoantibodies obtained from unmanipulated NZB mice were determined in BALB/c mice. Three (two IgG1 and one IgG2a) of four IgG monoclonal antibodies (mAb) and two of four IgM mAb were able to induce anemia following their i.p. injection. All five pathogenic anti-MRBC mAbs reacted only with MRBC, whereas non-pathogenic anti-MRBC mAbs showed binding to different species of RBC. Competition studies suggested the presence of at least two distinct epitopes recognized by our pathogenic anti-MRBC mAb. Histological examinations revealed that anemia resulted from either marked sequestration of agglutinated MRBC in spleens and livers or erythrophagocytosis, most remarkably by Kupffer cells in livers. This difference was correlated with the ability of each mAb to mediate Fc receptor-dependent phagocytosis by macrophages. The absence of complement-mediated hemolysis in vitro and the development of anemia in C5-deficient or C3-depleted mice indicated a minor role, if any, for complement-mediated lysis in the anemia induced by our anti-MRBC mAb. Our results suggest that (i) at least two different pathogenic epitopes are implicated in autoimmune hemolytic anemia; and (ii) sequestration of agglutinated MRBC in spleens and livers and Fc receptor-dependent phagocytosis, but not complement-mediated hemolysis, are the major mechanisms for the development of autoimmune hemolytic anemi

Aberrant High Expression of B Lymphocyte Chemokine (Blc/Cxcl13) by C11b+Cd11c+ Dendritic Cells in Murine Lupus and Preferential Chemotaxis of B1 Cells towards Blc

We observed here that the expression of B lymphocyte chemokine (BLC/CXCL13) was markedly enhanced in the thymus and kidney in aged (NZB × NZW)F1 (BWF1) mice developing lupus nephritis, but not in similarly aged NZB and NZW mice. BLC-positive cells were present in the cellular infiltrates in the target organs with a reticular pattern of staining. CD11b+CD11c+ dendritic cells were increased in the thymus and spleen in aged BWF1 mice and identified as the major cell source for BLC. CD4+ T cells as well as B cells were dramatically increased in the thymus in aged BWF1 mice, whereas no increase was observed in aged NZB and NZW mice. B1/B2 ratio in the thymus was significantly higher than those in the spleen and peripheral blood in aged BWF1 mice. Interestingly, BLC showed preferential chemotactic activity for B1 cells derived from several mouse strains, including nonautoimmune mice. Cell surface CXCR5 expression on B1 cells was significantly higher than that on B2 cells. Thus, aberrant high expression of BLC by myeloid dendritic cells in the target organs in aged BWF1 mice may play a pivotal role in breaking immune tolerance in the thymus and in recruiting autoantibody-producing B cells in the development of murine lupus

The outcomes of reconstruction using frozen autograft combined with iodine-coated implants for malignant bone tumors: Compared with non-coated implants

Objective: We perform reconstruction using frozen tumor bone treated by liquid nitrogen after excision of malignant bone tumors. To prevent post-operative infection, we use iodine-coated implants that we developed. The purpose of this study is to compare the outcome of reconstruction using frozen autograft with non-coated implants (group N) and iodine-coated implants (group I).Methods: Sixty-two patients were included in group N. The mean age was 31.9 ± 2.3 years. A total of 20 patients died and two were lost to follow-up, averaging 20.0 ± 2.9 months post-operatively, leaving 40 patients available for an assessment at a mean of 79.1 ± 5.8 months post-operatively. There were 38 patients in group I. The mean age was 29.8 ± 3.9 years. The mean follow-up period was 32.1 ± 3.0 months. All patients were alive at the latest follow-up. Survival of frozen bone was determined by Kaplan-Meier analysis.Results: In group N, survival of frozen bone was 80.7 ± 6.0% and 57.4 ± 10.2% at 5 and 10 years, respectively. Complications were encountered in 31 of 62 patients (50.0%), including deep infection in 10 (16.1%), fracture in 11 (17.7%), local soft-tissue recurrence in 6 (9.7%) and bone absorption in 4 (6.5%). In group I, survival of frozen bone was 86.7 ± 6.3% at 5 years. Complications were encountered in 8 of 38 patients (21.1%), including deep infection in one (2.6%), fracture in four (10.5%), local soft-tissue recurrence in two (5.3%) and bone absorption in one (2.6%). There was a significantly lower infection rate in group I (P = 0.032).Conclusion: Reconstruction using frozen autograft combined with iodine-coated implants for patients with malignant bone tumor is very useful method in which good limb function can be gained with minimized risk of infection. © The Author 2016. Published by Oxford University Press. All rights reserved.Article number hyw065 / Embargo Period 6 month

Natural Thymocytotoxic Autoantibody and Reactive Antigen in New Zealand Black and Other Mice

Naturally occurring thymocytotoxic autoantibody (NTA) was detected by cytotoxic test in the sera of very young New Zealand Black mice (within 1 month after birth); the incidence was 100% at 3 months of age. Some mice from other strains also had NTA, but at an older age and with lower incidence and antibody titer. NTA had optimal activity at 4°C but was also strongly reactive at 37°C. It was cytotoxic for thymocytes of all strains of mice tested. Whereas only thymocytes were highly sensitive to NTA, the reactive antigen was demonstrated by absorption test in the thymus, lymph node, spleen, and brain of adult mice. It could be demonstrated only in the thymus of newborn mice. The distribution of NTA-reactive antigen suggests the presence of an antigen distinct from any so far described on the cell surface of mouse thymocytes. Gel filtration of NZB mouse serum suggests that NTA is an IgM. Mouse thymocytes sensitized with NTA in vitro became highly susceptible to phagocytosis by syngeneic macrophages