Clonal analysis of autoreactive B cells in a murine model of autoimmune hemolytic anemia

Hybridoma technology was used to examine the repertoire of autoantibody producing B cells in mice with autoimmune hemolytic anemia induced by injection of rat red blood cells (RBC). The results point to the importance of suppressor T cells (Ts) in both the induction as well as the maintenance of the self-specific B-cell repertoire at the clonal level. Thus when normal BALB/c mice were immunized to provoke a high autoantibody response, the hybrids generated were mainly (97%) cross-reactive with mouse RBC, whereas after immunization to elicit Ts and a low autoantibody response, hybrids were mainly (87%) rat RBC specific. In addition, when hybrids were generated from rat RBC immunized (CBA X B10A)F1 mice, in which Ts levels had been depleted during ontogeny, hybrids with "forbidden" purely anti-self (mouse RBC) specificity were detected.     

Severe autoimmune hemolytic anemia in SIVsmm9-infected Macaca mulatta

One of 15 rhesus macaques infected with SIVsmm9 developed profound hemolysis with spherocytosis, reticulocytosis, and IgG and complement at the red blood cell surface. A female offspring born to this animal developed similar findings. Furthermore, cold agglutinins were noted in samples from both animals. Four of the 13 animals remaining in the cohort had weakly positive antiglobulin tests but were not anemic. Autoimmune hemolytic anemia may be an underrecognized cause of anemia in SIV infection.     

Splenic hematopoiesis in an experimental model of hemolytic anemia

The splenic hemopoiesis of rabbits, made anemic with acetylphenylhydrazine, and of control animals was investigated. Pieces of spleen of both groups were fixed in formalin and embedded in paraffin. Paraffin sections, cut 5-7 microns in thickness, were stained with hematoxylin-eosin, Giemsa, Perls' method for tissue iron (hemosiderin), and Perls-Chayen's method for iron stored in the hemoglobin. The erythroid line in the anemic rabbits, showed a marked increase of proerythroblasts and basophilic erythroblasts, while the poli and orthochromatic erythroblasts were less than their precursors. In contrast these cells were more than their precursors in control animals. There was no notable quantitative difference in the mature elements of this line in the anemic animals and in the controls. Megaloblasts and macroblasts were frequently observed in anemic spleens but they were practically absent in the controls. Regarding to other cell lineages, we noted in the anemic spleens many macrophages containing Perls and Perls-Chayen positive material and some megakaryocytes. Our results indicate that the APH-induced anemia stimulate the erythropoietic activity of the spleen in the rabbit, but the reversion of the amplification phase of the differentiation steps reveals that the erythropoietic process is ineffective. The presence of megalo- and macroblasts provide morphological evidence of dyserythropoiesis and the megakaryocytes suggest that under the anemia condition also the platelet regenerating process is stimulated.     

Enlargement of Lyt-2-positive T cells is associated with functional impairment and autoimmune hemolytic anemia in New Zealand Black mice

We investigated the relationship between the increased cell diameter of Lyt-2+ T cells and the development of autoimmune disease in aging NZB and NZB X NZW F1 hybrid (BW) mice. Individual animals were analyzed for Lyt-2+ T cell size (by narrow-angle forward light scatter), anti-erythrocyte autoantibodies, anemia, proteinuria, and splenomegaly. The peak light scatter of the Lyt-2+ T cells correlated with the level of anti-erythrocyte autoantibodies and severity of hemolytic anemia, but not with proteinuria or splenomegaly. The cell size of this T cell subset did not increase in old BW or in NZB mice homozygous for the xid gene (NZB.xid). The in vivo administration of bacterial lipopolysaccharide to young NZB mice did not stimulate the enlargement of Lyt-2+ T cells. Ly-2+ T cells from old NZB mice could be stimulated by concanavalin A (Con A) to express interleukin 2 (IL 2) receptors and to synthesize DNA in vitro. However, in vivo administration of Con A to old NZB mice did not induce the expression of IL 2 receptors on Lyt-2+ T cells. Further, in vivo T suppressor function was impaired in old NZB mice with enlarged Lyt-2+ T cells. Thus, the enlargement of Lyt-2+ T cells in old NZB mice appears related to impaired T cell function in vivo and is associated with the development of anti-erythrocyte autoantibodies and autoimmune hemolytic anemia.     

Memory T cells and their costimulators in human allograft injury

Both CD4(+) and CD8(+) human memory but not naive T cells respond to allogeneic human dermal microvascular endothelial cells (HDMEC) in vitro by secreting cytokines and by proliferating. Several recently identified costimulators, namely, 4-1BB ligand, ICOS ligand, and OX40 ligand, are up-regulated on cultured HDMEC in response to TNF or coculture with allogeneic T cells. Blockade of these costimulators each partially reduces IFN-gamma and IL-2 secretion and proliferation of previously resting memory T cells. The effects of these costimulators are overlapping but not identical. Memory but not naive T cells are the principal effectors of microvascular injury in human skin allografts following adoptive transfer into immunodeficient mice. Furthermore, blocking 4-1BB ligand, ICOS ligand, or OX40 ligand in this model reduces human skin allograft injury and T cell effector molecule expression. These data demonstrate that human memory T cells respond to microvascular endothelial cells and can injure allografts in vivo without priming. Furthermore, several recently described costimulators contribute to these processes.     

Targeting autoantigen-specific T cells and suppression of autoimmune encephalomyelitis with receptor-modified T lymphocytes

We demonstrate here the feasibility of antigen-specifically redirecting T cells against autoreactive T lymphocytes and thereby treating a model autoimmune disease. We created and transgenically expressed on T cells a heterodimeric chimeric receptor that genetically links an autoantigenic peptide, its restricting MHC, and the signal transduction domain of the T-cell receptor (TCR) zeta-chain. Engagement of the chimeric receptor by the TCR of autoreactive T cells activated the receptor-modified T cells in vitro and in vivo, inducing proliferation and cytolysis. Adoptively transferred receptor-modified T cells prevented and treated a model autoimmune disease, experimental allergic encephalomyelitis (EAE), even after epitope spreading had diversified the autoantigenic response. Treatment reduced disease severity and increased survival of affected animals, and was durable for >75 days. The receptor-modified cells acted both by strongly attenuating T-cell response to autoantigen as well as by shifting the residual response from an immunopathologic Th1 to a protective Th2 format.     

异基因造血干细胞移植后并发自身免疫性溶血性贫血的治疗进展

异基因造血干细胞移植（HSCT）后自身免疫性溶血性贫血（AIHA）是HSCT后并不少见的并发症,其发病率约1﹪~ 6﹪,不同于一般的AIHA,HSCT后AIHA发病机制尚未完全明确,可能与HSCT后受者体内免疫失调相关。危险因素与移植患者年龄小、非恶性疾病、使用无关供者、半相合供者移植、脐血移植、去T细胞移植及移植后并发慢性移植物抗宿主病（GVHD）等有关。皮质激素作为一线治疗,疗效有限,难以持续缓解,需联合使用利妥昔单抗（RTX）、大剂量丙种球蛋白等,甚至需要联合霉酚酸酯、环磷酰胺、西罗莫司、阿伦单抗、依库丽单抗或蛋白酶体抑制剂硼替佐米等免疫抑制剂治疗,部分患者需行血浆置换,偶有行脾切除术者。移植后AIHA总死亡率常高达50﹪,总体预后差于单纯AIHA。该综述旨在总结HSCT后并发AIHA的最新治疗进展,供临床医师参考。     

A model of hemopoietic stress in a lactate dehydrogenase mouse mutant with hemolytic anemia

A codominantly inherited mutation of the lactate dehydrogenase (LDH) in the C3H mouse causes a severe hemolytic anemia in homozygous mutants, whereas viability and fertility are close to normal. Investigation of multipotent hemopoietic stem cells (CFU-S), myeloid (GM-CFC) and erythroid progenitors (BFU-E, CFU-E) in femur and spleen indicates a general shift from bone marrow to splenic hemopoiesis. In terms of total body hemopoiesis, however, the BFU-E pool is 1.4- and the CFU-E pool 19-fold enlarged, whereas CFU-S and GM-CFC show little or no deviation from normal. It is concluded that this mouse mutant is an appropriate model of long-term hemopoietic stress showing that compensation in this severe hemolytic anemia is achieved primarily by an increase of the number of the most mature erythroid progenitors.     

Monocyte receptors for the Fc portion of IgG increase in number in autoimmune hemolytic anemia and other hemolytic states and are decreased by glucocorticoid therapy

Peripheral blood monocyte receptors for the Fc portion of IgG were quantitatively studied in 43 normal subjects, in 14 patients with warm antibody autoimmune hemolysis (AIHA), and in nine individuals with nonantibody-mediated hemolysis. Monocytes of normal females expressed significantly greater numbers of Fc gamma receptors than did similar cells from male subjects, with no difference in affinity for the IgG1 probe. Monocyte Fc gamma receptor number was increased in patients of both sexes with AIHA; a similar, but smaller, increase in monocyte Fc gamma receptor number was noted in patients with nonantibody-mediated hemolysis. Glucocorticoid administration was associated with a dose-dependent decrease in monocyte Fc gamma receptor number in normal volunteers and patients. Possible etiologic mechanisms and pathogenetic consequences of enhanced monocyte Fc gamma binding in AIHA are discussed.