Autoimmune Pathogenesis and Autoimmune Hemolytic Anemia

Genomic organization and gene evolution of two warm temperature acclimation proteins (Wap65s) of Micropterus salmoides and their responses to temperature and bacterial/viral infections

Warm temperature acclimation-related 65-kDa proteins (Wap65s) are fish plasma acute-phase glycoproteins homologous to hemopexin with high affinity and clearance for heme. The study characterized Mswap65-1 and Mswap65-2 genes in Micropterus salmoides. Structural analysis showed MsWap65s contained conserved heme-binding sites. MsWap65-1 had a chloride-binding site similar to hemopexin, while MsWap65-2 had an additional calcium-binding site. Phylogenetic and Ka/Ks analysis showed that fish Wap65s were evolutionarily conserved and underwent strong purifying selection. Functional divergence analysis indicated that fish Wap65-2 retained the putative function of ancestral Wap65, while Wap65-1 underwent neofunctional differentiation. QPCR showed Mswap65s were predominantly expressed in liver, but prolonged hyperthermy inhibited Mswap65-2 expression. Mswap65-2 expression was up-regulated in liver and spleen after Nocardia seriolae infection, while Mswap65-1 was down-regulated. MsWap65-2 may be associated with pathogenesis and play potential role in pathogen resistance. LMBV infection resulted in both significant downregulation of Mswap65s were both significantly down-regulated, with differences observed between sexes. We speculated the immune system might suppress expression after viral infection. Exogenous rMsWap65s were prepared, and injection of rMsWap65s alleviated phenylhydrazine-induced hemolysis and inhibited increases in heme, complement C3 and inflammatory symptoms. Our results contribute to an advanced understanding of the functions and mechanisms of MsWap65s in stress resistance.

Hemolysis-Inspired, Highly Sensitive, Label-Free IgM Detection Using Erythrocyte Membrane-Functionalized Nanomechanical Resonators

Immunoglobulin detection is important for immunoassays, such as diagnosing infectious diseases, evaluating immune status, and determining neutralizing antibody concentrations. However, since most immunoassays rely on labeling methods, there are limitations on determining the limit of detection (LOD) of biosensors. In addition, although the antigen must be immobilized via complex chemical treatment, it is difficult to precisely control the immobilization concentration. This reduces the reproducibility of the biosensor. In this study, we propose a label-free method for antibody detection using microcantilever-based nanomechanical resonators functionalized with erythrocyte membrane (EM). This label-free method focuses on the phenomenon of antibody binding to oligosaccharides (blood type antigen) on the surface of the erythrocyte. We established a method for extracting the EM from erythrocytes and fabricated an EM-functionalized microcantilever (MC), termed EMMC, by surface-coating EM layers on the MC. When the EMMC was treated with immunoglobulin M (IgM), the bioassay was successfully performed in the linear range from 2.2 pM to 22 nM, and the LOD was 2.0 pM. The EMMC also exhibited excellent selectivity compared to other biomolecules such as serum albumin, γ-globulin, and IgM with different paratopes. These results demonstrate that EMMC-based nanotechnology may be utilized in criminal investigations to identify blood types with minimal amounts of blood or to evaluate individual immunity through virus-neutralizing antibody detection.

High-resolution quantification of discrete phagocytic events by live cell time-lapse high-content microscopy imaging

Phagocytosis is a dynamic process central to immunity and tissue homeostasis. Current methods for quantification of phagocytosis largely rely on indirect or static measurements, such as target clearance or dye uptake, and thus provide limited information about engulfment rates or target processing. Improved kinetic measurements of phagocytosis could provide useful, basic insights in many areas. We present a live-cell, time-lapse and high-content microscopy imaging method based on the detection and quantification of fluorescent dye 'voids' within phagocytes that result from target internalization to quantify phagocytic events with high temporal resolution. Using this method, we measure target cell densities and antibody concentrations needed for optimal antibody-dependent cellular phagocytosis. We compare void formation and dye uptake methods for phagocytosis detection, and examine the connection between target cell engulfment and phagolysosomal processing. We demonstrate how this approach can be used to measure distinct forms of phagocytosis, and changes in macrophage morphology during phagocytosis related to both engulfment and target degradation. Our results provide a high-resolution method for quantifying phagocytosis that provides opportunities to better understand the cellular and molecular regulation of this fundamental biological process.

Clinical and laboratory features of autoimmune hemolytic anemia associated with immune checkpoint inhibitors

Immune checkpoint inhibitors (ICPis) are a novel class of immunotherapeutic agents that have revolutionized the treatment of cancer; however, these drugs can also cause a unique spectrum of autoimmune toxicity. Autoimmune hemolytic anemia (AIHA) is a rare, but often severe, complication of ICPis. We identified 14 patients from nine institutions across the United States who developed ICPi-AIHA. The median interval from ICPi initiation to development of AIHA was 55 days (interquartile range [IQR], 22-110 days). Results from the direct antiglobulin test (DAT) were available for 13 of 14 patients: 8 patients (62%) had a positive DAT and 5 (38%) had a negative DAT. The median pretreatment and nadir hemoglobin concentrations were 11.8 g/dL (IQR, 10.2-12.9 g/dL) and 6.3 g/dL (IQR, 6.1-8.0 g/dL), respectively. Four patients (29%) had a preexisting lymphoproliferative disorder, and two (14%) had a positive DAT prior to initiation of ICPi therapy. All patients were treated with glucocorticoids, with three requiring additional immunosuppressive therapy. Complete and partial recoveries of hemoglobin were achieved in 12 (86%) and 2 (14%) patients, respectively. Seven patients (50%) were rechallenged with ICPis, and one (14%) developed recurrent AIHA. Clinical and laboratory features of ICPi-AIHA were similar in DAT positive and negative patients. ICPi-AIHA shares many clinical features with primary AIHA; however, a unique aspect of ICPi-AIHA is a high incidence of DAT negativity. Glucocorticoids are an effective first-line treatment in the majority of patients with ICPi-AIHA, and most patients who are rechallenged with an ICPi do not appear to develop recurrence of AIHA.

Nutraceutical and Functional Foods in Treatment of Anemia

WHO database mentions that the global anemia-affected population is 24.8%. To name a few conditions in which compromisation of the red blood corpuscles and hemoglobin occurs are iron deficiency anemia, gestational anemia, anemia due to malaria and parasitism, hemolytic anemia, sickle cell anemia. The line of treatment in case of anemia involves administration of iron supplements, plasmapheresis, steroids, blood transfusion at regular intervals, and lifestyle changes. The systematic approach applied for the pharmaceutical molecules should be equally inculcated in the case of nutraceuticals. The traditional system when woven carefully with the novel drug delivery system will give effective nutrient delivery. Functional foods have inherent nutritional value. Nutraceuticals and functional food cannot cure the anemic condition, but help the patient lead life almost like a normal individual.

Guidelines on the Use of Therapeutic Apheresis in Clinical Practice-Evidence-Based Approach from the Writing Committee of the American Society for Apheresis: The Seventh Special Issue

The American Society for Apheresis (ASFA) Journal of Clinical Apheresis (JCA) Special Issue Writing Committee is charged with reviewing, updating, and categorizing indications for the evidence-based use of therapeutic apheresis in human disease. Since the 2007 JCA Special Issue (Fourth Edition), the Committee has incorporated systematic review and evidence-based approaches in the grading and categorization of apheresis indications. This Seventh Edition of the JCA Special Issue continues to maintain this methodology and rigor to make recommendations on the use of apheresis in a wide variety of diseases/conditions. The JCA Seventh Edition, like its predecessor, has consistently applied the category and grading system definitions in the fact sheets. The general layout and concept of a fact sheet that was used since the fourth edition has largely been maintained in this edition. Each fact sheet succinctly summarizes the evidence for the use of therapeutic apheresis in a specific disease entity. The Seventh Edition discusses 87 fact sheets (14 new fact sheets since the Sixth Edition) for therapeutic apheresis diseases and medical conditions, with 179 indications, which are separately graded and categorized within the listed fact sheets. Several diseases that are Category IV which have been described in detail in previous editions and do not have significant new evidence since the last publication are summarized in a separate table. The Seventh Edition of the JCA Special Issue serves as a key resource that guides the utilization of therapeutic apheresis in the treatment of human disease. J. Clin. Apheresis 31:149-162, 2016. © 2016 Wiley Periodicals, Inc.

Identification of Stages of Erythroid Differentiation in Bone Marrow and Erythrocyte Subpopulations in Blood Circulation that Are Preferentially Lost in Autoimmune Hemolytic Anemia in Mouse

Repeated weekly injections of rat erythrocytes produced autoimmune hemolytic anemia (AIHA) in C57BL/6 mice after 5–6 weeks. Using the double in vivo biotinylation (DIB) technique, recently developed in our laboratory, turnover of erythrocyte cohorts of different age groups during AIHA was monitored. Results indicate a significant decline in the proportion of reticulocytes, young and intermediate age groups of erythrocytes, but a significant increase in the proportion of old erythrocytes in blood circulation. Binding of the autoantibody was relatively higher to the young erythrocytes and higher levels of intracellular reactive oxygen species (ROS) were also seen in these cells. Erythropoietic activity in the bone marrows and the spleen of AIHA induced mice was examined by monitoring the relative proportion of erythroid cells at various stages of differentiation in these organs. Cells at different stages of differentiation were enumerated flow cytometrically by double staining with anti-Ter119 and anti-transferrin receptor (CD71) monoclonal antibodies. Erythroid cells in bone marrow declined significantly in AIHA induced mice, erythroblast C being most affected (50% decline). Erythroblast C also recorded high intracellular ROS level along with increased levels of membrane-bound autoantibody. No such decline was observed in spleen. A model of AIHA has been proposed indicating that binding of autoantibodies may not be a sufficient condition for destruction of erythroid cells in bone marrow and in blood circulation. Last stage of erythropoietic differentiation in bone marrow and early stages of erythrocytes in blood circulation are specifically susceptible to removal in AIHA.

Therapeutic Apheresis in Hematologic, Autoimmune and Dermatologic Diseases With Immunologic Origin

The process of curing a patient by removing his illness by extracting blood is a very old one. Many years ago, phlebotomy was practiced to cure illness. Now, this old process, placed on a rational basis with therapeutic apheresis (TA), is being followed in clinical practice. Therapeutic plasma exchange (TPE) with hollow fiber modules has been used in different severe diseases for more than 40 years. Based on many years of experience with the extracorporeal circulation in end-stage renal disease, the authors herein give an overview of TA in immunological diseases, especially in hematologic, autoimmune and dermatologic diseases. Updated information on immunology and molecular biology of different immunological diseases is discussed in relation to the rationale for apheresis therapy and its place in combination with other modern therapies. With the introduction of novel and effective biologic agents, TA is indicated only in severe cases, such as in rapid progression despite immunosuppressive therapy and/or biologic agents. In mild forms of autoimmune disease, treatment with immunosuppressive therapies and/or biologic agents seems to be sufficient. The prognosis of autoimmune diseases with varying organ manifestations has improved in recent years, due in part to very aggressive therapy schemes. For the immunological diseases that can be treated with TA, the guidelines of the German Working Group of Clinical Nephrology and of the Apheresis Applications Committee of the American Society for Apheresis are cited. TA has been shown to effectively remove the autoantibodies from blood and lead to rapid clinical improvement.

Comparison of cytokine responses between dogs with sepsis and dogs with immune-mediated hemolytic anemia

Cytokine abnormalities have been described previously in dogs with varied immune mediated and inflammatory conditions such as IMHA and sepsis. The purpose of this study was to establish references ranges for cytokine levels in dogs and to compare cytokine levels in normal dogs and dogs with two common inflammatory diseases (sepsis and IMHA). We hypothesized that cytokine response profiles in dogs with sepsis would be significantly different from those in dogs with IMHA due to the very different etiologies of the two diseases. Concentrations of 14 different cytokines in serum were measured and values grouped according to cytokine function. Serum from clinically normal dogs was used to establish cytokine concentration reference ranges. Rank values for each of the 4 cytokine groups were then compared statistically between healthy control, septic and IMHA dogs. This analysis revealed differences in cytokine groups between dogs with sepsis and IMHA when compared to healthy control dogs but no difference between dogs with either of these conditions. In conclustion, dogs in the early stage of sepsis and IMHA have similar circulating cytokines despite different etiologies suggesting activation of common immunologic pathways. This may have implications for immunotherapy of immune mediated diseases in dogs of varying etiology.

Autoimmune Hemolysis: A Journey through Time

The existence of autoimmune diseases in humans has been known for almost 100 years. Currently, autoimmune pathogenesis has been attributed to more than 40 human diseases; yet it is still not clear what immune abnormalities conclusively prove underlying autoimmune pathogenesis. Hence, although much has been learned, research is still needed for complete elucidation of the mechanisms of the immune dysregulation in AIHA. Better understanding of the underlying mechanism(s) may allow for development of more specific therapies of these not uncommon and often difficult-to-treat disorders.

Clearance of pathological antibodies using biomimetic nanoparticles

Pathological antibodies have been demonstrated to play a key role in type II immune hypersensitivity reactions, resulting in the destruction of healthy tissues and leading to considerable morbidity for the patient. Unfortunately, current treatments present significant iatrogenic risk while still falling short for many patients in achieving clinical remission. In the present work, we explored the capability of target cell membrane-coated nanoparticles to abrogate the effect of pathological antibodies in an effort to minimize disease burden, without the need for drug-based immune suppression. Inspired by antibody-driven pathology, we used intact RBC membranes stabilized by biodegradable polymeric nanoparticle cores to serve as an alternative target for pathological antibodies in an antibody-induced anemia disease model. Through both in vitro and in vivo studies, we demonstrated efficacy of RBC membrane-cloaked nanoparticles to bind and neutralize anti-RBC polyclonal IgG effectively, and thus preserve circulating RBCs.

Gammaherpesvirus latency induces antibody-associated thrombocytopenia in mice

Human herpesviruses establish lifelong latency. Viral recrudescence can lead to the development of cancers, immunoproliferative disorders, transplantation complications, and thrombocytopenia. Although platelet-specific autoantibodies have been reported in patients infected with the Epstein-Barr virus (EBV), the mechanisms by which thrombocytopenia is induced remain unclear, as do the relative contributions of lytic viral replication and latent viral gene expression. The human gammaherpesviruses are tightly restricted in their ability to infect other mammals, so they are difficult to study in live animal models. Here we show that infection of mice with murine gammaherpesvirus-68 (γHV68), a rodent-specific pathogen closely related to EBV, induces the production of platelet-binding antibodies and causes thrombocytopenia. Infection of antibody-deficient mice does not lead to thrombocytopenia, indicating the platelet decrease is mediated by antibody. Additionally, infection with a latency-null recombinant γHV68 does not induce thrombocytopenia, suggesting factors associated with viral latency drive the infection-induced antibody-mediated thrombocytopenia. These studies describe an important animal model of gammaherpesvirus-induced autoimmune thrombocytopenia and demonstrate that this pathology is mediated by antibody and dependent on viral latency. This model will allow studies of the underlying mechanisms of disease progression and the testing of therapeutic strategies for the alleviation of virus-induced thrombocytopenia.

Potentially antigenic RBC membrane proteins in dogs with primary immune-mediated hemolytic anemia

BACKGROUND

Primary immune-mediated hemolytic anemia (IMHA) is an important cause of morbidity and mortality in dogs. The mechanisms underlying autoimmune reactivity remain poorly understood.

OBJECTIVE

The aim of this study was to identify membrane proteins of RBCs that could be antigenic in dogs with primary IMHA.

METHODS

Antibodies were eluted with xylene from RBCs of 12 dogs with IMHA, 4 dogs with anemia due to causes other than IMHA, and 2 healthy dogs. Pooled RBC membrane proteins were prepared from blood of 17 healthy dogs. The eluted antibodies were then analyzed by immunoblotting for interactions with the pooled membrane proteins and autologous plasma. Bands present in the 12 dogs with IMHA but not in the 6 other dogs were considered potential autoantigens and were identified by liquid chromatography followed by tandem mass spectrometry.

RESULTS

RBC eluates from all 18 dogs had reactivity against band 3 protein. Antibodies to 6 additional proteins were uniquely identified in dogs with IMHA. Reactivity to calpain, complement component 3, and peroxiredoxin 2 was identified in 8, 8, and 4 of the 12 samples, respectively, from dogs with IMHA, but in none of the samples from the 6 dogs without IMHA.

CONCLUSIONS

Detection of universal immune reactivity against band 3 protein probably indicates recognition of senescent RBC. Proteins uniquely recognized by antibodies in dogs with IMHA are involved in oxidative stress and apoptosis (calpain), inflammation (complement), and scavenging of reactive oxygen species (peroxiredoxin 2). It remains to be determined if these proteins are important in initiating autoimmunity or if immunoglobulins targeting these proteins develop during IMHA.

Anti-CD20 monoclonal antibodies and their use in adult autoimmune hematological disorders

Autoimmune hematological disorders encompass a broad group of hematological conditions characterized by the loss of self-tolerance to a variety of antigens. Despite good response to first-line therapy in the majority of patients, relapses are common, necessitating new and safe therapeutic options. The anti-CD20 monoclonal antibody rituximab has led to substantial improvement in the treatment of malignant and immune-mediated disorders involving B cells. Although experience with rituximab in immune-mediated hematological disorders is rarely supported by randomized trials, there is now substantial experience with rituximab suggesting that anti-CD20 therapy is an effective and well-tolerated alternative to immunosuppressive therapy in these disorders. However, caution is needed based on recent reports describing-sometimes severe-rituximab-related complications.

Guidelines on the use of therapeutic apheresis in clinical practice--evidence-based approach from the Apheresis Applications Committee of the American Society for Apheresis

The American Society for Apheresis (ASFA) Apheresis Applications Committee is charged with a review and categorization of indications for therapeutic apheresis. Beginning with the 2007 ASFA Special Issue (fourth edition), the subcommittee has incorporated systematic review and evidence-based approach in the grading and categorization of indications. This Fifth ASFA Special Issue has further improved the process of using evidence-based medicine in the recommendations by refining the category definitions and by adding a grade of recommendation based on widely accepted GRADE system. The concept of a fact sheet was introduced in the Fourth edition and is only slightly modified in this current edition. The fact sheet succinctly summarizes the evidence for the use of therapeutic apheresis. The article consists of 59 fact sheets devoted to each disease entity currently categorized by the ASFA as category I through III. Category IV indications are also listed.

Rituximab is an effective and safe therapeutic alternative in adults with refractory and severe autoimmune hemolytic anemia

Rituximab-induced B-cell depletion has been proven to be a useful therapy for autoimmune hemolytic anemia (AIHA). The aim of this retrospective study was to evaluate the effectiveness of rituximab in the treatment of 36 patients with AIHA refractory to several treatments. These patients had received a median of four (one to eight) previous treatments, and 13 patients had undergone splenectomy. Rituximab was administered by intravenous infusion at a dose of 375 mg/m(2) once weekly for four doses in 29 patients, and 7 patients received one to six doses. Overall, 28 (77%) of 36 patients achieved response. Twenty-two patients (61%) reached a complete response (CR), and 6 patients (16%) obtained a partial response. All patients that reached CR (61%) were able to maintain the response during more than 6 months, with a median follow-up of 14 months (1-86 months). Sixteen patients maintained response for more than 1 year. The predictors of maintained response were achievement of CR and negative Coombs test result. Splenectomized patients showed a better response rate than those nonsplenectomized. Rituximab was well tolerated, and only one patient presented a transitory rash during infusion. Rituximab induced clinical responses in multitreated severe refractory both warm and cold AIHA patients with little toxicity, and consequently, this therapy should be considered as an early therapeutic option in this setting.

Direct antiglobulin test reactive with complement only in warm type autoimmune hemolytic anemia

Direct antiglobulin test (DAT) with only complement detected on red blood cells is a rare laboratory finding, and its significance in the setting of warm autoimmune hemolytic anemia (AIHA) is controversial. During 2 years (2003-2004) 277 patients with positive DAT were recorded in the blood bank registries, 17 of them had DAT reactive with C3 alone with no cold agglutinin or other nonimmune causes for hemolysis diagnosed. Red cell eluate disclosed small amounts of IgG in two patients. In nine patients no signs of clinical hemolysis were found, however, all these patients had underlying conditions that are known to be associated with red cells autoantibodies (autoimmune disorder or malignancy). Eight patients developed AIHA, seven of them with severe hemolysis. Three patients had idiopathic AIHA, and the others have been diagnosed with infectious, lymphoproliferative and autoimmune disorders. In two patients with acute infection the hemolytic process spontaneously resolved, three responded to corticosteroid therapy, while three patients were refractory to two lines of drug therapy and underwent splenectomy. Reticulocytopenia was found in four patients. Our results emphasize that AIHA with DAT reactive with complement alone is a rare disorder and might be accompanied by severe, refractory to conventional treatment and life-threatening hemolysis.

Chronic lymphocytic leukemia-associated autoimmune hemolytic anemia

The clinical course of patients with B-cell chronic lymphocytic leukemia (CLL) is often made complicated by autoimmune phenomena which mainly target the blood cells. Among them, the autoimmune hemolytic anemia (AIHA) is the most common form. On the other hand, it is believed that CLL is the most common of the known causes of AIHA. The source of any putative autoantibody (bystander nonmalignant cells or tumor cells) is not clear yet. Recently, it has been hypothesized that leukemic B-cells may also act as professional antigen presenting cells (APCs). With respect to the management of CLL-associated AIHA, steroids still represent the first-line treatment option. Intravenous immunoglobulin, immunosuppressive drugs, and splenectomy are also frequently used for steroid-refractory forms. Furthermore, although the case series is still too small, encouraging data is now supporting the use of monoclonal antibodies, in particular anti-CD20 rituximab, in managing this often life-threatening autoimmune complication of CLL.

STIM1 is essential for Fcγ receptor activation and autoimmune inflammation

Fcγ receptors (FcγRs) on mononuclear phagocytes trigger autoantibody and immune complex–induced diseases through coupling the self-reactive immunoglobulin G (IgG) response to innate effector pathways, such as phagocytosis, and the recruitment of inflammatory cells. FcRγ-based activation is critical in the pathogenesis of these diseases, although the contribution of FcγR-mediated calcium signaling in autoimmune injury is unclear. Here we show that macrophages lacking the endoplasmic reticulum–resident calcium sensor, STIM1, cannot activate FcγR-induced Ca2+ entry and phagocytosis. As a direct consequence, STIM1 deficiency results in resistance to experimental immune thrombocytopenia and anaphylaxis, autoimmune hemolytic anemia, and acute pneumonitis. These results establish STIM1 as a novel and essential component of FcγR activation and also indicate that inhibition of STIM1-dependent signaling might become a new strategy to prevent or treat IgG-dependent immunologic diseases.

New treatment options for immune-mediated hematological disorders

In recent years, there has been a tremendous increase in the number of clinical studies with monoclonal antibodies and small molecules in the treatment of hematological malignancies. Clinical observations have shown that some of these molecules may also aid in the treatment of immune-mediated hematological disorders. Moreover, immunotherapy has become an important treatment cornerstone in other, non-hematological, auto-immune diseases. This paper reviews the current state of the use of these new molecules in the treatment of the most frequently encountered immune-mediated hematological disorders: auto-immune hemolytic anemia (AIHA), idiopathic thrombocytopenic purpura (ITP), and thrombotic thrombocytopenic purpura (TTP).

Unraveling the immune response during AIHA

In this issue of Blood, Ward and colleagues make some novel fundamental observations on the nature of the immune response during autoimmune hemolytic anemia (AIHA). They show a key role for T regulatory cells (Tregs) in the pathogenesis of this autoimmune disease.

Initiation of AIHA: a study in scarlet

Knocking out the immunodominant antigen (Band 3) in a spontaneous model of mouse autoimmune hemolytic anemia demonstrates that full pathology still occurs even in the absence of the normal target of autoantibodies.

[Warm autoimmune hemolytic anemias and Evans syndrome in adults]

PURPOSE

The outcome of autoimmune hemolytic anemia (AIHA) and Evans syndrome (ES) in adults is not well-known and their management is mainly based on empirical data.

CURRENT KNOWLEDGE AND KEY POINTS

The main characteristics of both AIHA and ES are reviewed in this article, based on the data available in the literature and on our experience. Although controlled studies and evidence-based data are lacking, some recommendations regarding the minimal workup useful to search for an underlying disease can be made as well as proposals for a better therapeutic strategy of both disorders.

FUTURE PROSPECTS AND PROJECTS

A better knowledge of the mechanisms triggering AIHA and ES as well as therapeutic trials are needed in order to better stratify treatment taking into account the promising efficacy of rituximab.

Rituximab for warm-type idiopathic autoimmune hemolytic anemia: a retrospective study of 11 adult patients

Warm-type idiopathic autoimmune hemolytic anemia (AIHA) is a relatively common hematologic disorder resulting from autoantibody production against red blood cells. Steroids represent the first-line therapeutic option, and immunosuppressive agents as well as splenectomy are used for refractory cases. Recently, the anti-CD20 monoclonal antibody rituximab has been shown to control autoimmune hemolysis in patients with refractory chronic disease. We report results from a retrospective analysis of 11 adult patients receiving rituximab for steroid-refractory AIHA of the warm type at a mean age of 55 yr (range 23-81 yr). All patients were given methyl-prednisolone as first-line treatment and some of them also received azathioprine and intravenous high-dose immunoglobulins. One patient underwent splenectomy. All patients were considered refractory to steroids and/or immunosuppressive drugs and all were then given weekly rituximab (375 mg/m(2)) for four consecutive weeks. An increase in hemoglobin (Hgb) levels in response to rituximab, with a mean increment of 3.3 g/dL (95% CI 2.1-4.4), was observed in all cases. Four patients required packed red cell transfusions before starting rituximab and all became transfusion-free. At a mean follow-up of 604 d (range 30-2884 d) since the treatment of AIHA with rituximab, all patients are alive, eight (73%) of them in complete remission (CR) and three (27%) in partial remission (PR). A moderate hemolysis still persisted in six (54%) patients. In conclusion, our experience clearly demonstrates that anti-CD20 monoclonal antibody rituximab is an effective and safe alternative treatment option for idiopathic AIHA, in particular, for steroid-refractory disease.

[Antibody-mediated cell-specific hematopoietic autoimmune disorders]

Although it is clear that immunologic mechanisms play a significant role in the pathophysiology of many hematologic diseases, there are relative few situations where it is possible to gain a detailed understanding of immune damage in vivo in humans. Autoimmune hemolytic anemia, immune thrombocytopenia and immune neutropenia as antibody-mediated cell-specific disorders are of particular interest in this regard. Autoimmune hemolytic anemia represents a group of disorders in which individuals produce antibodies directed toward one or more of their own erythrocyte membrane antigens. This leads to destruction of the antibody-coated erythrocytes. The pathophysiology of the decreased erythrocyte survival has been examined with increasing sophistication for many years. This paper first discusses the underlying mechanisms responsible for autoimmune hemolytic anemias then consider immune thrombocytopenia and immune neutropenia.

Guidelines on the use of therapeutic apheresis in clinical practice—Evidence-based approach from the apheresis applications committee of the American society for apheresis

The American Society for Apheresis (ASFA) Apheresis Applications Committee is charged with a review and categorization of indications for therapeutic apheresis. This elaborate process had been undertaken every 7 years resulting in three prior publications in 1986, 1993, and 2000 of "The ASFA Special Issues." This article is the integral part of the Fourth ASFA Special Issue. The Fourth ASFA Special Issue is significantly modified in comparison to the previous editions. A new concept of a fact sheet has been introduced. The fact sheet succinctly summarizes the evidence for the use of therapeutic apheresis. A detailed description of the fact sheet is provided. The article consists of 53 fact sheets devoted to each disease entity currently categorized by the ASFA. Categories I, II, and III are defined as previously in the Third Special Issue. However, a few new therapeutic apheresis modalities, not yet approved in the United States or are currently in clinical trials, have been assigned category P (pending) by the ASFA Clinical Categories Subcommittee. The diseases assigned to category IV are discussed in a separate article in this issue.

Mouse bone marrow and peripheral blood erythroid cell counts are regulated by different autosomal genetic loci

Erythropoiesis is under fine control and genetic loci that affect it are likely to be important in a range of conditions. To assess the relative contributions of different genetic loci to parameters of erythropoiesis, we have measured RBC counts in the peripheral circulation and committed erythroid cells (RBC and small normoblasts) in the bone marrow in a cohort of (CBA/H x C57BL/6) F2 mice to map quantitative trait loci (QTL). Candidate genes were assessed using bioinformatics and DNA sequencing. Different autosomal loci affect bone marrow (chromosomes 5, 11 and 19) and peripheral blood (chromosome 4) erythroid cell counts but there may be a common chromosome X locus. Spleen weight QTL were found on chromosomes 3, 15 and 17. Surprisingly, erythropoietin (Epo) is the best candidate quantitative trait gene (QTG) in the chromosome 5 locus that affects bone marrow but not peripheral blood erythroid cell counts. Epo gene expression is known to be genetically regulated in mice, but our data suggest a tissue-specific role for epo in mouse erythropoiesis that is also genetically determined. The identity of the other QTG will be important both to further knowledge of the control of erythropoiesis and as potential modifier genes for haematological disorders.

Laparoscopic splenectomy: present status and future perspective

Laparoscopic splenectomy has become widely accepted as the approach of choice for the surgical treatment of benign and malignant hematologic diseases. Advances in technology have led to better outcomes for the procedure, and have allowed surgeons to apply the technique to disease processes that were at one time felt to be contraindications to laparoscopic splenectomy. However, challenges still remain. There is a steep learning curve associated with the procedure. The development of cost-effective laparoscopic simulators to target the skills required for laparoscopic splenectomy and other laparoscopic procedures is essential. The advent of devices which isolate and seal the large blood vessels that surround the spleen have reduced intra-operative bleeding and minimized conversions to open splenectomy. Improvements in optics and instrumentation, as well as robotic technology, will continue to define the frontier of minimally invasive surgery, and further facilitate the acceptance of laparoscopic splenectomy for the treatment of benign and malignant hematologic diseases.

Membrane complement regulatory proteins

A number of proteins anchored on the cell surface function to protect host tissues from bystander injury when complement is activated. In humans, they include decay-accelerating factor (DAF, CD55), membrane cofactor protein (MCP, CD46), complement receptor 1 (CR1, CD35) and CD59. Although disease conditions directly attributable to abnormal function of these proteins are relatively rare, it has become evident from recent studies using animal models that membrane complement regulatory proteins are important modulators of tissue injury in many autoimmune and inflammatory disease settings. Evidence is also emerging to support a role of these proteins in regulating cellular immunity. In this article, we highlight recent advances on the in vivo biology of membrane complement regulatory proteins and discuss their relevance in human disease pathogenesis and therapeutics.