Primary chronic cold agglutinin disease: an update on pathogenesis, clinical features and therapy

Hemolytic Anemia in the Setting of Atypical Pneumonia: A Case of Cold Agglutinin Disease

Cold agglutinin hemolytic anemia (cAHA) is a rare autoimmune disorder characterized by the production of cold agglutinins. We present a case of secondary cAHA in a 23-year-old female with severe anemia and unexplained hemolysis. The patient exhibited findings indicative of hemolysis and a positive direct antiglobulin test (DAT) with complement alone. Additional investigations revealed incidental lung infiltrates, negative serology for infections and autoimmune diseases, and a low cold agglutinin titer. The patient showed a favorable response to doxycycline and supportive therapy, including multiple packed red blood cell transfusions. At the two-week follow-up, the patient had a stable hemoglobin level with no evidence of ongoing hemolysis. This case highlights the importance of considering secondary cAHA in patients with cold symptoms or unexplained hemolysis. Primary cAHA patients may require more aggressive treatment, including rituximab and sutilumab.

Sutimlimab in patients with cold agglutinin disease: results of the randomized placebo-controlled phase 3 CADENZA trial

Sutimlimab, a first-in-class humanized immunoglobulin G4 (IgG4) monoclonal antibody that selectively inhibits the classical complement pathway at C1s, rapidly halted hemolysis in the single-arm CARDINAL study in recently transfused patients with cold agglutinin disease (CAD). CADENZA was a 26-week randomized, placebo-controlled phase 3 study to assess safety and efficacy of sutimlimab in patients with CAD without recent (within 6 months prior to enrollment) transfusion history. Forty-two patients with screening hemoglobin ≤10 g/dL, elevated bilirubin, and ≥1 CAD symptom received sutimlimab (n = 22) or placebo (n = 20) on days 0 and 7 and then biweekly. Composite primary endpoint criteria (hemoglobin increase ≥1.5 g/dL at treatment assessment timepoint [mean of weeks 23, 25, 26], avoidance of transfusion, and study-prohibited CAD therapy [weeks 5-26]) were met by 16 patients (73%) on sutimlimab, and 3 patients (15%) on placebo (odds ratio, 15.9 [95% confidence interval, 2.9, 88.0; P < .001]). Sutimlimab, but not placebo, significantly increased mean hemoglobin and FACIT-Fatigue scores at treatment assessment timepoint. Sutimlimab normalized mean bilirubin by week 1. Improvements correlated with near-complete inhibition of the classical complement pathway (2.3% mean activity at week 1) and C4 normalization. Twenty-one (96%) sutimlimab patients and 20 (100%) placebo patients experienced ≥1 treatment-emergent adverse event. Headache, hypertension, rhinitis, Raynaud phenomenon, and acrocyanosis were more frequent with sutimlimab vs placebo, with a difference of ≥3 patients between groups. Three sutimlimab patients discontinued owing to adverse events; no placebo patients discontinued. These data demonstrate that sutimlimab has potential to be an important advancement in the treatment of CAD. This trial was registered at www.clinicaltrials.gov as #NCT03347422.

Halting targeted and collateral damage to red blood cells by the complement system

The complement system is an important defense mechanism against pathogens; however, in certain pathologies, the system also attacks human cells, such as red blood cells (RBCs). In paroxysmal nocturnal hemoglobinuria (PNH), RBCs lack certain complement regulators which sensitize them to complement-mediated lysis, while in autoimmune hemolytic anemia (AIHA), antibodies against RBCs may initiate complement-mediated hemolysis. In recent years, complement inhibition has improved treatment prospects for these patients, with eculizumab now the standard of care for PNH patients. Current complement inhibitors are however not sufficient for all patients, and they come with high costs, patient burden, and increased infection risk. This review gives an overview of the underlying pathophysiology of complement-mediated hemolysis in PNH and AIHA, the role of therapeutic complement inhibition nowadays, and the high number of complement inhibitors currently under investigation, as for almost every complement protein, an inhibitor is being developed. The focus lies with novel therapeutics that inhibit complement activity specifically in the pathway that causes pathology or those that reduce costs or patient burden through novel administration routes.

Immunotactoid glomerulonephritis in a patient with cold agglutinins: causal association or mere coincidence?

We report a case of immunotactoid glomerulonephritis (ITG) in a patient with cold agglutinins. An 86-year-old Japanese male with a history of hypertension, dyslipidemia, and gastric malignancy presented to our hospital for the evaluation of proteinuria and hematuria. He had an elevated blood pressure of 200/77 mmHg and edema of the lower extremities. Initial blood test results revealed an impaired renal function (creatinine, 1.37 mg/dL) and hypoalbuminemia (albumin, 2.6 g/dL). His estimated daily urinary protein was 5.89 g/g creatinine, meeting the diagnostic criteria for nephrotic syndrome. The selectivity index for proteinuria indicated low selectivity (0.329). We conducted a renal biopsy to identify the cause of nephrotic syndrome. Immunofluorescence microscopy demonstrated positive staining of IgM, C4, and C1q. Electron microscopy exhibited mesangial expansion with inflammatory cells and a lobular structure, suggesting membranoproliferative glomerulonephritis. Subendothelial deposits containing microtubular structures with a diameter of approximately 30-200 nm were found, concurrent with the criteria for the diagnosis of ITG. Screening for lymphoproliferative diseases and immunological abnormalities revealed a positive direct Coombs test result and the presence of cold agglutinins. Paraproteinemia was absent. The similarities between cold agglutinin disease and ITG, including the production of autoantibodies and involvement of complement pathways, raise the possibility that cold agglutinins played a role in the development of ITG; however, we were unable to prove it due to difficulties in detecting cold agglutinins on renal histology. We discuss the possible implications for pathogenesis considering prior reports on nephrotic syndrome being potentially associated with cold agglutinins.

Changes in Complement Levels and Activity of Red Blood Cells, Fresh Frozen Plasma, and Platelet Concentrates During Storage

Complement cascade plays an important role in the field of transfusion medicine. The study aimed to detect the complement levels of different blood components and different blood types to explore the risk of transfusion of stored blood. The samples including red blood cells (n = 110), fresh frozen plasma (n = 120), and platelet concentrates (n = 104) from healthy blood donors in our center were collected. Complement components (C3, C4, C3b, C3d, and CH50) were assayed to evaluate the activation of complement. The complement levels of various blood components at different storage times were observed. The differences in complement levels of four blood types in various blood components were compared. The complement levels of red blood cells in storage were low, with no significant changes (P > 0.05). C3b and C3d levels in platelets began to significantly increase after storage for 3 days (P < 0.05). The fresh frozen plasma during storage had higher complement levels, and the concentrations of C3 and C4 decreased and C3b and C3d increased at month 4 (P < 0.05). The differences in complement levels of four blood types in various blood components did not significantly change (P > 0.05), but the C3b and C3d levels of AB fresh frozen plasma remained stable during storage, which different from other blood types. The transfusion of red blood cells was relatively safe in terms of complement activation. The activation of complement proteins occurred during the storage of platelet and plasma, except group AB plasma.

Defining autoimmune hemolytic anemia: a systematic review of the terminology used for diagnosis and treatment

The terminology applied to autoimmune hemolytic anemia (AIHA) seems inconsistent. We aimed to evaluate the consistency of definitions used for diagnosis and treatment. In this systematic review of literature from January 2006 to December 2015, we assessed heterogeneity in the definition of AIHA and its subtypes, refractory disease, disease phase, severity, criteria for treatment response, and response durability. A Medline search for anemia, hemolytic, autoimmune was supplemented with keyword searches. Main exclusions were conference abstracts, animal and non-English studies, and studies with <10 cases. Of 1371 articles retrieved, 1209 were excluded based on titles and abstracts. Two authors independently reviewed 10% and 16% of abstracts and full papers, respectively. After full-paper review, 84 studies were included. AIHA was most frequently (32 [52%] of 61) defined as hemolytic anemia with positive direct antiglobulin test (DAT) and exclusion of alternatives, but 10 of 32 also recognized DAT-negative AIHA. A lower threshold for diagnosis of DAT-negative AIHA was observed in literature on chronic lymphocytic leukemia. Definitions of anemia, hemolysis, and exclusion criteria showed substantial variation. Definitions of primary/secondary cold agglutinin disease/syndrome were not consistent. Forty-three studies provided criteria for treatment response, and other than studies from 1 center, these were almost entirely unique. Other criteria were rarely defined. Only 7, 0, 3, 2, 2, and 3 studies offered definitions of warm AIHA, paroxysmal cold hemoglobinuria, mixed AIHA, AIHA severity, disease phase, and refractory AIHA, respectively. Marked heterogeneity in the time period sampled indicates the need to standardize AIHA terminology.

Primera serie de casos reportada en Colombia de la enfermedad por aglutininas frías primaria y secundaria

Introducción: la enfermedad por aglutininas frías (EAF) es un trastorno hematológico primario o secundario, caracterizado por la anemia hemolítica autoinmune causada por los anticuerpos IgM a bajas temperaturas. Clínicamente, presenta parestesias y acrocianosis inducidos por frío y fiebre, aunque también puede ser asintomática y solo identificarse por alteraciones en el hemograma. Objetivo: describir las manifestaciones clínicas y de laboratorio, las causas primarias y secundarias de la EAF y compararlas con series de casos descritos en la literatura. Materiales y métodos: análisis retrospectivo de datos clínicos de pacientes del Hospital Universitario San Vicente Fundación de Medellín con resultados positivos para aglutininas frías. Dichos análisis se realizaron en el laboratorio de hematología de la Universidad de Antioquia, consideramos como positivo título ≥ 1: 64 o con la prueba de Coombs directa y positiva para anticuerpos fríos. Resultados: se incluyen los títulos de crioaglutininas de 23 casos con EAF: 6 formas primarias, 4 asociadas con los linfoma no Hodgkin (LNH), 8 secundarias a enfermedades infecciosas y autoinmunes y, 5 asociados con enfermedades misceláneas. Discusión y conclusiones: esta es la primera serie de casos en Colombia de EAF. La edad y género fueron similares a los datos reportados en la literatura. Observamos un mayor número de pacientes que presentaban anemia hemolítica y con síntomas asociados al frío. La relación hemoglobina hematocrito fue 1:2. Dentro de las causas secundarias destacamos las vasculitis, el lupus y la malaria. De las causas primarias las más frecuentes fueron los LNH, específicamente, el linfoplasmocítico. El tratamiento más utilizado para pacientes con EAF primaria incluyo rituximab.

A novel method for demonstrating cold agglutinin disease: a case report

Background

Cold agglutinin disease is a rare disorder characterized by an autoimmune hemolytic anemia occurring at low temperatures. Physical examination findings, often limited to acrocyanosis, are combined with a thermal amplitude test to help establish the diagnosis. Thermal amplitude testing determines the highest temperature at which the cold agglutination will occur and is an important parameter in diagnosing cold agglutinin disease.

Case presentation

Here we describe a 57-year-old white man of German and Nicaraguan descent with known chronic cold agglutinin disease who presented to our ophthalmology clinic for evaluation of a cataract. During routine cataract surgery, the lowered temperature of the conjunctiva from intermittent flow of balanced salt solution at room temperature induced a cold agglutination reaction in conjunctival vessels easily visible under a surgical microscope.

Conclusions

To the best of our knowledge, this method of demonstrating cold agglutinin disease has not been described in the literature and could easily be performed utilizing an ordinary slit lamp. This method could be used as an alternative and rapid screening method for cold agglutinin disease.

Electronic supplementary material

The online version of this article (10.1186/s13256-018-1573-7) contains supplementary material, which is available to authorized users.

Complement Activation and Inhibition in Autoimmune Hemolytic Anemia: Focus on Cold Agglutinin Disease

The classical complement pathway and, to some extent, the terminal pathway, are involved in the immune pathogenesis of autoimmune hemolytic anemia (AIHA). In primary cold agglutinin disease (CAD), secondary cold agglutinin syndrome and paroxysmal cold hemoglobinuria, the hemolytic process is entirely complement dependent. Complement activation also plays an important pathogenetic role in some warm-antibody AIHAs, especially when immunoglobulin M is involved. This review describes the complement-mediated hemolysis in AIHA with a major focus on CAD, in which activation of the classical pathway is essential and particularly relevant for complement-directed therapy. Several complement inhibitors are candidate therapeutic agents in CAD and other AIHAs, and some of these drugs seem very promising. The relevant in vitro findings, early clinical data and future perspectives are reviewed.

Eculizumab treatment: stochastic occurrence of C3 binding to individual PNH erythrocytes

BACKGROUND

C5 blockade by eculizumab prevents complement-mediated intravascular hemolysis in paroxysmal nocturnal hemoglobinuria (PNH). However, C3-bound PNH red blood cells (RBCs), arising in almost all treated patients, may undergo extravascular hemolysis reducing clinical benefits. Despite the uniform deficiency of CD55 and of CD59, there are always two distinct populations of PNH RBCs, with (C3+) and without (C3-) C3 binding.

METHODS

To investigate this paradox, the phenomenon has been modeled in vitro by incubating RBCs from eculizumab untreated PNH patients with compatible sera containing eculizumab, and by assessing the C3 binding after activation of complement alternative pathway.

RESULTS

When RBCs from untreated patients were exposed in vitro to activated complement in the context of C5-blockade, there was the prompt appearance of a distinct C3+ PNH RBC population whose size increased with time and also with the rate of complement activation. Eventually, all PNH RBCs become C3+ to the same extent, without differences between old and young (reticulocytes) PNH RBCs.

CONCLUSIONS

This study indicates that the distinct (C3+ and C3-) PNH RBC populations are not intrinsically different; rather, they result from a stochastic all-or-nothing phenomenon linked to the time-dependent cumulative probability of each individual PNH red cell to be exposed to levels of complement activation able to trigger C3 binding. These findings may envision novel approaches to reduce C3 opsonization and the subsequent extravascular hemolysis in PNH patients on eculizumab.

Cold agglutinin disease burden: a longitudinal analysis of anemia, medications, transfusions, and health care utilization

Cold agglutinin disease (CAD), a rare disease and subtype of autoimmune hemolytic anemia, is characterized by autoantibodies that bind to red blood cells at low temperatures. There is no established standard of care for CAD treatment and CAD cohort studies are limited by the rarity of the condition. The objectives of this study are to present the longitudinal experience of a CAD cohort from the United States, with a focus on anemia severity, use of medications and transfusions, and health care resource utilization. The Stanford Translational Research Integrated Database Environment database was used to retrospectively identify CAD patients diagnosed and treated at Stanford Health Care from 2000 to 2016. Twenty-nine patients were included in this analysis. There were 7.1 severe anemia events per patient-year observed over the follow-up time. For CAD patients treated at Stanford, there was a mean of 3.5 therapies per patient. Transfusions were given in at least 65% of the cohort with a mean of 11 transfusions per patient-year. For CAD-related health care use in the first year after disease onset, 93% used outpatient services with a median of 26 outpatient visits per patient. The data presented here likely represent the minimum number of events for these patients during this timeframe, as this single-center experience does not capture care from other providers. This longitudinal study of CAD patients demonstrates the severity of anemia and relapsing nature of the disease, even after administration of multiple therapies and transfusions.

Resolution of Serologic Problems Due to Cold Agglutinins in Chronic Lymphocytic Leukemia

INTRODUCTION

Autoimmune hemolytic anemia can be classified depending on presence of warm, cold or mixed type of autoantibodies that are directed against antigens on the red blood cell surface. Here we report a case of pathological cold agglutinin disease which was eventually detected due to blood group discrepancy.

CASE DETAILS

A request was sent to the blood bank for two units of packed red cells in a diagnosed case of CLL which showed type IV discrepancy during blood grouping.The discrepancy was subsequently resolved after warm saline washing of red cells along with repetition of reverse grouping with pre-warmed serum. The direct antiglobulin test was positive and revealed autoanibodies against C3b/C3d only. Indirect antiglobulin test was performed with 3-cell panel in a polyspecific gel card (IgG+C3d) showed a pan-reactive pattern along with a positive autocontrol. Subsequently a cold agglutinin titration was performed and titers of 1024 at 4 °C; titer of 2 at room temperature were detected. Dithiothreitol (DTT) treatment of serum was undertaken and IgM type of autoantibody was detected in this case confirming a case of secondary cold agglutinin disease in this patient. Two units of red cells were transfused to this patient after successfully performing cross-match with pre-warmed serum. It was advised from the blood bank that the blood should be transfused slowly through a blood-warmer and patient should be kept in warm condition to avoid in-vivo hemolysis due to high titer of cold agglutinin. The transfusion was uneventful and patient is on regular follow-up till now.

CONCLUSION

Thus we concluded that serological discrepancies observed in blood bank can successfully guide the bedside transfusion protocol in case of cold agglutinin disease.

[Clinical profile of autoimmune hemolytic anemia with monoclonal gammopathy IgMκ]

目的

探讨伴单克隆免疫球蛋白Mκ（IgMκ）血症的自身免疫性溶血性贫血（AIHA）临床特征。

方法

回顾性分析85例AIHA患者临床资料，观察伴单克隆IgMκ的AIHA患者一般临床特征、实验室检查特点及转归。

结果

85例AIHA患者中12例（14.1%）单克隆IgM κ阳性，其中4例温抗体型AIHA, 8例冷凝集素综合征（CAS）。4例温抗体型AIHA患者均为原发病例，免疫表型未见异常；8例CAS患者中，4例继发于小B细胞淋巴瘤，4例为原发CAS，免疫表型未见异常。4例温抗体型AIHA患者中2例TCR重排阳性；8例CAS患者中6例IgH重排阳性，1例TCR/IgH重排均阳性。4例温抗体型AIHA患者均给予糖皮质激素治疗，3例达完全缓解，1例部分缓解。8例CAS患者中3例给予小剂量利妥昔单抗治疗，2例部分缓解，1例无效；2例给予COP（环磷酰胺、长春新碱、甲泼尼龙）方案化疗，1例部分缓解，1例无效；2例HGB正常患者给予保暖对症治疗；1例院外行脾脏切除术，术后死于感染。

结论

CAS常伴有单克隆IgMκ，而温抗体型AIHA伴单克隆IgMκ较少见。

Acrocyanosis revealing chronic lymphocytic leukemia

Cold agglutinin disease arising in the context of chronic lymphocytic leukemia can misdiagnose a warm autoimmune hemolytic anemia.

Report of cold agglutinins in a patient with acute ischemic stroke

BACKGROUND

Studies on the role of cold agglutinins in the pathogenesis of acute ischemic stroke are scarce. We present a case of an elderly man with acute cerebral infarction probably due to cold agglutinin disease.

CASE PRESENTATION

On a cold morning, a 71-year-old male of Han nationality with a complaint of sudden onset left-sided weakness and difficulty in speaking was brought to the emergency department. Diffusion weighted magnetic resonance imaging of the brain showed a high-intensity area in the right basal ganglia and corona radiata. Laboratory test showed the presence of high titers of cold agglutinins. There was no history of common risk factors of atherosclerosis, such as hypertension, diabetes mellitus, coronary artery disease or smoking. After being exposed to warm temperature, and with corticosteroid therapy and blood transfusion, the patient's symptoms relieved rapidly.

CONCLUSION

We report here the first case of cerebral infarction probably due to the cold agglutinin disease. The underlying mechanism of cold agglutinins in the pathogenesis of acute ischemic stroke needs to be investigated further.

Cold Agglutinin Disease; A Laboratory Challenge

Introduction:

Autoimmune haemolytic anemia (AIHA) is a complex process characterized by an immune reaction against red blood cell self-antigens. The analysis of specimens, drawn from patients with cold auto-immune hemolytic anemia is a difficult problem for automated hematology analyzer. This paper was written to alert technologists and pathologists to the presence of cold agglutinins and its effect on laboratory tests.

Case Presentation:

A 72-year-old female presented to the Shafa laboratory for hematology profile evaluation. CBC indices showed invalid findings with the Sysmex automated hematology analyzer. Checking the laboratory process showed precipitation residue sticking to the sides of the tube. After warming the tubes, results become valid and the problem attributed to cold agglutinin disease. In this situation, aggregation of RBCs, which occurs at t < 30°C, causes invalid findings meanwhile working with automated hematology analyzer.

Conclusions:

Knowledge of this phenomenon can help prevent wasting too much time and make an early and accurate diagnosis.

New Insights in the Pathogenesis of Autoimmune Hemolytic Anemia

Autoimmune hemolytic anemia (AIHA) is caused by the increased destruction of red blood cells (RBCs) by anti-RBC autoantibodies with or without complement activation. RBC destruction may occur both by a direct lysis through the sequential activation of the final components of the complement cascade (membrane attack complex), or by antibody-dependent cell-mediated cytotoxicity (ADCC). The pathogenic role of autoantibodies depends on their class (the most frequent are IgG and IgM), subclass, thermal amplitude (warm and cold forms),as well as affinity and efficiency in activating complement. Several cytokines and cytotoxic mechanisms (CD8+ T and natural killer cells) are further involved in RBC destruction. Moreover, activated macrophages carrying Fc receptors may recognize and phagocyte erythrocytes opsonized by autoantibodies and complement. Direct complement-mediated lysis takes place mainly in the circulations and liver, whereas ADCC, cytotoxicity, and phagocytosis occur preferentially in the spleen and lymphoid organs. The degree of intravascular hemolysis is 10-fold greater than extravascular one. Finally, the efficacy of the erythroblastic compensatory response can greatly influence the clinical picture of AIHA. The interplay and relative burden of all these pathogenic mechanisms give reason for the great clinical heterogeneity of AIHAs, from fully compensated to rapidly evolving fatal cases.

Role of Complement in Autoimmune Hemolytic Anemia

The classification of autoimmune hemolytic anemias and the complement system are reviewed. In autoimmune hemolytic anemia of the warm antibody type, complement-mediated cell lysis is clinically relevant in a proportion of the patients but is hardly essential for hemolysis in most patients. Cold antibody-mediated autoimmune hemolytic anemias (primary cold agglutinin disease, secondary cold agglutinin syndrome and paroxysmal cold hemoglobinuria) are entirely complement-mediated disorders. In cold agglutinin disease, efficient therapies have been developed in order to target the pathogenic B-cell clone, but complement modulation remains promising in some clinical situations. No established therapy exists for secondary cold agglutinin syndrome and paroxysmal cold hemoglobinuria, and the possibility of therapeutic complement inhibition is interesting. Currently, complement modulation is not clinically documented in any autoimmune hemolytic anemia. The most relevant candidate drugs and possible target levels of action are discussed.

MYD88 L265P mutation analysis helps define nodal lymphoplasmacytic lymphoma

The diagnosis of lymphoplasmacytic lymphoma is often challenging, especially in extramedullary tissues where the differential diagnosis includes nodal marginal zone lymphoma, splenic marginal zone lymphoma, or other small B-cell neoplasms with plasmacytic differentiation. The MYD88 L265P mutation has been recently identified in >90% of bone-marrow-based lymphoplasmacytic lymphoma, but the incidence of this abnormality and corresponding morphologic correlates in nodal lymphoplasmacytic lymphoma have not been established. We analyzed 87 cases of extramedullary lymphoplasmacytic lymphoma, splenic marginal zone lymphoma, unclassifiable splenic B-cell lymphomas, nodal marginal zone lymphoma with plasmacytic differentiation, and chronic lymphocytic leukemia/small lymphocytic lymphoma with plasmacytic differentiation for MYD88 L265P. Eighteen cases (21%) were positive, including 9/9 (100%) lymphoplasmacytic lymphomas with classic histologic features, 5/12 (42%) cases that met 2008 WHO criteria for lymphoplasmacytic lymphoma but with atypical morphologic features, 3/15 (20%) cases initially considered nodal marginal zone lymphoma with plasmacytic differentiation, and 1/6 (17%) unclassifiable splenic B-cell lymphomas. The presence of MYD88 L265P was associated with IgM paraprotein (P<0.001) and a trend for bone marrow involvement (P=0.09). Each of 44 splenectomy-defined splenic marginal zone lymphomas (19 with plasmacytic differentiation) and the chronic lymphocytic leukemia/small lymphocytic lymphoma with plasmacytic differentiation were negative for the mutation. Morphologic re-review with knowledge of MYD88 mutation status and all available clinical features suggested all MYD88 mutated cases were consistent with lymphoplasmacytic lymphoma (either classic or variant histology), except for one case which remained most consistent with nodal marginal zone lymphoma with plasmacytic differentiation. These results demonstrate the importance of MYD88 mutational analysis in better defining lymphoplasmacytic lymphoma as a relatively monomorphic small B-cell lymphoma with plasmacytic differentiation that may show total nodal architectural effacement and follicular colonization. Cases previously considered lymphoplasmacytic lymphoma that are more polymorphous and are often associated with histiocytes should no longer be included in the lymphoplasmacytic lymphoma category. Clinicopathologic review suggests that although MYD88 mutated non-lymphoplasmacytic lymphoma small B-cell neoplasms exist, they are very uncommon.

Cold agglutinin-mediated autoimmune hemolytic anemia

Cold antibody types account for about 25% of autoimmune hemolytic anemias. Primary chronic cold agglutinin disease (CAD) is characterized by a clonal lymphoproliferative disorder. Secondary cold agglutinin syndrome (CAS) complicates specific infections and malignancies. Hemolysis in CAD and CAS is mediated by the classical complement pathway and is predominantly extravascular. Not all patients require treatment. Successful CAD therapy targets the pathogenic B-cell clone. Complement modulation seems promising in both CAD and CAS. Further development and documentation are necessary before clinical use. We review options for possible complement-directed therapy.

Red blood cell destruction in autoimmune hemolytic anemia: role of complement and potential new targets for therapy

Autoimmune hemolytic anemia (AIHA) is a collective term for several diseases characterized by autoantibody-initiated destruction of red blood cells (RBCs). Exact subclassification is essential. We provide a review of the respective types of AIHA with emphasis on mechanisms of RBC destruction, focusing in particular on complement involvement. Complement activation plays a definitive but limited role in warm-antibody AIHA (w-AIHA), whereas primary cold agglutinin disease (CAD), secondary cold agglutinin syndrome (CAS), and paroxysmal cold hemoglobinuria (PCH) are entirely complement-dependent disorders. The details of complement involvement differ among these subtypes. The theoretical background for therapeutic complement inhibition in selected patients is very strong in CAD, CAS, and PCH but more limited in w-AIHA. The optimal target complement component for inhibition is assumed to be important and highly dependent on the type of AIHA. Complement modulation is currently not an evidence-based therapy modality in any AIHA, but a number of experimental and preclinical studies are in progress and a few clinical observations have been reported. Clinical studies of new complement inhibitors are probably not far ahead.

Primary bone marrow lymphoma presenting with cold-type autoimmune hemolytic anemia

We report a rare case of primary bone marrow lymphoma with cold-type autoimmune hemolytic anemia (AIHA). A 70-year-old Japanese woman with suspected liver disorder presented to our hospital with palpitation. On physical examination, she had jaundice and signs of anemia. No lymphadenopathy or hepatosplenomegaly was noted. A direct antiglobulin test was positive for complement C3b and C3d. Anti-IgG testing was negative. Cold agglutinin was positive with a titer of 1:≥8,192, and haptoglobin was absent. A diagnosis of cold-type AIHA was made. Bone marrow biopsy revealed involvement with a population of lymphocytes that were positive for CD20 (L-26), CD79a, and Bcl-2. No lymphoma lesion was detected on computerized tomography or on upper and lower endoscopy. The patient was diagnosed with diffuse large B cell lymphoma (DLBCL) presenting with cold-type AIHA. She was treated with rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisolone, resulting in complete remission after six cycles. As of 22 months after presentation, no signs of cold-type AIHA or lymphoma were present.

70-year old female patient with mismatch between hematocrit and hemoglobin values: the effects of cold agglutinin on complete blood count

Introduction:

There are a number of pre-analytical and analytical factors, which cause false results in the complete blood count. The present case identifies cold agglutinins as the cause for the mismatch between hematocrit and hemoglobin values.

Materials and methods:

70-year old female patient had a history of cerebrovascular diseases and rheumatoid arthritis. During routine laboratory examination, the patient had normal leukocyte and platelet counts; however, the hemoglobin (Hb: 105 g/L) and hematocrit (HCT: 0.214 L/L) results were discordant. Hemolysis, lipemia and cold agglutinin were evaluated as possible reasons for the mismatch between hematocrit and hemoglobin values.

Results:

First blood sample was slightly hemolysed. Redrawn sample without hemolysis or lipemia was analyzed but the mismatch became even more distinct (Hb: 104 g/L and HCT: 0.08 L/L). In this sample, the titration of the cold agglutinin was determined and found to be positive at 1:64 dilution ratios. After an incubation of the sample at 37°C for 2 hours, reversibility of agglutination was observed.

Conclusion:

We conclude that cold agglutinins may interfere with the analysis of erythrocyte and erythrocyte-related parameters (HCT, MCV, MCH and MCHC); however, Hb, leukocyte and platelet counts are not affected.

Assessment of red blood cell parameters and peripheral smear at different temperatures in case of cold agglutination disease

Cold agglutination disease (CAD) is characterized by an auto-antibody which is able to agglutinate red blood cells (RBCs) at temperatures lower than that of the body, and subsequently to activate the complement system responsible for lysis of RBCs. Patients show hemolytic anemia of varying degrees of severity, which arise or worsen upon exposure to low temperatures. We describe a case who presented with fever and symptoms of asthenia. His investigations yielded bizarre RBC parameters which led to suspicion of a rare CAD, which was confirmed on reviewing RBC parameters, peripheral smear and direct Coomb's test at different temperatures. Hence, we suggest assessment of bizarre RBC parameters and peripheral smear can help in laboratory testing and diagnosis of CAD. It should also not pose embarrassment in laboratory testing to the pathologist for making an early and accurate diagnosis, thus emphasizing the need for an early treatment of CAD.

TNT003, an inhibitor of the serine protease C1s, prevents complement activation induced by cold agglutinins

Cold agglutinin–driven classical pathway activity terminates prior to the initiation of the terminal cascade in CAD patient blood. By inhibiting cold agglutinin–mediated complement deposition on the cellular membrane, TNT003 prevents RBCs from being phagocytosed.

Primary cold agglutinin-associated lymphoproliferative disease: a B-cell lymphoma of the bone marrow distinct from lymphoplasmacytic lymphoma

Primary chronic cold agglutinin disease is a rare hemolytic disease mediated by monoclonal IGHV4-34-encoded cold agglutinins with a predominant specificity for the blood group antigen I. Bone marrow from 54 patients was studied to type the underlying lymphoproliferative disorder better. Bone marrow biopsies showed circumscribed intra-parenchymatous nodules with small monotonous monoclonal B cells in 40/54 patients (median infiltration: 10% of marrow cells) with a CD20(+), IgMs(+), IgDs(+), CD27(+), CD5(-/+), CD11c(-), CD23(-), CD38(-) immunophenotype. Neither plasmacytoid cytological features nor expression of plasma cell differentiation-associated transcription factors MUM1, XBP1 and BLIMP1 were noted in these B cells. However, a limited number of mature monoclonal IgM(+), IgD(-) plasma cells were present outside the lymphoid nodules and were diffusely scattered throughout the marrow. Of interest, the MYD88 L265P mutation, typical of lymphoplasmacytic lymphoma, was not detected (17/17 cases). Somatically mutated monoclonal IGHV4-34 gene rearrangement was demonstrated in eight patients with frozen samples (mean sequence homology 95.4%). However, mutations of BCL6 intron 1 were not demonstrated, except in one patient, suggesting that the lymphoma cells had not matured in the germinal center. In conclusion, cold agglutinin-associated lymphoproliferative disease displays homogeneous histological and immunophenotypic features. The absence of plasmacytoid cells, the presence of plasma cells predominantly outside the nodular lymphoid infiltrates, IGHV4-34 restriction and absence of MYD88 L265P mutation strongly suggest that cold agglutinin-associated lymphoproliferative disease is a distinct entity that is different from lymphoplasmacytic lymphoma.

Cold autoimmune haemolytic anaemia secondary to Epstein Barr virus infection presenting with peripheral gangrene; case report

A sixty year old male presented with dark urine, symptomatic anaemia and peripheral gangrene following cold exposure. Investigations revealed that he had haemolysis and serological evidence of recent Epstein Barr virus infection. Although acrocyanosis is commonly associated with cold agglutinin disease, gangrene is a rare complication. Management of secondary cold agglutinin disease is mainly supportive.

Autoimmune hemolytic anemia: classification and therapeutic approaches

Autoimmune hemolytic anemia (AIHA) is a relatively uncommon cause of anemia. Classifications of AIHA include warm AIHA, cold AIHA (including mainly chronic cold agglutinin disease and paroxysmal cold hemoglobinuria), mixed-type AIHA and drug-induced AIHA. AIHA may also be further subdivided on the basis of etiology. Management of AIHA is based mainly on empirical data and on small, retrospective, uncontrolled studies. The therapeutic options for treating AIHA are increasing with monoclonal antibodies and, potentially, complement inhibitory drugs. Based on data available in the literature and our experience, we propose algorithms for the treatment of warm AIHA and cold agglutinin disease in adults. Therapeutic trials are needed in order to better stratify treatment, taking into account the promising efficacy of rituximab.

Cold agglutinin disease in fibrolamellar hepatocellular carcinoma: a rare association with a rare cancer variant

Cold agglutinin disease (CAD) is a rare autoimmune hemolytic anemia. Although it can occur secondary to lymphoproliferative disorders and autoimmune or infectious diseases, CAD is rarely reported as secondary to solid tumors. We report a case of a woman aged 18 years diagnosed with a well-differentiated hepatocellular carcinoma of the fibrolamellar subtype, who was shown to have CAD also. Her general condition, including CAD, improved after targeted therapy with sorafenib for the hepatocellular carcinoma and only conservative measures for the CAD that consisted of avoidance of cold. In summary, although it is an extremely rare association and less common than lymphoproliferative disorders, CAD can be associated with solid tumors.

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.

Case report: retinopathy in a patient with cold hemagglutinin disease

PURPOSE

We describe abnormalities of retinal vasculature and blood flow in a patient with cold hemagglutinin disease.

METHOD

Case report and literature review using the PubMed database.

RESULTS

A man with cold hemagglutinin disease and no visual symptoms was referred to the Eye Department with retinal abnormalities found during a routine optometrist examination. He was found to have scattered retinal hemorrhages, abnormal retinal vasculature resembling neovascularization (but that did not show leakage on fundus fluorescein angiography), and aggregated material flowing visibly in the retinal vessels.

CONCLUSION

No specific descriptions of retinopathy related to cold hemagglutinin disease have been previously published. We suggest that the abnormalities are secondary to areas of retinal ischemia, resulting in the development of a form of collateral circulation.

High response rate and durable remissions following fludarabine and rituximab combination therapy for chronic cold agglutinin disease

Most patients diagnosed with primary chronic cold agglutinin disease (CAD) have a clonal lymphoproliferative bone marrow disorder. Treatment with rituximab is the only well-documented effective therapy, leading to 45%-60% partial responses (PR). Complete responses (CR) are rare, and median response duration is only 11 months. In a prospective multicenter trial, 29 patients received rituximab 375 mg/m2 on days 1, 29, 57 and 85; and fludarabine orally, 40 mg/m2 on days 1-5, 29-34, 57-61 and 85-89. Twenty-two patients (76%) responded, 6 (21%) achieving CR and 16 (55%) PR. Among 10 patients nonresponsive to rituximab monotherapy, 1 achieved CR and 6 PR. Median increase in hemoglobin level was 3.1 g/dL among the responders and 4.0 g/dL in those who achieved CR. Lower quartile of response duration was not reached after 33 months. Estimated median response duration was more than 66 months. Grade 3-4 hematologic toxicity occurred in 12 patients (41%). In conclusion, fludarabine and rituximab combination therapy is very efficient in patients with CAD. Toxicity may be a concern, and benefits should be carefully weighed against risks in very old and comorbid patients. It remains to be established whether the combination should be first-line or an efficient second-line therapy in CAD patients requiring treatment. This study is registered at http://www.clinicaltrials.gov as NCT00373594.

[Bedside pretransfusion compatibility testing fiability with cold agglutinins during cardiopulmonary bypass associated hypothermia for cardiac surgery]

This case report is an example of a bedside pretransfusion compatibility testing issue. An 81-years-old woman was admitted in the operating room for aortic valve replacement under cardiopulmonary bypass. A conflict occurred during the bedside pretransfusion compatibility testing between the results of the patient and the packed red blood cells. Afterwards, the patient was diagnosed with cold agglutinins. It might have produced false positive results with the anti-A and anti-B reagents.

[Rheumatoid arthritis and autoimmune hemolysis: B-cell depletion for remission induction in a patient with rheumatoid arthritis and cold agglutinin disease]

Autoimmune hemolysis is a rare complication of systemic rheumatic diseases. We report on a 68-year-old female patient with established, long-standing rheumatoid arthritis, who complained of progressive weakness and worsening of her arthralgia under therapy with leflunomide. Physical and laboratory examination revealed autoimmune hemolysis due to cold agglutinin disease. As hemolysis and arthritis were refractory to steroid treatment, B-cell depletion with rituximab was performed leading to a marked reduction of hemolytic parameters as well as remission of her rheumatoid arthritis.

Rituximab in auto-immune haemolytic anaemia and immune thrombocytopenic purpura: a Belgian retrospective multicentric study

OBJECTIVES

For better characterizing the effect of anti-CD20 therapy, we analysed the use of rituximab in Belgian patients experiencing auto-immune haemolytic anaemia (AIHA) and immune thrombocytopenic purpura (ITP).

DESIGN

We performed a retrospective multicentric analysis of patients with AIHA and ITP treated with rituximab in Belgium.

SETTING

Haematological departments were invited to fill in a questionnaire about patient and disease characteristics.

SUBJECTS

All patients with AIHA and ITP, both primary and secondary to other diseases, who received one or more courses of rituximab during their disease course were included. Sixty-eight courses of rituximab in 53 patients with AIHA and 43 courses in 40 patients with ITP were analyzed.

INTERVENTION

Response rates, duration of response and factors predictive for response were assessed.

RESULTS

All patients were given rituximab after failing at least one previous line of treatment, including splenectomy in 19% and 72.5% of AIHA-patients and ITP-patients respectively. Overall response rates were 79.2% in AIHA and 70% in ITP, with a median follow-up since first rituximab administration of 15 months (range 0.5-62) in AIHA and 11 months (range 0-74) in ITP. Progression free survival at 1 and 2 years were 72% and 56% in AIHA and 70% and 44% in ITP. In this retrospective analysis we were not able to identify pretreatment characteristics predictive for response to rituximab. Nine patients with AIHA and three patients with ITP were given one or more additional courses of rituximab. Most of these patients, who had responded to a previous course, experienced a new response comparable to the previous one, both in terms of quality and of duration of response. Finally, the outcome of patients who failed to respond to rituximab therapy was poor both in terms of response to subsequent therapy and in terms of survival.

CONCLUSIONS

This study confirms that rituximab induces responses in a majority of previously treated patients with AIHA and ITP. Response duration generally exceeds 1 year. Retreatment with rituximab in responding patients is most often successful. The outcome of patients who fail on rituximab is poor. We were not able to identify pretreatment patient characteristics predicting for response.

Catastrophic multiple organ ischemia due to an anti-Pr cold agglutinin developing in a patient with mixed cryoglobulinemia after treatment with rituximab

Cold agglutinin disease occurring with cryoglobulinemia is a rare occurrence. Here, we report a patient with mixed cryoglobulinemia that was treated with rituximab and, after response, developed an anti-Pr cold agglutinin that manifested with hemolysis and microvascular occlusion causing mesenteric ischemia and cerebral infarction. Unlike previous reports of patients with cryoglobulinemia and cold agglutinin disease, our patient did not have a detectable cryoprecipitate when his cold agglutinin manifested.