Role of plasma cells in Waldenström macroglobulinaemia

The impact of individual clinical features in cold agglutinin disease: hemolytic versus non-hemolytic symptoms

INTRODUCTION

During the last decades, the pathogenesis of cold agglutinin disease (CAD) has been well elucidated and shown to be complex. Several documented or investigational therapies have been made available. This development has resulted in major therapeutic advances, but also in challenges in choice of therapy.

AREAS COVERED

In this review, we address each step in pathogenesis: bone marrow clonal lymphoproliferation, composition and effects of monoclonal cold agglutinin, non-complement mediated erythrocyte agglutination, complement-dependent hemolysis, and other effects of complement activation. We also discuss the heterogeneous clinical features and their relation to specific steps in pathogenesis, in particular with respect to the impact of complement involvement. CAD can be classified into three clinical phenotypes with consequences for established treatments as well as development of new therapies. Some promising future treatment approaches - beyond chemoimmunotherapy and complement inhibition - are reviewed.

EXPERT OPINION

The patient's individual clinical profile regarding complement involvement and hemolytic versus non-hemolytic features is important for the choice of treatment. Further development of treatment approaches is encouraged, and some candidate drugs are promising irrespective of clinical phenotype. Patients with CAD requiring therapy should be considered for inclusion in clinical trials.

Cold-antibody Autoimmune Hemolytic Anemia: its Association with Neoplastic Disease and Impact on Therapy

PURPOSE OF REVIEW

Cold-antibody mediated autoimmune hemolytic anemia (cAIHA) is subclassified as cold agglutinin disease (CAD), secondary cold agglutinin syndrome (CAS), and paroxysmal cold hemoglobinuria (PCH). This review aims to address the occurrence of neoplastic disorders with these three entities and analyze the impact of such neoplasias on treatment for cAIHA.

RECENT FINDINGS

"Primary" CAD is a distinct clonal B-cell lymphoproliferative disorder in probably all cases, although not classified as a malignant lymphoma. CAS is secondary to malignant lymphoma in a minority of cases. Recent findings allow a further clarification of these differential diagnoses and the therapeutic consequences of specific neoplastic entities. Appropriate diagnostic workup is critical for therapy in cAIHA. Patients with CAD should be treated if they have symptomatic anemia, significant fatigue, or bothersome circulatory symptoms. The distinction between CAD and CAS and the presence of any underlying malignancy in CAS have essential therapeutic implications.

Daratumumab monotherapy in refractory warm autoimmune hemolytic anemia and cold agglutinin disease

ABSTRACT

Autoimmune hemolytic anemia (AIHA) is a rare autoantibody-mediated disease. For steroid and/or rituximab-refractory AIHA, there is no consensus on optimal treatment. Daratumumab, a monoclonal antibody targeting CD38, could be beneficial by suppression of CD38+ plasma cells and thus autoantibody secretion. In addition, because CD38 is also expressed by activated T cells, daratumumab may also act via immunomodulatory effects. We evaluated the efficacy and safety of daratumumab monotherapy in an international retrospective study including 19 adult patients with heavily pretreated refractory AIHA. In warm AIHA (wAIHA, n = 12), overall response was 50% with a median response duration of 5.5 months (range, 2-12), including ongoing response in 2 patients after 6 and 12 months. Of 6 nonresponders, 4 had Evans syndrome. In cold AIHA (cAIHA, n = 7) overall hemoglobin (Hb) response was 57%, with ongoing response in 3 of 7 patients. One additional patient with nonanemic cAIHA was treated for severe acrocyanosis and reached a clinical acrocyanosis response as well as a Hb increase. Of 6 patients with cAIHA with acrocyanosis, 4 had improved symptoms after daratumumab treatment. In 2 patients with wAIHA treated with daratumumab, in whom we prospectively collected blood samples, we found complete CD38+ T-cell depletion after daratumumab, as well as altered T-cell subset differentiation and a severely diminished capacity for cell activation and proliferation. Reappearance of CD38+ T cells coincided with disease relapse in 1 patient. In conclusion, our data show that daratumumab therapy may be a treatment option for refractory AIHA. The observed immunomodulatory effects that may contribute to the clinical response deserve further exploration.

Case report: Autoimmune hemolytic anemia caused by warm and cold autoantibodies with complement activation-etiological and therapeutic issues

Introduction

Research on mixed warm and cold autoantibodies in autoimmune hemolytic anemia (AIHA) targeting erythrocytes [red blood cells (RBCs)] and platelets is scarcely reported.

Case presentation

In this study, we present the case of a 5-year-old boy with positive direct [anti-IgG (1+), anti-IgG-C3d (3+)], and indirect antiglobulin (Coombs) tests. The RBCs were coated with polyspecific-positive, warm IgG autoantibodies alongside activated complement components. Plasma-containing immunoglobulin M (IgM) class autoantibodies were found in 1:64 titers with a wide temperature range of 4°C-37°C. The platelets were also coated with IgM autoantibodies. There was a reduction in the levels of the classical and alternative complement pathways, such as C3, C4, ADAMTS13 metalloprotease activity, factor H antigen, complement factor B antigen, and C1q antigen alongside the elevated sC5b-9 terminal complement complex. Hematuria and/or proteinuria, reduced diuresis, and elevated levels of serum creatinine were absent. The kidney ultrasound report was normal. A recent combination of Epstein-Barr virus (EBV) and cytomegalovirus (CMV) infection was found. The first-line treatment consisted of intravenous methylprednisolone [4 mg/kg/body weight for the first 72 h (q12 h), followed by 2 mg/kg body weight for 21 consecutive days with a slow steroid reduction until plasmapheresis (PLEX)]. After the patient showed limited response to corticosteroid therapy, rituximab (375 mg/m2) was administered once a week (five doses in total), with vitamins B9 and B12. These strategies also showed limited (partial) therapeutic benefits. Therefore, the treatment was switched to PLEX (five cycles in total) and intravenous immunoglobulin (IVIg) (1 g/kg/5 days). This combination significantly improved RBC count and platelet levels, and C3 and C4 levels returned to normal. A follow-up of 2.5 years after treatment showed no sign of relapse. A genetic analysis revealed a rare heterozygous intronic variation (c.600-14C > T) and heterozygous Y402H polymorphism of the CFH gene. c.600-14C > T mutation was located near the 5' end of exon 6 in the gene encoding the complement C3 protein of unknown significance. We presumed that the complement regulators in our patient were sufficient to control complement activation and that complement blockade should be reserved only for devastating, life-threatening complement-related multiorgan failure.

Conclusion

We believe that EBV and CMV triggered AIHA, thus activating the complement cascade. Hence, we used corticosteroids, rituximab, vitamins B9 + B12, PLEX, and fresh frozen plasma (FFP) as treatment. Final remission was achieved with PLEX and FFP. However, an additional late effect of B12 rituximab and the disappearance of long-lived circulating plasma cells should not be completely ignored. Complement activation with a genetic background should be assessed in severe warm and cold hemolytic anemias caused by autoantibodies.

Diagnostics in Waldenström's macroglobulinemia: a consensus statement of the European Consortium for Waldenström's Macroglobulinemia

The diagnosis of Waldenström's macroglobulinemia (WM), an IgM-associated lymphoplasmacytic lymphoma, can be challenging due to the different forms of disease presentation. Furthermore, in recent years, WM has witnessed remarkable progress on the diagnostic front, as well as a deeper understanding of the disease biology, which has affected clinical practice. This, together with the increasing variety of tools and techniques available, makes it necessary to have a practical guidance for clinicians to perform the initial evaluation of patients with WM. In this paper, we present the consensus recommendations and laboratory requirements for the diagnosis of WM developed by the European Consortium of Waldenström's Macroglobulinemia (ECWM), for both clinical practice as well as the research/academical setting. We provide the procedures for multiparametric flow cytometry, fluorescence in situ hybridization and molecular tests, and with this offer guidance for a standardized diagnostic work-up and methodological workflow of patients with IgM monoclonal gammopathy of uncertain significance, asymptomatic and symptomatic WM.

How I treat cold agglutinin disease

The last decades have seen great progress in the treatment of cold agglutinin disease (CAD). Comparative trials are lacking, and recommendations must be based mainly on nonrandomized trials and will be influenced by personal experience. Herein, current treatment options are reviewed and linked to 3 cases, each addressing specific aspects of therapy. Two major steps in CAD pathogenesis are identified, clonal B-cell lymphoproliferation and complement-mediated hemolysis, each of which constitutes a target of therapy. Although drug treatment is not always indicated, patients with symptomatic anemia or other bothersome symptoms should be treated. The importance of avoiding ineffective therapies is underscored. Corticosteroids should not be used to treat CAD. Studies on safety and efficacy of relevant drugs and combinations are briefly described. The author recommends that B cell-directed approaches remain the first choice in most patients requiring treatment. The 4-cycle bendamustine plus rituximab combination is highly efficacious and sufficiently safe and induces durable responses in most patients, but the time to response can be many months. Rituximab monotherapy should be preferred in frail patients. The complement C1s inhibitor sutimlimab is an emerging option in the second line and may also find its place in the first line in specific situations.

SEROUS MACULAR DETACHMENT ASSOCIATED WITH WALDENSTROM MACROGLOBULINEMIA MANAGED WITH IBRUTINIB: A CASE REPORT AND NEW INSIGHTS INTO PATHOGENESIS

PURPOSE

To report a case of serous macular detachment in a patient with Waldenstrom macroglobulinemia treated with ibrutinib.

METHODS

The patient underwent a complete ophthalmic examination and imaging at presentation and at follow-up visits up to 13 months.

RESULTS

At presentation, there were serous macular detachments bilaterally with no dye leakage on fluorescein angiography or vasculature abnormalities on optical coherence tomography angiography. After treatment with ibrutinib, there was near resolution of the patient's retinopathy with an improvement in vision at 13 months' follow-up.

CONCLUSION

Serous macular detachments in Waldenstrom macroglobulinemia-associated retinopathy may be due to the disruption of the retinal pigment epithelium pump mechanism by hyperglobulinemia. The favorable course of this patient, treated with the novel tyrosine kinase inhibitor ibrutinib, suggests this may be the preferred treatment for Waldenstrom macroglobulinemia patients with associated retinopathy.

Cold agglutinin disease revisited: a multinational, observational study of 232 patients

We retrospectively studied 232 patients with cold agglutinin disease (CAD) at 24 centers in 5 countries. In Norway and a northern region of Italy, the study was close to being population-based. For the first time, we demonstrate fourfold differences between cold and warmer climates regarding prevalence (20 vs 5 cases/million) and incidence (1.9 vs 0.48 cases/million per year). Mean baseline hemoglobin level was 9.3 g/dL, but 27% had hemoglobin <8 g/dL. Identification of typical features of CAD-associated lymphoproliferative disorder in the bone marrow was greatly increased by centralized biopsy assessment. CAD seems to be associated with a slightly increased risk of venous thrombosis. This work includes a follow-up study of therapies, focusing on the long-term outcomes of the rituximab plus bendamustine and rituximab plus fludarabine regimens. Rituximab plus bendamustine therapy resulted in responses in 35 (78%) of 45 patients; 24 (53%) achieved complete response. Interestingly, these rates were still higher than observed in the original (2017) prospective trial, and we also found a shift toward deeper responses with time. This is explained by the prolonged time to response seen in many patients, probably related to long-lived plasma cells. In patients responding to rituximab-bendamustine, median response duration was not reached after 88 months, and estimated 5-year sustained remission was 77%. The regimen appeared safe regarding late-occurring malignancies. Rituximab plus fludarabine therapy seems to carry a higher risk of long-term adverse effects.

The BLIMP1-EZH2 nexus in a non-Hodgkin lymphoma

Waldenström's macroglobulinemia (WM) is a non-Hodgkin lymphoma, resulting in antibody-secreting lymphoplasmacytic cells in the bone marrow and pathologies resulting from high levels of monoclonal immunoglobulin M (IgM) in the blood. Despite the key role for BLIMP1 in plasma cell maturation and antibody secretion, its potential effect on WM cell biology has not yet been explored. Here we provide evidence of a crucial role for BLIMP1 in the survival of cells from WM cell line models and further demonstrate that BLIMP1 is necessary for the expression of the histone methyltransferase EZH2 in both WM and multiple myeloma cell lines. The effect of BLIMP1 on EZH2 levels is post-translational, at least partially through the regulation of proteasomal targeting of EZH2. Chromatin immunoprecipitation analysis and transcriptome profiling suggest that the two factors co-operate in regulating genes involved in cancer cell immune evasion. Co-cultures of natural killer cells and cells from a WM cell line further suggest that both factors participate in immune evasion by promoting escape from natural killer cell-mediated cytotoxicity. Together, the interplay of BLIMP1 and EZH2 plays a vital role in promoting the survival of WM cell lines, suggesting a role for the two factors in Waldenström's macroglobulinaemia.

New Insights in the Pathogenesis and Therapy of Cold Agglutinin-Mediated Autoimmune Hemolytic Anemia

Autoimmune hemolytic anemias mediated by cold agglutinins can be divided into cold agglutinin disease (CAD), which is a well-defined clinicopathologic entity and a clonal lymphoproliferative disorder, and secondary cold agglutinin syndrome (CAS), in which a similar picture of cold-hemolytic anemia occurs secondary to another distinct clinical disease. Thus, the pathogenesis in CAD is quite different from that of polyclonal autoimmune diseases such as warm-antibody AIHA. In both CAD and CAS, hemolysis is mediated by the classical complement pathway and therefore can result in generation of anaphylotoxins, such as complement split product 3a (C3a) and, to some extent, C5a. On the other hand, infection and inflammation can act as triggers and drivers of hemolysis, exemplified by exacerbation of CAD in situations with acute phase reaction and the role of specific infections (particularly Mycoplasma pneumoniae and Epstein-Barr virus) as causes of CAS. In this review, the putative mechanisms behind these phenomena will be explained along with other recent achievements in the understanding of pathogenesis in these disorders. Therapeutic approaches have been directed against the clonal lymphoproliferation in CAD or the underlying disease in CAS. Currently, novel targeted treatments, in particular complement-directed therapies, are also being rapidly developed and will be reviewed.

Characteristics of Waldenström Macroglobulinemia in Korean Patients According to Mutational Status of MYD88 and CXCR4: Analysis Using Ultra-Deep Sequencing

BACKGROUND

Little is known about the mutational frequency of myeloid differentiation factor 88 (MYD88) and C-X-C chemokine receptor type 4 (CXCR4) and the corresponding characteristics in Asian individuals afflicted with Waldenström macroglobulinemia (WM). We investigated the characteristics of WM according to mutational status of MYD88/CXCR4, and attempted to determine the lineage commitment among hematopoietic cells by MYD88^L265P single-cell sequencing on bone marrow (BM) smear slides.

MATERIALS AND METHODS

CXCR4 mutations (muts) were detected using ultra-deep sequencing using target capture. Mutational burden of MYD88 was assessed using real-time polymerase chain reaction. Single-cell sequencing for MYD88 was performed on lymphocytes, plasmacytoid lymphocytes, plasma cells, and neutrophils using laser microdissection.

RESULTS

Among 31 patients, the frequencies of MYD88/CXCR4 muts were as follows: MYD88 wild type (WT) CXCR4^WT (6 patients, 19.4%), MYD88^L265PCXCR4^WT (19 patients, 61.4%), MYD88^L265PCXCR4^mut (6 patients, 19.4%; 1 frameshift and 5 nonsense muts). Immunoglobulin M levels of MYD88^L265CXCR4^WT patients were significantly higher than those of MYD88^WTCXCR4^WT patients (P = .024). Tumor burden in BM was highest in patients with MYD88^L265PCXCR4^mut (82.0%), followed by MYD88^L265PCXCR4^WT (52.8%) and MYD88^WTCXCR4^WT (14.2%) (P < .001). The quantity of MYD88-mutated DNA tended to correlate with tumor burden in BM (correlation coefficient 0.647; P = .009). MYD88^L265P was detected in plasma cells, plasmacytoid lymphocytes, and lymphocytes but not neutrophils.

CONCLUSION

The frequency of MYD88/CXCR4 muts in Korean and Caucasian patients with WM was similar, however 5 of the 6 CXCR4 muts were nonsense-a proportion higher than reported frequencies in Caucasian individuals. Ultra-deep sequencing was capable of detecting CXCR4 muts not detectable using Sanger sequencing, suggesting a possible replacement of the B-cell sorting.

Recurrent chylothorax: a clinical mystery

Chylothorax is an unusual cause of pleural effusion, typically caused by trauma or malignancy. Waldenstrom's macroglobulinaemia (WM) is a clinicopathological entity demonstrating lymphoplasmacytic lymphoma in the bone marrow with an IgM monoclonal gammopathy in the blood. Recurrent chylous effusions are often resistant to conservative treatment and may require surgical intervention. We present a unique case of a 50-year-old woman with recurrent chylothorax secondary to WM that completely resolved with ibrutinib therapy. To our knowledge, this is the eighth such case reported in literature and the first case of successful resolution of chylothorax with monoclonal antibody therapy.