Successful treatment of IgM-monoclonal gammopathy of undetermined significance associated with cryoglobulinemia and cold agglutinin disease with immunochemotherapy with rituximab, fludarabine, and cyclophosphamide

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.

How I treat autoimmune hemolytic anemia

Autoimmune hemolytic anemia (AIHA) is an uncommon entity that presents diagnostic, prognostic, and therapeutic dilemmas despite being a well-recognized entity for over 150 years. This is because of significant differences in the rates of hemolysis and associated diseases and because there is considerable clinical heterogeneity. In addition, there is a lack of clinical trials required to refine and update standardized and evidence-based therapeutic approaches. To aid the clinician in AIHA management, we present four vignettes that represent and highlight distinct clinical presentations with separate diagnostic and therapeutic pathways that we use in our clinical practice setting. We also review the parameters present in diagnostic testing that allow for prognostic insight and present algorithms for both diagnosis and treatment of the AIHA patient in diverse situations. This is done in the hope that this review may offer guidance in regard to personalized therapy recommendations. A section is included for the diagnosis of suspected AIHA with negative test results, a relatively infrequent but challenging situation, in order to assist in the overall evaluation spectrum for these patients.

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.