[Application of the gel test using and anti-IgA antiglobulin for the immunologic diagnosis of autoimmune hemolytic anemia with a negative direct Coombs test]

Warm Autoimmune Hemolytic Anemia: Clinical Profile and Management

Background

Autoimmune hemolytic anemia (AIHA) is a rare autoimmune disease in which autoantibodies target red blood cells leading to marked decrease in their lifespan. The classification of AIHA is based on the immunochemical properties of the RBC autoantibody. Warm antibody AIHA (wAIHA) accounts for 75-80% of all adult AIHA cases. The treatment of wAIHA is mainly corticosteroids. Our retrospective study aimed to study the clinical profile and management of wAIHA.

Methods

Data of 75 patients admitted with wAIHA or presented to outpatient department (previous medical records) with wAIHA between January 2003 and January 2016 were analyzed.

Results

In our study, females constituted 12 and 26 patients of primary and secondary wAIHA, while males constituted 17 and 20 patients of primary and secondary wAIHA, respectively. Mean hemoglobin level at AIHA onset was found to be 7.1 ± 1.7 g/dL in primary wAIHA group and 6.3 ± 1.2 g/dL in secondary wAIHA group, which is statistically significant. Splenectomy was used as mode of treatment in one (3.4%) patient of primary wAIHA group and 15 (32.60%) patients of secondary wAIHA group, which is statistically significant. Mean age of wAIHA onset was 69.7 ± 21.5 years in wAIHA group secondary to lymphoma and 54.3 ± 25.7 years in other wAIHA group, which is statistically significant.

Conclusion

The most common causes of secondary wAIHA are B-cell lymphoma, systemic lupus erythematosus, rheumatoid arthritis, chronic lymphocytic leukemia (CLL), common variable immune deficiency, renal cell carcinoma and secondary to drug usage (alpha methyldopa and carbamazepine), respectively. Reducing the cumulative dose of corticosteroids with second line treatment whenever possible and therefore reducing the risk of sepsis, specifically in older patients with comorbidities will reduce morbidity and mortality.

Warm Autoimmune Hemolytic Anemia and Direct Antiglobulin Testing With a False-Negative Result in a 53-Year-Old Man: The DAT Will Set You Free

Warm autoimmune hemolytic anemia (WAIHA), the most common of the relatively uncommon autoimmune-mediated hemolytic anemias (AIHAs), is mediated by polyclonal immunoglobulin (Ig)G autoantibodies in most cases. Herein, we present a case of WAIHA involving a direct antiglobulin test (DAT) with an initially negative result. Using a modified DAT protocol, repeat testing of the same specimen material from a previously healthy 53-year-old man yielded positive results. This case demonstrates that investigation of an apparently negative DAT result plays a critical role in the differential diagnosis of patients with rapidly progressing hemolytic anemia and the reversal of that decline.

Immunotherapy treatments of warm autoimmune hemolytic anemia

Warm autoimmune hemolytic anemia (WAIHA) is one of four clinical types of autoimmune hemolytic anemia (AIHA), with the characteristics of autoantibodies maximally active at body temperature. It produces a variable anemia—sometimes mild and sometimes severe. With respect to the absence or presence of an underlying condition, WAIHA is either idiopathic (primary) or secondary, which determines the treatment strategies in practice. Conventional treatments include immune suppression with corticosteroids and, in some cases, splenectomy. In recent years, the number of clinical studies with monoclonal antibodies and immunosuppressants in the treatment of WAIHA increased as the knowledge of autoimmunity mechanisms extended. This thread of developing new tools of treating WAIHA is well exemplified with the success in using anti-CD20 monoclonal antibody, Rituximab. Following this success, other treatment methods based on the immune mechanisms of WAIHA have emerged. We reviewed these newly developed immunotherapy treatments here in order to provide the clinicians with more options in selecting the best therapy for patients with WAIHA, hoping to stimulate researchers to find more novel immunotherapy strategies.

[Autoimmune haemolytic anemia: diagnosis strategy and new treatments]

The pattern of autoimmune hemolytic anemia has changed significantly these last 15 years. With regard to the diagnosis strategy, the use of gel filtration technique to perform the direct antiglobulin test (DAT) has decreased the number of autoimmune haemolytic anemias with negative tests results. In recent years, autoimmune haemolytic anemia increased in patients receiving purine nucleoside analogues, blood transfusions, solid organ transplantation or hematopoietic stem cells transplantation. These difficult autoimmune haemolytic anemia cases need to use new kinds of treatments. With regard to the treatment, very little progress was made this latter 50 years. The discovery of the efficacy of anti-CD20 antibody in this disease represents a breakthrough. Nowdays, the second-line treatment includes rituximab or splenectomy. Sometimes, the anti-CD20 treatment could be proposed in first-line but some clinical trials are needed.

IgA-mediated human autoimmune hemolytic anemia as a result of hemagglutination in the spleen, but independent of complement activation and FcαRI

Autoimmune hemolytic anemia (AIHA) due to warm-acting IgA autoantibodies is rare. We explored the pathogenic mechanisms underlying destruction of red blood cells (RBCs) in a patient with severe AIHA mediated exclusively by polymeric immunoglobulin A (pIgA) anti-Band 3 autoantibodies. The follow-up period was 17 months. RBCs were not destroyed by complement activation as no deposition of complement was observed on the patient's RBCs. pIgA eluted from the patient's RBCs did not induce RBC destruction through phagocytosis by monocytes or antibody-dependent cell-mediated cytotoxicity by natural killer cells. Induction of eryptosis (ie, RBC apoptosis) due to direct alteration of the RBC membrane by pIgA autoantibodies was also excluded. By contrast, upon incubation with pIgA-opsonized RBCs, substantial RBC membrane transfers (ie, trogocytosis) to monocytes were observed that might contribute to RBC immune destruction. This effect was poorly inhibited by blockers of Fc receptors, excluding a major contribution of FcαRI to this process. Histologic analysis revealed a massive accumulation of agglutinated RBCs with little sign of erythrophagocytosis in the spleen. These results, together with the efficacy of splenectomy 17 months after AIHA onset, suggest that the trapping and subsequent sequestration of agglutinated RBCs in the spleen are the principal pathogenic mechanisms of pIgA-mediated AIHA.

Clinical application of a flow cytometric direct antiglobulin test

BACKGROUND

The clinical application of flow cytometric direct antiglobulin test (FC-DAT) has rarely been evaluated for patients with various diseases including immune and nonimmune hemolytic anemia.

STUDY DESIGN AND METHODS

Blood samples from 380 patients with a variety of diseases were studied using the tube direct DAT and FC-DAT. The results of tube DAT and FC-DAT were compared. The predictive values of DAT for hemolysis were evaluated.

RESULTS

Of 57 patients with autoimmune hemolytic anemia (AIHA), 6 of the 17 with a negative tube DAT (immunoglobulin G [IgG]) had a positive FC-DAT (IgG) and 23 of the 36 patients with a negative tube DAT (complement 3d [C3d]) had a positive FC-DAT (C3d). In 57 patients with AIHA, the incidence of positive results of FC-DAT (IgG) and tube DAT (IgG) were similar (42 positive vs. 40 positive); but in 323 patients without AIHA, the incidence of positive FC-DATs (IgG) was higher than that of tube DAT (IgG; 47 positive vs. 9 positive). The higher incidence of positive FC-DAT (C3d) than that of tube DAT (C3d) was seen in patients with AIHA (42 positive vs. 21 positive) as well as in patients without AIHA (61 positive vs. 5 positive). Both DAT (IgG) and DAT (C3d) positive has highest positive predictive value for hemolysis, followed by DAT (IgG) alone positive and DAT (C3d) alone positive.

CONCLUSIONS

FC-DAT is a complementary test for diagnosing AIHA. There is a synergistic effect of the red blood cell-bound IgG and complement in predicting hemolysis.

Anémie hémolytique immunoallergique due à l'ambroxol

INTRODUCTION

Drug-induced immune hemolytic anemia is a rare cause of hemolytic anemia.

CASE RECORD

A 68-year-old male patient developed an acute intravascular hemolysis with acute renal failure. Common causes of hemolysis were ruled out and the patient rapidly improved. An immune mechanism was confirmed by the positivity of the direct antiglobulin test with anti-IgA in the presence of ambroxol only, one of the drug the patient had received during 6 days before hospitalization.

DISCUSSION

To our knowledge, this is the first report of ambroxol-induced immune hemolytic anemia. This case also underlined that the direct antiglobulin test should also be performed with anti-IgA to rule out any false negative.

Laboratory diagnosis of autoimmune cytopenias

The past year's literature shows that little progress has been achieved in the laboratory diagnosis of autoimmune hemolytic anemia. The direct antiglobulin test is the only diagnostic test for autoimmune hemolytic anemia. Advantages of new techniques, such as the gel test, have to be determined. Today, cephalosporins are known to cause both drug-dependent and -independent autoantibodies. The diagnosis of idiopathic thrombocytopenic purpura is a clinical one. The new assays that measure antibodies against specific glycoproteins offer improved specificity. New laboratory advancements and accumulation of data on granulocytes' antigens and antibodies enabled us to recommend guidelines for the laboratory investigation of autoimmune neutropenia.