AUTOIMMUNE HAEMOLYTIC ANAEMIA: A SYSTEMATIC REVIEW

Abstract

Autoimmune haemolytic anaemia (AIHA) is a rare and heterogeneous haematological disorder. The diagnostic criteria of AIHA have been debatable and not clearly defined. We performed a systematic review to evaluate the various definitions of AIHA. The spectrum of clinical features is well established and does not need to be reviewed. However, the treatment as well as the outcome of AIHA has many controversies and will be reviewed in this article. The general terminology, ‘autoimmune haemolytic anaemia’ supplemented by the Medical search term (MeSH) for selected articles were gathered from PUBMED and COCHCRANE databases. Of the 2812 articles from these databases and 1837 articles from CLINICAL KEY from the years 2010 to 2020, in English full texts only, 57 articles fulfilled the inclusion and exclusion criteria. The definition of haemolytic anaemia was almost homogenous in 48 (84.2%) articles with minor variations in the description. AIHA is characterized by increased destruction of red blood cells (RBC) due to an immune-mediated process. Specific definitions of AIHA was not consistently described. A positive direct anti-globulin test (DAT) with laboratory evidence of haemolysis were the key diagnostic criteria described in 45 of the articles (75%). Clinical features of AIHA were almost similar across all articles viz. anaemic symptoms and complication of haemolysis. Corticosteroid remains the mainstay of treatment followed by anti-CD20 monoclonal antibody (rituximab), immunosuppressant, other biologics and intravenous immunoglobulin (IV Ig) have been used in general and specific AIHA. Treatment response criteria were provided in all the articles but different parameters were monitored and there was no uniformity. Complete remission (CR) was achieved in 25% - 88% of AIHA patients while 4% - 69% had a partial response (PR) to corticosteroid therapy in 11 studies. CR and PR was achieved in 4%-88% and 75%-86% patients respectively in 8 studies using rituximab. In patients who underwent splenectomy, only 4%-6% had CR in 3 studies while 1 study reported 75% PR. This review revealed both the homogeneity across the studies and areas of inconsistency in definitions and data interpretation.