Insight Into Aetiology and Severity of Hemolysis Associated with Immunoproteins on Red Cell Surface in Direct Antiglobulin Test Positive Auto-immune Hemolytic Anemia

The study aimed to find out the correlation of positive direct antiglobulin test (DAT) with features of autoimmune hemolysis in patients presenting to a tertiary care center in Northern India. Patient history, lab findings, and immune-hematological findings which can influence the management of patients with auto-immune hemolytic anemia were studied. DAT helps to differentiate immune hemolysis from non-immune hemolysis in patients with hemolytic anemia. A prospective study over 18 months was performed on DAT-positive samples of patients showing features of auto-immune hemolysis. The laboratory markers of hemolysis were correlated with immune-hematological studies like elution-adsorption, antibody specificity, and titer. Out of 1371 requests received for Immuno-hematological workup of patients with hemolysis, 92 (6.71%) met the inclusion criteria. Thirty (32.6%) patients were diagnosed with primary (Idiopathic) Auto-immune Hemolytic Anemia (AIHA), and the remaining 62(67.3%) patients had secondary AIHA. The gender distribution in primary AIHA was male: female as 1:2.7, while in secondary AIHA it was observed as male: female to be 1:1.3.The median age for primary AIHA was found to be 23.7 years (range 1 year to 48 years), and for secondary AIHA it was found to be 44.6 years (range 2 to 85 years). Of all AIHA patients tested, 85.8% showed the presence of warm autoantibodies in their sera while 7.6% had mixed-type AIHA and the remaining 6.5% had cold autoantibodies. The study highlights a strong association between higher strength of DAT positivity, multiple antibodies/immunoglobulins with complements coating red cells, and a higher titer of IgG and IgG1 & IgG3 subclass with the severity of hemolysis.