Diagnosis of Auto Immune Hemolytic Anemia by Detection of RBC-Bound IgG Antibodies, Using Flow-Cytometry

Auto Immune Hemolytic Anemia (AIHA) is one of the most common types of acquired hemolytic anaemias. Its main cause is auto antibody mediated rapid destruction of RBCs. Detection of these autoantibodies to erythrocytes is of fundamental importance for diagnosis. A number of methodologies have been tried for detection & evaluation of these autoantibodies. Demonstration of a positive Direct Antiglobulin Test (DAT) against these autoantibodies is an important serological assay in the diagnosis of auto immune hemolytic anemia (AIHA). This test is also considered as pathognomonic of immune-mediated hemolysis. This routinely used direct antiglobulin test (DAT) has the disadvantage of low sensitivity and does not detect low levels of red cell auto antibodies leading sometimes to false negative results. Flow cytometry can effectively diagnose such patients of auto immune hemolytic anemia with low levels of autoantibodies. Role of flow cytometry in the diagnosis of several non-malignant haematological disorders is being explored & present study has been conducted with the same objective.

This study was conducted with the following aims and objectives:

•To assess the utility of flow-cytometry (FCM) in the diagnosis of suspected AIHA patients.

•Compare the sensitivity of flow-cytometry (FCM) with Direct Antiglobulin Test (DAT) by Gel-card Test (GT).

•To assess the positivity in DAT negative cases by flow-cytometry in suspected AIHA cases.

This was a prospective study, carried out in Haematology Deptt of All India Institute of Medical Sciences, where patients with suspected auto immune hemolytic anemia (AIHA) were studied during two years period. Blood samples of suspected patients of AIHA were tested by Gel Card Test as well as by Flow cytometry for detection of RBC bound IgG.

A total of 50 patients with suspected diagnosis of auto immune hemolytic anemia (AIHA) were studied by flow-cytometry as well as by Gel card test (GT) for detection of RBC bound IgG. Out of these 50 cases, 41 cases have turned out to be positive and 9 were negative by flow-cytometry. The quantification of positivity by flow-cytometry was obtained by calculating percentage fluorescence. The same 50 cases were also tested by Gel card test (GT). By Gel card test, out of 50 cases, 34 were positive & 16 were negative. Therefore, there were 7 cases which were negative for RBC bound IgG by Gel card test and these were positive by flow-cytometry.

The flow cytometry figures of these cases will be shown & discussed in the presentation.

Flow-cytometry is a reliable and sensitive method of detecting RBC-bound IgG antibodies for the diagnosis of auto immune hemolytic anemia. This can be used as a new routine diagnostic technique for auto immune hemolytic anemia.

No relevant conflicts of interest to declare.