Relation of haemolytic anaemia and erythrocyte-bound IgG in alpha- and beta-thalassaemic syndromes.

There has been evidence that IgG-mediated phagocytosis plays some part in destruction of erythroid cells and subsequent anaemia in thalassaemia. In this study using direct immunofluorescence and flow cytometry, erythrocyte-bound IgG was studied in 53 and 33 beta-thal/Hb E and Hb H patients, respectively. The mean percentages of IgG-positive erythrocytes in both nonsplenectomized (4.4%) and splenectomized (24%) beta-thal/Hb E patients were significantly higher than that in normal subjects (1.0%); p < 0.05 and < 0.001, respectively. Splenectomized beta-thal/Hb E patients had significantly higher percentages of IgG-positive erythrocytes than the nonsplenectomized patients (p < 0.001). The mean percentages of IgG-positive erythrocytes in Hb H patients were comparable to those from normal controls. However, patients with alpha-thal 1/Hb CS had significantly higher IgG-positive erythrocytes than those with alpha-thal 1/alpha-thal 2 (p = 0.008). Splenectomized Hb H patients also had higher IgG-positive erythrocytes than nonsplenectomized Hb H patients (p < 0.039). During haemolytic crisis in some Hb H patients, high percentages of IgG-positive erythrocytes were also demonstrated. This study demonstrates the presence of increased IgG on erythrocytes in patients with beta-thal/Hb E and in those with Hb H disease following splenectomy or in haemolytic crisis.