INTRODUCTIONThalassaemia is one of the major public health problems in Malaysia. Regular monthly blood transfusion remains the main treatment for severe thalassaemia patients. One of the complications of blood transfusion is the formation by the recipients of alloantibodies and autoantibodies against red blood cell (RBC) antigen. The purpose of this study was to determine the prevalence of RBC autoantibodies among multiple-transfused thalassaemic patients in our institution and factors that contribute to its development.

METHODSA prospective study was conducted in Haematology Laboratory, Hospital Universiti Sains Malaysia between January 2004 and December 2004. A total of 63 thalassaemia patients, who received regular blood transfusion were included in this study. Clinical and serological data were collected and analysed prospectively. Blood samples were subjected to standard blood bank procedures for screening of antibodies and their subsequent identification using reagent of Diamed-ID Gel microtyping system.

RESULTSThere were 49 (77.8 percent) patients with Hb E/beta-thalassaemia, ten (15.9 percent) beta-thalassaemia major, three (4.7 percent) Hb H Constant Spring and one (1.6 percent) Hb H disease. Only one (1.6 percent) patient had autoantibodies. There were no statistical associations found between the formation of autoantibodies with age at the start of transfusion, number of packed cell transfused and splenectomy.

CONCLUSIONOur data showed a low autoimmunisation rate in multiple-transfused thalassaemia patients in our hospital.

Adolescent ; Adult ; Autoantibodies ; blood ; Blood Group Antigens ; immunology ; Child ; Child, Preschool ; Coombs Test ; Erythrocytes ; immunology ; Female ; Hospitals, University ; Humans ; Malaysia ; Male ; Middle Aged ; Prospective Studies ; Thalassemia ; blood ; Transfusion Reaction

Freeze drying is a dehydration method to dry bone under freezing environment, enabling removal of water with no or minimial effects on bone strength and durability. Larger size bones obviously require longer freeze drying time to reduce water content to the required level for long term storage at room temperature. For small size bone cubes or chips, it is a normal practice to pool cortical and cancellous bones for freeze drying. The study was aimed at determining if different type of bones of the same size influence the drying time. Human bone cubes of 10 mm x 10 mm x 10 mm were prepared from cortical bone of tibiae and cancellous bone from femoral heads. The bone cubes were freeze dried to reduce water content to less than 6%. Moisture content was monitored using gravimetric method.Weight and density of cortical bone were significantly higher than cancellous bone despite of having similar small size (p<0.05). Cortical bones (density 2.05 ± 0.35 g/cm3) with initial water content of 10.93% required 5 hours to freeze dry, while cancellous bone cubes (density 0.72 ± 0.44 g/cm3) with initial water content of 78.95% required only 1.87 hours. This study confirmed that the structure hence density of human bone cubes determine the freeze drying time. Therefore in the standard operating procedure for freeze drying of bone allograft cubes, high density cortical bone cubes and low density cancellous bone cubes must be freeze dried separately despite being of similar small size