Thrombotic thrombocytopenic purpura: three peripartum cases and diagnostic challenges.

Thrombotic thrombocytopenic purpura (TTP) is a medical emergency characterized by occlusive microangiopathy due to intravascular platelet aggregation. This event results in damage to the red blood cells (RBCs) known as microangiopathic hemolytic anemia (MAHA). Schistocytes are circulating fragments of damaged RBCs that have different morphological features including keratocytes, helmet cells, and spherocytes. It is critical to report even a small number of these abnormal RBCs in the peripheral blood and to be alert for the possible diagnosis of TTP, especially in unexplained anemia and thrombocytopenia. The application of pentad criteria in the diagnosis has been reviewed, and the challenges still remained on the hematologic evidence of this disorder. In the 3 cases discussed here, the red cell morphological diagnosis gave an impact on TTP diagnosis, but overdiagnosis might be encountered in obstetrical patients due to nonspecific diagnostic criteria.

Red cell phenotyping of blood from donors at the National blood center of Malaysia.

BACKGROUND: Human blood groups are polymorphic and inherited integral structures of the red cell membrane. More than 300 red cell antigens have been identified and further categorized into 30 major discrete systems. Their distribution varies in different communities and ethnic groups. AIMS: This work was set to determine the prevalence of red cell phenotypes in donors from the major ethnic groups in Malaysia, namely, Malays, Chinese, and Indians. MATERIALS AND METHODS: The work utilized the dextran acrylamide gel technique in which four types of gel cards were used to identify the blood groups of 594 subjects collected at the National Blood Transfusion Centre, Malaysia. RESULTS: Blood group O and CDe/CDe (R1R1) were the most common in all ethnic groups. The cde/cde (rr) was more prevalent amongst Indians. The rare phenotypes found were cDE/cDE(R2R2) and cDE/CDE(R2Rz). With the Lewis system, the distribution of Le(a-b+) was similar among the ethnic groups. The rarest phenotype Fy(a-b-) was discovered in two donors. Jk(a-b-) was found in seven Malays and in two Indians. In the MNSs system, MN was common in Malays and Chinese, while the MM was more common among Indians. The rare SS was found in 19 donors. Malay and Chinese subjects had high P1 Negative blood but Indians showed high P1 positive blood. Within the Kell System, the very rare KK type was found in six subjects. CONCLUSIONS: The results obtained serve as an established database for the distribution of red cell phenotypes based on the blood group systems of donors from the major ethnic groups in Malaysia.

Prevalence and specificities of red cell alloantibodies among blood recipients in the Malaysian state of Kelantan.

BACKGROUND: Red blood cell (RBC) alloantibodies may be formed following exposure to RBC antigens. In most cases, the alloimmunization develops during pregnancy or from previous blood transfusions. The RBC antigens and their alloantibodies vary among different human populations and ethnic groups, and they do have a clinical significance for their adverse immunological reactions. AIMS: This study aimed at studying the prevalence of RBC alloantibodies at the Blood Transfusion Unit of Hospital Raja Perempuan Zainab II in Kota Bharu, Malaysia. PATIENTS AND METHODS: A cross-sectional study was performed utilizing data obtained in the years 2007 and 2008. Data of antibody screening tests from 5719 patients were examined. RESULTS AND DISCUSSION: The overall prevalence of alloimmunization was 65 (1.13%). The majority of these had a single alloantibody (76.9%), whereas the remaining 23.1% had multiple antibodies. The anti-E antibody comprised the most common alloantibody (24.6%) followed by the anti-Lewis (a) antibodies (18.5%) and the anti-M antibody (13.8%). There were more female recipients than males. CONCLUSIONS: It was concluded that the findings of this work have been comparable with other published works, and that the main factors associated with alloantibody formation were multiple transfusions and pregnancies. The study also emphasizes the necessity for carrying out immunohematology studies prior to every blood transfusion especially in cases that require multiple transfusions for a long period of time such as in thalassemia patients.

The co-existence of pure red cell aplasia and autoimmune haemolytic anaemia in a child with malignant lymphoma.

The association between pure red cell aplasia (PRCA) and autoimmune haemolytic anaemia (AIHA) has rarely been reported. PRCA represents an isolated process, characterized by normochromic, normocytic anaemia, reticulocytopenia and erythroid hypoplasia in the bone marrow, and may be attributable to infection with Parvo virus B19. AIHA is a condition in which peripheral red blood cell destruction is induced by the presence of autoantibodies. However, the co-existence of these conditions is very rare, since only few cases of PRCA and AIHA associated with malignant lymphoma (ML) were reported. A case of PRCA and AIHA was detected and described, for the first time in Malaysia, in a 10-year-old child suffering from non-Hodgkin lymphoma from the Department of Haematology, Universiti Sains Malaysia. Following the induction course of chemotherapy, the patient turned anaemic, with tendency for red cell clumping, reticulocytopenia and anisocytosis. AIHA was suspected in spite of the weak Coomb reaction obtained. The bone marrow aspirate revealed the presence of giant pronormoblasts, suggesting PRCA. Serological tests for Parvo virus and other viruses were negative.