ABSTRACT
Soluble HLA (sHLA) are potential tumour markers released in order to counter immune surveillance. sHLA-class II is less known especially in acute lymphoblastic leukaemia (ALL). This study aimed to investigate soluble, surface and allelic expression of HLA Class II (sHLA-DR) in B-cell ALL patients and compare with soluble expression in normal individuals. A sandwich enzyme-linked immunosorbent assay (ELISA) was developed to measure soluble HLA-DRB1 in plasma. Flow cytometric analysis was performed to determine median fluorescence intensity in HLA-DR surface expression. HLA-DNA typing by polymerase chain reaction, sequence specific oligonucleotides, PCRSSO was performed to determine HLA-DRB1 type in ALL samples. Results showed sHLA-DRB1 (mean±SEM) was significantly increased (p=0.001) in plasma of ALL patients (0.260 ±0.057 μg/mL; n=30) compared to healthy controls (0.051 ± 0.007µg/mL; n=31) of Malay ethnicity. However, these levels did not correlate with percentage or median fluorescence intensity of HLA-DR expressed on leukemia blasts (CD19+CD34 ± CD45(lo)HLA-DR+) or in the normal B cell population (CD19+CD34- CD45(hi)HLA-DR+) of patients. No significant difference was observed in gender (male/female) or age (paediatric/adult). Only a trend in reduced sHLA was observed in patients carrying HLA-DR04. These results have to be validated with a larger number of samples.
ABSTRACT
BACKGROUND: In Malaysia, acute leukemia is the most common cancer among children below the age of 15. A case-control study was here conducted for cases from the Klang Valley, Malaysia, who received treatment at the National University of Malaysia Hospital (HUKM) and Kuala Lumpur General Hospital (GHKL). The main objective was to determine any association with environmental factors. METHODS: Case subjects were children aged below 15 years and diagnosed with acute leukemia in HUKM and GHKL between January 1, 2001 and May 30, 2007. Control subjects were children aged below 15 years who were diagnosed with any non-cancerous acute illnesses in these hospitals. A total of 128 case subjects and 128 control subjects were enrolled in this study. The information was collected using a structured questionnaire and a global positioning system (GPS) device. All factors were analyzed using unmatched logistic regression. RESULTS: The analysis showed that the occurrence of acute leukemia among children was strongly determined by the following factors: family income (odds ratio (OR) 0.19, 95% confidence interval (CI): 0.09-0.42), father with higher social contact (OR 7.61, 95% CI: 3.78-15.4), number of elder siblings (OR 0.36, 95% CI: 0.18-0.77), father who smokes (OR 2.78, 95% CI: 1.49-5.16), and the distance of the house from a power line (OR 2.30, 95% CI: 1.18-4.49). CONCLUSIONS: Some socioeconomic, demographic, and environmental factors are strong predictors of the occurrence of acute leukemia among children in Klang Valley, Malaysia. In terms of environmental factors, it is recommended that future housing areas should be developed at least 200 m away from power lines.
ABSTRACT
The aims of this study were to determine the types of cancers and hematological disorders in patients attending a pediatric hematology-oncology clinic. This was a prospective study at the Pediatric Institute, General Hospital Kuala Lumpur, Malaysia from June 2005-November 2006. During the 18-month study, 803 patients attended the clinic, 730 had oncological problems and 73 had hematological problems. The age range was from 2 months to 28 years (median 6 years). The patients were Malay (66%), Chinese (23%), Indian (10%) and other races (1%). Of the oncological patients, 51% had either leukemia (n=293) or lymphoma (n=77). The other most common diagnoses were retinoblastoma, followed by Wilm's tumor and germ cell tumors. Six patients (0.8%) developed a second malignant neoplasm. Of the hematological patients, 60% had platelet disorders, most commonly chronic immune thrombocytopenic purpura. Twenty-four per cent had bone marrow failure and 16% had red cell disorders.