| Recent studies have found that ABO blood group antigen was closely related to the onset and development of some tumors. More and more attention has been paid to the decrease of A/B blood group antigens caused by some tumors. It was known that the abnormal expression of A/B blood group antigens correlated to the biological behaviors of malignant tumors, such as the degree of malignancy, metastasis and prognosis. It had been reported more times in recent years about the lower expression of the A/B blood antigen on the surface of RBC from leukemia patients, but the sutdies such as the investigation from large samples, summary about regulation and study on the correlation were absent. This paper studied the correlation between blood group and leukemia disease by means of detecting the change of ABH blood group antigen on the surface of human RBC from hematologic disease patients and from healthy individuals as well as analyzing the diversity regular. The expression of ABH antigen about all samples were studied by FCS and Laser Scanning Confocal Microscopy after the healthy individuals and blood disease patients were divided into homozygote and heterozygote group by gene typing method. The amount of A/B antigens but H antigens on the surface of red cells of leukemia patients had significant change compared to the healthy individuals and no changed of the expression of A or B antigen. It explained that the reason of A/B antigen changed from leukemia patients was the decrease in the synthesis of A/B antigen, but not H antigen. Statistics analysis showed that there was close correlation between the depression of A/B antigen and the degree of malignant in leukemia, but there was no significant difference about the absent degree between A antigen and B antigen at same malignant blood disease (P>0.05). The expression of ABO gene about the healthy individuals and leukemia patients was detected by RT-PCR method for approaching the reason about lower expression of A/B blood group antigen in leukemia patients. The expression of ABO mRNA reduced in various extents as a decrease degree of ALL, CML and AML by detecting and contrasting the ABO mRNA from leukemia patients and corresponded with the regulation of A/B antigens decrease degree. It was showed that there was little difference about the expression of ABO mRNA at same leukemia with different ABO blood type by statistics analysis, while no statistics difference at each blood type (P<0.001). The conclusion could be drew that the low expression of ABO blood group antigen on the RBC surface of leukemia patients correlated with low expression of ABO glycosyltransferase. The expression of ABO glycosyltransferase was correlated with the regulation of gene expression. As the binding site with the RNA polymerase, the promoter was the location of transcription initiation, playing a key role in gene expressing and synthesis of protein in regulation of gene expression. The promoter of ABO gene was studied in this paper for researching the correlation between the absent of A/B antigen and the change of promoter including gene mutation and methylation in leukemia patients. The regulation of methylation site at promoter in leukemia patients was also studied. Comparing the sequence of blood disease patients to that of healthy individual, it showed that CpG island's sequences of ABO gene promoter were highly identical and didn't occur any mutation, it suggested that the CpG islands on the promoter of ABO gene was highly conservative. Methylated sits were found at CpG islands on ABO gene promoter from leukemia patients but healthy individuals after modified DNA with bisulfite. The results indicated that methylation of CpG islands in the promoter of ABO gene may be the reason of A/B antigens underexpression in leukemia. Otherwise, it was also found that the C residues at the position of -102, -101, -100, -99 and -97 were methylated at the ABO gene promoter of leukemia patients and methylation at these sits may be the specific characteristic of leukemia as a significant molecule marker at early stage diagnosis to leukemia. The methylation amplified production of ABO gene was connected to vector and transfected to E coli. Clones were chosen for sequencing. It indicated that there was a methylation site at C–102 site from the sequencing result, as well as polymorphism of methylation was found at promoter of ABO gene from leukemia patients. The MSP-PCR aimed to detect C–102 site whether methylation or not could distinguish leukemia patients from healthy individuals and anaemic patients for the DNA form leukemia patients but the healthy individuals and aplastic anemia patients could be amplified by M primer after modified with bisulfite, so that it may be used as a marker at differential diagnosis of leukemia in the early stage. In recent years, haemopoietic stem cell transplant has been widely used in leukemia medical treatment. ABO blood group is intimate correlated with immunological rejection, although only HLA not ABO blood group compatible is requirement in haemopoietic stem cell transplant. The tests which to evaluate the effectiveness of hemopoietic stem cell translation were blood conversional test and STR test. It can't evaluate the effect well because of the limitation of the tests. The possibility to evaluate the effectiveness by detecting the methylation of ABO gene promoter and expression of ABO mRNA for a better way to real-time evaluation was approached based on the study of correlation between ABO blood group and malignant blood disease. 4 leukemia patients which had transplanted haemopoietic stem cell for treatment were studied. The effectiveness of transplant was observed by detecting the expression of ABO mRNA and C–102 site methylation at the ABO gene promoter. No C–102 site methylation were found in those patients by MSP-PCR, it explained that no recurrence of leukemia was occur after transplant. The expression of ABO mRNA were in a changed process after transplant in leukemia, correspond to the change of patient's condition and clinical symptom, for this reason, dynamic and real time state for evaluating effectiveness of transplant could be obtained by detecting the expression of ABO mRNA. It needs to explain that all we found was just a phenomenon because of the limit case, persuasive evidence must base on penetrating study.This study detected and summarized the regulation about the expression of ABO blood antigen and ABO mRNA. It was found that the reason which caused the depressed expression of ABO gene in leukemia patients was methylation at promoter of ABO gene. A specific methylation site was found which maybe have diagnostic value. The expression mechanism of ABO gene in leukemia patients was researched from protein to RNA and DNA. Based on the study, it proposed that the effectiveness of hemopoietic stem cell translation could be evaluated by MSP-PCR and detecting the expression of ABO gene while no paper mentions this way. The expression of ABO blood group still needs to study furthermore, whether or not correlated with proceeding and prognosis of leukemia. It may be used in the early detection, diagnosis, intervention and prognosis of leukemia by studying the expression of the ABO blood group antigen and relative gene in leukemia. |
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