OBJECTIVETo probe into the occurrence rates of the effective antigen combinations which were used to detect the minimal residual disease (MRD) by flow cytometry in childhood B-lineage acute lymphoblastic leukemia (B-ALL), as well as the relationship between clinical-biologic factors and different combinations.

METHODSAmong the 327 B-ALL children enrolled in our study, 289 cases were identified with at least one antigen combination as MRD marker. Their bone marrow samples were monitored by using 9 combinations with 4 antigens each, analyzed the occurrence rates and compared them with international reports. Also the differences in the distribution of each antibody combination in the different clinical-biologic groups were compared by the chi-square test and Fisher's exact test.

RESULTS(1) Totally 327 cases of childhood B-ALL were screened for antibody combinations of interest and 88.4 percent of them (289 cases) were identified with effective antibody combinations. (2) The occurrence frequencies of antigen combinations were different. The highest frequency was seen with TdT/CD10/CD34/CD19 combination which was 70.59 percent. Expressions of antigen combinations in Chinese children were different from those in western countries. (3) Some antibody combinations presented different frequency among different clinical groups. CD38/CD10/CD34/CD19 was expressed more often in samples of relapsed patients (P = 0.045). CD66c/CD10/CD34/CD19 expression was significantly higher in BCR/ABL positive group (P = 0.037) and relapsed patients group (P = 0.047). TdT/CD10/CD34/CD19 was expressed more in MLL-AF4 negative group (P = 0.005) and Prednisone Good Response group (P = 0.002). CD58/CD10/CD34/CD19 was correlated with low relapse rate (P = 0.032).

CONCLUSION(1) The coverage rate of 9 antigen combinations in our study was 88.4%. The occurrences of frequency of different antibody combinations in B-ALL were different, and also different from that of western countries. The occurrence frequencies of antibody combinations CD21/CD10/CD34/CD19, CD22/CD10/CD34/CD19, CD10/CD56/CD34/-CD19 and TdT/Cu/CD34/CD19 were lower than those of the western report, while CD38/CD10/-CD34/CD19, CD45/CD19/CD10/CD34, CD58/CD10/CD34/CD19 and CD66c/CD10/CD34/CD19 were similar to those of the reports from western countries. (2) TdT/CD10/CD34/CD19 may work as a simplified method to detect MRD in Chinese population. (3) The occurrence frequency of CD38/CD10/CD34/CD19, CD45/CD19/CD10/CD34, CD58/CD10/CD34/CD19, TdT/CD10/CD34/CD19 could be effective remediation and evidence to evaluate the remission quality and guide the therapy, especially for those with no original MRD marker record. (4) CD58/CD10/CD34/CD19 and TdT/CD10/CD34/CD19 may correlate with good prognosis, but CD66c/CD10/CD34/CD19 and CD38/CD10/CD34/CD19 may predict poor prognosis. These results might contribute to individual risk evaluation and guide the therapy selection.