CD123在急性早幼粒细胞白血病微小残留病检测中的应用

为了探讨CD123联合应用其它免疫标志检测急性早幼粒细胞白血病(APL)中微小残留病(MRD)的作用及意义,采用四色流式细胞术(FCM)分析了186例初诊APL患者的免疫表型特点及20例正常骨髓中与APL细胞表型相同的细胞所占比例,并应用以CD34/CD117/CD123/HLA-DR为主的4色抗体组合对172份标本进行MRD检测并与实时定量PCR结果相比较。172份标本包括19例连续随访APL患者的116份骨髓或外周血标本和47例距初诊3个月至2年不等的非连续随访患者的56份骨髓标本,其中形态学完全缓解(CR)后117份,CR前55份标本。对18份标本同时加做抗体组合CD9/CD117/CD34/CD33检测。结果表明:初诊APL患者除高表达CD9、CD33、CD117和低表达CD34、HLA-DR外,CD123的阳性表达率为100%(30/30);正常骨髓中CD117+CD34-CD123+HLA-DR-细胞和CD117+CD34-CD9+CD33+细胞在有核细胞中的比例分别为(0.066±0.012)%和(0.089±0·066)%,与APL患者相比相差4个对数级;随访期内,19例患者全部获得形态学CR,中位时间为4周(3-6周),13例FCM结果转阴的中位时间为7.5周(5-11周),11例PCR结果转阴的中位时间为8周(5-12周);形态学CR后随访的117份标本中41份FCM检测MRD呈阳性,8份标本CD117+CD34-CD123+HLA-DR-细胞比例>5%,中位值为9.02%(5.26%-18.14%),33份标本CD117+CD34-CD123+HLA-DR-细胞比例<5%,中位值为0·48%(0.02%-4.70%);CD117+CD34-细胞中CD123+HLA-DR-细胞的中位相对比例分别为86.77%(63.29%-92.62%)和63.59%(15.11%-98.36%);FCM与PCR同时检测MRD结果显示,FCM(+)标本中95.9%(93/97)PCR为阳性,FCM的假阳性率为4.1%(4/97),PCR的假阴性率为8.75%(7/93)。FCMMRD(-)标本中,92%(69/75)PCR阴性,8%(6/75)为PCR阳性。连续随访的116份标本和形态学CR后的117份标本显示,CD117+CD34-CD123+HLA-DR-细胞比例与实时定量PCR检测的mRNA水平基本一致,两者均有一定的相关性(r=0.824,P<0.001和r=0.754,P<0.001)。结论:应用CD34/CD117/CD123/HLA-DR为主的2组4色抗体组合检测APL患者中的MRD简单可行,可与PCR检测相互补充。

Application of CD123 in Detection of Minimal Residual Disease in Acute Promyelocytic Leukemia

The study was aimed to investigate the role and significance of CD123 with other immunological markers in detecting minimal residual disease (MRD) of APL patients. The immunophenotypes of 186 newly diagnosed APL patients and the percentages of cells identical with APL cell immunophenotypes in 20 normal bone marrow samples were analyzed using four-color flow cytometry. MRD in 172 specimens were monitored by mainly using CD34/CD117/CD123/HLA-DR four-color antibody panels, meanwhile 18 specimens were analyzed with the second antibody combination: CD9/CD117/CD34/CD33, simultaneously and the results were compared with real-time PCR. One hundred and sixteen of 172 bone marrow (BM) or peripheral blood (PB) specimens were from follow-up 19 newly diagnosed APL patients and the rest 56 samples were from 47 patients treated 3 to 24 months later. Among them, 117 samples and 55 samples were collected after achieving morphologic complete remission (mCR) and before achieving mCR respectively. The results of immunophenotyping demonstrated that except CD9, CD33 and CD117 were high-expressed and CD34 and HLA-DR were rarely expressed, the CD123 was expressed in 30/30 (100%) APL patients. The percentages of CD117(+)CD34(-)CD123(+)HLA-DR(-) and CD117(+)CD34(-)CD9(+)CD33(+) cells in nucleated cells were 0.066% +/- 0.012% and 0.089% +/- 0.066% in 20 normal bone marrow samples. The median time of achieving morphology complete remission in 19 APL patients was 4 weeks (3 - 6 weeks). The median time of FCM and PCR results turned to be negative in 13 APL patients was 7.5 weeks (5 - 11) and the median time of PCR results turned to be negative in 11 APL patients was 8 weeks (5 - 12). 41/117 (35.04%) samples were MRD positive by FCM after achieving mCR. The ratio of CD117(+)CD34(-)CD123(+)HLA-DR(-) cells was < 5% in 33 specimens, but > 5% in another 8 specimens, their median percentages of CD117(+)CD34(-)CD123(+)HLA-DR(-) cells were 0.48% (range 0.02% - 4.70%) and 9.02% (range 5.26% - 18.14%) respectively. The median relative percentages of CD123(+)HLA-DR(-) cells in CD117(+)CD34(-) population were 63.59% (range 15.11% - 98.36%) and 86.77% (range 63.29% - 92.62%) respectively. In FCM MRD positive samples, 95.9% (93/97) were PCR positive, the false positive rate of FCM and the false negative rate of PCR were 4.1% (4/97) and 8.75% (7/93) respectively. In FCM negative samples, 92% (69/75) were PCR negative and 8% (6/75) were PCR positive. The percentages of CD117(+)CD34(-)CD123(+)HLA-DR(-) cells in 116 consecutive specimens and 117 specimens of mCR were related to PML/RARalpha quantified by real-time PCR (r = 0.824, P < 0.001 and r = 0.754, P < 0.001 respectively). It is concluded that the detection of APL patients by means of two sets of antibody panels is simple and suitable, which is complementary to PCR in monitoring MRD of APL patients.