Bachir Fatima, Bennani Sanae, Lahjouji Ali, Cherkaoui Siham, Harif M'hamed, Khattab Mohamed, Nassereddine Ilham, Zafad Saadia, El Aouad Rajae
Laboratoire de cytométrie en flux, Institut National d'Hygiène, Rabat, Morocco.
Int J Pediatr. 2009;2009:674801. doi: 10.1155/2009/674801. Epub 2009 Jul 19.
We present the incidence and the immunologic characteristics of acute lymphoblastic leukemia (ALL) subsets in Moroccan children. We studied 279 unselected patients below the age of 18 years with newly diagnosed ALL. Cases were classified according to immunophenotype: 216 (77.42%) precursor B-cell phenotype (pB-cell), mature B-cell in 4 (1.43%), and T-cell in 59 (21.15%) cases. The subclassification using the CD10 antibody revealed 197 cases pB-ALL CD10+ (91.2%) and 9 cases T-ALL CD10+ (19.2%). The age distribution showed a peak in incidence between 3 and 5 years among the pB-cell ALLs subtype. There was a significantly higher frequency of males in the T-ALL subset (M/F ratio: 2.93 : 1) and more females in the T-ALL CD10+ subset when compared with the T-ALL CD10- subset. All tested pB-cell-lineage ALLs expressed CD19, CD79a, and surface CD22, terminal deoxynucleotidyl transferase (TdT) was detectable in 89.9% of cases, and cells in 74.1% of cases express CD34. All tested T-lineage ALL cells have surface CD7 and cytoplasmic CD3 (cCD3) antigens, CD5 was found in 98.2% cases, and 70.5% express TdT. CD1a, surface CD3 (sCD3), and CD4 are detected in more than 80% of cases; this frequency is higher than the 45% generally observed. Myeloid antigens occur more frequently and were expressed in 124 (57.4%) of pB-cell-ALL cases and 20 (33.9%) of T-cell ALL cases. Our results show that the distribution of ALLs in Moroccan children is similar with the general distribution pattern in developed countries except for the high frequency of T-ALL phenotype. The phenotypic profiles of our patients are close to those reported in literature for B-lineage ALLs; for the T-cell ALL subgroup, the blast cells express more CD1a, surface CD3, and CD4 while expressing less TdT. The high frequency of CD1a expression resulted in an excess of the common thymocyte subtype.
我们呈现了摩洛哥儿童急性淋巴细胞白血病（ALL）各亚型的发病率及免疫特征。我们研究了279例年龄在18岁以下新诊断为ALL的未经过挑选的患者。病例根据免疫表型分类：216例（77.42%）为前体B细胞表型（pB细胞），4例（1.43%）为成熟B细胞，59例（21.15%）为T细胞。使用CD10抗体进行的亚分类显示，197例pB-ALL CD10+（91.2%）和9例T-ALL CD10+（19.2%）。年龄分布显示，pB细胞ALL亚型的发病率在3至5岁之间出现峰值。T-ALL亚组中男性的频率显著更高（男/女比例：2.93 : 1），与T-ALL CD10-亚组相比，T-ALL CD10+亚组中的女性更多。所有检测的pB细胞系ALL均表达CD19、CD79a和表面CD22，89.9%的病例可检测到末端脱氧核苷酸转移酶（TdT），74.1%的病例细胞表达CD34。所有检测的T细胞系ALL细胞均有表面CD7和细胞质CD3（cCD3）抗原，98.2%的病例中发现CD5，70.5%表达TdT。超过80%的病例检测到CD1a、表面CD3（sCD3）和CD4；该频率高于通常观察到的45%。髓系抗原出现频率更高，在124例（57.4%）pB细胞ALL病例和20例（33.9%）T细胞ALL病例中表达。我们的结果表明，摩洛哥儿童ALL的分布与发达国家的总体分布模式相似，但T-ALL表型的频率较高。我们患者的表型特征与文献报道的B系ALL接近；对于T细胞ALL亚组，原始细胞表达更多的CD1a、表面CD3和CD4，而表达较少的TdT。CD1a表达的高频率导致普通胸腺细胞亚型过多。
