Spinelli O, Giussani U, Borleri G, Lazzari M, Michelato A, Dotti G, Barbui T, Rambaldi A
Divisione di Ematologia e Centro Trasfusionale, Ospedali Riuniti di Bergamo, Italy.
Haematologica. 2000 Nov;85(11):1153-7.
Leukemia relapse occurring in donor cells after allogeneic hematopoietic stem cell transplantation has been reported in rare cases. Cytogenetic analysis and molecular probing of variable number of tandem repeats (VNTRs) have been used to confirm this unusual event in the few cases so far reported in the literature. The aim of this study was to demonstrate that extensive molecular characterization of leukemic cells at diagnosis and relapse may be necessary to avoid many technical pitfalls possibly leading to an erroneous diagnosis of leukemia relapse in donor cells after allogeneic transplantation.
We report the case of a 49- year old man who received an allogeneic transplantation from his HLA-identical sister because of BCR-ABL+ acute lymphoblastic leukemia (ALL). After having achieved complete hematologic and molecular remission, two years later an overt leukemia relapse occurred with cytogenetic findings suggesting a leukemia relapse in donor cells. The donor or patient origin of leukemic cells at relapse was further investigated by fluorescence in situ hybridization (FISH) karyotyping, reverse transcription (RT) polymerase chain reaction (PCR) analysis of BCR-ABL chimeric transcripts, PCR amplification of several VNTRs and the Y chromosome-specific DYS14 sequence and finally by amplification, cloning and sequencing of the CDRIII region of the immunoglobulin heavy chain (IgH) gene.
At the time of relapse, conventional and FISH karyotyping revealed the presence of a Phl+ chromosome and a female karyotype in all the 25 metaphases analyzed and PCR amplification of the Y chromosome-specific DYS14 sequence was negative. Moreover, the molecular evaluation of hematopoietic chimerism performed by the NZ-22 VNTR allowed us to demonstrate that at the time of relapse, a consistent proportion of hematopoietic cells was of donor origin. However, the molecular cloning and sequencing of the CDRIII region of the immunoglobuin heavy chain (IgH) gene rearrangement in leukemic blasts at diagnosis and relapse demonstrated their identity thus formally proving the patient origin of both leukemic clones.
While the simplest interpretation of the apparent female karyotype at relapse is the consequence of a loss of the Y chromosome which in leukemic blasts took place along with duplication of an X-chromosome, this case strongly emphasizes the need for accurate and extensive molecular characterization to prove the donor origin of a leukemia relapse after allogeneic transplantation.
异基因造血干细胞移植后供体细胞中发生白血病复发的情况已有罕见报道。细胞遗传学分析和可变串联重复序列（VNTR）的分子探测已被用于在文献中迄今报道的少数病例中证实这一异常事件。本研究的目的是证明在诊断和复发时对白血病细胞进行广泛的分子特征分析可能是必要的，以避免许多可能导致异基因移植后供体细胞中白血病复发错误诊断的技术陷阱。
我们报告了一名49岁男性的病例，他因BCR-ABL+急性淋巴细胞白血病（ALL）接受了来自其 HLA 相同姐妹的异基因移植。在实现完全血液学和分子缓解后，两年后出现明显的白血病复发，细胞遗传学结果提示供体细胞白血病复发。通过荧光原位杂交（FISH）核型分析、BCR-ABL嵌合转录本的逆转录（RT）聚合酶链反应（PCR）分析、多个VNTR以及Y染色体特异性DYS14序列的PCR扩增，最后通过免疫球蛋白重链（IgH）基因CDRIII区域的扩增、克隆和测序，进一步研究复发时白血病细胞的供体或患者来源。
复发时，常规和FISH核型分析在所有分析的25个中期相中均显示存在Phl+染色体和女性核型，Y染色体特异性DYS14序列的PCR扩增为阴性。此外，通过NZ-22 VNTR进行的造血嵌合体分子评估使我们能够证明复发时，相当比例的造血细胞来自供体。然而，诊断和复发时白血病母细胞中免疫球蛋白重链（IgH）基因重排的CDRIII区域的分子克隆和测序显示它们是相同的，从而正式证明两个白血病克隆均来自患者。
虽然复发时明显的女性核型最简单的解释是Y染色体丢失的结果，而在白血病母细胞中Y染色体丢失与X染色体复制同时发生，但该病例强烈强调了进行准确和广泛的分子特征分析以证明异基因移植后白血病复发的供体来源的必要性。
