Kpa, (Penney), a new antigen in the Kell blood group system

The Kell blood group system has now been complicated by the finding of a new antigen, Penney (Kp^a), and possibly two others (Kp^b and Kp^c). Kp^a is found in about 2 per cent of Bostonians. It is of minor importance clinically because of its infrequency, but has considerable importance in blood typing tests for exclusion of paternity.

Résumé

Un nouvel antigène appartenant au système Kell et désigné Penney (Kp^a) a été découvert, et l'existence de deux autres antigènes (Kp^b et Kp^c) semble possible. Kp^a se trouve chez environ 2% des habitants de Boston. Le nouvel antigène est, au point de vue clinique, d'intérêt médiocre à cause de sa rareté, mais il est important dans les tests sérologiques pour l'exclusion de la paternité

Zusammenfassung

Ein neues, dem Kell-System zugehöriges Blutgruppenantigen Penney (Kp^a) wird beschrieben. Nebst K, k und Kp^a enthält das Kell-System wahrscheinlich noch zwei weitere Antigene, die vorlaufig als Kp^b und Kp^c bezeichnet wurden. Die Häufigkeit von Kp^a beträgt in Boston 2 %. Angesichts der relativen Seltenheit dieses Antigens ist seine klinische Bedeutung gering. Bei Vaterschaftsuntersuchungen hingegen ist dieses Antigen unter Umständen von erheblicher Bedeutung.     

Characterization of the blood group Kell (K1) antigen with a human monoclonal antibody

A human monoclonal anti-Kell (K1) antibody secreted by an Epstein-Barr virus (EBV)-transformed B-cell line was used for binding studies and immunopurification of the K1 blood group antigen. The 125I-labeled antibody bound to 4 to 5 x 10(3) and 2.5 to 3 x 10(3) antigenic sites on K1K1 and K1K2 erythrocytes, respectively, with an affinity constant of 5 x 10(8) mol/L-1. Immunoprecipitation analysis showed that the K1 antigen is carried by a 93 Kd glycoprotein containing several cysteine residues, and approximately six N-glycosidically linked sugar chains but no detectable O-linked sugar. A minor labeled component of 32 Kd was also immunoprecipitated from K1K1 RBCs but the 93- and 32-Kd components were absent from K2K2 and Kell null erythrocytes. Under nonreducing conditions, three bands were detected at 200 (weak), 120, and 93 Kd. We suggest that the 120-Kd component represents a heterodimer of the 93- and 32-Kd proteins covalently linked by disulfide bridge(s). The 93-Kd glycoprotein is a transmembrane component which interacts with the membrane skeleton but is distinct from band 3 as shown by one-dimensional peptide mapping. The site density of K1 antigen blood group on Gerbich-negative RBCs (Ge:-2,-3) was threefold lower than on K1K1 erythrocytes, but the qualitative properties of the 93-Kd component were not modified.     

A combination of the effects of rare genotypes at the XK and KEL blood group loci results in absence of Kell system antigens from the red blood cells

The 22 antigens of the Kell blood group system are located on a red blood cell (RBC) membrane glycoprotein that shows sequence homology with a family of metalloendopeptidases. Expression of the Kell system antigens is partially governed by XK, an X-linked gene that encodes the Kx protein; absence of Kx results in reduced Kell antigen expression. Almost total absence of Kell antigens from the RBCs of a German man with no symptoms of neuroacanthocytosis could not be due to the Kell- null phenotype, Ko, because his RBCs had very weak expression of Kx antigen and his three children were Kp(a + b+). Kell antigens were normal on the RBCs of his son but weak on those of his two daughters. An Nla III restriction fragment-length polymorphism within the KEL gene showed the Kpa/Kpa genotype in the propositus. Sequencing of his XK gene showed a single base change within the donor splice consensus sequence of intron 2. A BsaAl restriction fragment-length polymorphism showed the mutation in both of his daughters but not in his son. The extreme depression of the Kell antigens of the propositus must be due to a combination of effects, ie, homozygosity for Kpa and deficiency of Kx protein, each of which is capable of causing some degree of weakening of Kell antigens.     

3D analysis of CROMER (DAF) and a new antigen CRAG

BackgroundCromer antigens are carried on decay accelerating factor (DAF, CD55), for which the crystal structure is available. We investigated two samples with an unidentified antibody to a high prevalence antigen and evaluate the location and characteristics of amino acids associated with antigens on the CD55 by 3D modelling.Materials and methodsAntigen typing and antibody identification were by standard methods. CD55 was sequenced, and Cromer variants were generated using the protein’s crystal structure (1OK3, chain A). Antigen-associated residues and intraprotein interactions were investigated in 3D (Naccess, Protein Interactions Calculator).ResultsThe antibody in the sample from a woman of Kashmiri descent was identified as anti-IFC (anti-CROM7). Her RBCs were negative for high-prevalence Cromer antigens including IFC. CD55 sequencing revealed a silent c.147G>A (p.Leu49=) and c.148G>T (p.Glu50Ter) changes, designated CROM*01N.05. The antibody in the sample from a woman of Greek ancestry was only compatible with IFC− RBCs but her RBCs were positive for known high-prevalence Cromer antigens. CD55 sequencing found she was homozygous for c.173A>G (p.Asp58Gly). The high prevalence antigen was named CRAG (ISBT CROM18 or 021018) and the allele designated CROM*01.-18. By 3D analysis, all known antigen-associated residues, including the new CRAG antigen, were exposed at the protein surface. Interactions between antigen-associated residues within the same CD55 domains were identified.DiscussionIdentification of antibodies to high prevalence Cromer antigens can be challenging. The surface exposure of antigen-associated residues likely accounts for their immunogenicity. 3D analysis of CD55 provides insight into previous serologic observations regarding the influence of some Cromer antigens on the expression of others.     

Molecular basis of the rare gene complex, DIVa(C)-, which encodes four low-prevalence antigens in the Rh blood group system

Background Over 40 years ago, an unusual Rh phenotype denoted DIVa(C)‐ was identified in a case of fatal haemolytic disease of the newborn in the third child of Madame Nou. Her RBCs expressed a partial D, weak C and four low‐prevalence Rh antigens: Go^a (RH30), Rh33 (RH33), Riv (RH45) and FPTT (RH50). The purpose of this study was to determine the molecular basis associated with this rare DIVa(C)‐ complex. Material and Methods Blood samples were from three donors previously identified as carrying the DIVa(C)‐ haplotype. Molecular analyses were performed by standard methods. Results The three donors were heterozygous for RHD and RHD*DIVa.2, and all carried a compound hybrid allele at the RHCE locus. This hybrid RHCE allele contained exons 2 and 3 from RHD*DIVa.2 and exon 5 from RHD [RHCE*CE‐DIVa.2(2‐3)‐CE‐D(5)‐CE] and is in cis to RHD*DIVa.2. The RHCE allele on the in trans chromosome differs between the donors and is RHCE*cE in donor 1, RHCE*ce (254C, 733G) in donor 2 and RHCE*ce in donor 3. Conclusions The RHD*DIVa.2 encodes the Go^a antigen, whereas the compound hybrid allele most likely encodes Rh33, Riv and FPTT. The weakly expressed C antigen on RBCs with the DIVa(C)‐ phenotype could be encoded by exons 2 and 3 from RHD*DIVa.2 in the compound hybrid. This is the first report of RHD*DIVa.2 being involved in a hybrid gene at the RHCE locus. As only one example of anti‐Riv has been described, our molecular analysis and findings provide a tool by which to predict Riv expression.     

Distribution of Diego blood group alleles and identification of four novel mutations on exon 19 of SLC4A1 gene in the Chinese Han population by polymerase chain reaction sequence–based typing

Background The Diego blood group system plays an important role in transfusion medicine. Genotyping of DI1 and DI2 alleles is helpful for the investigation into haemolytic disease of the newborn (HDN) and for the development of rare blood group databases. Here, we set up a polymerase chain reaction sequence–based typing (PCR‐SBT) method for genotyping of Diego blood group alleles. Study Design and Methods Specific primers for exon 19 of the solute carrier family 4, anion exchanger, member1 (SLC4A1) gene were designed, and our PCR‐SBT method was established and optimized for Diego genotyping. A total of 1053 samples from the Chinese Han population and the family members of a rare proband with DI1/DI1 genotype were investigated by the PCR‐SBT method. An allele‐specific primer PCR (PCR‐ASP) was used to verify the reliability of the PCR‐SBT method. Results The frequencies of DI1 and DI2 alleles in the Chinese Han population were 0·0247 and 0·9753, respectively. Six new single nucleotide polymorphisms (SNPs) were found in the sequenced regions of the SLC4A1 gene, and four novel SNPs located in the exon 19, in which one SNP could cause an amino acid alteration of Ala858Ser on erythrocyte anion exchanger protein 1. The genotypes for Diego blood group were identical among 41 selected samples with PCR‐ASP and PCR‐SBT. Conclusion The PCR‐SBT method can be used in Diego genotyping as a substitute of serological technique when the antisera is lacking and was suitable for screening large numbers of donors in rare blood group databases.     

Molecular genotyping and frequencies of A 1 , A 2 , B, O 1 and O 2 alleles of the ABO blood group system in a Kuwaiti population

Expression of the highly polymorphic ABO gene cluster is commonly investigated for blood transfusion and analysis, but little information is available for Middle Eastern populations. This study determined the major ABO allele frequency in a Kuwaiti Arab cohort using a multiplex PCR–RFLP technique; 355 unrelated blood donors of phenotype A¹ (46), A² (31), A¹B (6), A²B (4), B (97) and O (171) were genotyped. DNA fragments of 252 (251 for O ¹ ) and 843 (842 for A ² ) bp spanning the two major exons, 6 and 7, of the ABO gene were amplified and digested with HpaII and KpnI. Thirteen different genotypes could be identified when combining the A ¹ , A ² , B, O ¹ and O ² alleles from the digestion patterns: 1 A ¹ A ¹ (0.28%), 6 A ¹ A ² (1.69%), 38 A ¹ O ¹ (10.71%), 1 A ¹ O ² (0.28%), 1 A ² A ² (0.28%), 30 A ² O ¹ (8.45%), 6 A ¹ B (1.69%), 4 A ² B (1.13%), 12 BB (3.38%), 79 BO ¹ (22.25%), 6 BO ² (1.69%), 167 O ¹ O ¹ (47.04%) and 4 O ¹ O ² (1.13%). Two of the combinations (A ² O ² , O ² O ² ) were not found. All genotypes determined were consistent with the serotypes. The frequencies of the five alleles in the Kuwaiti sample population were ABO*A¹ = 0.0746, ABO*A² = 0.0592, ABO*B = 0.1676, ABO*O¹ = 0.6831 and ABO*O² = 0.0155. These results are discussed with reference to gene frequencies reported for other ethnic groups.     

Genetic typing of human platelet antigen 1 (HPA-1) by oligonucleotide ligation assay in a specific and reliable semi-automated system

Genotyping of platelet alloantigens with the possibility of using any type of cellular material as a source of DNA has become a preferred procedure, particularly in thrombocytopenic patients when platelet counts are too low for phenotyping. Recently human platelet antigen 1 (HPA-1) has been identified as an inherited risk factor for coronary thrombosis. The different detection methods currently used have disadvantages for large-scale DNA diagnosis, including the need for electrophoresis (allele-specific restriction enzyme analysis, amplification with sequence-specific primers) or the potential risk of reduced specificity (allele-specific oligonucleotide hybridization). In this report we describe the adaptation of an automated oligonucleotide ligation assay to genotype HPA-1 in polymerase chain reaction (PCR)-amplified DNA samples. HPA-1a and HPA-1b phenotypes corresponded to the results of the different genotyping assays. The genotypes determined with the ELISA-based PCR-oligonucleotide ligation assay were in 100% concordance with the results obtained by conventional allele-specific restriction enzyme site analysis and PCR amplification with sequence-specific primers. The automated oligonucleotide ligation assay provides a rapid, reliable, nonisotopic method to genotype human platelet antigens that can rapidly be applied to large population screening.     

HBeAg(+)与HBeAg(-)乙型肝炎病毒携带者外周血CD4~+CD25~+调节性T淋巴细胞比例的变化及意义

目的探讨HBeAg(+)与HBeAg(-)HBV携带者外周血中CD4+CD25+调节性T淋巴细胞(Treg)的变化及其意义。方法 HBeAg(+)与HBeAg(-)HBV携带者两组各50例患者,应用流式细胞仪测定外周血CD3+T淋巴细胞所占比例、CD4+和CD8+T淋巴细胞所占比例及其比值、CD4+CD25+Treg所占比例;以同期门诊健康体检者20例为健康对照组。结果与健康对照组相比,HBeAg(+)与HBeAg(-)HBV携带者,在外周血CD3+T淋巴细胞、CD4+与CD8+T淋巴细胞所占比例差异无统计学意义。CD4+与CD8+T淋巴细胞比值,在HBeAg(+)HBV携带者有升高趋势,但与HBeAg(-)HBV携带者和对照组比较差异无统计学意义。HBeAg(+)HBV携带者,CD4+CD25+Treg所占比例较对照组明显升高,而HBeAg(-)HBV携带者,CD4+CD25+Treg所占比例较对照组明显降低,差异均有统计学意义。结论尽管肝功能在正常范围,HBeAg(+)与HBeAg(-)HBV携带者外周血CD4+CD25+Treg比例不同,HBeAg(+)HBV携带者高于健康对照组,而HBeAg(-)HBV携带者低于健康对照组,提示HBeAg(+)与HBeAg(-)HBV携带者处于不同的免疫状态。     

Hemojuvelin (HJV) mutations in persons of European, African-American and Asian ancestry with adult onset haemochromatosis

Mutations in the chromosome 1q-linked gene hemojuvelin (HJV) have recently been found to be a cause of juvenile haemochromatosis. We addressed the question of whether hemojuvelin mutations may influence the phenotype of patients with adult-onset haemochromatosis with or without mutations of the HFE gene. We sequenced the complete coding region of 133 subjects with iron overload. To screen a large number of patients, we also developed conditions for analysis by denaturing high-performance liquid chromatography (dHPLC). This diagnostic modality detects many mutations of the HJV gene. One patient with severe iron overload was found to be a compound heterozygote for HJV mutations, one of which had previously been identified in patients with juvenile haemochromatosis (G320V) and the other was novel (C321W). A number of other mutations were identified, but none were clearly associated with increases in the body iron burden. Notable among these was a DNA triplet insert, predicting an insertion of glycine, found in two African-American subjects, one with and one without iron storage disease.     

针刺百会、大椎对老年性痴呆大鼠脑内SOD及AChE的影响

目的探讨针刺百会、大椎对老年性痴呆大鼠的脑内超氧化物歧化酶(SOD)及乙酰胆碱酯酶(AChE)含量的影响。方法选用纯系Wistar老年大鼠52只,随机分为假手术组、模型组、针刺组和西药组,采用β-淀粉样蛋白向海马CA1区定向注射制作老年性痴呆模型,进行百会、大椎针刺治疗。检测大鼠脑内SOD及AChE的含量。结果针刺老年性痴呆大鼠的百会、大椎穴,可明显提高脑组织内SOD的含量,降低脑组织内AChE的含量,与模型组比较有统计学意义(P<0.05)。结论针刺能提高老年性痴呆大鼠的学习记忆能力,改善自由基代谢,促进老年性痴呆大鼠的智能恢复。     

Schistosoma mansoni gene GP22 encodes the tegumental antigen sm25: (1) antibodies to a predicted B-cell epitope of Sm25 cross-react with other candidate vaccine worm antigens; (2) characterization of a recombinant product containing tandem-repeats of this peptide as a vaccine

Monospecific antibodies against two putative epitopes of schistosome protein encoded by gene GP22 (182 codons, no introns) were used to probe worm extracts fractionated by lentil-lectin affinity chromatography or by electrophoresis. Anti-peptide-alpha (codons 70-84) exclusively identifies the N-glycanase-sensitive, 25 kDa tegumental glycoprotein Sm25 in the lectin-bound fraction of detergent-solubilized adult worm extract S3. In contrast, antipeptide-delta (codons 151-162) does not react with Sm25 but cross-reacts with other schistosome proteins, including candidate vaccine antigens paramyosin (Sm97) and glutathione-S-transferases (Sm26, Sm28, Sj26). Recombinant protein r4 x 47, constructed to express multiple copies of codon sequence 117-163 (containing delta), reacts with anti-delta and is uniquely recognized by protective Fischer twice-infected (F-2x) rat antiserum. Immunization with r4 x 47 induces antibodies with cross reactivities similar to anti-delta, but which also recognize Sm25. Despite these cross-reactivities with protective antigens, rodents vaccinated with r4 x 47 were not protected against cercarial infection. On the basis of these data, two hypotheses are proposed: (1) antigenic epitopes other than delta are present within the r4 x 47 sequence which induce antibodies reactive with Sm25 and/or (2) peptide-delta assumes alternative antigenic conformations, dependent upon the context of neighbouring sequences, some of which mimic epitopes of proteins encoded by other schistosome genes. These mimotopes are not targets of protective antibodies.     

FLAG (Fludarabine,Cytarabine, G-CSF) as a second line therapy for acute lymphoblastic leukemia with myeloid antigen expression: in vitro and in vivo effects

Abstract: Thirteen consecutive adult patients with primary refractory (n = 5) or relapsed (n = 8) acute lymphoblastic leukemia (ALL) were treated by an induction schedule (FLAG) consisting of Fludarabine (30 mg/sqm/d) plus high dose Cytarabine (HD-ara-C: 2 g/sqm/d) (d 1–5) and G-CSF (from d 0 to polymorphonuclear recovery). Patients achieving complete remission (CR) were administered a second FLAG course as consolidation and were then submitted to an individualized program of post-remission therapy, depending on the patient's age and performance status. CR was achieved in 8/12 evaluable cases (67%). The median CR duration was 22.5 w. CR attainment was significantly related to the co-expression of lymphoid and myeloid antigens. ALL/My+ patients achieved CR in 6/6 evaluable cases vs. 2/6 for ALL/My^-. In vitro ³H ara-C incorporation into cellular DNA resulted significantly increased by Fludarabine (in 7/9 tested cases) and, furthermore, by the association of Fludarabine-G-CSF in 5 evaluable ALL/My+ cases; in contrast, no effect of G-CSF addition to Fludarabine was observed in 4 ALL/My^–. Myelosuppression was observed in all patients: the median time to neutrophils >0.5 × 10⁹/l was 16.3 d (range 13–22) and 16.2 d (range 9–29) to platelets>20 × 10⁹/l. Nonhematological toxicity was minimal. In conclusion, FLAG is an active and tolerable combination in refractory ALL, particularly in cases with myeloid antigen expression where G-CSF appears to improve efficacy, probably increasing ara-C incorporation into the DNA of leukemic cells.     

Low-molecular-weight protein (LMP)2/LMP7 abnormality underlies the downregulation of human leukocyte antigen class I antigen in a hepatocellular carcinoma cell line

BACKGROUND: Tumor cells may alter the expression of numerous components involved in antigen-processing machinery to decrease human leukocyte antigen (HLA) class I expression, allowing the tumor cells to escape immune surveillance. The purpose of the present study was to investigate the involvement of these components in the downregulation of HLA class I expression in human hepatocellular carcinoma cell line BEL7,404. METHODS: Expression of HLA-I and antigen presentation-related genes were analyzed by flow cytometry and polymerase chain reaction. The HLA class I-deficient BEL7,404 cell was transfected with the low-molecular-weight protein (LMP) 2 and LMP7 gene and were analyzed by flow cytometry for restoration of surface HLA class I expression. RESULTS: The BEL7,404 cells downregulated the expression of HLA class I antigen and lacked expression of LMP2 and LMP7. Interferon (IFN)-gamma treatment increased the expression of LMP2 but not LMP7. The LMP2-transfected BEL7,404 cells or LMP2 and LMP7-cotransfected cells restored surface HLA class I expression while LMP7-transfected cells did not. However, in IFN-gamma-treated BEL7,404 cells, transfection with the LMP7 gene induced more HLA class I expression than mock transfection. CONCLUSIONS: The LMP2 gene was required for the expression of HLA class I molecules in BEL7,404. The LMP7 was not the major reason for loss of HLA class I in BEL7,404 cells, although the supply of exogenous LMP7 could increase surface expression of HLA class I antigen.     

Evaluation of red blood cell and platelet antigen genotyping platforms (ID CORE XT/ID HPA XT) in routine clinical practice

Background

High-throughput genotyping platforms enable simultaneous analysis of multiple polymorphisms for blood group typing. BLOODchip^® ID is a genotyping platform based on Luminex^® xMAP technology for simultaneous determination of 37 red blood cell (RBC) antigens (ID CORE XT) and 18 human platelet antigens (HPA) (ID HPA XT) using the BIDS XT software.

Materials and methods

In this international multicentre study, the performance of ID CORE XT and ID HPA XT, using the centres’ current genotyping methods as the reference for comparison, and the usability and practicality of these systems, were evaluated under working laboratory conditions. DNA was extracted from whole blood in EDTA with Qiagen methodologies. Ninety-six previously phenotyped/genotyped samples were processed per assay: 87 testing samples plus five positive controls and four negative controls.

Results

Results were available for 519 samples: 258 with ID CORE XT and 261 with ID HPA XT. There were three “no calls” that were either caused by human error or resolved after repeating the test. Agreement between the tests and reference methods was 99.94% for ID CORE XT (9,540/9,546 antigens determined) and 100% for ID HPA XT (all 4,698 alleles determined). There were six discrepancies in antigen results in five RBC samples, four of which (in VS, N, S and Do^a) could not be investigated due to lack of sufficient sample to perform additional tests and two of which (in S and C) were resolved in favour of ID CORE XT (100% accuracy). The total hands-on time was 28–41 minutes for a batch of 16 samples. Compared with the reference platforms, ID CORE XT and ID HPA XT were considered simpler to use and had shorter processing times.

Discussion

ID CORE XT and ID HPA XT genotyping platforms for RBC and platelet systems were accurate and user-friendly in working laboratory settings.     

Differential tissue expression of the Lewis blood group antigens: enzymatic, immunohistologic, and immunochemical evidence for Lewis a and b antigen expression in Le(a-b-) individuals

The Lewis blood group system comprises two main carbohydrate antigens, Le(a) and Le(b). Lewis typing has traditionally been based on serologic determinations using erythrocytes and saliva. Several recent studies have demonstrated that erythrocyte Lewis phenotype may change during pregnancy or disease, and inappropriate Lewis antigens have been found in both normal and neoplastic tissue. To evaluate whether these observations are in conflict with the presently proposed genetic and biosynthetic basis of the Lewis blood group system, we performed a combined enzymatic, immunohistologic, and immunochemical study of Lewis antigen expression in normal and neoplastic tissues, as well as erythrocytes, plasma, and saliva of Le(a-b-)-typed individuals. Of six cancer-bearing patients typed Le(a-b-), three were identified as nongenuine owing to the presence of alpha 1----4fucosyltransferase activity (alpha 1----4FT) and Lewis antigens in saliva and three were identified as genuine (lacking alpha 1----4FT and Lewis antigens in saliva). These genuine Le(a-b-) individuals were shown to express significant alpha 1----4FT in tissues, and Lewis antigens were detected in tissues by immunohistology as well as immunochemistry. We conclude that the Lewis phenotype obtained by serologic determination of erythrocytes and saliva does not apply to all tissues. We discuss biosynthetic and genetic consequences of this finding.     

Prognostic implications of mutations and expression of the Wilms tumor 1 (WT1) gene in adult acute T-lymphoblastic leukemia

Background

The role of the Wilms tumor 1 gene (WT1) in acute leukemias has been underscored by mutations found in acute myeloid leukemia identifying patients with inferior survival. Furthermore, aberrant expression of WT1 in acute myeloid leukemia was associated with an increased risk of relapse. No larger studies have performed a combined approach including WT1 mutation and expression analyses in acute T-lymphoblastic leukemia.

Design and Methods

We analyzed the WT1 mutations and the expression status in a total of 252 consecutive adult patients with newly diagnosed T-lymphoblastic leukemia, who were registered on the GMALL 06/99 and 07/03 protocols and had sufficient material available. The GMALL protocols included intensive chemotherapy as well as stem cell transplantation according to a risk-based model with indication for stem cell transplantation in first complete remission for early and mature T-lymphoblastic leukemia patients; patients with thymic T-lymphoblastic leukemia were allocated to a standard risk group and treated with intensive chemotherapy.

Results

Twenty of the 238 patients analyzed had WT1 mutations (WT1mut) in exon 7. WT1mut cases were characterized by immature features such as an early immunophenotype and higher WT1 expression. In thymic T-lymphoblastic leukemia, WT1mut patients had an inferior relapse-free survival compared to WT1 wild-type patients. T-lymphoblastic leukemia patients with aberrant WT1 expression (high or negative) showed a higher relapse rate and an inferior outcome compared to patients with intermediate WT1 expression. In the standard risk group of thymic T-lymphoblastic leukemia, aberrant WT1 expression was predictive for an inferior relapse-free survival as compared to patients with intermediate expression. In multivariate analysis, WT1 expression was of independent prognostic significance for relapse-free survival.

Conclusions

WT1 mutations were associated with an inferior relapse-free survival in standard risk thymic T-lymphoblastic leukemia patients. Moreover, altered expression associated with inferior outcome also suggests a role of WT1 in T-lymphoblastic leukemia and the potential use of molecularly-based treatment stratification to improve outcome.