Risk Factor For Chronic Lymphocytic Leukemia Research Articles

Evaluation the -174G>C Genetic Polymorphism of Interleukin-6 in Iranian Patients with Chronic Lymphocytic Leukemia.

Interleukin-6 (IL-6) is involved in inflammation and has a significant role in chronic lymphocytic leukemia (CLL) progression. Accordingly, IL-6 level may increase in CLL-affected patients compared to healthy individuals. The -174G>C single nucleotide polymorphism (SNP) in IL-6 promoter region has been related to differences in IL-6 transcription. Therefore, we investigated the possible association of IL-6 polymorphism with CLL. We examined the -174G>C SNP in IL-6 gene and studied its possible relationship with CLL in affected patients and in healthy controls using Amplification Refractory Mutation System- polymerase chain reaction genotyping method. IL-6 plasma level was measured in both studied groups. According to the results, IL-6 mean plasma concentration was increased significantly in the CLL patients compared to the controls. However, 174G>C genotype of the IL-6 gene was not associated with CLL. Furthermore, there were no significant differences in the distribution of allele and genotype frequencies between the CLL-affected patients and the controls (P>0.05). Our study showed that -174G>C SNP in promotor of IL-6 gene could not be considered a risk factor for CLL. Larger prospective studies should be performed to confirm our results.

P53 p.Pro72Arg (rs1042522) and Mouse Double Minute 2 (MDM2) Single-Nucleotide Polymorphism (SNP) 309 Variants and Their Interaction in Chronic Lymphocytic Leukemia(CLL): A Survey in CLL Patients from Western Iran.

Background: Chronic lymphocytic leukemia (CLL) is the most common leukemia in adults. The MDM2 and p53 are interacting proteins that play crucial roles in cell biology. Genetic variations of p53 and MDM2 have been identified in many cancers including CLL; among which are SNP309 in the promoter of MDM2 and SNP codon72 in p53. Materials and Methods: In this study, we sought to find the impact of two SNPs of p53 and MDM2 in the pathogenesis of CLL. A total of 100 CLL patients and 102 healthy controls were recruited. Genomic DNA was extracted, and genotyping was performed using the PCR-RFLP method. The allele and genotype associations were analyzed using the χ2 test. The gene-gene interaction analysis was studied using GMDR v0.9. Results: Our study found the absence of a significant difference between CLL patients and controls related to the allelic frequencies or genotypic distributions for both MDM2 SNP309 and p53 codon72. A significantly higher frequency of p53 C allele was found in patients with disease duration of more than 36 compared to those less than 36 months. However, GMDR analysis suggests genetic interaction between the genes under study. Conclusion: Our findings indicated each polymorphism of p53 codon72 and MDM2 (SNP309) was not a risk factor for CLL but the p53 C allele could be associated with the disease duration. Besides, the interaction between p53/MDM2 genotypes may confer susceptibility to CLL. Our study could be useful in genetic association studies of CLL and the role of gene-gene interactions in the susceptibility to the disease.

IGLV3-21*01 is an inherited risk factor for CLL through the acquisition of a single-point mutation enabling autonomous BCR signaling

The prognosis of chronic lymphocytic leukemia (CLL) depends on different markers, including cytogenetic aberrations, oncogenic mutations, and mutational status of the immunoglobulin (Ig) heavy-chain variable (IGHV) gene. The number of IGHV mutations distinguishes mutated (M) CLL with a markedly superior prognosis from unmutated (UM) CLL cases. In addition, B cell antigen receptor (BCR) stereotypes as defined by IGHV usage and complementarity-determining regions (CDRs) classify ∼30% of CLL cases into prognostically important subsets. Subset 2 expresses a BCR with the combination of IGHV3-21-derived heavy chains (HCs) with IGLV3-21-derived light chains (LCs), and is associated with an unfavorable prognosis. Importantly, the subset 2 LC carries a single-point mutation, termed R110, at the junction between the variable and constant LC regions. By analyzing 4 independent clinical cohorts through BCR sequencing and by immunophenotyping with antibodies specifically recognizing wild-type IGLV3-21 and R110-mutated IGLV3-21 (IGLV3-21R110), we show that IGLV3-21R110-expressing CLL represents a distinct subset with poor prognosis independent of IGHV mutations. Compared with other alleles, only IGLV3-21*01 facilitates effective homotypic BCR-BCR interaction that results in autonomous, oncogenic BCR signaling after acquiring R110 as a single-point mutation. Presumably, this mutation acts as a standalone driver that transforms IGLV3-21*01-expressing B cells to develop CLL. Thus, we propose to expand the conventional definition of CLL subset 2 to subset 2L by including all IGLV3-21R110-expressing CLL cases regardless of IGHV mutational status. Moreover, the generation of monoclonal antibodies recognizing IGLV3-21 or mutated IGLV3-21R110 facilitates the recognition of B cells carrying this mutation in CLL patients or healthy donors.

Treatment algorithm for Japanese patients with chronic lymphocytic leukemia in the era of novel targeted therapies.

Treatment for patients with chronic lymphocytic leukemia (CLL) is becoming more individualized due to the recent introduction of novel molecularly targeted therapies into the therapeutic armamentarium. Genomic and molecular risk factors in CLL patients determine the individual risk for disease progression and response to therapy, and can impact survival. In this review article, we discuss current treatment strategies for CLL patients in Japan, where the novel targeted agents, the BTK inhibitor ibrutinib and BCL2 antagonist venetoclax, now are available and increasingly used in clinical practice. We also discuss the importance of CLL risk factors for making therapy decisions, focusing on immunoglobulin variable region heavy chain (IGHV) mutation status, 11q deletion, and 17p deletion. Treatment approaches for CLL have rapidly changed in the past few years because of these new targeted agents. They are highly effective, well tolerated, and have been demonstrated in a series of large randomized clinical trials to improve survival when compared with conventional chemotherapy-based treatment. Therefore, for most patients, especially high-risk CLL patients, BTK inhibitor and BCL2 antagonist therapies are preferred over chemo-immunotherapy. Currently ongoing studies seek to determine the best sequence for these new agents and whether a combination therapy approach is beneficial. With these developments, a new era of chemotherapy-free treatment for CLL patients is expected.

A Phase II Trial of Ibrutinib and PD-1 Blockade in Asymptomatic High Risk Chronic Lymphocytic Leukemia to Improve Immune Function

Background: Chronic lymphocytic leukemia (CLL) is the most common chronic leukemia. Patients in active surveillance with untreated high-risk CLL (defined as presence of del17p or TP53, del11q or ATM mutation or unmutated IGVH) have an unmet need as they tend to progress rapidly and develop resistance to standard therapies. There is evidence that deferring treatment in high-risk patients may be detrimental due to a more aggressive course of disease and that patients with clonal evolution into high-risk features may fare even worse prognosis (Shanafelt et al, JCO 2006). The CLL12 trial (ibrutinib for asymptomatic high risk CLL patients, Langerbeins et al ICML2019) showed event (EFS) and progression (PFS) free survival benefit when compared to placebo. In addition, T-cell dysfunction and immunosuppressive environment have been shown in CLL. The rationale of the trial is that the combination of PD1:PDL1 Blockade (PDB) and ibrutinib will reverse T cell dysfunction commonly seen in CLL patients, potentiating more robust anti-infective and anti-tumor immune responses. Methods: This is a phase 2 clinical trial. Enrollment goal: 25. Treatment will consist of the combination of pembrolizumab (Pem) 200 mg IV every 3 weeks and ibrutinib 420 mg daily orally (to be started after 2nd infusion of PDB) for up to 51 weeks, as depicted in Figure 1. Eligibility criteria includes: Age > 18, confirmed diagnosis of CLL, presence of at least 1 high risk factor for CLL (Del17p, Del11q and or unmutated IGVH), and not meeting iwCLL criteria to start treatment. Primary endpoints are incidence of complete remission (CR) and time to CLL response. Secondary endpoints: overall response rate (ORR), restoration of immune response (decreased markers of T-cell exhaustion and improvement in quantitative immunoglobulins), safety, PFS. Exploratory biomarkers include evaluation of T-cell and B-cell function and cytokine profile at different time points through therapy. Disclosures Chavez: Karyopharm: Membership on an entity's Board of Directors or advisory committees; Genentech: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Bayer: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Kite: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Novartis: Membership on an entity's Board of Directors or advisory committees. Nodzon:Pfizer: Consultancy; Pharmacyclics: Consultancy; Genentech: Consultancy, Other: Speaker Fees; Abbvie: Other: Speaker Fees. Pinilla Ibarz:Novartis: Consultancy; Bristol-Myers Squibb: Consultancy; Takeda: Consultancy, Speakers Bureau; Abbvie: Consultancy, Speakers Bureau; Janssen: Consultancy, Speakers Bureau; Teva: Consultancy; TG Therapeutics: Consultancy; Bayer: Speakers Bureau; Sanofi: Speakers Bureau. OffLabel Disclosure: The combination of PD1:PDL1 Blockade (PDB) and ibrutinib will reverse T cell dysfunction commonly seen in CLL patients, potentiating more robust anti-infective and anti-tumor immune responses

County level incidence rates of chronic lymphocytic leukemia are associated with residential radon levels.

Aim:We previously reported that incidence rates for chronic lymphocytic leukemia (CLL) among US states are significantly correlated with levels of residential radon (RR). Because these correlations could be influenced by confounding and/or misclassification among large geographic units, we reinvestigated them using smaller geographic units that better reflect exposure and disease at the individual level.Methods:We examined the relationships between CLL and RR per county in 478 counties with publicly-available data.Results:After adjustment for ultraviolet radiation, a possible risk factor for CLL, county rates for CLL and RR were significantly correlated among males and females both together and separately (p < 0.0001).Conclusion:CLL is significantly associated with RR at the county level.

SCYLD expression leads to CLL in mice and men

Abstract A tightly regulated NF-κB pathway is very important for B cell homeostasis. Aberrant activation of NF-κB is involved in the development of chronic lymphocytic leukemia (CLL). The deubiquitinating enzyme CYLD, acts as a negative regulator of NF-κB by removing K63-linked ubiquitin chains from its target proteins. Here, we show that the B cell specific deletion of full-length CYLD and expression of the shorter splice form (sCYLD) lacking the binding sites for TRAF2 and NEMO, leads to the dramatic expansion of CD5 positive B cells, a hallmark of CLL. These cells accumulate in the blood and lymphatic organs with age, and show characteristic up-regulation of typical CLL-markers such as ZAP-70 and Bcl-2. A20, another negative regulator of NF-κB targets some of the same proteins as CYLD, thereby potentially compensating for the lack of FL-CYLD. We crossed sCYLD mice to a B cell specific A20 knockout. In these mice, the CLL phenotype progresses more rapidly probably due to an increase of NF-κB activity, up to the point where 100% of the B cells are CD5+. These cells show oligoclonal expansion, infiltrate the liver and the lungs, and accumulate in all lymphatic organs. Interestingly, we could show that some human CLL patients also express sCYLD, whereas none of the healthy controls do. These findings indicate that sCYLD is a new risk factor for CLL and implies that disrupted alternative splicing of key NF-κB regulators lead to the development of CLL.

The Transcription Factor IRF4 Is Crucial for CLL Progression and Regulates Survival and Proliferation in a Microenvironment Related Manner

Introduction: Chronic Lymphocytic Leukemia (CLL) is characterized by an accumulation of CD19+ CD5+ CLL cells in the peripheral blood and the lymphoid compartments. The disease is still incurable despite recent advances in the development of novel therapy concepts (e.g. inhibitors of BCR signaling). Although it is not entirely clear how CLL develops, proliferation centers located in the lymph node and the bone marrow are thought to be the crucial niche that provides the surrounding in which CLL cells originate and re-establish the clone after therapy, leading to relapse in almost 100% of CLL patients. In analogous normal lymphoproliferative environments the transcription factor IRF4 plays an important role in controlling B cell maturation, differentiation, proliferation and survival. A SNP in the human IRF4 3’UTR was linked to CLL susceptibility (DiBernardo Nat.Gen. 2008) and in the mouse model germline deletion of IRF4 in all lineages contributed to CLL development in the New Zealand Black and in the VH11 mouse model (Shukla Blood 2013, Ma J.Biol.Chem. 2013).Methods: CLL samples were collected from the peripheral blood of CLL patients according to the Declaration of Helsinki and with written informed consent. IRF4 mRNA expression analyses were performed in purified CD19+ CLL cells using TaqMan Real Time PCR. In vitro studies were performed in soloculture without stimulation or in coculture systems mimicking the lymph node microenvironment, as previously described (Asslaber Br.J.Haematol. 2013). IRF4 knockdown was performed using lipofection and IRF4 specific siRNAs or non-targeting control siRNAs. IRF4 protein expression was measured by intracellular flow cytometry. Proliferation was detected by Ki-67 intracellular staining. All intracellular stainings were performed after gating on viable CD19+ CD5+ CLL cells. Cell death was assessed by Annexin V / 7AAD staining or using a fixable viability dye.Results: Overall, IRF4 mRNA expression was decreased in CLL patients (N=101) when compared to healthy donors (N=8, P=0.04). In the CLL cohort low IRF4 mRNA expression (cut-off determined by ROC analysis and Youden Index calculation) was significantly correlated with earlier time to treatment (median treatment-free survival: 40 month in the IRF4LOW and 69 month in the IRF4HIGH CLL patient group (P<0.01)). This was proved to be independent of mutation state and other CLL risk factors in multivariate analysis. Using in vitro knockdown of IRF4 in solo- and coculture models we found that lowered expression of IRF4 was associated with increased CLL cell survival and abrogated spontaneous apoptosis (N=11, P<0.01). Moreover, we detected a failure of CLL cells to respond to CD40L signals derived from the microenvironment after IRF4 knockdown, which was associated with abrogated proliferation (N=9, P<0.01). Indeed microenvironmental stimuli (e.g. CD40L ligation or addition of activated T cells) were required to maintain IRF4 expression in vitro (N=17, P < 0.001) which also corresponds to our observation that IRF4 positive CLL cells were highly overrepresented in the CXCR4dim CD5brightCLL population (N = 55, P < 0.0001) which is considered to be the proliferative CLL cell fraction emigrated from the lymph node (Calissano Mol. Med. 2011).Conclusion: We demonstrate that low IRF4 expression is an independent negative prognostic marker for CLL progression. In the microenvironmental context IRF4 plays a dual role, with high expression limiting CLL survival on the one hand but being a crucial mediator of CD40L mediated proliferation on the other hand. While our data suggest that IRF4 is upregulated in response to microenvironmental stimuli the association of low IRF4 levels with bad prognosis suggests that IRF4 levels may serve to limit CLL growth by enhancing cell death responses. The exact mechanisms by which IRF4 impacts CLL pathophysiology is currently being investigated in vivo using B-cell specific IRF4-deficient CLL mouse models. DisclosuresNo relevant conflicts of interest to declare.

Abstract 274: Occupational exposure to agricultural pesticides and CLL risk

Abstract Background Previous literature regarding the association between occupational exposure to agricultural pesticides and non-Hodgkin lymphoma (NHL) risk has been inconsistent, particularly when looking at specific lymphoma subtypes. Most recently, a large European case-control study showed an elevated risk of chronic lymphocytic leukemia (CLL) among those ever exposed to inorganic and organic pesticides with the strongest association among those exposed to organophosphates. However, when restricting the analysis to subjects with high confidence of exposure, these associations were attenuated (Cocco P., 2013). We used case-control data from the Mayo Clinic to evaluate whether there is an increased risk of CLL among individuals with known occupational exposure to agricultural pesticides. Methods We evaluated pesticide exposure and CLL risk in a clinic-based study of newly diagnosed CLL cases and frequency-matched controls enrolled at the Mayo Clinic from 2002-2012. 200 CLL cases and 474 controls returned a detailed farming and pesticide exposure questionnaire that was modeled after the Agricultural Health Study, where exposure was based on pesticide-specific application. Unconditional logistic regression, adjusted for age and sex, was used to estimate odds ratios (ORs) and 95% confidence intervals (CI). We evaluated the effect of each pesticide individually, by chemical class of pesticides, and by an aggregate of multiple pesticide exposure on CLL risk. Results Among those participants with detailed farming data, the mean age of CLL diagnosis was 66 years and 76% were male; for controls, the mean age at enrollment was 65 years and 66% were male. Risk of CLL was mildly elevated, but not significant, amongst those with application of any pesticide (OR 1.39; 95% C.I. 0.92-2.10). When broken down by chemical class, risk of CLL was also mildly elevated, but not significant, for application of organophosphates and carbamates (OR 1.21; 95% CI 0.84-1.73; OR 1.21; 95% 0.85-1.73, respectively). Organochlorines, phenoxy compounds, pyrethriods and triazines showed no evidence of an elevated risk, nor did we see evidence of a trend that CLL risk increases with number of pesticides applied. Discussion Our preliminary results provide inconclusive support for the role of pesticide exposure as a possible risk factor for CLL. However our sample size was small. Additional data will be incorporated, including confidence of exposure measures, as well as other modifying factors, to further evaluate these results. Citation Format: Emily J. Hallberg, Sara J. Achenbach, Kari G. Rabe, Timothy G. Call, Cristine Allmer, Tait D. Shanafelt, Mark Liebow, Neil E. Kay, James R. Cerhan, Susan L. Slager. Occupational exposure to agricultural pesticides and CLL risk. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 274. doi:10.1158/1538-7445.AM2014-274

The times they are a-changin': prognostic markers in the new era of BCR-targeting therapies for CLL.

Given the highly variable clinical presentation and prognosis in patients with chronic lymphocytic leukemia (CLL), prognostic markers have typically been used for estimating the risk of disease progression and prognosis in individual patients. The traditional clinical staging systems continue to be used for treatment decisions, but they do not allow for predictions in early-stage patients. Molecular and cytogenetic risk factors allow us to predict the risk for disease progression response to 'standard' therapy and prognosis. Increasing evidence indicates robust connections of several CLL risk factor markers to B-cell receptor (BCR) function and signaling. Several CLL risk factors (immunoglobulin heavy chain variable region mutational status, CD38 and ZAP-70 expression, CCL3 plasma levels) are related to the function of the BCR, a key factor in CLL pathogenesis. Their implications in the context of novel BCR-targeted therapies will be discussed. With the emergence of inhibitors of BCR-associated kinases (Btk-, Syk- and PI3 kinase inhibitors) in CLL and other B cell malignancies, BCR-related risk factors may help with identification of patients who are likely to respond and/or for response assessment (i.e., CCL3 plasma levels). The negative prognostic impact of BCR-related risk factors may improve with the use of these new, targeted agents.

Minimal Residual Disease (MRD) Re-Growth Kinetics Are An Independent Predictor for Progression Free Survival (PFS) in Chronic Lymphocytic Leukemia (CLL) and Are Related to Biologically Defined CLL-Subgroups– Results From the CLL8 Trial of the German CLL Study Group (GCLLSG)

Abstract 1777MRD single time point assessments during therapy and at the end of treatment have been identified as independent predictors of PFS and overall survival in CLL patients (pts) by our group and others. However, it is currently unknown whether MRD kinetics during follow-up (FU) also have prognostic significance and whether kinetics show associations with CLL risk features. We therefore investigated MRD during treatment-free FU within the CLL8 trial of the GCLLSG (phase III, front-line RFC vs FC, Hallek et al., Lancet 2010)MRD kinetics were analyzed in 256 pts who had not progressed 1 year after completion of therapy and for whom at least 2 peripheral blood MRD assessments during the subsequent year were available. The slope of the common logarithm of MRD / time was calculated for 193 patients with at least 2 positive MRD measurements. Median MRD increase was 6.3fold during the observation period for the whole group (i.e. 0.80 log MRD unit increase / year). We compared groups of pts who (1) were always MRD negative (25% of all 256 pts), (2) had measurable disease with a slope below median (slow re-growth, 37% of pts), and (3) had measurable disease with a slope above median (fast re-growth, 39 %). The medians of the first measurable MRD levels during observation did not differ significantly between groups 2 (4.3 × 10−3) and 3 (1.7 × 10−3, p=.16). Pts with faster MRD re-growth kinetics (group 3) experienced a shorter median PFS (40 months) than pts with slower re-growth (group 2, 66 months), whereas median PFS has not been reached in pts who were always MRD negative (group 1, log-rank p= 3 × 10−14). Compared to group 1, group 2 and 3 pts carried increasingly higher risks of progression (HR 3.1 and 7.7, resp.). Pts showing a slow re-growth pattern (group 2) had a 2.5fold lower risk of clinical progression than pts with a greater MRD slope (group 3, p=5 × 10−6). The prognostic significance of MRD kinetics for PFS was also tested in Cox regression analysis together with clinical response, deletion 17p, IGHV mutational status, number of treatment cycles, treatment arm, thymidine kinase, beta2-microglobulin, pre-therapeutic WBC and MRD levels 1 year after completion of therapy. MRD kinetics (p=4×10−9), MRD levels (7×10−14), cycle number (8×10−5) and IGHV mutational status (1×10−3) remained independently significant for PFS in this multivariate analysis.We next correlated MRD slopes during the second year of FU and prognostic features in 204 pts (groups 2 and 3 plus 11 pts with early clinical relapse but measurable MRD slope during second FU year). Pts who required treatment within 2 years from diagnosis experienced a faster re-growth after therapy (.92/a) than pts with a longer treatment-free interval (.68, p=.04). The slope was significantly lower in pts with Binet A disease prior to therapy (.43/a) than in Binet B (.77/a, p =.03) and Binet C (.88/a, p=.02) pts. Pts carrying a chromosomal deletion (del) 13q as single abnormality had a significantly slower MRD re-growth pattern (.58/a) than those with del(11q) (1.0/a, p=.0004) or without cytogenetic abnormalities (1.1/a, p=.001), while the difference to pts with 12q+ (.71/a) was not significant. Pts with a mutated IGHV gene progressed slower (.54/a) than those with unmutated IGHV (.96/a, p=.0002). A thymidine kinase of at least 10 U/L was associated with a steeper MRD slope (.82/a) than lower levels (.61/a, p=.03). MRD slopes were not significantly associated with gender, WBC prior to therapy, beta2-microglobuline levels, presence of B-symptoms, or treatment arm.We demonstrate for the first time the independent prognostic significance of MRD kinetics during FU in CLL. MRD kinetics improve the prediction of PFS even when single time point MRD assessments during FU and other major risk features in CLL are additionally considered. MRD kinetics classify known CLL risk factors into two groups. IGHV, cytogenetics, thymidine kinase, stage, and time to treatment distinguish CLL subgroups with different re-growth kinetics, likely characterizing the relationship of proliferation to spontaneous apoptosis of the CLL clone itself. Other risk features did not show an association with kinetics in spite of proven significance in the CLL8 trial. Those features likely identify differences in responsiveness to therapy. We hypothesize that maintenance strategies will chance the course of the disease most effectively in patients who are responsive to therapy but relapse early due to fast CLL re-growth. Disclosures:Boettcher:Hoffmann La Roche: Honoraria, Research Funding, Travel Grants. Ritgen:Hoffmann La Roche: Research Funding. Fischer:Hoffmann La Roche: Travel grants. Stilgenbauer:Hoffmann La Roche: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Travel Grants. Fingerle-Rowson:Hoffmann-La Roche: Employment. Fink:F. Hoffmann La Roche: Travel grants. Wenger:Hoffmann La Roche: Employment, Equity Ownership. Mendila:Hoffmann La Roche: Employment, Equity Ownership. Wendtner:Hoffmann-La Roche: Honoraria, Research Funding. Eichhorst:Hoffmann La Roche: Honoraria, Research Funding, Travel Grants. Hallek:Hoffmann-La Roche: Honoraria, Research Funding. Kneba:Hoffmann La Roche: Honoraria, Research Funding.

Complete Donor Chimerism Predicts Molecular Remission in High Risk CLL Following Nonmyeloablative Transplantation.

Introduction: The ability to define high-risk cohorts of chronic lymphocytic leukemia (CLL) patients has led to clinical trials exploring the utility of early aggressive interventions. Recent work, such as that by the Spanish GELCAB group, demonstrates that molecular remission is an appropriate therapeutic goal for high risk CLL. However, molecular remission may not be evident in some patients until 9 to 12 months post-hematopoietic cell transplant (HCT), even with highly sensitive minimal residual disease (MRD) testing methods. To facilitate clinical management of these patients during the first year after HCT, we evaluated HCT and CLL risk factors for predictive associations to molecular remission as determined by MRD monitoring in 19 patients undergoing nonmyeloablative allogeneic HCT.Methods: Nineteen high-risk CLL patients received a nonmyeloablative transplant preparative regimen consisting of total lymphoid irradiation and anti-thymocyte globulin, followed by rituximab 375mg/m2 on days 56, 63, 70, and 77 after transplant. Median follow-up was 611 days, with a range of 1–3 years.Peripheral blood was collected pre-HCT, and post-HCT monthly for six months, then every 3 months thereafter.Serial assessment of MRD by allele-specific oligonucleotide quantitative PCR (ASOQ-PCR) was performed (177 analyses), using a TaqMan probe specific for the unique CDR3 region of the clonal IgH gene rearrangement. Molecular remission was defined as two consecutive measurements of 2 30 copies/ug WBC-DNA (1.8E-4 cells) at a minimum interval of 30 days.Molecular remission, as determined by the MRD analyses, was compared by univariate analyses with CLL and HCT risk factors. The CLL risk factors evaluated were VH-mutation status, high risk cytogenetics (deletions or mutations of p53 and/or ATM), and fludarabine refractoriness. Allogeneic HCT risk factors evaluated were lymph node >5cm, elapsed time from diagnosis to HCT, disease status before HCT, MRD level before HCT, number of prior treatment regimens, related vs. unrelated donor, female donor to male recipient and time to establish full donor chimerism. Data for the latter was obtained by serial PB analyses of T-cell (CD3+) and NK-cell (CD56+) donor chimerism (119 analyses) by DNA fragment analysis of serial tandem repeat (STR) polymorphisms. Samples were collected in parallel with the MRD specimens. Complete donor chimerism (CDC) was defined as ≥95% donor for both T- and NK-cells. Because of the therapeutic use of rituximab in this trial, B-cell (CD19+) chimerism was not included in our analysis.Results: Twelve of 19 patients (63%) achieved molecular remission by one year. Univariate analyses of found no statistically significant association between this “MR” group –those that attain molecular remission at one year – and any of the factors studied except complete T/NK donor chimerism. Table 1 shows that CDC precedes and predicts molecular remission.Table 1. Time to complete donor chimerism in patients that achieve molecular remission by one year post HCT (“MR group”)days post-HCTPercent of MR group in CDCp-valued+9058% (7/12)0.0113d+12075% (9/12)0.0037d+15083% (10/12)0.0013d+18092% (11/12)0.0002d+18092% (11/12)0.0002d+365100% (12/12)Figure 1 is an example of the univariate analyses comparing chimerism data with time to molecular remission, here showing the percent of patients achieving durable molecular remission for two groups of patients – those showing CDC by d+150 post HCT and those whose chimerism is <95% at that time.Conclusion: Extensive ASO-Q-PCR MRD and donor-chimeric status monitoring was performed in this study, demonstrating that complete donor chimerism (CD3 and CD56) in nonmyeloablative allogeneic HCT for CLL is strong predictor for achieving molecular remission by one year post transplantation. [Display omitted]

Inherited predisposition to chronic lymphocytic leukemia

Inherited susceptibility to chronic lymphocytic leukemia (CLL) has been recognized for decades. Approximately 10% of individuals with CLL report a family history of CLL or a related lymphoproliferative disorder, and genetic predisposition is the best understood risk factor for CLL. Studies of familial CLL have suggested that the disease features are largely similar to sporadic CLL, although recent data suggest that familial CLL may more commonly show somatic hypermutation of the immunoglobulin heavy-chain variable region, suggesting a more indolent disease course. Monoclonal B-cell lymphocytosis (MBL) has been identified recently as a likely precursor to CLL; it is found in the general population with increasing age and enriched in unaffected relatives of individuals with familial CLL. Studies of MBL as well as mouse models of CLL may lead to better understanding of early CLL pathogenesis that is relevant to familial predisposition. To date, the identification of genes that predispose to familial CLL has been slow, primarily due to the relatively few families available for study, the small size of those families and disease causation most likely by multiple genes that each confer smaller risks. In the coming years, the application of systematic genomics approaches to familial CLL should, hopefully, lead to the identification of novel loci involved in the disease.

Investigation of an NQO1 polymorphism as a possible risk and prognostic factor for chronic lymphocytic leukemia

NAD(P)H:quinoneoxidoreductase 1 (NQO1) inhibits some cancers and increases p53 and apoptosis in cells. Due to an inactivating polymorphism, 10% of humans have no NQO1 activity. A case:control study suggested that chronic lymphocytic leukemia (CLL) patients may have an increased incidence of the NQO1 null genotype compared with controls. NQO1 genotype did not correlate with various CLL prognostic factors, but we observed a trend toward lower drug response in patients with the NQO1 null genotype. Inhibiting NQO1 activity decreased p53 levels and drug induced apoptosis in CLL cells. These results raise the possibility that the NQO1 polymorphism may be a risk factor for CLL and a predictor of response to chemotherapy.