Improved Innate Immune Function in Patients with Chronic Lymphocytic Leukemia Treated with Targeted Therapy in Clinical Trials

PURPOSE

Patients with chronic lymphocytic leukemia (CLL) have increased risk of severe infections. Although adaptive immune dysfunction is well described, clinical tools for identifying patients at risk are lacking, warranting investigation of additional immune components. In contrast to chemotherapy, targeted agents could spare or even improve innate immune function. Therefore, we investigated innate immune phenotypes and function in patients with CLL before and during targeted treatment.

EXPERIMENTAL DESIGN

Baseline and consecutive blood samples were collected from patients with CLL treated with acalabrutinib (n = 17) or ibrutinib+venetoclax (n = 18) in clinical trials. Innate immune function was assessed by TruCulture, a whole-blood ligand-stimulation assay quantifying cytokine release in response to standardized stimuli. Innate immune phenotypes were characterized by flow cytometry. As a proxy for infections, we mapped antimicrobial use before and during treatment.

RESULTS

At baseline, patients with CLL displayed impaired stimulated cytokine responses to the endotoxin lipopolysaccharide (LPS) along with deactivated monocytes, enrichment of myeloid-derived suppressor cells and metamyelocytes, and elevated (unstimulated) proinflammatory cytokines. Two/three cycles of acalabrutinib or ibrutinib normalized LPS-stimulated responses, in parallel with decreased duration of infections. Innate immune profiles and elevated proinflammatory cytokines further normalized during longer-term acalabrutinib or ibrutinib+venetoclax, paralleled by decreased infection frequency.

CONCLUSIONS

Innate immune impairment and infection susceptibility in patients with CLL were restored in parallel during targeted therapy. Thus, targeted treatment may reduce the risk of infections in CLL, as currently under investigation in the PreVent-ACaLL phase 2 trial of acalabrutinib+venetoclax for high-risk CLL (NCT03868722).

COVID-19 severity in patients with chronic lymphocytic leukemia treated with venetoclax: a single-center observational cohort study

Patients with chronic lymphocytic leukemia (CLL) are at high risk of developing severe COVID-19. The present study was undertaken to elucidate COVID-19 related morbidity and mortality in CLL patients treated with venetoclax. We present a single-center study of 108 patients with small lymphocytic lymphoma or CLL treated with venetoclax. Primary outcome was 30-day COVID-19 mortality. Secondary outcomes included COVID-19 severity and hospitalization rate. Forty-eight (44%) patients had PCR-verified SARS-COV-2 between March 2020 and January 2023. Thirty-six patients (75%) presented with asymptomatic/mild COVID-19 and 12 (25%) with severe/critical disease. The hospitalization rate was 46% with a 30-day mortality rate of only 4% and severe comorbidities as the primary cause of death. COVID-19 severity and mortality were similar before and during the Omicron era. High CIRS-scores (P < 0.02) and thrombocytopenia (P < 0.01) were more frequent in patients with severe/critical disease. In real-world data, most venetoclax treated patients presented with mild COVID-19. Hospitalization and mortality rates were low compared to data of general CLL populations. Our data indicate that venetoclax was a safe treatment option for CLL patients during the pandemic.

It is feasible and safe to stop specialized follow-up of asymptomatic lower risk chronic lymphocytic leukemia

Approximately half of patients with chronic lymphocytic leukemia (CLL) will never require treatment, still they are recommended life-long specialized follow-up (sFU). To prioritize health care resources, local hospital management implemented ending sFU in asymptomatic patients with CLL international prognostic index (CLL-IPI) and CLL without need of treatment (CLL-WONT) low to intermediate risk, who were covered by universal health care. To evaluate the feasibility and safety of ending sFU, we investigated 3-year clinical outcomes among 112 patients selected by clinical assessment to end sFU as compared with 88 patients continuing sFU. Patients who ended sFU were older but otherwise lower risk compared with patients continuing sFU. Overall survival (OS) was similar in patients ending and continuing sFU (3-year OS 87% and 80%, respectively; P=0.16). Hospital visits per patient-year were lower (median 0.7 vs 4.3, P<0.0001) and time to first infection was longer (P=0.035) in patients ending sFU as compared with those who continued sFU: this included fewer COVID infections (8 [7%] vs 17 [18%]; P=0.029) and shorter in-hospital antimicrobial treatment (median 4 vs 12 days, respectively; P=0.026). Finally, one in six patients got re-referred including 4 patients meeting iwCLL criteria for need of treatment. This also resulted in a lower 3-year first treatment rate for patients ending sFU compared with patients continuing sFU (4% vs 23%, respectively; P<0.0001). In conclusion, it is feasible and safe to end sFU for patients with CLL who have low to intermediate risk CLL-IPI and CLL-WONT scores upon thorough clinical evaluation prior to ending specialized follow-up.

Treatment effect modifiers in hospitalised patients with COVID-19 receiving remdesivir and dexamethasone

BACKGROUND

The combined effectiveness of remdesivir and dexamethasone in subgroups of hospitalised patients with COVID-19 is poorly investigated.

METHODS

In this nationwide retrospective cohort study, we included 3826 patients with COVID-19 hospitalised between February 2020 and April 2021. The primary outcomes were use of invasive mechanical ventilation and 30-day mortality, comparing a cohort treated with remdesivir and dexamethasone with a previous cohort treated without remdesivir and dexamethasone. We used inverse probability of treatment weighting logistic regression to assess associations with progression to invasive mechanical ventilation and 30-day mortality between the two cohorts. The analyses were conducted overall and by subgroups based on patient characteristics.

RESULTS

Odds ratio for progression to invasive mechanical ventilation and 30-day mortality in individuals treated with remdesivir and dexamethasone compared to treatment with standard of care alone was 0.46 (95% confidence interval, 0.37-0.57) and 0.47 (95% confidence interval, 0.39-0.56), respectively. The reduced risk of mortality was observed in elderly patients, overweight patients and in patients requiring supplemental oxygen at admission, regardless of sex, comorbidities and symptom duration.

CONCLUSIONS

Patients treated with remdesivir and dexamethasone had significantly improved outcomes compared to patients treated with standard of care alone. These effects were observed in most patient subgroups.

Erratum: Author Correction: Early stimulated immune responses predict clinical disease severity in hospitalized COVID-19 patients

[This corrects the article DOI: 10.1038/s43856-022-00178-5.].

Different prognostic impact of recurrent gene mutations in chronic lymphocytic leukemia depending on IGHV gene somatic hypermutation status: a study by ERIC in HARMONY

Recent evidence suggests that the prognostic impact of gene mutations in patients with chronic lymphocytic leukemia (CLL) may differ depending on the immunoglobulin heavy variable (IGHV) gene somatic hypermutation (SHM) status. In this study, we assessed the impact of nine recurrently mutated genes (BIRC3, EGR2, MYD88, NFKBIE, NOTCH1, POT1, SF3B1, TP53, and XPO1) in pre-treatment samples from 4580 patients with CLL, using time-to-first-treatment (TTFT) as the primary end-point in relation to IGHV gene SHM status. Mutations were detected in 1588 (34.7%) patients at frequencies ranging from 2.3-9.8% with mutations in NOTCH1 being the most frequent. In both univariate and multivariate analyses, mutations in all genes except MYD88 were associated with a significantly shorter TTFT. In multivariate analysis of Binet stage A patients, performed separately for IGHV-mutated (M-CLL) and unmutated CLL (U-CLL), a different spectrum of gene alterations independently predicted short TTFT within the two subgroups. While SF3B1 and XPO1 mutations were independent prognostic variables in both U-CLL and M-CLL, TP53, BIRC3 and EGR2 aberrations were significant predictors only in U-CLL, and NOTCH1 and NFKBIE only in M-CLL. Our findings underscore the need for a compartmentalized approach to identify high-risk patients, particularly among M-CLL patients, with potential implications for stratified management.

Early stimulated immune responses predict clinical disease severity in hospitalized COVID-19 patients

Background

The immune pathogenesis underlying the diverse clinical course of COVID-19 is poorly understood. Currently, there is an unmet need in daily clinical practice for early biomarkers and improved risk stratification tools to help identify and monitor COVID-19 patients at risk of severe disease.

Methods

We performed longitudinal assessment of stimulated immune responses in 30 patients hospitalized with COVID-19. We used the TruCulture whole-blood ligand-stimulation assay applying standardized stimuli to activate distinct immune pathways, allowing quantification of cytokine responses. We further characterized immune cell subsets by flow cytometry and used this deep immunophenotyping data to map the course of clinical disease within and between patients.

Results

Here we demonstrate impairments in innate immune response pathways at time of COVID-19 hospitalization that are associated with the development of severe disease. We show that these impairments are transient in those discharged from hospital, as illustrated by functional and cellular immune reconstitution. Specifically, we identify lower levels of LPS-stimulated IL-1β, and R848-stimulated IL-12 and IL-17A, at hospital admission to be significantly associated with increasing COVID-19 disease severity during hospitalization. Furthermore, we propose a stimulated immune response signature for predicting risk of developing severe or critical COVID-19 disease at time of hospitalization, to validate in larger cohorts.

Conclusions

We identify early impairments in innate immune responses that are associated with subsequent COVID-19 disease severity. Our findings provide basis for early identification of patients at risk of severe disease which may have significant implications for the early management of patients hospitalized with COVID-19.

Pre-diagnostic trajectories of lymphocytosis predict time to treatment and death in patients with chronic lymphocytic leukemia

Background

The dynamics of pre-diagnostic lymphocytosis in patients with ensuing chronic lymphocytic leukemia (CLL) need to be explored as a better understanding of disease progression may improve treatment options and even lead to disease avoidance approaches. Our aim was to investigate the development of lymphocytosis prior to diagnosis in a population-based cohort of patients with CLL and to assess the prognostic information in these pre-diagnostic measurements.

Methods

All patients diagnosed with CLL in the Greater Copenhagen area between 2008 and 2016 were included in the study. Pre-diagnostic blood test results were obtained from the Copenhagen Primary Care Laboratory Database encompassing all blood tests requested by Copenhagen general practitioners. Using pre-diagnostic measurements, we developed a model to assess the prognosis following diagnosis. Our model accounts for known prognostic factors and corresponds to lymphocyte dynamics after diagnosis.

Results

We explore trajectories of lymphocytosis, associated with known recurrent mutations. We show that the pre-diagnostic trajectories are an independent predictor of time to treatment. The implementation of pre-diagnostic lymphocytosis slope groups improved the model predictions (compared to CLL-IPI alone) for treatment throughout the period. The model can manage the heterogeneous data that are to be expected from the real-world setting and adds further prognostic information.

Conclusions

Our findings further knowledge of the development of CLL and may eventually make prophylactic measures possible.

While clinicians largely agree that patients with chronic lymphocytic leukemia (CLL) have increased levels of white blood cells in the years preceding their diagnosis, there is less certainty as to how and when this increase occurs. A better understanding of how white blood cell levels change during this period might help us to predict who will become ill and require treatment. In this work, we explore patterns of white blood cell growth and develop a tool to predict the time to treatment for CLL based on these growth rates. Using our tool in the clinic might help clinicians to decide who needs treatment for CLL and when, potentially leading to better outcomes for patients.

Andersen et al. evaluate lymphocyte dynamics in chronic lymphocytic leukemia (CLL) patients prior to diagnosis. The authors develop a model to predict risk of requiring CLL treatment or death based on pre-diagnostic lymphocyte growth rates.

Identifying patients with chronic lymphocytic leukemia without need of treatment: End of endless watch and wait?

INTRODUCTION

Early-stage chronic lymphocytic leukemia (CLL) challenges specialized management and follow-up.

METHODS

We developed and validated a prognostic index to identify newly diagnosed patients without need of treatment (CLL-WONT) by a training/validation approach using data on 4708 patients. Composite scores derived from weighted hazards by multivariable analysis defined CLL-WONT risk groups.

RESULTS

Age (>65 years: 1 point), Binet stage (B: 2 points), lactate dehydrogenase (LDH) (>205 U/L: 1 point), absolute lymphocyte count (15-30 × 10⁹ /L: 1 point; >30 × 10⁹ /L; 2 points), β2-microglobulin (>4 mg/L: 1 point), IGHV mutation status (unmutated: 1 point), and 11q or 17p deletion (1 point) were independently associated with shorter time to first treatment (TTFT). Low-risk patients demonstrated 5-year TTFT of 2% by internal validation, but 7-19% by external validation. Including all patients with complete scores, the 5-year TTFT was 10% for the 756 (39%) CLL-WONT low-risk patients, and the 704 (37%) patients who were both CLL-WONT and CLL-IPI low risk demonstrated even lower 5-year TTFT (8%).

CONCLUSION

We have adopted the CLL-WONT at an institution covering 1 800 000 individuals to allow patients with both low-risk CLL-WONT and CLL-IPI to be managed by primary healthcare providers, thereby prioritizing specialized hematology services for patients in dire need.

Facilitating EMA binding test performance using fluorescent beads combined with next‐generation sequencing

The eosin‐5′‐maleimide (EMA) binding test is widely used as diagnostic test for hereditary spherocytosis (HS), one of the most common haemolytic disorders in Caucasian populations. We recently described the advantages of replacing the use of healthy control blood samples with fluorescent beads in a modified EMA binding assay. In this study we further explore this novel approach. We performed targeted next‐generation sequencing, modified EMA binding test and osmotic gradient ektacytometry on consecutive individuals referred to our laboratory on the suspicion of HS. In total, 33 of 95 carried a (likely) pathogenic variant, and 24 had variants of uncertain significance (VUS). We identified a total 79 different (likely) pathogenic variants and VUS, including 43 novel mutations. Discarding VUS and recessive mutations in STPA1, we used the occurrence of (likely) pathogenic variants to generate a diagnostic threshold for our modified EMA binding test. Twenty‐one of 23 individuals with non‐SPTA1 (likely) pathogenic variants had EMA ≥ 43.6 AU, which was the optimal threshold in receiver operating characteristic (ROC) analysis. Accuracy was excellent at 93.4% and close to that of osmotic gradient ektacytometry (98.7%). In conclusion, we were able to simplify the EMA‐binding test by using rainbow beads as reference and (likely) pathogenic variants to define an accurate cut‐off value.

Improved survival among hospitalized patients with COVID-19 treated with remdesivir and dexamethasone. A nationwide population-based cohort study

Background

There are limited data on outcomes of moderate to severe coronavirus disease 2019 (COVID-19) among patients treated with remdesivir and dexamethasone in a real-world setting. We sought to compare the effectiveness of standard of care (SOC) alone versus SOC plus remdesivir and dexamethasone.

Methods

Two population-based nationwide cohorts of individuals hospitalized with COVID-19 during February through December 2020 were studied. Death within 30 days and need of mechanical ventilation (MV) were compared by inverse probability of treatment weighted (ITPW) logistic regression analysis and shown as odds ratio (OR) with 95% confidence interval (CI).

Results

The 30-days mortality rate of 1694 individuals treated with remdesivir and dexamethasone in addition to SOC was 12.6% compared to 19.7% for 1053 individuals receiving SOC alone. This corresponded to a weighted OR of 30-day mortality of 0.47 (95% CI: .38–.57) for patients treated with remdesivir and dexamethasone compared to patients receiving SOC alone. Similarly, progression to MV was reduced (OR 0.36; 95% CI: .29–.46).

Conclusions

Treatment of moderate to severe COVID-19 during June through December that included remdesivir and dexamethasone was associated with reduced 30-day mortality and need of MV compared to treatment in February through May.

Clinical Outcomes in Patients with Multi-Hit TP53 Chronic Lymphocytic Leukemia Treated with Ibrutinib

PURPOSE

TP53 aberration (TP53 mutation and/or 17p deletion) is the most important predictive marker in chronic lymphocytic leukemia (CLL). Although each TP53 aberration is considered an equal prognosticator, the prognostic value of carrying isolated (single-hit) or multiple (multi-hit) TP53 aberrations remains unclear, particularly in the context of targeted agents.

PATIENTS AND METHODS

We performed deep sequencing of TP53 using baseline samples collected from 51 TP53 aberrant patients treated with ibrutinib in a phase II study (NCT01500733).

RESULTS

We identified TP53 mutations in 43 patients (84%) and del(17p) in 47 (92%); 9 and 42 patients carried single-hit and multi-hit TP53, respectively. The multi-hit TP53 subgroup was enriched with younger patients who had prior treatments and unmutated immunoglobulin heavy-chain variable region gene status. We observed significantly shorter overall survival, progression-free survival (PFS), and time-to-progression (TTP) in patients with multi-hit TP53 compared with those with single-hit TP53. Clinical outcomes were similar in patient subgroups stratified by 2 or >2 TP53 aberrations. In multivariable analyses, multi-hit TP53 CLL was independently associated with inferior PFS and TTP. In sensitivity analyses, excluding mutations below 1% VAF demonstrated similar outcome. Results were validated in an independent population-based cohort of 112 patients with CLL treated with ibrutinib.

CONCLUSIONS

In this study, single-hit TP53 defines a distinct subgroup of patients with an excellent long-term response to single-agent ibrutinib, whereas multi-hit TP53 is independently associated with shorter PFS. These results warrant further investigations on prognostication and management of multi-hit TP53 CLL.See related commentary by Bomben et al., p. 4462.

Prognostic factors of 90-day mortality in patients hospitalised with COVID-19

INTRODUCTION

Mortality due to COVID-19 is higher among elderly patients with comorbidities. Even so, prognostication in COVID-19 remains limited.

METHODS

We assessed 90-day mortality stratified by comorbidities, routine biochemical markers and oxygen need in a consecutive single-centre cohort from 2 March to 2 June 2020.

RESULTS

We included 263 hospitalised patients with laboratory-confirmed COVID-19. On admission, fitness for intensive care was determined in 254 patients including 98 (39%) with a do-not-resuscitate order. Ninety-day overall mortality was 29%, whereas intensive care unit (ICU) mortality was 35% (14/40). Alcohol abuse, liver disease and elevated urea were strongly associated with mortality in univariable analyses. In a mutually adjusted multivariable analysis, we found an independent incremental increase in 90-day mortality with each increasing age by decade (hazard ratio (HR) = 1.5; 95% confidence interval (CI): 1.2-1.9), Charlson Comorbidity Index (CCI) score (HR = 1.2; 95% CI: 1.0-1.4), number of abnormal blood tests (HR = 1.2; 95% CI: 1.1-1.3) and l/min. of supplemental oxygen (HR = 1.1; 95% CI: 1.1-1.2).

CONCLUSIONS

The overall mortality was similar to that of other hospitalised patients, whereas the ICU mortality was lower than expected. On admission, each additional age by decade, CCI score, number of abnormal blood tests and magnitude of supplemental oxygen were independently associated with increased mortality.

FUNDING

none.

TRIAL REGISTRATION

not relevant.

Improving the EMA Binding Test by Using Commercially Available Fluorescent Beads

Hereditary spherocytosis (HS) is a common anemia caused by germline mutations in red blood cell cytoskeleton proteins. The flow cytometry-based eosin-5′-maleimide (EMA) binding test is most frequently employed for reliable diagnostics. To perform this test, a number of healthy and ideally also age-matched controls are required, which can be challenging and complicates interlaboratory comparisons. To overcome this limitation, we modified the EMA binding test by replacing healthy controls with commercially available fluorescent beads. Blood samples from 289 individuals with suspected HS were analyzed using the EMA binding test with fluorescent beads and benchmarked against regular EMA binding test using two control samples. Using osmotic gradient ektacytometry as validation, 112 individuals (38.8%) were diagnosed with HS. Performance of the modified EMA binding test was not compromised (accuracy 90.3%) compared to EMA binding test using matched controls (accuracy 88.6%). Based on these findings, we conclude that the modified EMA binding test with fluorescent beads is an attractive alternative, especially in laboratories without easy access to matched controls. Furthermore, as fluorescent beads are stable and easily commutable, they could facilitate both interlaboratory comparisons and quality assessment programs.

Richter's transformation in patients with chronic lymphocytic leukaemia: a Nationwide Epidemiological Study

Richter's transformation (RT) refers to the development of an aggressive lymphoma in patients with chronic lymphocytic leukemia (CLL). Approximately, 2-10% of patients with CLL develop RT, most often as diffuse large B-cell lymphoma. To assess the incidence of RT, we examined risk factors for RT and death among patients with RT in a nationwide CLL cohort (from 2008 to 2016). Among 3772 patients, 113 had biopsy-proven RT. With a median follow-up of 4.3 years, the 5-year cumulative incidence of RT was 2.8%. Advanced Binet stage (B/C) (p<.001), unmutated IGHV (p<.001), and del(17p) (p<.001) were independently associated with risk of developing RT. Half of the patients with RT (49%) were treatment-naïve prior to transformation and demonstrated longer survival after RT compared to patients previously treated for CLL (6.1 vs. 2.8 years, p=.03). Whether this finding could be explained by a higher proportion of clonally unrelated RT among treatment-naïve patients, remain to be addressed.

The Number of Signaling Pathways Altered by Driver Mutations in Chronic Lymphocytic Leukemia Impacts Disease Outcome

PURPOSE

Investigation of signaling pathways altered by recurrent gene mutations and their clinical impact in a consecutive cohort of patients with newly diagnosed chronic lymphocytic leukemia (CLL). The heterogeneous clinical course and genetic complexity of CLL warrant improved molecular prognostication. However, the prognostic value of recurrent mutations at the time of diagnosis remains unclear.

EXPERIMENTAL DESIGN

We sequenced samples from 314 consecutive, newly diagnosed patients with CLL to investigate the clinical impact of 56 recurrently mutated genes assessed by next-generation sequencing.

RESULTS

Mutations were identified in 70% of patients with enrichment among IGHV unmutated cases. With 6.5 years of follow-up, 15 mutated genes investigated at the time of diagnosis demonstrated significant impact on time to first treatment (TTFT). Carrying driver mutations was associated with shorter TTFT and poor overall survival. For outcome from CLL diagnosis, the number of signaling pathways altered by driver mutations stratified patients better than the number of driver mutations. Moreover, we demonstrated gradual impact on TTFT with increasing number of altered pathways independent of CLL-IPI risk. Thus, a 25-gene, pathway-based biomarker assessing recurrent mutations refines prognostication in CLL, in particular for CLL-IPI low- and intermediate-risk patients. External validation emphasized that a broad gene panel including low burden mutations was key for the biomarker based on altered pathways.

CONCLUSIONS

We propose to include the number of pathways altered by driver mutations as a biomarker together with CLL-IPI in prospective studies of CLL from time of diagnosis for incorporation into clinical care and personalized follow-up and treatment.

Risk factors associated with Richter's transformation in patients with chronic lymphocytic leukaemia: protocol for a retrospective population-based cohort study

INTRODUCTION

Richter's transformation (RT) refers to the development of an aggressive lymphoma in patients with chronic lymphocytic leukaemia (CLL) or small lymphocytic lymphoma. Studies have shown that 2-10% of patients with CLL develop RT including diffuse large B-cell lymphoma (DLBCL) and less common Hodgkin lymphoma (HL). This study aims to assess the risk factors for RT of CLL in a nationwide cohort. Additionally, we want to examine prognostic factors in patients with RT. These findings may guide management of treated as well as untreated patients with CLL in the risk of RT.

METHODS

Clinical data for patients diagnosed with CLL between 2008 and 2016 will be retrieved from the Danish National CLL registry (DCLLR). Using the Danish unique person identification number, clinical data will be merged with histologically verified DLBCL and/or HL diagnoses retrieved from the Danish National Pathology Data Bank. This will ensure complete follow-up for all patients.The DCLLR includes data from more than 4000 patients with CLL ensuring a median follow-up of 3 years. With the reported incidences (2-10%) of RT, we expect to identify 80-200 CLL patients with RT enabling analysis of overall survival following RT. From time of CLL diagnosis, estimates of cumulative incidence of RT will be calculated using the Aalen-Johansen estimator. From time of RT diagnosis, survival analysis will be performed by Kaplan-Meier method. Cox proportional hazards models will be used for multivariable survival analysis.

ETHICS AND DISSEMINATION

Approvals for data collection and analysis was obtained from the Danish Data Protection Agency and the Danish Health Authorities. All data will be managed confidentially according to guidelines and legislation. The dissemination will include a publication of scientific papers and/or presentations of the study findings at international conferences.

Deep targeted sequencing of TP53 in chronic lymphocytic leukemia: clinical impact at diagnosis and at time of treatment

In chronic lymphocytic leukemia, TP53 mutations and deletion of chromosome 17p are well-characterized biomarkers associated with poor progression-free and overall survival following chemoimmunotherapy. Patients harboring low burden TP53 mutations with variant allele frequencies of 0.3-15% have been shown to have similar dismal outcome as those with high burden mutations. We here describe a highly sensitive deep targeted next-generation sequencing assay allowing for the detection of TP53 mutations as low as 0.2% variant allele frequency. Within a consecutive, single center cohort of 290 newly diagnosed patients with chronic lymphocytic leukemia, deletion of chromosome 17p was the only TP53 aberration significantly associated with shorter overall survival and treatment-free survival. We were unable to demonstrate any impact of TP53 mutations, whether high burden (variant allele frequency >10%) or low burden (variant allele frequency ≤10%), in the absence of deletion of chromosome 17p. In addition, the impact of high burden TP53 aberration (deletion of chromosome 17p and/or TP53 mutation with variant allele frequency >10%) was only evident for patients with IGHV unmutated status; no impact of TP53 aberrations on outcome was seen for patients with IGHV mutated status. In 61 patients at time of treatment, the prognostic impact of TP53 mutations over 1% variant allele frequency could be confirmed. This study furthers the identification of a clinical significant limit of detection for robust TP53 mutation analysis in chronic lymphocytic leukemia. Multicenter studies are needed for validation of ultra-sensitive TP53 mutation assays in order to define and implement a technical as well as a clinical lower limit of detection.

Novel 31.2 kb α0 Deletion in a Palestinian Family with α-Thalassemia

A previously unknown α(0) deletion, designated - -(DANE), was found in three generations of a Danish family of Palestinian origin. Six patients were heterozygous and three patients had deletional Hb H (β4) disease with a compound heterozygosity for the common -α(3.7) (rightward) deletion. Multiplex ligation-dependent probe amplification (MLPA) supplemented by repeated polymerase chain reaction (PCR) amplification identified the 5' and 3' breakpoints in the α-globin gene cluster. This novel 31.2 kb deletion (NG_000006.1: g.8800_40007del31208) leads to the removal of the HBZ, HBA2 and HBA1 genes.