BCL3 rearrangements in B-cell lymphoid neoplasms occur in two breakpoint clusters associated with different diseases.

The t(14;19)(q32;q13) often juxtaposes BCL3 with immunoglobulin heavy chain (IGH) resulting in overexpression of the gene. In contrast to other oncogenic translocations, BCL3 rearrangement (BCL3-R) has been associated with a broad spectrum of lymphoid neoplasms. Here we report an integrative whole-genome sequence, transcriptomic, and DNA methylation analysis of 13 lymphoid neoplasms with BCL3-R. The resolution of the breakpoints at single base-pair revealed that they occur in two clusters at 5' (n=9) and 3' (n=4) regions of BCL3 associated with two different biological and clinical entities. Both breakpoints were mediated by aberrant class switch recombination of the IGH locus. However, the 5' breakpoints (upstream) juxtaposed BCL3 next to an IGH enhancer leading to overexpression of the gene whereas the 3' breakpoints (downstream) positioned BCL3 outside the influence of the IGH and were not associated with its expression. Upstream BCL3-R tumors had unmutated IGHV, trisomy 12, and mutated genes frequently seen in chronic lymphocytic leukemia (CLL) but had an atypical CLL morphology, immunophenotype, DNA methylome, and expression profile that differ from conventional CLL. In contrast, downstream BCL3-R neoplasms were atypical splenic or nodal marginal zone lymphomas (MZL) with mutated IGHV, complex karyotypes and mutated genes typical of MZL. Two of the latter four tumors transformed to a large B-cell lymphoma. We designed a novel fluorescence in situ hybridization assay that recognizes the two different breakpoints and validated these findings in 17 independent tumors. Overall, upstream or downstream breakpoints of BCL3-R are mainly associated with two subtypes of lymphoid neoplasms with different (epi)genomic, expression, and clinicopathological features resembling atypical CLL and MZL, respectively.

Adherence to the Western, Prudent, and Mediterranean dietary patterns and chronic lymphocytic leukemia in the MCC-Spain study.

Diet is a modifiable risk factor for several neoplasms but evidence for chronic lymphocytic leukemia (CLL) is sparse. Previous studies examining the association between single-food items and CLL risk have yielded mixed results, while few studies have been conducted on overall diet, reporting inconclusive findings. This study aimed to evaluate the association between adherence to three dietary patterns and CLL in the multicase-control study (MCC-Spain) study. Anthropometric, sociodemographic, medical and dietary information was collected for 369 CLL cases and 1605 controls. Three validated dietary patterns, Western, Prudent and Mediterranean, were reconstructed in the MCC-Spain data. The association between adherence to each dietary pattern and CLL was assessed, overall and by Rai stage, using mixed logistic regression models adjusted for potential confounders. High adherence to a Western dietary pattern (i.e. high intake of high-fat dairy products, processed meat, refined grains, sweets, caloric drinks, and convenience food) was associated with CLL [ORQ4 vs. Q1=1.63 (95%CI 1.11; 2.39); P-trend=0.02; OR 1-SD increase=1.19 (95%CI: 1.03; 1.37)], independently of Rai stages. No differences in the association were observed according to sex, Body Mass Index, energy intake, tobacco, physical activity, working on a farm, or family history of hematologic malignancies. No associations were observed for Mediterranean and Prudent dietary patterns and CLL. This study provides the first evidence for an association between a Western dietary pattern and CLL, suggesting that a proportion of CLL cases could be prevented by modifying dietary habits. Further research, especially with a prospective design, is warranted to confirm these findings.

The prohibitin-binding compound fluorizoline induces apoptosis in chronic lymphocytic leukemia cells through the upregulation of NOXA and synergizes with ibrutinib, 5-aminoimidazole-4-carboxamide riboside or venetoclax.

Fluorizoline is a new synthetic molecule that induces apoptosis by selectively targeting prohibitins. In the study herein, the pro-apoptotic effect of fluorizoline was assessed in 34 primary samples from patients with chronic lymphocytic leukemia. Fluorizoline induced apoptosis in chronic lymphocytic leukemia cells at concentrations in the low micromolar range. All primary samples were sensitive to fluorizoline irrespective of patients' clinical or genetic features, whereas normal T lymphocytes were less sensitive. Fluorizoline increased the protein levels of the pro-apoptotic B-cell lymphoma 2 family member NOXA in chronic lymphocytic leukemia cells. Furthermore, fluorizoline synergized with ibrutinib, 5-aminoimidazole-4-carboxamide riboside or venetoclax to induce apoptosis. These results suggest that targeting prohibitins could be a new therapeutic strategy for chronic lymphocytic leukemia.

Night shift work and chronic lymphocytic leukemia in the MCC-Spain case-control study.

Chronic lymphocytic leukemia (CLL) has few known modifiable risk factors. Recently, circadian disruption has been proposed as a potential contributor to lymphoid neoplasms' etiology. Serum melatonin levels have been found to be significantly lower in CLL subjects compared with healthy controls, and also, CLL prognosis has been related to alterations in the circadian molecular signaling. We performed the first investigation of an association between night shift work and CLL in 321 incident CLL cases and 1728 population-based controls in five areas of Spain. Participants were interviewed face-to-face by trained interviewers to collect information on sociodemographic factors, familial, medical and occupational history, including work shifts and other lifestyle factors. We used logistic regression models adjusted for potential confounders to estimate odds ratios (OR) and 95% confidence intervals (CI). Seventy-nine cases (25%) and 339 controls (20%) had performed night work. Overall, working in night shifts was not associated with CLL (OR = 1.06; 95% CI = 0.78-1.45, compared with day work). However, long-term night shift (>20 years) was positively associated with CLL (OR(tertile 3 vs . day-work) = 1.77; 95% = 1.14-2.74), although no linear trend was observed (P trend = 0.18). This association was observed among those with rotating (OR(tertile 3 vs . day-work) = 2.29; 95% CI = 1.33-3.92; P trend = 0.07), but not permanent night shifts (OR(tertile 3 vs . day-work) = 1.16; 95% CI = 0.60-2.25; P trend = 0.86). The association between CLL and long-term rotating night shift warrants further investigation.

CD34 expression and the outcome of nucleophosmin 1-mutated acute myeloid leukemia.

CD34 positivity has been considered as an adverse prognostic factor in acute myeloid leukemia (AML). Although nucleophosmin 1-mutated (NPM1m) AML is usually CD34 negative, this marker may be expressed at diagnosis or acquired at relapse in a variable number of cases. Our objective was to ascertain if CD34 expression has any influence on the general outcome of this form of acute leukemia. Analysis of clinical outcome (complete remissions, relapses, disease-free survival, and overall survival) was performed depending on the degree of expression of CD34 determined by flow cytometry, in 67 adult patients with NPM1m AML. CD34 expression did not have any influence on the variables analyzed whatever the percentage of blasts expressing this marker. In contrast to other forms of AML, CD34 expression is not an unfavorable prognostic factor in NPM1m AML, neither at diagnosis nor at relapse.

Multilineage dysplasia is associated with a poorer prognosis in patients with de novo acute myeloid leukemia with intermediate-risk cytogenetics and wild-type NPM1.

Acute myeloid leukemia (AML) with myelodysplasia-related changes is characterized by the presence of multilineage dysplasia (MLD), frequently related to high-risk cytogenetics and poor outcome. However, the presence of MLD does not modify the favorable prognostic impact of NPM1 mutation. The prognosis of patients with AML presenting marked dysplasia lacking high-risk cytogenetics and NPM1 mutation is uncertain. We evaluated the prognostic impact of MLD in 177 patients with intermediate-risk cytogenetics AML (IR-AML) and wild-type NPM1. Patients were categorized as MLD-WHO (WHO myelodysplasia criteria; n = 43, 24 %), MLD-NRW (significant MLD non-reaching WHO criteria; n = 16, 9 %), absent MLD (n = 80, 45 %), or non-evaluable MLD (n = 38, 22 %). No differences concerning the main characteristics were observed between patients with or without MLD. Outcome of patients with MLD-WHO and MLD-NRW was similar, and significantly worse than patients lacking MLD. The presence of MLD (66 vs. 80 %, p = 0.03; HR, 95 % CI = 2.3, 1.08-4.08) and higher leukocyte count at diagnosis was the only variable associated with lower probability of complete remission after frontline therapy. Concerning survival, age and leukocytes showed an independent prognostic value, whereas MLD showed a trend to a negative impact (p = 0.087, HR, 95 % CI = 1.426, 0.95-2.142). Moreover, after excluding patients receiving an allogeneic stem cell transplantation in first CR, MLD was associated with a shorter survival (HR, 95 % CI = 1.599, 1.026-2.492; p = 0.038). In conclusion, MLD identifies a subgroup of patients with poorer outcome among patients with IR-AML and wild-type NPM1.

Consumption of Ultra-Processed Food and Drinks and Chronic Lymphocytic Leukemia in the MCC-Spain Study.

Chronic lymphocytic leukemia (CLL) is the most common leukemia in adults in Western countries. Its etiology is largely unknown but increasing incidence rates observed worldwide suggest that lifestyle and environmental factors such as diet might play a role in the development of CLL. Hence, we hypothesized that the consumption of ultra-processed food and drinks (UPF) might be associated with CLL. Data from a Spanish population-based case-control study (MCC-Spain study) including 230 CLL cases (recruited within three years of diagnosis) and 1634 population-based controls were used. The usual diet during the previous year was collected through a validated food frequency questionnaire and food and drink consumption was categorized using the NOVA classification scheme. Logistic regression models adjusted for potential confounders were used. Overall, no association was reported between the consumption of UPF and CLL cases (OR per each 10% increase of the relative contribution of UPF to total dietary intake = 1.09 (95% CI: 0.94; 1.25)), independently of the Rai stage at diagnosis. However, when analyses were restricted to cases diagnosed within <1 year (incident), each 10% increment in the consumption of UPF was associated with a 22% higher odds ratio of CLL (95% CI: 1.02, 1.47) suggesting that the overall results might be affected by the inclusion of prevalent cases, who might have changed their dietary habits after cancer diagnosis. Given the low number of cases in the subgroup analyses and multiple tests performed, chance findings cannot totally be ruled out. Nonetheless, positive associations found in CLL incident cases merit further research, ideally in well-powered studies with a prospective design.

Occupational Exposure to Pesticides and Chronic Lymphocytic Leukaemia in the MCC-Spain Study.

We aimed to study the association between occupational exposure to pesticides and chronic lymphocytic leukemia (CLL) in Spain. Occupational exposure to pesticides (four insecticides, four herbicides and two fungicides) was evaluated using a job-exposure matrix for the Spanish population (MatEmESp) among 302 CLL cases and 1567 population controls in five regions of Spain, 2010-2013. Cumulative exposure scores (CES) were obtained by summing across the exposed jobs the product of prevalence, intensity and duration of exposure to each active substance. Principal components analysis (PCA) and logistic regression models adjusted for age, sex, region, education and occupational exposure to solvents were used. Around 20% of controls and 29% of cases were exposed to one or more pesticides. Compared to non-exposed, subjects in the highest tertile (3rd tertile) of CES of insecticides, herbicides, fungicides were more likely to have CLL [OR (95% CI), P-trend; 2.10 (1.38; 3.19), 0.002; 1.77 (1.12; 2.80), 0.12; and 1.67 (1.06; 2.64), 0.10, respectively). Following PCA, the first component (PC1, explaining 70% of the variation) equally led by seven active substances (the insecticide pyrethrin, all herbicides, all fungicides) was associated with a 26% higher odds of having CLL for 1-standard deviation increase in PC1 (95% CI: 1.14 to 1.40). These results confirm previous associations between CLL and exposure to pesticides and provide additional evidence by application groups and active substance. However, more research is needed to disentangle independent effects of individual active substances.

Adherence to the 2018 WCRF/AICR cancer prevention guidelines and chronic lymphocytic leukemia in the MCC-Spain study.

INTRODUCTION: Preventable risk factors for chronic lymphocytic leukemia (CLL) remain largely unknown. The aim of this study was to evaluate the association between adherence to nutrition-based guidelines for cancer prevention and CLL, in the MCC-Spain case-control study. METHODS: A total of 318 CLL cases and 1293 population-based controls were included in the present study. The World Cancer Research Fund/American Institute for Cancer Research (WCRC/AICR) score based on the 2018 recommendations for cancer prevention (on body fatness, physical activity, and diet) was constructed. We used logistic regression analysis adjusting for potential confounders. RESULTS: Individuals in the highest tertile of the WCRF/AICR score had an odds ratio for CLL of 1.25 (95 % CI 0.91; 1.73) compared with individuals with low adherence (p-trend = 0.172). Each point increment in the score was associated with an OR for CLL of 1.06 (95 % CI 0.91; 1.23). Analyses by severity of disease did not show significant heterogeneity of effects. CONCLUSION: Overall, our results do not support an association between the WCRF/AICR score and CLL, yet we might have been limited by statistical power and study design to detect modest associations. Further research, ideally with a prospective design, long follow-up, and including additional lymphoma subtypes, is warranted to confirm the impact of composite healthy lifestyle behaviors on lymphoma risk.

Akt inhibitors induce apoptosis in chronic lymphocytic leukemia cells.

BACKGROUND: The phosphatidylinositol-3-kinase/Akt pathway has been described to be critical in the survival of chronic lymphocytic leukemia cells. In this study we analyzed the effect of two selective chemical inhibitors of Akt (Akti-1/2 and A-443654) on the survival of chronic lymphocytic leukemia cells. DESIGN AND METHODS: Using cytometry we studied the cytotoxic effects of Akt inhibitors on peripheral B and T lymphocytes from patients with chronic lymphocytic leukemia and from healthy donors. We studied the changes induced by Akti-1/2 and A-443654 at the mRNA level by performing reverse transcriptase multiplex ligation-dependent probe amplification. We also studied the changes induced by both Akt inhibitors in some BCL-2 protein family members on chronic lymphocytic leukemia cells by western blotting. Moreover, we analyzed the cytotoxic effect of Akt inhibitors in patients' cells with deleted/mutated TP53. RESULTS: Both inhibitors induced apoptosis in chronic lymphocytic leukemia cells in a dose-dependent manner. Moreover, B cells from patients with chronic lymphocytic leukemia were more sensitive to Akt inhibitors than T cells from leukemic patients, and B or T cells from healthy donors. Survival factors for chronic lymphocytic leukemia cells, such as interleukin-4 and stromal cell-derived factor-1alpha, were not able to block the apoptosis induced by either Akt inhibitor. Akti-1/2 did not induce any change in the mRNA expression profile of genes involved in apoptosis, while A-443654 induced some changes, including an increase in NOXA and PUMA mRNA levels, suggesting the existence of additional targets for A-443654. Both inhibitors induced an increase in PUMA and NOXA protein levels, and a decrease in MCL-1 protein level. Moreover, Akti-1/2 and A-443654 induced apoptosis irrespective of TP53 status. CONCLUSIONS: These results demonstrate that Akt inhibitors induce apoptosis of chronic lymphocytic leukemia cells and might be a new therapeutic option for the treatment of chronic lymphocytic leukemia.

The Dietary Inflammatory Index and Chronic Lymphocytic Leukaemia in the MCC Spain Study.

Chronic inflammation plays a role in the development of chronic lymphocytic leukaemia (CLL), and diet might modulate chronic inflammation. This study aims to evaluate the association between the dietary inflammatory index (DII®) and CLL. A total of 366 CLL cases and 1643 controls of the Spanish multicase-control (MCC) Spain study were included. The inflammatory potential of the diet was assessed using the energy-adjusted dietary inflammatory index (E-DII) based on 30 items from a validated semi-quantitative food frequency questionnaire. Odds ratios (OR) and 95% confidence intervals (CI) were estimated using logistic regression models controlling for potential confounders. Overall, a modest, non-statistically significant, positive association was observed between CLL and E-DII scores (OR for a one-unit increase in E-DII: 1.05 (CI 95%: 0.99, 1.12), p-value = 0.09 and by tertiles: ORT2vsT1: 1.20 (CI 95%: 0.90, 1.59); OR T3vsT1: 1.21 (CI 95%: 0.90, 1.62), p trend = 0.21). These results were independent from disease severity (p-het: 0.70), time from diagnosis (p-het: 0.67) and CLL treatment received (p-het: 0.56). No interactions were detected. In conclusion, the consumption of a diet with high pro-inflammatory components was not significantly associated with CLL. Changes towards a more pro-inflammatory dietary pattern in younger generations not included here warrant future research.

Established and suggested exposures on CLL/SLL etiology: Results from the CLL-MCC-Spain study.

INTRODUCTION: Chronic Lymphocytic Leukemia (CLL/SLL) is the most common adult leukemia in Western countries. Although it is mostly an indolent disease it is still incurable and with limited knowledge in relation to its etiology. We aim to confirm and quantify established risk factors for CLL/SLL using a multi-center epidemiological population-based case-control study on CLL/SLL as well as to explore new exposures inconclusively associated with CLL/SLL METHODS: Using the framework provided by the large MCC-Spain case-control study, we explored established and suggested risk factors associated with CLL/SLL using data collected through a face-to-face interview. We estimated odds ratios (OR) and confidence intervals (CI) adjusted by basic confounders, in 1,845 controls from the general population and 560 CLL/SLL from 5 different Spanish regions. RESULTS: Among the established risk factors, CLL/SLL cases were 3 times more likely to report first degree relatives with an hematological cancer (OR = 3.11, 95% CI 2.10 to 4.61) and nearly twice likely to have ever worked in agriculture (OR = 1.70, 95% CI = 1.34 to 2.16). New findings suggest that women with CLL/SLL were more likely to have central obesity (OR = 1.67 95% CI = 1.12 to 2.48). An inverse association was found for current alcohol consumption (p-trend<0.016) and for type II diabetes. CONCLUSION: We confirmed previous established risk factors for CLL/SLL. Among the new findings, further research of central obesity as preventable exposure and the treatment for type II diabetes are warranted.

Liver transplantation across Rh blood group barriers increases the risk of biliary complications.

BACKGROUND: Cold ischemia time and the presence of postoperative hepatic arterial thrombosis have been associated with biliary complications (BC) after liver transplantation. An ABO-incompatible blood group has also been suggested as a factor for predisposal towards BC. However, the influence of Rh nonidentity has not been studied previously. MATERIALS: Three hundred fifty six liver transplants were performed from 1995 to 2000 at our hospital. BC incidence and risk factors were studied in 345 patients. RESULTS: Seventy patients (20%) presented BC after liver transplantation. Bile leakage (24/45%) and stenotic anastomosis (21/30%) were the most frequent complications. Presence of BC in Rh-nonidentical graft-host cases (23/76, 30%) was higher than in Rh-identical grafts (47/269, 17%) (P=0.01). BC was also more frequent in grafts with arterial thrombosis (9/25, 36% vs 60/319, 19%; P=0.03) and grafts with cold ischemia time longer than 430 min (26/174, 15% vs 44/171, 26%; P=0.01). Multivariate logistic regression confirmed that Rh graft-host nonidentical blood groups [RR=2(1.1-3.6); P=0.02], arterial thrombosis [RR=2.6(1.1-6.4); P=0.02] and cold ischemia time longer than 430 min [RR=1.8(1-3.2); P=0.02] were risk factors for presenting BC. CONCLUSION: Liver transplantation using Rh graft-host nonidentical blood groups leads to a greater incidence of BC.

Distinction between asymptomatic monoclonal B-cell lymphocytosis with cyclin D1 overexpression and mantle cell lymphoma: from molecular profiling to flow cytometry.

PURPOSE: According to current diagnostic criteria, mantle cell lymphoma (MCL) encompasses the usual, aggressive variants and rare, nonnodal cases with monoclonal asymptomatic lymphocytosis, cyclin D1-positive (MALD1). We aimed to understand the biology behind this clinical heterogeneity and to identify markers for adequate identification of MALD1 cases. EXPERIMENTAL DESIGN: We compared 17 typical MCL cases with a homogeneous group of 13 untreated MALD1 cases (median follow-up, 71 months). We conducted gene expression profiling with functional analysis in five MCL and five MALD1. Results were validated in 12 MCL and 8 MALD1 additional cases by quantitative reverse transcription polymerase chain reaction (qRT-PCR) and in 24 MCL and 13 MALD1 cases by flow cytometry. Classification and regression trees strategy was used to generate an algorithm based on CD38 and CD200 expression by flow cytometry. RESULTS: We found 171 differentially expressed genes with enrichment of neoplastic behavior and cell proliferation signatures in MCL. Conversely, MALD1 was enriched in gene sets related to immune activation and inflammatory responses. CD38 and CD200 were differentially expressed between MCL and MALD1 and confirmed by flow cytometry (median CD38, 89% vs. 14%; median CD200, 0% vs. 24%, respectively). Assessment of both proteins allowed classifying 85% (11 of 13) of MALD1 cases whereas 15% remained unclassified. SOX11 expression by qRT-PCR was significantly different between MCL and MALD1 groups but did not improve the classification. CONCLUSION: We show for the first time that MALD1, in contrast to MCL, is characterized by immune activation and driven by inflammatory cues. Assessment of CD38/CD200 by flow cytometry is useful to distinguish most cases of MALD1 from MCL in the clinical setting. MALD1 should be identified and segregated from the current MCL category to avoid overdiagnosis and unnecessary treatment.

Prospective study of clinical and biological prognostic factors at diagnosis in patients with early stage B-cell chronic lymphocytic leukemia.

Retrospective series have reported many clinical and biological significant prognostic factors in chronic lymphocytic leukemia (CLL). We describe a prospective cohort of 135 patients with CLL homogeneously studied at diagnosis for prognostic factors. Biological variables analyzed were CD38 and ZAP-70 expression, fluorescence in situ hybridization (FISH) for 13q-, +12, 11q-, and 17p-, and conventional cytogenetics. Univariate and multivariate analysis for progression-free survival (PFS) were performed in patients with early stage (Rai 0-1) CLL. CD38 was positive in 42 (31.6%) patients and ZAP-70 in 47 (35.9%). The most frequent FISH finding was isolated 13q- in 50 (38.5%) patients, and 17p- -was found in 11 (8.4%). Among 135 patients, 114 (84.4%) were Rai 0-1 at diagnosis and 39 (28.9%) presented adenopathies. With a median follow-up of 39 months, the presence of lymphadenopathy in patients with Rai 0-1 stage CLL was the only significant variable for predicting PFS in multivariate analysis (odds ratio [OR] 7, 95% confidence interval [CI] 2.2-22, p = 0.001). When only biological factors were analyzed, CD38 expression (OR 3.2, 95% CI 1.1-9.3, p = 0.03) and 17p- (OR 3.5, 95% CI 0.95-13.1, p = 0.05) correlated with worse PFS. A longer follow-up is necessary to analyze the prognostic value of these variables regarding overall survival.

Analysis of apoptosis regulatory genes altered by histone deacetylase inhibitors in chronic lymphocytic leukemia cells.

Histone deacetylases (HDACs) play a key role in the regulation of acetylation status not only of histones but also of many other non-histone proteins involved in cell cycle regulation, differentiation or apoptosis. Therefore, histone deacetylase inhibitors (HDACi) have emerged as promising anticancer agents. Herein, we report the characterization of apoptosis in B-cell chronic lymphocytic leukemia (CLL) induced by two HDACi, Kendine 92 and SAHA. Both inhibitors induce dose-, time- and caspase-dependent apoptosis through the mitochondrial pathway. Interestingly, Kendine 92 and SAHA show a selective cytotoxicity for B lymphocytes and induce apoptosis in CLL cells with mutated or deleted TP53 as effectively as in tumor cells harboring wild-type TP53. The pattern of apoptosis-related gene and protein expression profile has been characterized. It has shown to be irrespective of TP53 status and highly similar between SAHA and Kendine 92 exposure. The balance between the increased BAD, BNIP3L, BNIP3, BIM, PUMA and AIF mRNA expression levels, and decreased expression of BCL-W, BCL-2, BFL-1, XIAP and FLIP indicates global changes in the apoptosis mRNA expression profile consistent with the apoptotic outcome. Protein expression analysis shows increased levels of NOXA, BIM and PUMA proteins upon Kendine 92 and SAHA treatment. Our results highlight the capability of these molecules to induce apoptosis not only in a selective manner but also in those cells frequently resistant to standard treatments. Thus, Kendine 92 is a novel HDACi with anticancer efficacy for non-proliferating CLL cells.

[Persistent polyclonal B-cell lymphocytosis: study of 35 cases]. / Linfocitosis B policlonal persistente: estudio de 35 casos.

BACKGROUND AND OBJECTIVES: Persistent polyclonal B-cell lymphocytosis (PPBL) is a rare entity, presenting especially in adult smoker women. It is characterized by an increase of serum IgM, DR7-HLA haplotype, cytogenetic abnormalities and multiple IgH/BCL-2 rearrangements. To date, it has not been elucidated whether this is a benign or premalignant disorder. We analyzed the PPBL characteristics with especial attention to its evolution. PATIENTS AND METHODS: Thirty-five PPBL patients from 5 hospitals in Catalonia were retrospectively analyzed. A simultaneous morphologic review of the blood smears was performed by members of the GCCH in a 16 multiple-observer optic microscope. Clinical and biological data were also analyzed. RESULTS: PPBL presents in the majority of cases with persistent polyclonal B-cell lymphocytosis and affects primarily smoker women. The morphologic hallmark, in absence of viral infections, is the presence of activated lymphocytes with bilobulated and/or cleaved nuclei, and nuclear pockets in the ultrastructural study. Increased serum IgM, HLA-DR7 haplotype, chromosomal abnormalities such as i(3)(q10) and multiple IgH/BCL-2 rearrangements were detected. Thirty-four out of 35 patients are alive after a median follow up of 70.7 months. One patient died because of lung adenocarcinoma and another developed a follicular lymphoma without relation to PPBL. CONCLUSIONS: PPBL has an asymptomatic and stable evolution, although it frequently presents genetic abnormalities. It remains unknown whether it is a premalignant entity, similar to monoclonal gammopathies of unknown significance. Hence, accurate cytologic diagnosis and follow-up are essential.