Differentiating chronic lymphocytic leukemia from monoclonal B-lymphocytosis according to clinical outcome: on behalf of the GIMEMA chronic lymphoproliferative diseases working group

Immunophenotyping for the Assessment of Asymptomatic Lymphocytosis: A Retrospective Analysis and National Survey

Asymptomatic lymphocytosis poses a common challenge in haematology. Immunophenotyping can establish whether a clonal population is present, but it is expensive and the benefit of diagnosing asymptomatic patients is unproven. This study aimed to establish data to guide the use of immunophenotyping. We analysed the proportion of lymphocytosis in full blood count (FBC) samples across a five-year period within a large UK National Health Service (NHS) trust. Persistent lymphocytosis was present in 0.18% (437/242678) of repeat community samples. Of samples sent for immunophenotyping, 743/784 (95%) with a lymphocyte count > 10 × 109/L had a clonal population, compared to 223/1696 (14%) with a lymphocyte count < 5 × 109/L. We followed up a longitudinal cohort of asymptomatic patients with clonal lymphocytosis to determine how many required treatment. The minority (11/46) of patients needed treatment within 9 years of follow-up. Of patients needing treatment, 10/11 (91%) had a presenting lymphocyte count > 10 × 109/L. In all cases, treatment was initiated when the patient became symptomatic. We propose a lymphocyte count threshold of > 10 × 109/L for referral and immunophenotyping in patients with asymptomatic lymphocytosis. This approach aims to balance safety and cost-effectiveness and reflects uncertainty in the value of diagnosis for asymptomatic patients.

Multiple COVID-19 vaccine doses in CLL and MBL improve immune responses with progressive and high seroconversion

Patients with chronic lymphocytic leukemia (CLL) or monoclonal B-lymphocytosis (MBL) have impaired response to COVID-19 vaccination. A total of 258 patients (215 with CLL and 43 with MBL) had antispike antibody levels evaluable for statistical analysis. The overall seroconversion rate in patients with CLL was 94.2% (antispike antibodies ≥50 AU/mL) and 100% in patients with MBL after multiple vaccine doses. After 3 doses (post-D3) in 167 patients with CLL, 73.7% were seropositive, 17.4% had antispike antibody levels between 50 and 999 AU/mL, and 56.3% had antispike antibody levels ≥1000 AU/mL, with a median rise from 144.6 to 1800.7 AU/mL. Of patients who were seronegative post-D2, 39.7% seroconverted post-D3. For those who then remained seronegative after their previous dose, seroconversion occurred in 40.6% post-D4, 46.2% post-D5, 16.7% post-D6, and 0% after D7 or D8. After seroconversion, most had a progressive increase in antispike antibody levels. Neutralization was associated with higher antispike antibody levels, more vaccine doses, and earlier severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants; neutralizing antibody against early clade D614G was detected in 65.3%, against Delta in 52.0%, and against Omicron in 36.5%. SARS-CoV-2-specific T-cell production of interferon γ and interleukin 2 occurred in 73.9% and 60.9%, respectively, of 23 patients tested. After multiple vaccine doses, by multivariate analysis, immunoglobulin M ≥0.53 g/L, immunoglobulin subclass G3 ≥0.22 g/L and absence of current CLL therapy were independent predictors of positive serological responses. Multiple sequential COVID-19 vaccination significantly increased seroconversion and antispike antibody levels in patients with CLL or MBL.

Monoclonal B-cell Lymphocytosis - a review of diagnostic criteria, biology, natural history, and clinical management

Since first described almost two decades ago, there has been significant evolution in our definition and understanding of the biology and implications of monoclonal B-cell lymphocytosis (MBL). This review provides an overview of the definition, classification, biology, and natural history of MBL, mainly focused on the dominant CLL-like phenotype form of MBL. The increasingly recognized implications of MBL with respect to immune dysfunction are discussed, particularly in view of the COVID-19 pandemic, along with management recommendations for MBL in the clinic.

HSPB8 counteracts tumor activity of BRAF- and NRAS-mutant melanoma cells by modulation of RAS-prenylation and autophagy

Cutaneous melanoma is one of the most aggressive and lethal forms of skin cancer. Some specific driver mutations have been described in multiple oncogenes including BRAF and NRAS that are mutated in 60-70% and 15-20% of melanoma, respectively. The aim of this study was to evaluate the role of Small Heat Shock Protein B8 (HSPB8) on cell growth and migration of both BLM (BRAF^wt/NRAS^Q61R) and A375 (BRAF^V600E/NRAS^wt) human melanoma cell lines. HSPB8 is a member of the HSPB family of chaperones involved in protein quality control (PQC) system and contributes to chaperone assisted selective autophagy (CASA) as well as in the regulation of mitotic spindle. In cancer, HSPB8 has anti- or pro-tumoral action depending on tumor type. In melanoma cell lines characterized by low HSPB8 levels, we demonstrated that the restoration of HSPB8 expression causes cell growth arrest, reversion of EMT (Epithelial-Mesenchymal Transition)-like phenotype switching and antimigratory effect, independently from the cell mutational status. We demonstrated that HSPB8 regulates the levels of the active prenylated form of NRAS in NRAS-mutant and NRAS-wild-type melanoma cell lines. Consequently, the inhibition of NRAS impairs the activation of Akt/mTOR pathway inducing autophagy activation. Autophagy can play a dual role in regulating cell death and survival. We have therefore demonstrated that HSPB8-induced autophagy is a crucial event that counteracts cell growth in melanoma. Collectively, our results suggest that HSPB8 has an antitumoral action in melanoma cells characterized by BRAF and NRAS mutations.

Understanding Monoclonal B Cell Lymphocytosis: An Interplay of Genetic and Microenvironmental Factors

The term monoclonal B-cell lymphocytosis (MBL) describes the presence of a clonal B cell population with a count of less than 5 × 10⁹/L and no symptoms or signs of disease. Based on the B cell count, MBL is further classified into 2 distinct subtypes: 'low-count' and 'high-count' MBL. High-count MBL shares a series of biological and clinical features with chronic lymphocytic leukemia (CLL), at least of the indolent type, and evolves to CLL requiring treatment at a rate of 1-2% per year, whereas 'low-count' MBL seems to be distinct, likely representing an immunological rather than a pre-malignant condition. That notwithstanding, both subtypes of MBL can carry 'CLL-specific' genomic aberrations such as cytogenetic abnormalities and gene mutations, yet to a much lesser extent compared to CLL. These findings suggest that such aberrations are mostly relevant for disease progression rather than disease onset, indirectly pointing to microenvironmental drive as a key contributor to the emergence of MBL. Understanding microenvironmental interactions is therefore anticipated to elucidate MBL ontogeny and, most importantly, the relationship between MBL and CLL.

The CLL International Prognostic Index predicts outcomes in monoclonal B-cell lymphocytosis and Rai 0 CLL

The utility of the chronic lymphocytic leukemia-international prognostic index (CLL-IPI) in predicting outcomes of individuals with Rai 0 stage CLL and monoclonal B-cell lymphocytosis (MBL) is unclear. We identified 969 individuals (415 MBL and 554 Rai 0 CLL; median age, 64 years; 65% men) seen at Mayo Clinic between 1 January 2001 and 1 October 2018, and ascertained time to first therapy (TTFT) and overall survival (OS). After a median follow up of 7 years, the risk of disease progression needing therapy was 2.9%/y for MBL (median, not reached) and 5%/y for Rai 0 CLL (median, 10.4 years). Among patients with low, intermediate, and high/very high-risk CLL-IPI risk groups, the estimated 5-year risk of TTFT was 13.5%, 30%, and 58%, respectively, P< .0001 (c-statistic = 0.69); and the estimated 5-year OS was 96.3%, 91.5%, and 76%, respectively, P< .0001 (c-statistic = 0.65). In a multivariable analysis of absolute B-cell count with individual factors of the CLL-IPI, the absolute B-cell count was associated with shorter TTFT (hazard ratio [HR] for each 10 × 109/L increase: 1.31; P< .0001) and shorter OS (HR: 1.1; P = .02). The OS of the entire cohort was similar to that of the age- and sex-matched general population of Minnesota (P = .17), although Rai 0 CLL patients with high and very high-risk CLL-IPI score had significantly shorter OS (P= .01 and P= .0001, respectively). The results of this study demonstrate the ability of CLL-IPI to predict time from diagnosis to first treatment (an end point not affected by therapy) in a large cohort of patients whose only manifestation of disease is a circulating clonal lymphocyte population.

Chronic Lymphocytic Leukemia

Patients with chronic lymphocytic leukemia can be divided into three categories: those who are minimally affected by the problem, often never requiring therapy; those that initially follow an indolent course but subsequently progress and require therapy; and those that from the point of diagnosis exhibit an aggressive disease necessitating treatment. Likewise, such patients pass through three phases: development of the disease, diagnosis, and need for therapy. Finally, the leukemic clones of all patients appear to require continuous input from the exterior, most often through membrane receptors, to allow them to survive and grow. This review is presented according to the temporal course that the disease follows, focusing on those external influences from the tissue microenvironment (TME) that support the time lines as well as those internal influences that are inherited or develop as genetic and epigenetic changes occurring over the time line. Regarding the former, special emphasis is placed on the input provided via the B-cell receptor for antigen and the C-X-C-motif chemokine receptor-4 and the therapeutic agents that block these inputs. Regarding the latter, prominence is laid upon inherited susceptibility genes and the genetic and epigenetic abnormalities that lead to the developmental and progression of the disease.

Immunophenotypic profile and clinical outcome of monoclonal B-cell lymphocytosis in kidney transplantation

Monoclonal B-cell lymphocytosis (MBL) is a lymphoproliferative disorder characterized by clonal expansion of a B-cell population in peripheral blood of otherwise healthy subjects. MBL is divided into CLL (chronic lymphocytic leukemia)-like, atypical CLL-like and non-CLL MBL. The aim of this study was to evaluate immunophenotypic characteristics and clinical outcomes of MBL in kidney transplant (KT) recipients. We retrospectively evaluated 593 kidney transplant (KT) recipients in follow-up at our center. Among them, 157 patients underwent peripheral blood flow cytometry for different clinical indications. A 6-color panel flow cytometry was used to diagnose MBL. This condition was detected in 5 of 157 KT recipients. Immunophenotypic characterization of MBL showed four cases of non-CLL MBL and one case of CLL-like MBL. At presentation, median age was 65 years (range 61-73). After a median follow-up of 3.1 years (95%CI; 1.1-5) from diagnosis, patients did not progress either to CLL or to lymphoma. The disorder did not increase the risk of malignancy, severe infections, graft loss and mortality among our KT recipients. Surprisingly, all cases were also affected by concomitant monoclonal gammopathy of undetermined significance, which did not progress to multiple myeloma during follow-up. In conclusion, our data suggest that MBL is an age-related disorder, with non-CLL MBL being the most common subtype among KT recipients.

HLA specificities are associated with prognosis in IGHV-mutated CLL-like high-count monoclonal B cell lymphocytosis

Introduction

Molecular alterations leading progression of asymptomatic CLL-like high-count monoclonal B lymphocytosis (hiMBL) to chronic lymphocytic leukemia (CLL) remain poorly understood. Recently, genome-wide association studies have found 6p21.3, where the human leukocyte antigen (HLA) system is coded, to be a susceptibility risk region for CLL. Previous studies have produced discrepant results regarding the association between HLA and CLL development and outcome, but no studies have been performed on hiMBL.

Aims

We evaluated the role of HLA class I (-A, -B and -C) and class II (-DRB1 and -DQB1) in hiMBL/CLL susceptibility, hiMBL progression to CLL, and treatment requirement in a large series of 263 patients diagnosed in our center with hiMBL (n = 156) or Binet A CLL (n = 107).

Results

No consistent association between HLA specificities and hiMBL or CLL susceptibility was found. With a median follow-up of 7.7 years, 48/156 hiMBLs (33%) evolved to asymptomatic CLLs, while 16 hiMBLs (10%) and 44 CLLs (41%) required treatment. No HLA specificities were found to be significantly associated with hiMBL progression or treatment in the whole cohort. However, within antigen-experienced immunoglobulin heavy-chain (IGHV)-mutated hiMBLs, which represents the highest proportion of hiMBL cases (81%), the presence of HLA-DQB1*03 showed a trend to a higher risk of progression to CLL (60% vs. 26%, P = 0.062). Moreover, HLA-DQB1*02 specificity was associated with a lesser requirement for 15-year treatment (10% vs. 36%, P = 0.012).

Conclusion

In conclusion, our results suggest a role for HLA in IGHV-mutated hiMBL prognosis, and are consistent with the growing evidence of the influence of 6p21 on predisposition to CLL. Larger non-biased series are required to enable definitive conclusions to be drawn.

Surface Profiling of Extracellular Vesicles from Plasma or Ascites Fluid Using DotScan Antibody Microarrays

DotScan antibody microarrays were initially developed for the extensive surface profiling of live leukemia and lymphoma cells. DotScan's diagnostic capability was validated with an extensive clinical trial using mononuclear cells from the blood or bone marrow of leukemia or lymphoma patients. DotScan has also been used for the profiling of surface proteins on peripheral blood mononuclear cells (PBMC) from patients with HIV, liver disease, and stable and progressive B-cell chronic lymphocytic leukemia (CLL). Fluorescence multiplexing allowed the simultaneous profiling of cancer cells and leukocytes from disaggregated colorectal and melanoma tumor biopsies after capture on DotScan. In this chapter, we have used DotScan for the surface profiling of extracellular vesicles (EV) recovered from conditioned growth medium of cancer cell lines and the blood of patients with CLL. The detection of captured EV was performed by enhanced chemiluminescence (ECL) using biotinylated antibodies that recognized antigens expressed on the surface of the EV subset of interest. DotScan was also used to profile EV from the blood of healthy individuals and the ascites fluid of ovarian cancer patients. DotScan binding patterns of EV from human plasma and other body fluids may yield diagnostic or prognostic signatures for monitoring the incidence, treatment, and progression of cancers.

Present and future of personalized medicine in CLL

Medicine has been 'personalized' (i.e. centred in persons) since its foundation. Recently, however, the term 'personalized medicine' (or, better, 'precision medicine') has been introduced to define 'a form of medicine that uses information about a person's genes, proteins, and environment to prevent, diagnose, and treat disease'. This concept has gained momentum thanks to next-generation-sequencing (NGS) techniques that allow identification of molecular characteristics unique to the patient and to the tumour. It is hoped that NGS will not only contribute to a better understanding of chronic lymphocytic leukaemia (CLL), but will identify disease subsets that could benefit from specific treatment interventions. Recent advances in diagnosis (e.g. high-resolution immunophenotyping, markers of genetic abnormalities), prognosis (e.g. biomarkers), response predictors [e.g. del(17p)/TP53 mutations even at subclonal level], treatment (e.g. BCR signalling inhibitors, BCL2 antagonists, CAR-T cells) and methods to evaluate minimal residual disease constitute good examples of tools facilitating 'personalized' management of patients with CLL.

Chronic lymphocytic leukaemia

Chronic lymphocytic leukaemia (CLL) is the most common leukaemia among the adults in the Western World. CLL (and the corresponding nodal entity small lymphocytic lymphoma, SLL) is classified as a lymphoproliferative disorder characterised by the relentless accumulation of mature B-lymphocytes showing a peculiar immunophenotype in the peripheral blood, bone marrow, lymph nodes and spleen. CLL clinical course is very heterogeneous: the majority of patients follow an indolent clinical course with no or delayed treatment need and with a prolonged survival, while others experience aggressive disease requiring early treatment followed by frequent relapses. In the last decade, the improved understanding of CLL pathogenesis shed light on premalignant conditions (i.e., monoclonal B-cell lymphocytosis, MBL), defined new prognostic and predictive markers, improving patient stratification, but also broadened the therapeutic armamentarium with novel agents, targeting fundamental signaling pathways.

Extensive surface protein profiles of extracellular vesicles from cancer cells may provide diagnostic signatures from blood samples

Extracellular vesicles (EV) are membranous particles (30–1,000 nm in diameter) secreted by cells. Important biological functions have been attributed to 2 subsets of EV, the exosomes (bud from endosomal membranes) and the microvesicles (MV; bud from plasma membranes). Since both types of particles contain surface proteins derived from their cell of origin, their detection in blood may enable diagnosis and prognosis of disease. We have used an antibody microarray (DotScan) to compare the surface protein profiles of live cancer cells with those of their EV, based on their binding patterns to immobilized antibodies. Initially, EV derived from the cancer cell lines, LIM1215 (colorectal cancer) and MEC1 (B-cell chronic lymphocytic leukaemia; CLL), were used for assay optimization. Biotinylated antibodies specific for EpCAM (CD326) and CD19, respectively, were used to detect captured particles by enhanced chemiluminescence. Subsequently, this approach was used to profile CD19⁺ EV from the plasma of CLL patients. These EV expressed a subset (~40%) of the proteins detected on CLL cells from the same patients: moderate or high levels of CD5, CD19, CD31, CD44, CD55, CD62L, CD82, HLA-A,B,C, HLA-DR; low levels of CD21, CD49c, CD63. None of these proteins was detected on EV from the plasma of age- and gender-matched healthy individuals.

What does it mean I have a monoclonal B-cell lymphocytosis?: Recent insights and new challenges

Monoclonal B-cell lymphocytosis (MBL) is defined as a laboratory abnormality where small (<5 x 10(9)/L) clonal B-cell populations are detected in the peripheral blood of otherwise healthy subjects. According to the immunophenotype, MBL is labeled as chronic lymphocytic leukemia (CLL)-like (75% of cases), atypical CLL, and CD5-negative. Concentration of clonal B cells differentiates low- (LC) and high-count (HC)-MBL (< or ≥ 0.5 x 10(9)/L, respectively). Thanks to technical improvements, we are able to identify CLL-like clonal B-cell populations at increased frequency with age, but we are still far from understanding its relationship with clinically overt CLL. LC-MBL, requiring high-throughput screening technique to be identified in population studies, seems to be a bird of a different feather and several hints suggest that LC-MBL is related to aging and/or chronic antigenic stimulation. Immunogenetic, cytogenetic and genetic data support the notion that HC-MBL, usually identified in the clinical setting, is a premalignant condition and, based on biological parameters, it is frequently difficult to differentiate it from early stage CLL. The rapid improvement and widespread availability of cutting-edge technology, in particular next-generation sequencing (NGS), raises hope that we are getting closer to unveiling the fundamental nature of MBL and CLL and how they are related to each other.

Risk of non-hematologic cancer in individuals with high-count monoclonal B-cell lymphocytosis

It is unknown whether individuals with monoclonal B-cell lymphocytosis (MBL) are at risk for adverse outcomes associated with chronic lymphocytic leukemia (CLL), such as the risk of non-hematologic cancer. We identified all locally residing individuals diagnosed with high-count MBL at Mayo Clinic between 1999 and 2009 and compared their rates of non-hematologic cancer with that of patients with CLL and two control cohorts: general medicine patients and patients who underwent clinical evaluation with flow cytometry but who had no hematologic malignancy. After excluding individuals with prior cancers, there were 107 high-count MBL cases, 132 CLL cases, 589 clinic controls and 482 flow cytometry controls. With 4.6 years median follow-up, 14 (13%) individuals with high-count MBL, 21 (4%) clinic controls (comparison MBL P<0.0001), 18 (4%) flow controls (comparison MBL P=0.0001) and 16 (12%) CLL patients (comparison MBL P=0.82) developed non-hematologic cancer. On multivariable Cox regression analysis, individuals with high-count MBL had higher risk of non-hematologic cancer compared with flow controls (hazard ratio (HR)=2.36; P=0.04) and borderline higher risk compared with clinic controls (HR=2.00; P=0.07). Patients with high-count MBL appear to be at increased risk for non-hematologic cancer, further reinforcing that high-count MBL has a distinct clinical phenotype despite low risk of progression to CLL.

Monoclonal B-cell lymphocytosis and early-stage chronic lymphocytic leukemia: diagnosis, natural history, and risk stratification

Monoclonal B lymphocytosis (MBL) is defined as the presence of a clonal B-cell population in the peripheral blood with fewer than 5 × 10(9)/L B-cells and no other signs of a lymphoproliferative disorder. The majority of cases of MBL have the immunophenotype of chronic lymphocytic leukemia (CLL). MBL can be categorized as either low count or high count based on whether the B-cell count is above or below 0.5 × 10(9)/L. Low-count MBL can be detected in ∼5% of adults over the age of 40 years when assessed using standard-sensitivity flow cytometry assays. A number of biological and genetic characteristics distinguish low-count from high-count MBL. Whereas low-count MBL rarely progresses to CLL, high-count MBL progresses to CLL requiring therapy at a rate of 1% to 2% per year. High-count MBL is distinguished from Rai 0 CLL based on whether the B-cell count is above or below 5 × 10(9)/L. Although individuals with both high-count MBL and CLL Rai stage 0 are at increased risk of infections and second cancers, the risk of progression requiring treatment and the potential to shorten life expectancy are greater for CLL. This review highlights challenging questions regarding the classification, risk stratification, management, and supportive care of patients with MBL and CLL.

Prevalence of monoclonal B lymphocytosis in first-degree relatives of chronic lymphocytic leukemia patients in Turkey

Objective:

Monoclonal B lymphocytosis (MBL) is considered to be a precursor state for chronic lymphocytic leukemia (CLL). This study was planned to evaluate the MBL prevalence in first-degree relatives of CLL patients in Turkey, which is considered to be an ethnic and geographic bridge between the Eastern and Western worlds.

Materials and Methods:

A total of 136 volunteers [median age: 40 (17-77) years; male/female: 60/76] from 61 families were included. Flow cytometry analysis by 4-colour staining was used for MBL diagnosis.

Results:

MBL was demonstrated in 17 cases (12.5%). A total of 14 cases (10.3%) were classified as CLL-like MBL, while 3 (2.2%) exhibited a non-CLL-like phenotype. The prevalence of MBL was 12.72% in subjects aged less than 40 years, 12.28% in subjects between 40 and 60 years, and 40% in subjects over 60 years, without statistical significance (p>0.05). A total of 115 cases were evaluated for intermarriage, which was observed in 19 cases (16.5%). The prevalence of MBL did not differ based on intermarriage status (p>0.05).

Conclusion:

The current report is the first MBL prevalence study in a Eurasian population that demonstrates a similar distribution pattern of MBL in Anatolian CLL kindreds. Further efforts should be made to refine our understanding of the natural history and clinical outcomes of MBL.

Clinical presentation, progression, and outcome of patients with clonal B-cell counts of less than 5 × 10(9)/l, 5 to 10 × 10(9)/l, and more than 10 × 10(9)/l and chronic lymphocytic leukemia immunophenotype

OBJECTIVES

The flow cytometric evaluation of peripheral lymphocytosis has led to a dramatic increase in the diagnosis of early stage chronic lymphocytic leukemia (CLL) and monoclonal B-cell lymphocytosis (MBL). Few studies exist to better delineate the natural history and differences between MBL and CLL.

METHODS

Applying the recently updated B-lymphocyte threshold of 5 × 10(9) B lymphocytes/L for the diagnosis of CLL, we evaluated the differences in initial presentation, disease progression, time to treatment (TTT), and 10-year overall survival rates between patients with less than 5 × 10 × 10(9)/L, 5 to 10 × 10(9)/L, and more than 10 × 10(9)/L B cells. These clinical/treatment parameters were also compared among the MBL, 5 to 10 CLL Rai stage 0, and more than 10 CLL Rai stage 0 groups.

RESULTS

In total, 310 patients were included, with 67 in the less than 5, 75 in the 5 to 10, and 168 in the more than 10 B-cell groups. Statistically significant differences were seen when comparing the 5 to 10 and more than 10 B-cell groups regarding anemia (P = .021 for median hemoglobin; P = .028 for anemia <11 g/dL), platelet count (P = .041 for median platelet count), splenomegaly (P = .013), initial management plan (P = .012 for observation; P = .0021 for treatment with chemotherapy), and TTT (P = .0033). No statistically significant difference was seen among the MBL, 5 to 10, and more than 10 CLL Rai stage 0 groups regarding TTT and 10-year overall survival.

CONCLUSIONS

Findings suggest that patients with B-cell counts of 5 to 10 × 10(9)/L behave clinically more similar to patients with B-cell counts of less than 5 × 10(9)/L.

Immunophenotypic analysis reveals heterogeneity and common biologic aspects in monoclonal B-cell lymphocytosis

Monoclonal B-cell lymphocytosis (MBL) is the presence of small B-cell clones in the peripheral blood of healthy subjects. Most MBL have the characteristic phenotype of chronic lymphocyte leukemia (chronic lymphocytic leukemia (CLL)-like MBL), and depending on the number of monoclonal B-cells, may characterize a preclinical stage of the CLL. However, there are also MBL with an atypical (CD5(+) CD20(+/bright) CD23(dim/-) ) or a CD5(neg) phenotype, which remain largely unexplored. We performed an extended immunophenotypic, cytogenetic, and hematologic analysis in 75 CLL-like, 39 atypical, 50 CD5(neg) , and 7 biphenotypic MBL cases to detect differences or similarities among the MBL subsets. The phenotypic analysis showed expression variations in many surface markers and a wide spectrum of disease-specific phenotypes within each MBL subtype. Interphase fluorescent in situ hybridization analysis showed a different panel of aberrations according to the phenotype. Overall, del(13q14) and +12 were the most common abnormalities (39%), whereas del(11q13), del(17p13), and del(6q23) were detected only in 3, 1, and 0 cases, respectively. A comparison of MBL with overt chronic lymphoproliferations revealed common aspects in the preclinical state, regarding both the kind of cytogenetic aberrations detected and the lymphocyte composition. Our findings highlight not only the heterogeneity among MBL subsets but also indicate common biologic features which differentiate MBL from clinical disease.

Prospective study of prognostic factors in asymptomatic patients with B-cell chronic lymphocytic leukemia-like lymphocytosis: the cut-off of 11 × 10(9)/L monoclonal lymphocytes better identifies subgroups with different outcomes

The arbitrary threshold of 5 × 10(9)/L chronic lymphocytic leukemia (CLL)-like lymphocytes differentiates monoclonal B lymphocytosis (MBL) from CLL. There are no prospective studies that search for the optimal cut-off of monoclonal lymphocytes able to predict outcome and simultaneously analyze the prognostic value of classic, immunophenotypic, and cytogenetic variables in patients with asymptomatic clonal CLL lymphocytosis (ACL), which includes MBL plus Rai 0 CLL patients. From 2003 to 2010, 231 ACL patients were enrolled in this study. Patients with 11q deletion and atypical lymphocyte morphology at diagnosis had shorter progression-free survival (PFS) (p = 0.007 and p = 0.015, respectively) and treatment-free survival (TFS) (p = 0.009 and p = 0.017, respectively). Elevated beta-2 microglobulin (B2M) also correlated with worse TFS (p = 0.002). The optimal threshold of monoclonal lymphocytes independently correlated with survival was 11 × 10(9)/L (p = 0.000 for PFS and p = 0.016 for TFS). As conclusion, monoclonal lymphocytosis higher than 11 × 10(9)/L better identifies two subgroups of patients with different outcomes than the standard cut-off value of 5 × 10(9)/L. Atypical lymphocyte morphology, 11q deletion and elevated B2M had a negative impact on the survival in ACL patients.

Do biologic parameters affect the time to first treatment of clinical monoclonal B-cell lymphocytosis and chronic lymphocytic leukemia Rai stage 0? Results of a prospective analysis

BACKGROUND

We investigated the clinical relevance of classic and new prognostic markers, immunoglobulin heavy-chain variable (IGHV) gene mutational status, and chromosomal abnormalities in clinical monoclonal B lymphocytosis (cMBL) compared with chronic lymphocytic leukemia (CLL) Rai stage 0.

PATIENTS AND METHODS

We analyzed the clinical outcomes in terms of the time to the first treatment (TTFT) of a prospective cohort, including 125 patients with cMBL and 197 patients with CLL Rai stage 0.

RESULTS

In the overall patient population, prognostic parameters such as IGHV gene mutational status (P < .0001), CD38 expression (P < .0001), 70-kDa zeta-associated protein (ZAP-70) expression (P < .0001), and cytogenetic abnormalities (P = .01) predicted for TTFT on univariate analysis. IGHV gene identity was significant on multivariate analysis (P < .0001), regardless of the B-cell cutoff (5.0 or 10 × 10(9) B cells/L). A prognostic stratification using the combination of IGHV mutational status and absolute B-cell lymphocytosis identified 3 different groups that were significantly different with respect to the TTFT (P < .0001).

CONCLUSION

In the present series of patients with cMBL and CLL Rai stage 0, we have confirmed that IGHV mutation status appeared to be the best predictor of TTFT. In addition, when associated with the B-cell count, IGHV mutational status might help to better stratify patients into more precise subgroups.

Changes in the incidence, pattern of presentation and clinical outcome of early chronic lymphocytic leukemia patients using the 2008 International Workshop on CLL guidelines

OBJECTIVES

Before 2008, diagnosis of chronic lymphocytic leukemia (CLL) relied on 1996 National Cancer Institute Working Group criteria which required an absolute lymphocyte count of 5.0 × 10(9)/l or higher. The up-dated 2008 International Workshop on CLL (IWCLL) guidelines recommend using the B-cell count as a basis for the diagnosis of CLL and indicate a B-cell threshold of 5.0 × 10(9)/l. The objective of this study was to assess the effects of these changes on the pattern of presentation and clinical outcome of early CLL.

METHODS

For this purpose we analysed 414 patients with previously untreated, Binet stage A CLL diagnosed between January 2006 and December 2010 and registered prospectively at a national database.

RESULTS

After patients were reclassified according to updated 2008 IWCLL guidelines, 130 Rai stage 0 CLL patients were reclassifed as clinical monoclonal B-cell lymphocytosis, resulting in a 31.4% decrease (from 414 to 284) in the diagnosis of early stage CLL. Moreover, a shift towards a more advanced Rai clinical stage under 2008 IWCLL criteria was observed. Finally, the estimated 3-year time to first treatment decreased from 77.2 to 69.9% according to whether 1996 National Cancer Institute Working Group criteria or 2008 IWCLL criteria were used.

CONCLUSION

In conclusion, the 2008 IWCLL guidelines modify the distribution of Rai stage at diagnosis and shorten the time to first treatment in early CLL patients. We expect that these changes might be considered in the interpretation of epidemiologic studies in CLL and in designing clinical trials of early therapeutic intervention in patients with asymptomatic CLL.

Predictive significance of absolute lymphocyte count and morphology in adults with a new onset peripheral blood lymphocytosis

Aims

Lymphocytosis is commonly encountered in the haematology laboratory. Evaluation of blood films is an important screening tool for differentiating between reactive and malignant processes. The optimal lymphocyte number to trigger morphological evaluation of the smear has not been well defined in the literature. Likewise, the significance of lymphocyte morphology has not been well studied and there are no consensus guidelines or follow-up recommendations available. We attempt to evaluate the significance of lymphocyte morphology and to define the best possible cut-off value of absolute lymphocyte count for morphology review.

Methods

71 adult patients with newly detected lymphocytosis of 5.0×109/L or more were categorised to either a reactive process or a lymphoproliferative disorder. We performed statistical analysis and morphology review to compare the difference in age, gender, lymphocyte count and morphological features between the two groups. Receiver operating characteristic analysis was performed to determine an optimal lymphocyte number to trigger morphology review.

Results

Lymphoproliferative disorders are associated with advanced age and higher lymphocyte count. Sensitivity, specificity, positive predictive value, negative predictive value and accuracy of lymphocyte morphology as a screening test were 0.9, 0.59, 0.60, 0.58 and 0.71, respectively. The optimal cut-off of lymphocyte number for morphology review was found to be close to 7×109/L.

Conclusions

We found a moderate interobserver agreement for the morphological assessment. ‘Reactive’ morphology was very predictive of a reactive process, but ‘malignant’ morphology was a poor predictor of a lymphoproliferative disorder.

A prognostic algorithm including a modified version of MD Anderson Cancer Center (MDACC) score predicts time to first treatment of patients with clinical monoclonal lymphocytosis (cMBL)/Rai stage 0 chronic lymphocytic leukemia (CLL)

We propose an algorithm based on a slightly modified version of MD Anderson Cancer Center (MDACC) score (i.e., mutational status of IgVH, LDH, presence of high-risk FISH abnormalities), β2-microglobulin and separation of clinical monoclonal B-cell lymphocytosis (cMBL) from chronic lymphocytic leukemia (CLL) to predict time to first treatment (TTFT) of a prospective multicentre cohort including 83 cMBL and 136 CLL Rai stage 0 patients. Patients with MDACC score point ≥38, at any level of β2-microglobulin and irrespective of whether they fulfilled 2008 International Workshop on CLL (IWCLL) criteria for CLL Rai stage 0 or cMBL, experienced the worst clinical outcome (5-year TTFT, 24%) and formed the high-risk group. In contrast, subjects with a diagnosis of cMBL, MDACC score point <38 and β2-microglobulin ≤ UNL had the best clinical outcome (5-year TTFT, 100%) and constituted the low-risk group. The intermediate group included patients in Rai stage 0, MDACC score point <38, and any level of β2-microglobulin, and patients with cMBL, MDACC score point <38, and β2-microglobulin ≥ UNL. Cases showing these features can be grouped together to form the intermediate-risk group (5-year TTFT, 65%). Although the separation between cMBL and Rai stage 0, as proposed by the 2008 IWCLL guidelines, has clinical implications, the model we propose may help to classify patients with cMBL and Rai stage 0 into more precise subgroups suggesting that a prognostic separation of these entities based solely on clonal B-cell threshold may be unsatisfactory.

Incidence of chronic lymphocytic leukemia and high-count monoclonal B-cell lymphocytosis using the 2008 guidelines

BACKGROUND

The 1996 National Cancer Institute Working Group (NCI-WG 96) guidelines classified disease in individuals who had a B-cell clone with chronic lymphocytic leukemia (CLL) immunophenotype as CLL if their absolute lymphocyte count was ≥5 × 10(9)/L. The 2008 International Workshop on CLL guidelines (IWCLL 2008) classified disease as CLL if the absolute B-cell count was ≥5 × 10(9)/L or as monoclonal B-cell lymphocytosis (MBL) if the absolute B-cell count was <5 × 10(9)/L. The objective of the current study of Olmsted County, Minnesota, was to assess the effects of these changes on incidence rates and presentation from 2000 to 2010.

METHODS

Using diagnostic indices available through the Rochester Epidemiology Project and the Mayo CLL database, the authors identified all patients with newly diagnosed CLL and high-count MBL from 2000 to 2010. Age-specific and sex-specific incidence rates were determined.

RESULTS

According to NCI-WG 96 criteria, there were 115 patients with CLL and 8 patients with MBL during the period studied. Using the IWCLL 2008 classification, there were 79 patients with CLL and 40 patients with MBL. Rai stage distribution (low risk, intermediate risk, and high risk) using NCI-WG 96 criteria was 60.9%, 33.9%, and 5.2%, respectively, compared with 43%, 49.4%, and 7.6%, respectively, using IWCLL 2008 criteria. The age-adjusted and sex-adjusted incidence rates (per 100,000) for CLL and MBL were 10.0 and 0.66, respectively, using NCI-WG 96 criteria versus 6.8 and 3.5, respectively, using IWCLL 2008 criteria. The median time to treatment according to NCI-WG 96 criteria was 9.2 years versus 6.5 years with IWCLL 2008 criteria.

CONCLUSIONS

Use of the IWCLL 2008 guidelines reduced the incidence of CLL, altered the distribution of initial Rai stage at diagnosis, and shortened the median time to treatment.

Monoclonal B-cell lymphocytosis

Monoclonal B-cell lymphocytosis (MBL) is an asymptomatic hematologic condition defined by the presence of a small (<5 x 10(9)/L) clonal B-cell population in the peripheral blood in the absence of lymph-node enlargement, cytopenias or autoimmune diseases. It is found in approximately 3-12% of normal persons depending on the accuracy of analytical techniques applied. According to the immunophenotypic profile of clonal B-cells, the majority of MBL cases (75%) are classified as chronic lymphocytic leukemia (CLL)-like. This form may progress into CLL at a rate of 1-2% per year. It is thought that CLL is always preceded by MBL. The remaining MBL cases are defined as atypical CLL-like (CD5+/CD20(bright)) and CD5(-) MBL. The MBL clone size is quite heterogenous. Accordingly, two forms of MBL are identified: i) high-count, or 'clinical' MBL, in which an evidence of lymphocytosis (<5 x 10(9)/L clonal B-cells) is seen, and ii) a low-count MBL, in which a normal leukocyte count is found and that is identified only in population-screening studies. Both forms of MBL may carry the cytogenetic abnormalities that are the hallmark of CLL, including 13q-, 17p- and trisomy 12. Consistent with the indolent phenotype of this condition, genetic lesions, such as TP53, ATM, NOTCH1 and SF3B1 mutations, usually associated with high-risk CLL, are rarely seen. Overall, no prognostic indicator of evolution of MBL to overt CLL has been found at present time. However, taking into account this possibility, a clinical and lab monitoring (at least annually), is recommended.

MBL versus CLL: how important is the distinction?

Monoclonal B-cell lymphocytosis (MBL) is defined as a clonal B-cell expansion whereby the B-cell count is less than 5 × 10(9)/L and no symptoms or signs of lymphoproliferative disorders are detected. Based on B-cell count, MBL is further divided into low-count and clinical MBL. While low-count MBL seems to carry relevance mostly from an immunological perspective, clinical MBL and chronic lymphocytic leukemia appear to be overlapping entities. Only a deeper knowledge of molecular pathways and microenvironmental influences involved in disease evolution will help to solve the main clinical issue, i.e. how to differentiate nonprogressive and progressive cases requiring intensive follow-up.

Monoclonal B cell lymphocytosis and "in situ" lymphoma

The finding of monoclonal B-cell populations not fulfilling criteria for a lymphoid malignancy has given great impulse to study mechanisms involved in lymphomagenesis and factors responsible for the transition from B-cell precursor states to overt lymphoproliferative disorders. Monoclonal B cell expansions were initially recognized in peripheral blood of otherwise healthy subjects (thus defined monoclonal B-cell lymphocytosis, MBL) and in most cases share the immunophenotypic profile of chronic lymphocytic leukemia (CLL). The clinical relevance of this phenomenon is different according to B-cell count: high-count MBL is considered a preneoplastic condition and progresses to CLL requiring treatment at a rate of 1-2% per year, while low-count MBL, though persisting over time, has not shown a clinical correlation with frank leukemia so far. MBL other than CLL-like represent a minority of cases and are ill-defined entities for which clinical and biological information is still scanty. In situ follicular lymphoma (FL) and mantle cell lymphoma (MCL) are characterized by the localization of atypical lymphoid cells, carrying t(14;18)(q32;q21) or t(11;14)(q13;q32), only in the germinal centers and mantle zones respectively, where their normal counterparts are localized. The localization of these cells indicates that germinal centers or mantle zones provide appropriate microenvironments for cells carrying these oncogenic alterations to survive or proliferate. The progression of these lesions to overt lymphomas occurs rarely and may require the accumulation of additional genetic events. Individuals with these lymphoid proliferations should be managed with caution.

Monoclonal B cell lymphocytosis--what does it really mean?

Monoclonal B cell Lymphocytosis (MBL) or similar terms have been used for decades to describe the presence of light-chain restricted B lymphocytes with uncertain clinical significance, usually having a phenotype consistent with chronic lymphocytic leukemia (CLL). As diagnostic technology improved, ever smaller monoclonal B cell populations were identifiable in the population, and approximately half of people over 90 years old have a minimal (<1 cell/μL) circulating CLL-like B cell population. These minimal CLL-like B cell populations share some molecular characteristics with CLL, but have no clinical significance. In contrast, CLL-like MBL cases detected through hospital investigations are biologically indistinguishable from early stage CLL, but the neoplastic B cell levels are usually stable over time and the risk of progressive disease requiring treatment is much lower than for early stage CLL. However, there is usually partial or complete depletion of normal B cells, with an increased relative risk of severe infection, comparable to early stage CLL, which may impair overall survival.

Nodal and leukemic small B-cell neoplasms

The small B-cell neoplasms represent some of the most frequently encountered lymphoproliferative disorders in routine surgical pathology practice. This report reviews the current diagnostic criteria for classifying small B-cell neoplasms and distinguishing them from newly recognized precursor conditions that do not appear to represent overt lymphomas. Newly available immunohistochemical stains and molecular studies that may assist in the diagnosis and classification of these neoplasms are also discussed.

External validation on a prospective basis of a nomogram for predicting the time to first treatment in patients with chronic lymphocytic leukemia

BACKGROUND

A nomogram that incorporates traditional and newer prognostic factors to identify patients with chronic lymphocytic leukemia (CLL) who are at high risk of receiving therapy was developed by investigators at The University of Texas M. D. Anderson Cancer Center (MDACC). Because the model required validation before its extensive use could be recommended, the authors sought to externally validate the nomogram in an independent, community-based cohort of patients with CLL.

METHODS

In total, 328 previously untreated patients with newly diagnosed, asymptomatic, Binet stage A CLL from different primary hematology centers who were registered on a prospective basis during 2006 to 2010 on an observational database of the Italian Lymphoma Study Group were considered suitable for external validation of the model.

RESULTS

A total point score was calculated for each patient using a formula proposed by MDACC investigators, and the median score was 19.9 (range, 0-69.5). Furthermore, when the score was evaluated as continuous variable (ie, by measuring the risk of each point increase), the total point score was associated with the time to first treatment (hazard ratio [HR], 1.04; 95% confidence interval [CI], 1.02-1.05; P < .0001). Receiver operating characteristic analysis identified a point score of 25 (area under curve; 0.64; sensitivity, 61.5; specificity, 72.1; P < .0001) as the best threshold capable of separating patients who needed therapy from patients who did not (HR, 3.27; 95% CI, 2,07-5.18; P < .0001). The prognostic index category also remained a predictor of the time to first treatment when the analysis was limited to patients with Rai stage 0 disease (HR, 4.05; 95% CI, 2.25-7.52; P < .0001). Finally, a goodness-of-fit test demonstrated that the nomogram model had a significantly good fit at 2 years (correlation coefficient [r(2) ] = 0.966; P = .002).

CONCLUSIONS

The current results confirmed the ability of a newly developed prognostic index to predict the time to first treatment among previously untreated patients with CLL who had early disease and extended the utility of the model to those with Rai stage 0 disease. In addition, the actual and predicted time to first treatment outcomes revealed good agreement, suggesting that, externally, the results provided by the model are well calibrated. Cancer 2013. © 2012 American Cancer Society.

The initial approach to patients with chronic lymphocytic leukemia diagnosed in day-to-day practice

SUMMARY As chronic lymphocytic leukemia (CLL) research increases and new technologies and drugs become available, the landscape of this disease becomes more complex. It is this complexity that suggests the use of practical recommendations in day-to-day practice. The close relationship between early CLL and clinical monoclonal B lymphocytosis regarding clinically relevant parameters does not provide evidence to strictly separate these entities by a distinct threshold of clonal B cells. Prognostic testing and staging procedures based on costs and logistics should be favored at diagnosis, while assessment of more specific markers predicting treatment-related outcome (i.e., 17p del/P53 mutation) should be reserved to patients for whom treatment is required. A diagnosis of CLL, especially in younger patients (<55 years), may cause a number of fears and worries with regard to the course–outcome of the disease. Therefore, communication between the patient and doctor should be informative with respect to the impact of disease on the patient’s affective, social and economic spheres. Finally, current available guidelines should drive the choices of physicians who currently treat CLL patients, with room allowed for consideration of emerging new evidence, physician practice style, patient preference, clinical judgment and patient quality of life. Doctors should also keep in mind that people with CLL want to live their lives as normally as possible; therefore, every effort should be made to ensure the achievement of this goal.

Clinical aspects of monoclonal B-cell lymphocytosis

BACKGROUND

Monoclonal B-cell lymphocytosis (MBL) is an asymptomatic precursor condition for chronic lymphocytic leukemia (CLL). It is defined by the presence of small clones of aberrant B cells in the peripheral blood, with a total B-cell count below the threshold for diagnosis of CLL (<5.0x10(9) cells/L).

METHODS

The authors review current literature on the prevalence of MBL, and the clinical course of this CLL precursor condition, and recommended management for individuals with MBL.

RESULTS

MBL occurs in approximately 4% to 5% of healthy adults. While most cases of CLL are preceded by MBL, progression to leukemia requiring CLL treatment occurs in only 1% to 2% of individuals with MBL per year. The absolute B-cell count is most strongly associated with progression, and patients with low-count MBL identified in population screening studies rarely develop CLL. Studies are ongoing to better define the relationship between MBL and CLL and to identify prognostic indicators that predict which patients will progress to CLL. Given their elevated risk of developing malignancy, individuals with clinical MBL should be monitored at least annually for progressive lymphocytosis and signs or symptoms of CLL.

CONCLUSIONS

Many of the epidemiologic and genetic factors associated with MBL development and its progression to CLL have not yet been identified. However, ongoing studies by many research groups are aimed at answering these questions to facilitate management of individuals with this premalignant condition. In addition, active investigation of MBL will likely yield new insights into the biology of CLL, potentially identifying new therapeutic targets for this incurable disease.

The current lymphoma classification: new concepts and practical applications triumphs and woes

The World Health Organization (WHO) classification of lymphomas updated in 2008 represents an international consensus for diagnosis of lymphoid neoplasms based on the recognition of distinct disease entities by applying a constellation of clinical and laboratory features. The 2008 classification has refined and clarified the definitions of well-recognized diseases, identified new entities and variants, and incorporated emerging concepts in the understanding of lymphoid neoplasms. Rather than being a theoretical scheme this classification has used data from published literature. Recent knowledge of molecular pathways has led to identification and development of new diagnostic tools, like gene expression profiling, which could complement existing technologies. However, some questions remain unresolved, such as the extent to which specific genetic or molecular alterations define certain tumors. In general, practical considerations and economics preclude a heavily molecular and genetic approach. The significance of early or precursor lesions and the identification of certain lymphoid neoplasms is less clear at present, but understanding is evolving. The borderline categories having overlapping features with large B-cell lymphomas, as well as some of the provisional entities, are subject to debate and lack consensus in management. Lastly, the sheer number of entities may be overwhelming, especially, for the diagnosing pathologist, who do not see enough of these on a regular basis.

[Leukemia- and lymphoma-associated flow cytometric, cytogenetic, and molecular genetic aberrations in healthy individuals]

Most leukemia and lymphoma cases are characterized by specific flow cytometric, cytogenetic and molecular genetic aberrations, which can also be detected in healthy individuals in some cases. The authors review the literature concerning monoclonal B-cell lymphocytosis, and the occurrence of chromosomal translocations t(14;18) and t(11;14), NPM-ALK fusion gene, JAK2 V617F mutation, BCR-ABL1 fusion gene, ETV6-RUNX1(TEL-AML1), MLL-AF4 and PML-RARA fusion gene in healthy individuals. At present, we do not know the importance of these aberrations. From the authors review it is evident that this phenomenon has both theoretical and practical (diagnostic, prognostic, and therapeutic) significance.

Monoclonal B-cell lymphocytosis: right track or red herring?

Monoclonal B-cell lymphocytosis (MBL), a newly recognized entity found in approximately 3% of normal persons, precedes chronic lymphocytic leukemia. However, MBLs progress into overt malignancy only in a very minor portion of cases, thus raising the clinical concern of whether and how we can discriminate at diagnosis which rare cases will evolve into a fully fledged tumor. Understanding the molecular/biologic features underlying the risk of progression may significantly modify our strategies for correctly managing B-cell premalignant states. MBL cells bear the same chromosomal abnormalities of chronic lymphocytic leukemia. Genome-wide sequencing and animal models indicate that genetic abnormalities disrupting the control of cell growth and survival cooperate with microenvironment-triggered events, mainly represented by antigen-mediated B-cell receptor and coreceptor stimulation, to trigger and fuel clonal expansion. The initial functional activation of survival/proliferation pathways may later become subsidized by autonomous genetic abnormalities (eg, a single mutation) affecting the same or parallel critical signaling pathway(s).

Monoclonal B-cell lymphocytosis is closely related to chronic lymphocytic leukaemia and may be better classified as early-stage CLL

The World Health Organization classification uses a cut-off point of 5·0 × 10(9)/l cells with a chronic lymphocytic leukaemia (CLL)-phenotype in peripheral blood to discriminate between monoclonal B-lymphocytosis (MBL) and B-CLL. This study analysed 298 MBL patients by multi-parameter flow cytometry, chromosome banding analysis (CBA)/fluorescence in situ hybridization (FISH), and IGHV mutation status and compared them with 356 CLL patients. In MBL, CBA more frequently revealed a normal karyotype and FISH identified less frequently del(6q), del(13q) (as sole alterations), and del(17)(p13). Within the MBL cohort, a shorter time to treatment (TTT) was found for ZAP-70-positivity, 14q32/IGH-translocations (CBA), del(11)(q22·3) (FISH) and unmutated IGHV status. Higher CD38 and ZAP-70 expression, del(11)(q22·3) (FISH), trisomy 12 (FISH), and 14q32/IGH-translocations (CBA) were correlated with a shorter TTT in the combined cohort (MBL + CLL); a sole del(13)(q14) (FISH) correlated with longer TTT. Regarding overall survival, unmutated IGHV status and 'other' alterations (CBA) had an adverse impact. There was no correlation between the concentration of CLL-cells and TTT or overall survival. Multivariate analysis confirmed a negative impact on TTT for del(11)(q22·3)/ATM, trisomy 12 (both by FISH), and 14q32/IGH-translocations by CBA. These data emphasize a close relationship between MBL and CLL regarding clinically relevant parameters and provide no evidence to strictly separate these entities by a distinct threshold of clonal B-cells.

Reassessment of small lymphocytic lymphoma in the era of monoclonal B-cell lymphocytosis

BACKGROUND

In the 2008 World Health Organization classification, small lymphocytic lymphoma is defined as a neoplasm with the tissue morphology and immunophenotype of chronic lymphocytic leukemia, but with absence of leukemia. Minimal criteria of tissue involvement to separate small lymphocytic lymphoma from monoclonal B-cell lymphocytosis have not been defined.

DESIGN AND METHODS

We reviewed the clinicopathological features of 36 patients with extramedullary tissue biopsies containing chronic lymphocytic leukemia-type cells and less than 5×10(9)/L peripheral blood monoclonal B cells. Pathological features (extent and patterns of involvement, architectural preservation, presence of proliferation centers) as well as cytogenetic and radiological findings were examined in relation to clinical outcome.

RESULTS

The biopsies were performed to evaluate lymphadenopathy in 20 patients and for other reasons (most frequently staging of a non-hematologic neoplasm) in 16 patients. At latest follow-up (median 23 months), 21 untreated patients had no or stable lymphadenopathy, 3 had regressed lymphadenopathy, and 12 had developed progressive lymphadenopathy and/or received therapy for chronic lymphocytic leukemia/small lymphocytic lymphoma. Features associated with progression/treatment included lymph nodes 1.5 cm or greater on imaging studies (P=0.01) and presence of proliferation centers in the biopsied tissue (P=0.004). Neither the size nor extent of involvement of the excised lymph node correlated with progression/treatment.

CONCLUSIONS

Our findings suggest that biopsies containing chronic lymphocytic leukemia-type cells, but lacking proliferation centers and with non-enlarged or only slightly enlarged lymph nodes on imaging, represent a very indolent disease that may best be considered a tissue equivalent of monoclonal B-cell lymphocytosis rather than overt small lymphocytic lymphoma. We propose that such cases be designated as tissue involvement by chronic lymphocytic leukemia/small lymphocytic lymphoma-like cells of uncertain significance.

The 2008 WHO classification of lymphoid neoplasms and beyond: evolving concepts and practical applications

The World Health Organization classification of lymphoid neoplasms updated in 2008 represents a worldwide consensus on the diagnosis of these tumors and is based on the recognition of distinct diseases, using a multidisciplinary approach. The updated classification refined the definitions of well-recognized diseases, identified new entities and variants, and incorporated emerging concepts in the understanding of lymphoid neoplasms. However, some questions were unresolved, such as the extent to which specific genetic or molecular alterations define certain tumors, and the status of provisional entities, categories for which the World Health Organization working groups felt there was insufficient evidence to recognize as distinct diseases at this time. In addition, since its publication, new findings and ideas have been generated. This review summarizes the scientific rationale for the classification, emphasizing changes that have had an effect on practice guidelines. The authors address the criteria and significance of early or precursor lesions and the identification of certain lymphoid neoplasms largely associated with particular age groups, such as children and the elderly. The issue of borderline categories having overlapping features with large B-cell lymphomas, as well as several provisional entities, is reviewed. These new observations chart a course for future research in the field.