Evaluation of B-cell clonality in archival skin biopsy samples of cutaneous B-cell lymphoma by immunoglobulin heavy chain gene polymerase chain reaction

Update in Diagnosis and Management of Primary Cutaneous B-Cell Lymphomas

Primary cutaneous lymphomas are a rare group of diseases, with an estimated incidence of 0.5-1 case per 100,000 people per year. Primary cutaneous B-cell lymphomas (pCBCLs) represent 25-30% of all primary cutaneous lymphomas. There are three main subtypes of pCBCL: primary cutaneous marginal zone lymphoma, primary cutaneous follicle center lymphoma, and primary cutaneous diffuse large B-cell lymphoma, leg type. Cutaneous B-cell lymphomas have a broad spectrum of clinical presentations, which makes diagnostic and therapeutic strategies challenging. To date, treatment recommendations for cutaneous B-cell lymphomas have been largely based on small retrospective studies and institutional experience. Recently, the pharmacotherapeutic landscape has expanded to include drugs that may modify the underlying disease pathology of pCBCLs, representing new therapeutic modalities for this rare group of diseases. Novel therapies used for other systemic B-cell lymphomas show promise for the treatment of pCBCLs and are being increasingly considered. These new therapies are divided into five main groups: monoclonal antibodies, immune checkpoint inhibitors, small-molecule inhibitors, bispecific T-cell engaging, and chimeric antigen receptor T cell. In this review, we discuss the clinical, histopathological, molecular, and cytogenetic features of the most common pCBCL subtypes with a focus on current and innovative therapeutic developments in their management. These emerging treatment strategies for B-cell lymphomas and cutaneous B-cell lymphomas may represent novel first-line options for the management of these rare diseases.

No evidence of Borrelia in Cutaneous Infiltrates of B-cell lymphomas with a highly sensitive, semi-nested real time Polymerase chain reaction (PCR) targeting the 5S-23S intergenic spacer region (IGS)

BACKROUND

The role of Borrelia in the development of skin lymphomas has been under discussion for decades. A similar association has been shown for Helicobacter pylori and gastric lymphomas (MALT type). Nevertheless, few molecular studies investigated Borrelia in skin lymphomas and the results are controversial.

METHODS

We analysed 46 formalin-fixed, paraffin-embedded skin specimens of clincopathologically confirmed B-cell lymphomas (15 marginal zone lymphomas; 20 follicular lymphomas; 3 diffuse large B-cell lymphomas; 8 secondary cutaneous infiltrates) taken from 36 patients from Northern Germany, an endemic area for Borrelia. Fifteen pseudolymphomatous lesions of cutaneous Borreliosis served as control. Both groups were examined with a real time (rt) PCR and a semi-nested PCR targeting the 5S-23S intergenic spacer region (IGS). A multiplex PCR was used to investigate B-cell clonality in all lymphomatous infiltrates (Biomed Primers).

RESULTS

With both assays no B. burgdorferi-specific DNA was identified in any of the B-cell lymphomas, while all 15 Borreliosis specimens gave a positive PCR result in the semi-nested PCR protocol, 12 were also positive in the rt PCR (p<.01). All B-cell lymphomas showed monoclonal IgH-Rearrangement. Analysis of cutaneous B-cell lymphomas from available studies including ours (n=334) reveals an Odds ratio < 1.

CONCLUSION

While some previous studies suggested an association between B. burgdorferi and the development of cutaneous B-cell lymphomas in endemic areas, we were unable to confirm this in our patients, despite a highly sensitive Borrelia PCR assay. Our results including meta-analysis of previous studies question the need for antibiotic therapy in patients with cutaneous B-cell lymphomas.

Kappa and lambda immunohistochemistry and in situ hybridization in the evaluation of atypical cutaneous lymphoid infiltrates

BACKGROUND

Atypical cutaneous lymphoid infiltrates are challenging lesions in dermatopathology. We present a summary of the literature regarding kappa and lambda immunohistochemistry (IHC) and in situ hybridization (ISH) in the evaluation of atypical cutaneous or mucosal lymphoid infiltrates.

METHODS

Relevant articles from 1967 to 2018 in the English language were identified and summarized. In the absence of larger studies, case series of n ≥ 3 were included.

RESULTS

Sixty-three articles assessing kappa and lambda IHC and/or ISH were identified. Most focused on marginal zone lymphomas. Other lymphomas included follicle center lymphoma, diffuse large B-cell lymphoma, chronic lymphocytic leukemia/small lymphocytic lymphoma, mantle cell lymphoma, lymphoplasmacytic lymphoma, plasmablastic lymphoma, multiple myeloma, monoclonal gammopathy of undetermined significance, and polyneuropathy, organomegaly, endocrinopathy, monoclonal protein, skin changes (POEMS). Non-neoplastic lesions included reactive lymphoid hyperplasia, cutaneous plasmacytosis, connective tissue disease, IgG4-related disease, acrodermatitis chronic atrophicans, Zoon balanitis, dermatitides, and infiltrates around epithelial dysplasias/neoplasias.

CONCLUSION

Kappa and lambda IHC and ISH are useful tools in the evaluation of cutaneous B-cell lymphomas and plasma cell neoplasms. The literature supports that the detection of light-chain restriction by IHC and ISH is one of the most useful findings in the differential diagnosis of reactive lymphoid hyperplasia vs B-cell lymphoma with plasmacytic differentiation.

B-cell oligoclonal expansions in renal tissue of patients with immune-mediated glomerular disease

B-cell clonal expansion has been sporadically described in the blood and/or renal tissue of patients with glomerulonephritides, albeit with unclear pathogenetic role. Herein, using spectratyping analysis, we observed oligoclonal intrarenal B-cell populations in 59% of glomerulonephritis patients with podocyte injury (6/7 with focal segmental glomerulosclerosis, 1/3 minimal change disease, 1/3 idiopathic membranous nephropathy, 3/4 IgA nephropathy, 2/5 membranous lupus nephritis), 20% of glomerulonephritis patients without podocyte involvement (4/13 with mesangial or proliferative lupus nephritis, 0/3 idiopathic membranoproliferative glomerulonephritis, 0/4 pauci-immune vasculitis) and 17% of control patients with renal cancer. In multivariate analysis, oligoclonal B-cells were associated with podocyte injury and the grade of glomerulosclerosis (both p = .009). B-cell oligoclonal expansions were not found in the paired peripheral blood samples. We postulate that B-cell expansion in the kidney results from local stimuli, including antigens expressed on podocytes. Further studies to unravel the role of oligoclonal B-cells in (auto)immune-mediated kidney disease are warranted.

[Aggressive primary cutaneous B-cell lymphomas and novel EBV+ entities]

Primary cutaneous large B‑cell lymphomas (PCBLT), EBV-positive large B‑cell lymphomas, not otherwise specified (EBV+ DLBCL, NOS), and primary cutaneous intravascular large B‑cell lymphomas (PCIVLBL) are recognized as cutaneous lymphomas with intermediate to poor prognosis. Differentiation from indolent B‑cell lymphomas or other pathologies of the skin can be complex, both clinically and histologically, but vital for the outcome of the patient. The combination of immunotherapy and polychemotherapy regimens, such as R‑CHOP, has led to significant improvements in prognosis, especially in diffuse large B‑cell lymphomas. Therapeutic decisions need to be individually made for each patient, ideally within an interdisciplinary tumor conference. Immunosenescence may be an important factor in the pathogenesis of EBV+ DLBCL, NOS in elderly individuals. Their prognosis is less favorable than that of patients with EBV-negative PCBLT, whereby this has been observed particularly in elderly patients. One third of patients with PCIVLBL progress to systemic disease. The occurrence of nodal manifestation is rarely observed. Symptoms may vary depending on the organ system involved. Currently there are no evidence-based therapy recommendations due to the rarity of the disease. EBV-positive mucocutaneous ulcer is a new provisional category in the current WHO classification for lymphoid neoplasms. It has been segregated from EBV+ DLBCL, NOS due to its self-limiting course and good response to conservative therapy.

Determination of VH Family Usage in B-Cell Malignancies via the BIOMED-2 IGH PCR Clonality Assay

OBJECTIVES

To determine whether V H family usage in B-cell lymphoproliferative disorders can be deduced from polymerase chain reaction (PCR) product-length information obtained through the BIOMED-2 (Invivoscribe, San Diego, CA) clonality assay.

METHODS

We develop an algorithm that uses the sizing information of the BIOMED-2 immunoglobulin heavy chain (IGH) clonality assay to deduce V H family usage. PCR with family-specific primers on 51 clinical samples containing 54 rearranged alleles were used to validate the algorithm.

RESULTS

The clonal PCR products in different framework reactions contain the same NDN segment (because they are from the same allele). Subtracting the size of the framework III product from the size of the framework I and II products yields the relative position of the framework primer binding sites for the V H segment used. The V H family can be assigned with these relative positions because they are V H family specific in the BIOMED-2 assay. The V H family assigned by the algorithm was concordant with family-specific PCR results for 49 (96%) of the 51 specimens.

CONCLUSIONS

We have developed an algorithm that can correctly assign V H family usage when all three BIOMED-2 framework reactions produced clonal products. Given the wide adoption of BIOMED-2 assay, the algorithm can facilitate collection of IGH V H usage data without additional cost to the laboratories.

Approach to Cutaneous Lymphoid Infiltrates: When to Consider Lymphoma?

Cutaneous lymphoid infiltrates (CLIs) are common in routine dermatopathology. However, differentiating a reactive CLI from a malignant lymphocytic infiltrate is often a significant challenge since many inflammatory dermatoses can clinically and/or histopathologically mimic cutaneous lymphomas, coined pseudolymphomas. We conducted a literature review from 1966 to July 1, 2015, at PubMed.gov using the search terms: Cutaneous lymphoma, cutaneous pseudolymphoma, cutaneous lymphoid hyperplasia, simulants/mimics/imitators of cutaneous lymphomas, and cutaneous lymphoid infiltrates. The diagnostic approach to CLIs and the most common differential imitators of lymphoma is discussed herein based on six predominant morphologic and immunophenotypic, histopathologic patterns: (1) Superficial dermal T-cell infiltrates (2) superficial and deep dermal perivascular and/or nodular natural killer/T-cell infiltrates (3) pan-dermal diffuse T-cell infiltrates (4) panniculitic T-cell infiltrates (5) small cell predominant B-cell infiltrates, and (6) large-cell predominant B-cell infiltrates. Since no single histopathological feature is sufficient to discern between a benign and a malignant CLI, the overall balance of clinical, histopathological, immunophenotypic, and molecular features should be considered carefully to establish a diagnosis. Despite advances in ancillary studies such as immunohistochemistry and molecular clonality, these studies often display specificity and sensitivity limitations. Therefore, proper clinicopathological correlation still remains the gold standard for the precise diagnosis of CLIs.

Applied Protein and Molecular Techniques for Characterization of B Cell Neoplasms in Horses

Mature B cell neoplasms cover a spectrum of diseases involving lymphoid tissues (lymphoma) or blood (leukemia), with an overlap between these two presentations. Previous studies describing equine lymphoid neoplasias have not included analyses of clonality using molecular techniques. The objective of this study was to use molecular techniques to advance the classification of B cell lymphoproliferative diseases in five adult equine patients with a rare condition of monoclonal gammopathy, B cell leukemia, and concurrent lymphadenopathy (lymphoma/leukemia). The B cell neoplasms were phenotypically characterized by gene and cell surface molecule expression, secreted immunoglobulin (Ig) isotype concentrations, Ig heavy-chain variable (IGHV) region domain sequencing, and spectratyping. All five patients had hyperglobulinemia due to IgG1 or IgG4/7 monoclonal gammopathy. Peripheral blood leukocyte immunophenotyping revealed high proportions of IgG1- or IgG4/7-positive cells and relative T cell lymphopenia. Most leukemic cells lacked the surface B cell markers CD19 and CD21. IGHG1 or IGHG4/7 gene expression was consistent with surface protein expression, and secreted isotype and Ig spectratyping revealed one dominant monoclonal peak. The mRNA expression of the B cell-associated developmental genes EBF1, PAX5, and CD19 was high compared to that of the plasma cell-associated marker CD38. Sequence analysis of the IGHV domain of leukemic cells revealed mutated Igs. In conclusion, the protein and molecular techniques used in this study identified neoplastic cells compatible with a developmental transition between B cell and plasma cell stages, and they can be used for the classification of equine B cell lymphoproliferative disease.

Cutaneous lymphomas: an update. Part 2: B-cell lymphomas and related conditions. Am J Dermatopathol. 2014;36:197-208; quiz 209-10. [PMID: 24658377 DOI: 10.1097/dad.0b013e318289b20e]

: Primary cutaneous B-cell lymphomas (PCBCL) are the second most common form of primary cutaneous lymphomas and account for approximately 25%-30% of all primary cutaneous lymphomas. Both forms of low-grade malignant PCBCL, primary cutaneous follicle center lymphoma (PCFCL) and primary cutaneous marginal zone lymphoma of mucosa-associated lymphoid tissue-type (MALT lymphoma) (PCMZL) represent the vast majority of PCBCL and show an indolent slowly progressive course and an excellent prognosis despite a high recurrence rate. Genetic analysis indicates that PCMZL differ from other forms of extranodal MALT lymphomas. The more common class-switched and the non-class-switched form of PCMZL can be distinguished as two distinctive subsets that differ in the cellular composition, IgM expression, and biological behavior with extracutaneous involvement found in the non-class-switched form. Recently, unusual clinical and histological forms of PCMZL and PCFCL manifesting with miliary or agminated lesions have been described that are diagnostically challenging. In contrast to PCMZL and PCFCL, primary cutaneous diffuse large B-cell lymphoma, leg type, and other rare forms of large B-cell lymphomas such as intravascular large B-cell lymphoma have an unfavorable prognosis. There is an emerging group of Epstein-Barr virus (EBV)-driven B-cell lymphoproliferations including posttransplant lymphoproliferative disorders and mucocutaneous ulcer occurring in immunocompromised patients and EBV-associated diffuse large B-cell lymphoma of the elderly arising in the setting of senescence-linked immunodeficiency. This review reports on recent findings expanding the spectrum of clinicopathological features, differential diagnostic aspects, and the pathogenesis of PCBCL and discusses the group of EBV-associated B-cell lymphoproliferations involving the skin.

Capturing needles in haystacks: a comparison of B-cell receptor sequencing methods

Background

Deep-sequencing methods are rapidly developing in the field of B-cell receptor (BCR) and T-cell receptor (TCR) diversity. These promise to revolutionise our understanding of adaptive immune dynamics, identify novel antibodies, and allow monitoring of minimal residual disease. However, different methods for BCR and TCR enrichment and amplification have been proposed. Here we perform the first systematic comparison between different methods of enrichment, amplification and sequencing for generating BCR and TCR repertoires using large sample numbers.

Results

Resampling from the same RNA or cDNA pool results in highly correlated and reproducible repertoires, but resampling low frequency clones leads to stochastic variance. Repertoires generated by different sequencing methods (454 Roche and Illumina MiSeq) and amplification methods (multiplex PCR, 5’ Rapid amplification of cDNA ends (5’RACE), and RNA-capture) are highly correlated, and resulting IgHV gene frequencies between the different methods were not significantly different. Read length has an impact on captured repertoire structure, and ultimately full-length BCR sequences are most informative for repertoire analysis as diversity outside of the CDR is very useful for phylogenetic analysis. Additionally, we show RNA-based BCR repertoires are more informative than using DNA.

Conclusions

Repertoires generated by different sequencing and amplification methods are consistent, but we show that read lengths, depths and error profiles should be considered in experimental design, and multiple sampling approaches could be employed to minimise stochastic sampling variation. This detailed investigation of immune repertoire sequencing methods is essential for informing basic and clinical research.

Electronic supplementary material

The online version of this article (doi:10.1186/s12865-014-0029-0) contains supplementary material, which is available to authorized users.

PCR Analysis of IgH and TCR-γ Gene Rearrangements as a Confirmatory Diagnostic Tool for Lymphoproliferative Disorders

This study investigates PCR analysis of immunoglobulin heavy chain (IgH) and T cell receptor (TCR) gene rearrangements on paraffin-embedded tissue sections and bone marrow aspirates of patients suspected to have lymphoproliferative disorders but with inconclusive diagnosis in histopathological examination. 130 samples of patients with inconclusive immunohistochemistry results were evaluated for clonal rearrangement of IgH and TCR genes. Based on histopathology examination, the patients were divided into three groups: the first group without any definite diagnosis of lymphoproliferative disorders (60 cases, 46.2 %), the second group suspected to have a lymphoproliferative disorder but in favor of benign disorders (19 cases, 14.6 %) and the third group suspect to lymphoproliferative disorders but relatively in favor of malignant disorders (51 cases, 39.2 %). After DNA extraction and quality control, semi-nested PCR was performed using consensus primers for amplification of TCR-γ and CDR-3 regions of IgH genes. PCR products were analyzed after heteroduplex analysis using polyacrylamide gel electrophoresis, and were subject to silver staining. Totally, in over half of the cases (55.4 %), a monoclonal pattern was found in IgH or TCR-γ genes rearrangements. Monoclonal IgH gene rearrangement was detected in 48.1 % of patients, whereas monoclonal TCR-γ gene rearrangement was found in 33.6 % of them, which was not statistically significant (P = 0.008). Only in 32 patients (24.6 %) were the results of TCR-γ and IgH gene rearrangements consistent with respect to the presence (2.3 %) or absence (22.3 %) of monoclonality. Finally, PCR analysis of TCR-γ and IgH gene rearrangements led to definite diagnosis in 105 patients (80.8 %), and only 25 cases (19.2 %) remained inconclusive. Our results emphasize the usefulness of gene rearrangement study in cases without a definite diagnosis in immunohistochemistry studies. Multiple PCR analysis results when combined with patient's clinical course and immunohistochemistry can lead to early diagnosis and subsequent therapy.

Clonality analysis of lymphoid proliferations using the BIOMED-2 clonality assays: a single institution experience

Background

Clonality determination in patients with lymphoproliferative disorders can improve the final diagnosis. The aim of our study was to evaluate the applicative value of standardized BIOMED-2 gene clonality assay protocols for the analysis of clonality of lymphocytes in a group of different lymphoid proliferations.

Materials and methods.

With this purpose, 121 specimens from 91 patients with suspected lymphoproliferations submitted for routine diagnostics from January to December 2011 were retrospectively analyzed. According to the final diagnosis, our series comprised 32 cases of B-cell lymphomas, 38 cases of non-Hodgkin’s T-cell lymphomas and 51 cases of reactive lymphoid proliferations. Clonality testing was performed using the BIOMED-2 clonality assays.

Results

The determined sensitivity of the TCR assay was 91.9%, while the sensitivity of the IGH assay was 74.2%. The determined specificity of the IGH assay was 73.3% in the group of lymphomas and 87.2% in the group of reactive lesions. The determined specificity of the TCR assay was 62.5% in the group of lymphomas and 54.3% in the group of reactive lesions.

Conclusions

In the present study, we confirmed the utility of standardized BIOMED-2 clonality assays for the detection of clonality in a routine diagnostical setting of non-Hodgkin’s lymphomas. Reactions for the detection of the complete IGH rearrangements and reactions for the detection of the TCR rearrangements are a good choice for clonality testing of a wide range of lymphoid proliferations and specimen types while the reactions for the detection of incomplete IGH rearrangements have not shown any additional diagnostic value.

Network properties derived from deep sequencing of human B-cell receptor repertoires delineate B-cell populations

The adaptive immune response selectively expands B- and T-cell clones following antigen recognition by B- and T-cell receptors (BCR and TCR), respectively. Next-generation sequencing is a powerful tool for dissecting the BCR and TCR populations at high resolution, but robust computational analyses are required to interpret such sequencing. Here, we develop a novel computational approach for BCR repertoire analysis using established next-generation sequencing methods coupled with network construction and population analysis. BCR sequences organize into networks based on sequence diversity, with differences in network connectivity clearly distinguishing between diverse repertoires of healthy individuals and clonally expanded repertoires from individuals with chronic lymphocytic leukemia (CLL) and other clonal blood disorders. Network population measures defined by the Gini Index and cluster sizes quantify the BCR clonality status and are robust to sampling and sequencing depths. BCR network analysis therefore allows the direct and quantifiable comparison of BCR repertoires between samples and intra-individual population changes between temporal or spatially separated samples and over the course of therapy.

A parallel comparison of T-cell clonality assessment between an in-house PCR assay and the BIOMED-2 assay leading to an efficient and cost-effective strategy

AIMS

Diagnosis of T-cell lymphoproliferation is sometimes challenging, and in certain instances pathologists rely heavily on the clonality assessment results of T-cell receptor (TCR) gene rearrangement (TCR-GR). Many investigators have designed various in-house primer sets for PCR-based study targeting different loci of TCR genes. In recent years, the commercial BIOMED-2 protocols have become available. The in-house primers are very cheap while the BIOMED-2 primers are expensive. This parallel study aimed to compare the sensitivity of the in-house TCRG primers (two reactions) and the BIOMED-2 TCR primers (six reactions) in an attempt to develop a sensitive and cost-effective strategy for TCR-GR assessment.

METHODS

PCR-based analysis was performed on 69 samples of T-lineage neoplasms including 60 formalin-fixed paraffin-embedded (FFPE) tissues, 5 samples from peripheral blood (PB) and 4 samples from bone marrow (BM) aspirate.

RESULTS

Forty-seven (78%) FFPE and all PB or BM aspirate samples yielded control DNA products suitable for clonality assessment including 4 precursor and 50 mature T-cell neoplasms. The detection rates of clonal TCR-GR were 63% (34/54) by the two in-house TCRG primers, 85% (46/54) by all six BIOMED-2 reactions, 91% (49/54) by combining the in-house and BIOMED-2 TCRG reactions and 94% (51/54) by combining the in-house and all BIOMED-2 reactions. By using the in-house and BIOMED-2 TCRG reactions with a total of four tubes, clonal TCR-GR was detected in 91% of the cases. The reagent cost for this combination was one-third of that for the six BIOMED-2 reactions and the detection rate was also higher than the latter alone (91% vs 85%).

CONCLUSIONS

As the in-house primers were custom made and are much cheaper than the commercial kits, the authors concluded that this four-tube strategy was cost-effective and efficient for TCR-GR clonality assessment.

The value of molecular diagnostics in primary cutaneous B-cell lymphomas in the context of clinical findings, histology, and immunohistochemistry

BACKGROUND

Primary cutaneous B-cell lymphoma (PCBCL) is classified into 3 major subtypes: primary cutaneous follicle center lymphoma (PCFCL); primary cutaneous marginal zone B-cell lymphoma (PCMZL); and primary cutaneous diffuse large B-cell lymphoma, leg type (PCLBCL, LT). Diagnosis of PCBCL is mainly based on clinical and (immuno)-histochemical grounds.

OBJECTIVE

We investigated the diagnostic value of the BIOMED-2 Concerted Action BMH4 CT98-3936 protocol in PCBCL.

METHODS

We analyzed with the BIOMED-2 Concerted Action BMH4 CT98-3936 protocol skin specimens from patients with well-defined clinical and (immuno)-histologic PCBCL (n = 18) in comparison with benign lymphocytic infiltrates (n = 9). For molecular staging we also investigated 13 extracutaneous samples from 6 patients with PCLBCL, LT. Each sample was investigated at least twice.

RESULTS

Monoclonality was detected in all of 5 PCFCL; 5 of 6 PCMZL; all of 6 PCLBCL, LT; and 2 of 9 benign lymphocytic infiltrates. In 5 of 6 patients with PCLBCL, LT, a clone corresponding to the clone detected in the skin was detected in 3 of 5 bone-marrow, 4 of 5 blood, and 1 of 3 lymph node specimens. DNA amplification using tubes A and B of IgH was not possible in PCFCL/PCMZL, benign lymphocytic infiltrates, and extracutaneous specimens of PCLBCL, LT, even after repeated analysis up to 11 times. Pseudomonoclonality was identified by repeated analyses in one case of PCMZL and in one case of benign lymphocytic infiltrate.

LIMITATIONS

A multicentric, randomized, blinded study is necessary to confirm our results.

CONCLUSION

Molecular diagnosis supports the clinical and (immuno)-histologic diagnosis in PCBCL. In PCLBCL, LT, molecular staging may be useful. Tubes C through E of IgH and Igκ analyses seem to be superior to tubes A and B of IgH. Each sample should be analyzed at least twice to assess the possibility of pseudomonoclonality.

Application of BIOMED-2 clonality assays to formalin-fixed paraffin embedded follicular lymphoma specimens: Superior performance of the IGK assays compared to IGH for suboptimal specimens

The BIOMED-2 PCR-based immunoglobulin gene rearrangement assays have quickly become the most commonly used laboratory method for detection of B-cell clonality. Therefore, the reliability of these assays under various conditions has become increasingly important. When studying paired cases of follicular lymphoma (FL) from individual patients, we used these assays to assess clonality in 40 formalin-fixed paraffin-embedded (FFPE) specimens from 19 patients diagnosed with FL. The assays of IGH rearrangement failed to give a clonal result in 26/40 (65%) specimens, while the IGK assays failed in only 3/40 (8%) specimens. The high failure rate of the IGH assays for this set of FFPE lymphomas cannot be explained by systematic problems with DNA extraction or amplification because the same IGH assays resulted in a low failure rate (3/32, 9%) for FFPE small lymphocytic lymphoma/chronic lymphocytic leukemia specimens and for fresh frozen FL specimens (1/6, 17%). Furthermore, in a second validation set of 13 FFPE follicular lymphoma the failure rate was 9/13 (69%). Therefore, the BIOMED-2 IGH assay did not perform well on FFPE follicular lymphoma specimens, and the IGK assay may be superior for assessing clonality when no fresh/frozen tissue is available.

European Organization for Research and Treatment of Cancer and International Society for Cutaneous Lymphoma consensus recommendations for the management of cutaneous B-cell lymphomas. Blood. 2008;112:1600-1609. [PMID: 18567836 DOI: 10.1182/blood-2008-04-152850]

Primary cutaneous B-cell lymphomas (CBCL) represent approximately 20% to 25% of all primary cutaneous lymphomas. With the advent of the World Health Organization-European Organization for Research and Treatment of Cancer (EORTC) Consensus Classification for Cutaneous Lymphomas in 2005, uniform terminology and classification for this rare group of neoplasms were introduced. However, staging procedures and treatment strategies still vary between different cutaneous lymphoma centers, which may be because consensus recommendations for the management of CBCL have never been published. Based on an extensive literature search and discussions within the EORTC Cutaneous Lymphoma Group and the International Society for Cutaneous Lymphomas, the present report aims to provide uniform recommendations for the management of the 3 main groups of CBCL. Because no systematic reviews or (randomized) controlled trials were available, these recommendations are mainly based on retrospective studies and small cohort studies. Despite these limitations, there was consensus among the members of the multidisciplinary expert panel that these recommendations reflect the state-of-the-art management as currently practiced in major cutaneous lymphoma centers. They may therefore contribute to uniform staging and treatment and form the basis for future clinical trials in patients with a CBCL.

A limited number of IgH-primers binding to framework region 1 is sufficient to detect the majority of mature small B-cell non-Hodgkin lymphomas on formalin-fixed paraffin-embedded tissue by PCR

IGH gene rearrangement analysis by PCR is the widely accepted tool to determine clonality of B-cell lymphoid proliferations on formalin-fixed, paraffin-embedded tissue, but the results are often unsatisfying in terms of sensitivity. This is mainly due to poor quality DNA because of degradation and hence difficulties to amplify products of the needed length. Therefore, most previous attempts to determine clonality have depended on primers binding to framework region 3 thus producing amplification products of relatively short length. In order to improve clonality analyses, we have developed a sensitive monoplex PCR-protocol using primers binding to framework region 1 with extended cycling (42 cycles) and subsequent heteroduplex analysis. For comparison, multiplex reactions with alternative primers binding to framework region 1 according to the BIOMED-2 protocol were analyzed. By the two methods combined, we were able to detect clonality of 94% (16/17) of mature small B-cell non-Hodgkin lymphomas. The results suggest that PCR with primers binding to frame work region 1 may be the method of choice when assessing clonality of mature small B-cell non-Hodgkin lymphomas on formalin-fixed tissue.

A practical strategy for the routine use of BIOMED-2 PCR assays for detection of B- and T-cell clonality in diagnostic haematopathology

BIOMED-2 polymerase chain reaction (PCR) assays for clonality analysis of immunoglobulin (IG) and T-cell receptor (TCR) gene rearrangements were evaluated in routine haematopathological practice where paraffin-embedded tissues constitute the majority of specimens. One hundred and twenty-five fresh/frozen and 316 paraffin specimens were analysed for DNA quality and clonality. Seventy-nine per cent of paraffin specimens yielded PCR products of over 300 bp. These specimens and all fresh/frozen specimens were analysed with the complete set of BIOMED-2 reactions for IG (8 reactions) and/or TCR (6 reactions) gene rearrangements. The rate of detection of clonality was 96% in mature B-cell neoplasms and 98% in mature T-cell neoplasms and there were no significant differences in these rates between paraffin and fresh/frozen specimens. As the value of sole use of any individual BIOMED-2 reaction in clonality detection was limited, we assessed combinations of reactions that gave the greatest sensitivity with fewest reactions and were applicable for both fresh/frozen and paraffin specimens. For IG gene rearrangements, three reactions combining one targeting the IG heavy chain framework-2 region and two targeting the IG kappa locus achieved a 91% detection rate. For TCR gene rearrangements, the two TCR gamma reactions gave a 94% detection rate. We therefore recommend this strategy as the first-line assays for routine B- and T-cell clonality analysis in diagnostic haematopathology.

Molecular genetic analysis of haematological malignancies II: mature lymphoid neoplasms

Molecular genetic techniques have become an integral part of the diagnostic assessment for many lymphomas and other chronic lymphoid neoplasms. The demonstration of a clonal immunoglobulin or T cell receptor gene rearrangement offers a useful diagnostic tool in cases where the diagnosis is equivocal. Molecular genetic detection of other genomic rearrangements may not only assist with the diagnosis but can also provide important prognostic information. Many of these rearrangements can act as molecular markers for the detection of low levels of residual disease. In this review, we discuss the applications of molecular genetic analysis to the chronic lymphoid malignancies. The review concentrates on those disorders for which molecular genetic analysis can offer diagnostic and/or prognostic information.

Bone marrow trephines containing lymphoid aggregates from patients with rheumatoid and other autoimmune disorders frequently show clonal B-cell infiltrates

In bone marrow trephines, morphological and immunohistochemical criteria may not be sufficient to discriminate reactive from malignant lymphoid infiltrates. The aim of this study was to determine whether the detection of clonal immunoglobulin heavy chain (IGH) gene rearrangements is a reliable and specific marker for malignant B-cell clones in bone marrow biopsies. Bone marrow trephines with infiltration by different types of low-grade B-cell non-Hodgkin lymphoma (n = 32), reactive lymphoid hyperplasia (n = 18), and reactive lymphoid aggregates (n = 15), including 5 patients with rheumatoid or other autoimmune disorders, were analyzed by morphology, immunohistochemistry, IGH gene rearrangement (polymerase chain reaction), and DNA sequence analysis in selected cases. In 22 (68.8%) of 32 patients with B-cell non-Hodgkin lymphoma, a clonal IGH gene rearrangement was detected. Of the reactive cases, 1 of 18 patients with lymphoid hyperplasia demonstrated clonality, and 9 (60%) of 15 patients with reactive lymphoid aggregates gave a clonal result (GeneScan analysis). DNA sequence analysis was performed in 7 of the latter patients confirming clonality in 6. Four of the patients with B-cell clonality had an autoimmune disorder. None of these patients developed a malignant lymphoma during follow-up. Thus, the molecular detection of a clonal rearrangement of the IGH gene may support the diagnosis of a malignant lymphoma infiltrating the bone marrow. However, morphologically and immunohistochemically benign lymphoid aggregates might also harbor B-cell clones especially in patients with autoimmune disorders. Therefore, the detection of clonality has to be interpreted with utmost care and does not qualify for the unequivocal diagnosis of a malignant B-cell lymphoma.