Diagnostic Utility of a Clonality Test for Lymphoproliferative Diseases in Koreans Using the BIOMED-2 PCR Assay

Enhancing diagnosis of T-cell lymphoma using non-recombined T-cell receptor sequences

Clonality assessment, which can detect neoplastic T cells by identifying the uniquely recombined T-cell receptor (TCR) genes, provides important support in the diagnosis of T-cell lymphoma (TCL). BIOMED-2 is the gold standard clonality assay and has proven to be effective in European TCL patients. However, we failed to prove its sensitivity in Taiwanese TCL patients, especially based on the TCRβ gene. To explore potential impact of genetic background in the BIOMED-2 test, we analyzed TCRβ sequences of 21 healthy individuals and two TCL patients. This analysis suggests that genetic variations in the BIOMED-2 primer sites could not explain the difference in sensitivity. The BIOMED-2 test results of the two TCL patients were positive and negative, respectively. Interestingly, a higher percentage (>81%) of non-recombined TCRβ sequences was observed in the test-negative patient than those of the test-positive patient and all healthy individuals (13~66%). The result suggests a new TCR target for enhancing TCL diagnosis. To further explore the hypothesis, we proposed a cost-effective digital PCR assay that quantifies the relative abundance of non-recombined TCRβ sequences containing a J2-2P~J2-3 segment. With the digital PCR assay, bone marrow specimens from TCL patients (n=9) showed a positive outcome (i.e., the relative abundance of the J2-2P~J2-3 sequences ≧5%), whereas non-TCL patients (n=6) gave a negative result. As five of nine TCL patients had a negative BIOMED-2 test result, the J2-2P~J2-3 sequences may improve TCL detection. This is the first report showing the capability of characterizing non-recombined TCR sequences as a supplementary strategy for the BIOMED-2 clonality test.

Experiencia en el uso de protocolos Biomed-2 para el estudio de reordenamientos de TCR e inmunoglobulinas en proliferaciones linfoides en el Instituto Nacional de Cancerología, Colombia

Introducción.

El consorcio europeo BIOMED-2 se creó para determinar si una población linfoide de difícil clasificación patológica es clonal. En Colombia, la implementación de estas pruebas comenzó en el 2015 en el Instituto Nacional de Cancerología E.S.E. (Bogotá).

Objetivos.

Determinar el comportamiento de las pruebas de reordenamiento clonal o clonalidad linfoide. y determinar las dificultades de su uso en nuestro medio verificando su adaptación local y los resultados en una serie retrospectiva de casos y consecutiva de proliferaciones linfoides sometidas a los protocolos BIOMED-2.

Materiales y métodos.

A partir de las historias clínicas, se recolectaron los datos clínicos e histológicos y los resultados de los análisis de los reordenamientos en todos los casos de proliferaciones linfoides sometidas a los protocolos BIOMED-2, entre febrero de 2015 y mayo de 2019.

Resultados.

Se hallaron 132 casos, de los cuales 47 se clasificaron mediante los protocolos de Biomed-2 como hiperplasias linfoides reactivas, 62 como linfomas T, 19 como linfomas B y 3 como neoplasias linfoides de linaje no establecido. Solo en un caso falló la extracción de ADN. Según estos resultados, la mayor dificultad diagnóstica para el patólogo fue el análisis de los infiltrados linfoides T, la mayoría (44) de los cuales correspondía a lesiones cutáneas.

Conclusiones.

Las pruebas de clonalidad pueden usarse en tejidos de diversa calidad en nuestro medio como ayuda en el diagnóstico de proliferaciones linfoides de difícil clasificación. Es importante hacerlas e interpretarlas de manera multidisciplinaria y considerar cada caso por separado.

Combined detection of lymphocyte clonality and MALT1 translocations in bronchoalveolar lavage fluid for diagnosing pulmonary lymphomas

Diagnosis of pulmonary lymphoma using small tissue samples is difficult and often requires surgical procedures; thus, a less invasive sampling method is desirable. We previously showed that pulmonary mucosa-associated lymphoid tissue (MALT) lymphoma can be diagnosed by detecting MALT lymphoma translocation gene 1 (MALT1) translocations in bronchoalveolar lavage fluid (BALF) cells. Analysis of B-cell clonality based on immunoglobulin heavy chain (IGH) gene rearrangements was also reportedly useful for diagnosing pulmonary lymphoma. The aim of this prospective multicenter study was to evaluate the yet unknown diagnostic potential of combined detection of MALT1 translocations and clonality using BALF. We analyzed B- and T-cell clonality based on IGH and T-cell receptor (TCR) rearrangements together with MALT1 translocations using BALF of patients with clinically suspected pulmonary lymphomas. In total, 39 patients were evaluated and categorized into three groups: B-cell lymphoma, lymphoproliferative disorders, and other diseases. IGH rearrangement detection for B-cell lymphoma diagnosis exhibited sensitivity and specificity of 88.9% and 90.0%, respectively. TCR rearrangements were not observed in patients with B-cell lymphomas. The presence of IGH rearrangements together with the absence of TCR rearrangements indicated 96.0% specificity for the diagnosis of B-cell lymphoma. The sensitivity and specificity of MALT1 translocations for diagnosing MALT lymphoma were 28.6% and 100%, respectively. The combined detection of lymphocyte clonality and MALT1 translocations using BALF is suitable for screening and diagnosis of B-cell lymphomas. Analysis of specific genes such as MALT1 should improve the precision of B-cell lymphoma diagnosis.

The utility and limitations of B- and T-cell gene rearrangement studies in evaluating lymphoproliferative disorders

A hallmark of lymphoid malignancies is the presence of a monoclonal lymphocyte population. Monoclonality of B- and T-cell populations can be established through immunoglobulin (IG) or T-cell receptor (TCR) gene rearrangement analysis, respectively. The biological rationale of IG and TCR gene rearrangement analysis is that due to the extensive combinatorial repertoire made possible by V(D)J recombination in lymphocytes, it is unlikely that any substantive lymphocyte population would share the same IG or TCR gene rearrangement pattern unless there is an underlying neoplastic or reactive origin. Modern IG and TCR gene rearrangement analysis is typically performed by polymerase chain reaction (PCR) using commercially available primer sets followed by gel capillary electrophoresis. This process is highly sensitive in the detection of nearly all lymphoid malignancies. Several pitfalls and limitations, both biological and technical, apply to IG/TCR gene rearrangement analysis, but these can be minimised with high quality controls, performance of assays in duplicate, and adherence to strict criteria for interpreting and reporting results. Next generation sequencing (NGS) will likely replace PCR based methods of IG/TCR gene rearrangement analysis but is not yet widespread due to the absence of standardised protocols and multicentre validation.

Differentiation of lymphocytic-plasmacytic enteropathy and small cell lymphoma in cats using histology-guided mass spectrometry

BACKGROUND

Differentiation of lymphocytic-plasmacytic enteropathy (LPE) from small cell lymphoma (SCL) in cats can be challenging.

HYPOTHESIS/OBJECTIVE

Histology-guided mass spectrometry (HGMS) is a suitable method for the differentiation of LPE from SCL in cats.

ANIMALS

Forty-one cats with LPE and 52 cats with SCL.

METHODS

This is a retrospective clinicopathologic study. Duodenal tissue samples of 17 cats with LPE and 22 cats with SCL were subjected to HGMS, and the acquired data were used to develop a linear discriminate analysis (LDA) machine learning algorithm. The algorithm was subsequently validated using a separate set of 24 cats with LPE and 30 cats with SCL. Cases were classified as LPE or SCL based on a consensus by an expert panel consisting of 5-7 board-certified veterinary specialists. Histopathology, immunohistochemistry, and clonality testing were available for all cats. The panel consensus classification served as a reference for the calculation of test performance parameters.

RESULTS

Relative sensitivity, specificity, and accuracy of HGMS were 86.7% (95% confidence interval [CI]: 74.5%-98.8%), 91.7% (95% CI: 80.6%-100%), and 88.9% (95% CI: 80.5%-97.3%), respectively. Comparatively, the clonality testing had a sensitivity, specificity, and accuracy of 85.7% (95% CI: 72.8%-98.7%), 33.3% (95% CI: 14.5%-52.2%), and 61.5% (95% CI: 48.3%-74.8%) relative to the panel decision.

CONCLUSIONS AND CLINICAL IMPORTANCE

Histology-guided mass spectrometry was a reliable technique for the differentiation of LPE from SCL in duodenal formalin-fixed paraffin-embedded samples of cats and might have advantages over tests currently considered state of the art.

T-Cell Receptor Rearrangements Determined Using Fragment Analysis in Patients With T-Acute Lymphoblastic Leukemia

Background

Chromosomal abnormalities and common genetic rearrangements related to T-acute lymphoblastic leukemia (T-ALL) are not clear. We investigated T-cell receptor (TCR) rearrangement in Korean T-ALL patients by fragment analysis, examining frequency, association between clinicopathologic characteristics and TCR clonality, and feasibility for detecting minimal residual disease (MRD).

Methods

In 51 Korean patients diagnosed as having T-ALL, TCR rearrangement was analyzed using the IdentiClone TCR gene clonality assay (InVivoScribe Technologies, San Diego, CA, USA) from archived bone marrow specimens. Limit of detection (LOD) and clonal stability at relapse were evaluated. The association between clinical prognosis and TCR clonality was examind by age and immunophenotypic classification.

Results

Thirty-eight patients (74.5%) had 62 clonal products of TCRβ, TCRγ, and/or TCRδ rearrangements at diagnosis. Children with T-ALL (<12 years) showed a higher frequency of clonality (93.8%) than adolescents/adults (65.7%; ≥12 years). Patients with a mature immunophenotype (84.4%) showed a relatively higher frequency of clonality than those with the immature immunophenotype (57.9%). Survival and event-free survival were not influenced by immunophenotype or TCR clonality. The LOD was 1%. Clonal evolution at the relapse period was noted.

Conclusions

The overall detection rate of TCR clonality was 74.5%. Survival did not differ by TCR clonality or immunophenotype and age group. Fragment analysis of TCR rearrangement cannot be used to assess MRD due to low sensitivity. Further research on the relationship between prognosis and frequency of TCR rearrangements is needed, using more sensitive methods to detect clonality and monitor MRD.

Monitoring immunoglobulin heavy chain and T-cell receptor gene rearrangement in cfDNA as minimal residual disease detection for patients with acute myeloid leukemia

The present study aimed to examine whether monoclonal immunoglobulin heavy chain (IGH) or T-cell receptor (TCR) gene rearrangement in cell-free DNA (cfDNA) may be used for minimal residual disease (MRD) monitoring in patients with acute myeloid leukemia (AML). Monoclonal IGH and TCR rearrangement in cfDNA were monitored in patients with AML. A total of 94 (40%) patients had monoclonal IGH or TCR rearrangements in cfDNA at diagnosis; 84% of these patients (79 cases) achieved complete remission following 1–3 courses of induction chemotherapy. Among these cases, 89.9% were negative for monoclonal IGH or TCR rearrangement in cfDNA following consolidation chemotherapies. A total of 8 patients with consistently positive monoclonal IGH or TCR rearrangement in cfDNA relapsed within 6–10 months. During follow up, 39 patients demonstrated positive monoclonal IGH or TCR rearrangement in cfDNA and relapsed. Recurrence of monoclonal IGH or TCR rearrangement in cfDNA was observed 1–3 months earlier than bone marrow relapse and 11 patients with solitary extramedullary relapse demonstrated positive monoclonal IGH or TCR rearrangement recurrence in cfDNA. In conclusion, the detection of monoclonal IGH and TCR rearrangement in cfDNA may represent a useful tool for MRD monitoring in patients with AML.

Nasal-type NK/T-cell lymphomas are more frequently T rather than NK lineage based on T-cell receptor gene, RNA, and protein studies: lineage does not predict clinical behavior

Extranodal natural killer (NK)/T-cell lymphoma (ENKTL), nasal type, comprises NK or cytotoxic T cells. We evaluated the clinical impact of cell type and the usefulness of T-cell receptor (TCR) gene transcripts in distinguishing cell lineage. One hundred and eight cases of ENKTL were analyzed for TCR gene rearrangements using the BIOMED-2 protocol and for TCR gene expression using immunohistochemistry for TCR-βF1 and TCR-cγM1, and RNA in situ hybridization for TCR gene transcripts. Prognostic factors were analyzed. Among the 108 cases, 44 were monoclonal for a TCR rearrangement (40%) while 64 (60%) were undefinable. The monoclonal cases expressed TCR-βF1 in 14 out of 40 cases (35%) and TCR-cγM1 in 1 out of 44 cases (2%). The 64 undetermined cases expressed TCR-βF1 in 15 cases (23%) and TCR-cγM1 in 1 (2%). Thirteen of 40 TCR-β constant gene transcript-positive cases (33%) expressed TCR-βF1 and one of nine TCR-γ constant gene transcript-positive cases (11%) expressed TCR-cγM1. TCR gene transcripts were not useful in the distinction of cell lineages. TCR gene transcripts were positive in ENKTLs as well as in normal B cells and aggressive NK-cell leukemia. Based on gene rearrangements and immunohistochemistry for TCR, there were 60 T-cell type cases (56%), 32 NK-cell type cases (30%), and 16 cases with an undetermined cell type (14%). TCR protein was expressed in 30/60 T-ENKTLs (50%) in a variable fraction of tumor cells. There were no significant differences in clinical findings or overall patient survival between T- or NK-cell types of ENKTL, although those with a T-cell type tended to show a better prognosis for those with localized nasal lymphomas. Univariate and multivariate analysis showed that a non-nasal ENKTL, age >60 years, high level of lactate dehydrogenase, bone marrow involvement, and the absence of radiotherapy were independent prognostic factors.

The prognostic significance of monoclonal immunoglobulin gene rearrangement in conjunction with histologic B-cell aggregates in the bone marrow of patients with diffuse large B-cell lymphoma

Bone marrow involvement (BMI) is a well‐known poor prognostic factor in patients with diffuse large B‐cell lymphoma (DLBCL). This study robustly investigated the significance of monoclonal immunoglobulin gene rearrangement combined with histologic B‐cell aggregates in bone marrow (BM) in the detection of a poor prognostic group. Pretreatment BM samples of 394 DLBCL patients were analyzed via the immunoglobulin gene rearrangement study and the microscopic examination. Monoclonal immunoglobulin gene rearrangement was detected in 25.4% of cases. Histologic B‐cell aggregates with the features of large B‐cell lymphoma aggregates, small cell B‐cell lymphoma aggregates, or B‐cell aggregates of unknown biological potential were observed in 12% of cases (6.9%, 1.3%, and 3.8%, respectively). Histologic B‐cell aggregates were more associated with monoclonality than polyclonality. Cases with both monoclonality and histologic B‐cell aggregates demonstrated close association with poor prognostic factors such as a higher International Prognostic Index score and showed an inferior overall survival rate when compared to cases with only monoclonality or only histologic B‐cell aggregates. From the findings, a combination of monoclonality and histologic B‐cell aggregates within the bone marrow was highly associated with poor prognosis and could be used to determine high‐risk DLBLC patients with greater sensitivity and specificity than conventional microscopic examination or immunoglobulin gene rearrangement study alone.

Evaluation diagnostic usefulness of immunoglobulin light chains (Igκ, Igλ) and incomplete IGH D-J clonal gene rearrangements in patients with B-cell non-Hodgkin lymphomas using BIOMED-2 protocol

PURPOSE

Evaluation diagnostic usefulness of immunoglobulin light chains (Igκ, Igλ) and incomplete IGH D-J clonal gene rearrangements in formalin-fixed, paraffin-embedded (FFPE) tissue of patients with B-cell non-Hodgkin lymphomas (B-NHL).

MATERIALS AND METHODS

This study was performed on samples from 70 patients with B-NHL, including two cases of follicular lymphoma (FL), 20 cases of diffuse large B-cell lymphoma (DLBCL), one case of mantle cell lymphoma (MCL), and 47 cases of B-cell neoplasm (non-classified), which had been previously assessed for complete IGH clonality, and failure to clarify gene rearrangements. We used a gold standard multiplex PCR protocol provided by European Biomedicine and Health (BIOMED-2) Concerted Action Project BMH4-CT98-3936 for improvement of diagnosis and analysis of clonality gene rearrangement in lymphoma malignancies.

RESULTS

Our results revealed a total positive monoclonality of 89 % (62/70) in Igκ, Igλ, and 11.4 % (8/70) polyclonality in gene rearrangements assay. The samples with positive clonality consisting (Igκ: 45 %, Igλ: 55 %) in DLBCL, (Igκ: 100 %) in FL, (Igλ: 100 %) in MCL, and (Igκ: 47 %, Igλ: 36 %) in B-cell neoplasm non-classified. None of the incomplete IGH D-J immunoglobulin gene families (0 %) showed monoclonality, and all samples demonstrated polyclonality pattern.

CONCLUSIONS

Our findings on FFPE tissue revealed that immunoglobulin light chains clonality gene rearrangements assays using BIOMED-2 protocol, could be considered a valuable and reliable method for clonality detection, particularly in cases of failure of complete IGH gene rearrangements analysis. Clonal Ig gene rearrangements assay is applicable for routine diagnostic testing of lymphoproliferative disorders and as a reliable method for differentiating between malignant and benign lymphoma disorders.