Detection of clonal T-cell receptor gamma gene rearrangements in paraffin-embedded tissue by polymerase chain reaction and nonradioactive single-strand conformational polymorphism analysis

Clinicopathologic and Genetic Features of Primary T-cell Lymphomas of the Central Nervous System: An Analysis of 11 Cases Using Targeted Gene Sequencing

Primary central nervous system lymphoma (PCNSL) of peripheral T-cell lineage (T-PCNSL) is rare, and its genetic and clinicopathologic features remain unclear. Here, we present 11 cases of T-PCNSL in immunocompetent individuals from a single institute, focusing on their genetic alterations. Seven cases were subject to targeted panel sequencing covering 120 lymphoma-related genes. Nine of the eleven cases were classified as peripheral T-cell lymphoma, not otherwise specified (PTCL-NOS), of which one was of γδT-cell lineage. There was one case of anaplastic lymphoma kinase-positive anaplastic large cell lymphoma and another of extranodal natural killer (NK)/T-cell lymphoma (ENKTL) of αβT-cell lineage. The male to female ratio was 7 : 4 and the age ranged from 3 to 75 years (median, 61 y). Most patients presented with neurological deficits (n=10) and showed multifocal lesions (n=9) and deep brain structure involvement (n=9). Tumor cells were mostly small-to-medium, and T-cell monoclonality was detected in all nine evaluated cases. PTCL-NOS was CD4-positive (n=4), CD8-positive (n=3), mixed CD4-positive and CD8-positive (n=1), or CD4/CD8-double-negative (n=1, γδT-cell type). Cytotoxic molecule expression was observed in 4 (67%) of the 6 evaluated cases. Pathogenic alterations were found in 4 patients: one PTCL-NOS case had a frameshift mutation in KMT2C, another PTCL-NOS case harbored a truncating mutation in TET2, and another (γδT-cell-PTCL-NOS) harbored NRAS G12S and JAK3 M511I mutations, and homozygous deletions of CDKN2A and CDKN2B. The ENKTL (αβT-cell lineage) case harbored mutations in genes ARID1B, FAS, TP53, BCOR, KMT2C, POT1, and PRDM1. In conclusion, most of the T-PCNSL were PTCL-NOS, but sporadic cases of other subtypes including γδT-cell lymphoma, anaplastic lymphoma kinase-positive anaplastic large cell lymphoma, and ENKTL were also encountered. Immunophenotypic analysis, clonality test, and targeted gene sequencing along with clinicoradiologic evaluation, may be helpful for establishing the diagnosis of T-PCNSL. Moreover, this study demonstrates genetic alterations with potential diagnostic and therapeutic utility in T-PCNSL.

Sal-Like Protein 4 Transcription Factor: A Significant Diagnostic Biomarker Involved in Childhood ALL Resistance and Relapse

Purpose

Sal‐like protein 4 transcription factor (SALL4) is a stem cell transcription factor that plays an essential role in the maintenance and self-renewal of embryonic and hematopoietic stem cells, functioning as an oncogene in several cancers. However, the role of SALL4 in the biological behavior of childhood acute lymphoblastic leukemia and its relationship with multidrug resistance and relapse has remained largely unknown.

Patients and Methods

Quantitative real-time polymerase chain reaction (qRT-PCR) was used to characterize the expression pattern of SALL4 in the bone marrow samples of 43 patients with Philadelphia negative ALL and 18 children in the non-cancer control group. The presence of minimal residual disease was measured a year after the initial therapy using SSCP (single-strand conformation polymorphism). In addition, the correlation between the expression of SALL4 and ABCA3 in relapsed patients was analyzed statistically.

Results

Results showed an overexpression of SALL4 in de novo patients compared with the control group (P=0.0001, AUC= 0.93), indicating the importance of this gene in the induction of leukemia. A significant increase in the ABCA3 expression levels was revealed in the relapsed patients, in comparison with the drug-sensitive group (P = 0.0005). The leukemogenetic effect of SALL4 can be related to the effect of this gene on the maintenance of pluripotency in cancer stem cells. Results also suggest that the expression of SALL4 can be considered as a diagnostic marker for pediatric ALL. Moreover, SALL4 expression levels in the minimal residual disease positive (mrd+) ALL group was significantly higher than those in the mrd− group (p=0.0001, AUC= 0.92).

Conclusion

These data demonstrate the prognostic impact of SALL4 in childhood ALL. Our findings also indicated a direct correlation between the mRNA expression levels of SALL4 and ABCA3 transporter in the relapsed group of ALL patients (r=0.7). These results describe a possible mechanism by which SALL4 may lead to the development of multidrug resistance.

Specific TCR gene rearrangements in mycosis fungoides: does advanced clinical stage show a preference?

AIMS

The relationship between the presence of specific T-cell receptor (TCR) gene rearrangements and clinical stage in mycosis fungoides (MF) has not been studied. We analysed a cohort of patients with a diagnosis of MF to determine the different types of specific TCR gene rearrangements present and their relationship to disease stage.

METHODS

A retrospective chart review was used to select patients with a diagnosis of MF who had a skin biopsy and a positive TCR gene rearrangement study in either blood or tissue and at least 2 years of clinical follow-up.

RESULTS

43 patients were identified and divided into two groups. The first group consisted of 23 patients with early stage disease (IA-IIA) that was either stable or went into partial or complete remission with minimal intervention. None of these patients advanced to late stage disease. The second group consisted of 20 patients who had either late stage disease at diagnosis or progressed to late stage disease at some point in time. In the first group, only 4/23 (17%) patients had a single TCR gene rearrangement in the Vɣ1-8 region. In contrast, the second group had 13/20 (65%) patients with a single TCR gene rearrangement in the Vɣ1-8 region (p=0.002).

CONCLUSION

The presence of a single TCR gene rearrangement in the Vɣ1-8 region could possibly be related to a more advanced stage of MF. However, more comprehensive studies, such as next generation sequencing, with a larger cohort is necessary for a more definitive conclusion.

MicroRNA-326 and microRNA-200c: Two novel biomarkers for diagnosis and prognosis of pediatric acute lymphoblastic leukemia

Multidrug resistance (MDR) is considered as the major obstacle for treating pediatric acute lymphoblastic leukemia (ALL). MicroRNAs (miRNAs) are small non coding RNAs which may potentially regulate response to chemotherapy. In this study, total RNA was isolated from bone marrow samples of 46 children with de novo ALL and 16 controls. Quantitative reverse transcriptase polymerase chain reaction was used to investigate the expression profile of the predicted miRNAs; miR-326 and miR-200c, and their predicted targets ABCA2, and ABCA3 transporters. The presence of minimal residual disease was studied using PCR-SSCP (single-strand conformation polymorphism) 1 year after treatment. The association between the miRNA expression and drug resistance was analyzed statistically. Results showed a significant down-regulation of both miR-326 and miR-200c expressions in ALL patients compared with non-cancer controls (P = 0.0002, AUC = 0.813 and P = 0.035, AUC = 0.79, respectively). A considerable negative association between miR-326 expression and MDR was identified which could raise the risk of chemoresistance by 4.8- fold. The expression profiles of miR-326 and ABCA2 transporter were inversely correlated. Data revealed, a novel diagnostic role for miR-326 and miR-200c as potential biomarkers of pediatric ALL. Down-regulation of miR-326 was introduced, for the first time, as a prognostic factor for drug resistance in childhood ALL. To the best of our knowledge, this is the first time that ABCA2 transporter is proposed as a target gene for miR-326, through which it can exert its impact on drug resistance. These data may provide novel approaches to new therapeutics and diagnostics.

Molecular Testing of Lymphoproliferative Disorders: Current Status and Perspectives

Molecular pathologic testing plays an important role for the diagnosis, prognostication and decision of treatment strategy in lymphoproliferative disease. Here, we briefly review the molecular tests currently used for lymphoproliferative disease and those which will be implicated in clinical practice in the near future. Specifically, this guideline addresses the clonality test for B- and T-cell proliferative lesions, molecular cytogenetic tests for malignant lymphoma, determination of cell-of-origin in diffuse large B-cell lymphoma, and molecular genetic alterations incorporated in the 2016 revision of the World Health Organization classification of lymphoid neoplasms. Finally, a new perspective on the next-generation sequencing for diagnostic, prognostic, and therapeutic purpose in malignant lymphoma will be summarized.

Characterization of Feline Immunoglobulin Heavy Chain Variable Region Genes for the Molecular Diagnosis of B-cell Neoplasia

To develop a molecular-based assay so that the diagnosis of feline B-cell neoplasia can be facilitated, we have characterized 24 feline immunoglobulin heavy chain variable region ( IGH V) complementary DNA (cDNA) transcripts. Structural homology with rearranged human IGH V genes was found, and the sequence information was used to design a feline-specific polymerase chain reaction (PCR)-based assay to amplify the complementarity determining region 3 as a marker for B-cell clonality. Conserved primers derived from the second and third framework regions of V gene segments were used in conjunction with 2 sequence-specific primers and 1 degenerate primer derived from the J gene segments. Each PCR reaction was run in duplicate, and both native and denatured PCR products were evaluated using polyacrylamide gel electrophoresis. Formalin-fixed, paraffin-embedded (FFPE) tissue sections from cats with confirmed B-cell neoplasia (diffuse large B-cell lymphoma, plasmacytoma, and myeloma) were examined, and 15/22 (68.2%) cats produced results indicative of the presence of a monoclonal population of B cells. The evaluation of denatured PCR products (heteroduplex analysis) facilitated a more accurate interpretation in 3/15 (20%) cats. Pseudoclonality was a major reason for the failure to detect monoclonality. Poor DNA quality is a significant concern and was responsible for the removal of 2 cats from the study. Using this assay, FFPE normal feline lymphoid tissues and unfixed peripheral blood mononuclear cells were determined to be composed of polyclonal populations of B cells. This assay represents a useful adjunctive diagnostic tool for the diagnosis and investigation of feline B-cell lymphoproliferative disorders.

EBV-Positive T/NK-Cell Lymphoproliferative Disease of Childhood

Background

Epstein-Barr virus (EBV)-associated hemophagocytic lymphohistiocytosis (HLH), EBV-positive systemic T-cell lymphoproliferative disease (STLPD) of childhood, and chronic active EBV (CAEBV) infection may develop after primary EBV infection. This study reviewed the clinicopathological spectrum of EBV-associated T- and natural killer (NK)-cell LPD, including STLPD and CAEBV infection, with an analysis of T-cell clonality.

Methods

Clinicopathological features of seven patients with EBV-associated HLH or STLPD and 12 patients with CAEBV infection were reviewed. Immunohistochemical staining and a T-cell receptor (TCR) gene rearrangement study were performed.

Results

STLPD and EBV-positive HLH showed significantly overlapping clinicopathological findings. One patient with STLPD and one patient with EBV-positive HLH demonstrated moderate to severe atypia of the infiltrating lymphocytes, whereas the remaining patients lacked significant atypia. Twelve patients had CAEBV infection, four of whom suffered mosquito-bite hypersensitivity, five showed NK lymphocytosis, and one suffered hydroa vacciniforme. Infiltrating lymphocytes were predominantly small and devoid of atypia. Hemophagocytic histiocytosis was found in seven of 11 patients. Monoclonality was detected in three (50%) of the six patients with successful TCR gene analysis.

Conclusions

EBV-positive HLH and STLPD share similar clinicopathological findings and may constitute a continuous spectrum of acute EBV-associated T- or NK-cell proliferative disorders. The distinction of EBV-positive T-cell LPD from EBV-positive HLH may be difficult during routine diagnoses because of the technical limitations of clonality assessment.

The significance of multiplex PCR/heteroduplex analysis-based TCR-γ gene rearrangement combined with laser-capture microdissection in the diagnosis of early mycosis fungoides

BACKGROUND

The diagnosis of early mycosis fungoides (MF) is a big challenge to dermatologists and dermatopathologists because it lacks specific clinicopathologic features.

METHODS

Fifty-two paraffin-embedded skin samples from 50 patients, including 31 with suspected MF, 10 with typical MF and 9 with benign inflammatory dermatosis (BID), were obtained from our archives. DNA was extracted both by traditional phenol-chloroform method and by the laser-capture microdissection (LCM)-proteinase K approach. The T(VG) /T(JG) , V(2-5) /V(8-12) /JGT(1) and BIOMED-2-TCR-γ primers were used to assess TCR-γ monoclonal rearrangement as measured by polymerase chain reaction (PCR).

RESULTS

In the suspected MF group, clonal TCR-γ gene rearrangements were detected in 11/31 cases (35.5%) by phenol-chloroform DNA extraction and in 25/31 cases (80.7%) by LCM-proteinase K extraction (p < 0.05). While T-cell clonality was detected in 8/10 cases (80%) by the phenol-chloroform method and 10/10 cases (100%) by LCM (p > 0.05) in the typical MF group, no TCR-γ monoclonal rearrangement was detected in the BID group.

CONCLUSIONS

The strategy of multiple PCR/heteroduplex analysis for TCR-γ gene rearrangement combined with LCM increases the detection rate of clonal TCR-γ gene rearrangement in early MF cases and could provide strong evidence to confirm the diagnosis of early MF.

Comparison of BIOMED-2 versus laboratory-developed polymerase chain reaction assays for detecting T-cell receptor-gamma gene rearrangements

Detecting clonal T-cell receptor (TCR)-gamma gene rearrangements (GRs) is an important adjunct test for diagnosing T-cell lymphoma. We compared a recently described assay (BIOMED-2 protocol), which targets multiple variable (V) gene segments in two polymerase chain reaction (PCR) reactions (multi-V), with a frequently referenced assay that targets a single V gene segment in four separate PCR reactions (mono-V). A total of 144 consecutive clinical DNA samples were prospectively tested for T-cell clonality by PCR using laboratory-developed mono-V and commercial multi-V primer sets for TCR-gamma GR. The combination of TCR-beta, mono-V TCR-gamma and multi-V TCR-gamma detected more clonal cases (68/144, 47%) than any individual PCR assay. We detected clonal TCR-beta GR in 47/68 (69%) cases. Using either mono-V or multi-V TCR-gamma primers, the sensitivities for detecting clonality were 52/68 (76%) or 51/68 (75%). Using both mono-V and multi-V TCR-gamma primers improved the sensitivity for detecting clonality, 60/68 (88%). Combining either mono-V or multi-V TCR-gamma primers with TCR-beta primers also improved the sensitivity, 64/68 (94%). Significantly, TCR-gamma V11 GRs could only be detected using the mono-V-PCR primers. We conclude that using more than one T-cell PCR assay can enhance the overall sensitivity for detecting T-cell clonality.

Mycosis fungoides as an ichthyosiform eruption

Ichthyosiform eruption as a specific manifestation of mycosis fungoides is very rare and only a few such cases have currently been reported in the medical literature. A 63-year-old Korean man presented with a 4-year history of a pruritic ichthyotic eruption. There was no personal or family history of ichthyosis or atopy. The ichthyosiform skin changes involved the abdomen, arms, thighs and shins. The face, palms and soles were spared. There was no peripheral lymphadenopathy or organomegaly. The typical lesions of mycosis fungoides were not present. The results of the routine investigations were normal or negative. A skin biopsy specimen revealed the findings of early mycosis fungoides. He was successfully treated with photochemotherapy.

Primary T-cell lymphoma of the thyroid associated with Hashimoto's thyroiditis, histologically mimicking MALT-lymphoma

Most of thyroid lymphomas are B-lineage, and T-cell lymphomas are rare. Here, we report a case of primary thyroid T-cell lymphoma associated with Hashimoto's thyroiditis. A 48-yr-old woman presented with incidentally found neck mass. Histologically, the resected right lobe of the thyroid was replaced by monomorphic small atypical lymphoid cells with lymphoepithelial lesion-like change, most of which were immunoreactive for CD3, CD8, betaF-1, and TIA-1. Peripheral T-cell lymphoma, unspecified, was finally diagnosed after molecular study for TCR-gamma gene rearrangement. This is the second case of cytotoxic T-cell lymphoma reported in the thyroid gland so far. Unique association between thyroid follicles and neoplastic lymphocytes may be characteristic feature of this type of T-cell lymphoma.

Follicular dendritic cell sarcoma with immature T-cell proliferation

Follicular dendritic cell sarcoma is characterized by proliferation of spindled to ovoid cells reminiscent of follicular dendritic cells. However, the association of follicular dendritic cell sarcoma with a dense infiltration of immature T cells has not hitherto been reported. We report an unusual case of follicular dendritic cell sarcoma of the mesentery with immature T-cell proliferation in a 68-year-old man. The infiltrating immature T cells demonstrated expression of CD3, CD1a, TdT, and coexpression of CD4 and CD8 by immunohistochemistry. In addition, the patient was subsequently diagnosed with myasthenia gravis and paraneoplastic pemphigus and died of distant metastasis within 2 years after initial diagnosis of follicular dendritic cell sarcoma. The aggressive clinical course of this case contrasts with the indolent course of follicular dendritic cell sarcomas, and thus, the prognostic implications of follicular dendritic cell sarcoma with immature T-cell proliferation require clarification. The complication of myasthenia gravis and paraneoplastic pemphigus may suggest that immature T-cell proliferation has an autoimmunity-related systemic influence.

Composite marginal zone B cell lymphoma and enteropathy-type T cell lymphoma of the stomach: a case report

We describe a 64-year-old patient with gastric synchronous extranodal marginal zone B cell lymphoma of mucosa-associated lymphoid tissue and enteropathy-type T cell lymphoma. The simultaneous occurrence of mucosa-associated lymphoid tissue lymphoma and enteropathy-type T cell lymphoma is exceptional and has never been reported. We discuss the possible pathogenetic relationship between the two neoplasms.

CNS lymphomatoid granulomatosis with lymph node and bone marrow involvements

Lymphomatoid granulomatosis (LYG) in the CNS is an uncommon lymphoproliferative disease with characteristic angiocentric lymphoreticular proliferative and granulomatous lesions exhibiting low-grade malignant potential. Here we report a rare case of CNS-LYG, which disseminated to the lymph node and bone marrow. A 50-year-old man was diagnosed with CNS-LYG based on brain biopsy showing perivascular infiltration of CD3-positive small T-lymphocytes without overt nuclear atypism. Eight months after the initial neurological symptoms, inguinal lymph node swelling was found and histopathologically diagnosed as peripheral T-cell lymphoma. TCRgamma-gene rearrangement study using both paraffin-embedded specimens of brain and inguinal lymph node demonstrated an identical clonal band. Considering the clinical course, we concluded lymph node involvement of CNS-LYG, suggesting the malignant potential of CNS-LYG.

Histopathologic-molecular correlation in early mycosis fungoides using T-cell receptor gamma gene rearrangement by polymerase chain reaction with laser capture microdissection

BACKGROUND/PURPOSE

Early mycosis fungoides (MF) is difficult to distinguish from other benign inflammatory dermatoses. We evaluated clonal T-cell receptor (TCR) gamma gene rearrangement by polymerase chain reaction (PCR) as a surrogate to histologic diagnosis in early MF.

METHODS

Twenty paraffin-embedded skin biopsies from nine patients diagnosed with MF were included. Two multiplex PCR encompassing various Vgamma and Jgamma regions were used to detect TCRgamma gene rearrangements. Histologic diagnoses were categorized as "diagnostic", "consistent", "suggestive", or "nondiagnostic". We compared TCRgamma PCR results with histologic parameters to determine the differences between PCR-positive and PCR-negative groups.

RESULTS

TCRgamma PCR was positive in 53% (8/15) of the patch stage, in 100% (2/2) of the plaque stage, and in 100% (3/3) of the tumor stage. TCRgamma PCR was positive in 50% (4/8) of the specimens in both the diagnostic and consistent of MF groups, 71% (5/7) in the suggestive of MF group. We found that inflammation was more severe in PCR-negative specimens. Papillary dermal fibrosis was common, and differed significantly between PCR-positive and PCR-negative groups (p = 0.01). T-cell monoclonality was detected in one nondiagnostic lesion in a patient with psoriasis and MF.

CONCLUSION

TCRgamma PCR allows the diagnosis of MF in patients with lymphocyte-poor lesions, suggestive of MF pathologically. TCRgamma PCR is more likely to be negative with moderate to severe inflammation, particularly with papillary dermal fibrosis. We suggest that the ratio of malignant clonal to reactive T-cells is critical for MF diagnosis.

Comparative investigations of T cell receptor gamma gene rearrangements in frozen and formalin-fixed paraffin wax-embedded tissues by capillary electrophoresis

AIM

To compare clonal T cell receptor gamma (TCRgamma) gene rearrangements in frozen and formalin-fixed paraffin wax-embedded (FFPE) tissue, using capillary electrophoresis for use in diagnostics, as T cell lymphomas may be difficult to diagnose by conventional methods.

METHODS

The DNA for PCR was extracted from frozen and FFPE tissue, cell lines and blood. PCR primers Vgamma1-8, Vgamma9, Vgamma10 or Vgamma11 (5' end labelled) combined with a mixture of JgammaP1/JgammaP/JgammaP2/Jgamma2 (unlabelled) were used. Monoclonal cases were sequenced and clonality, reproducibility, sensitivity and specificity analyses were carried out.

RESULTS

In all cases the molecular test was found to be in agreement with the histological diagnosis. Discrepancies were found between frozen and FFPE tissue in 18 of 56 (32%) tests. The method was highly reproducible. The sensitivity was found to be 0.5% for cell lines and 1% for patient specimens and the specificity 100%. The junctional region between the Vgamma and Jgamma segments was specific for each patient.

CONCLUSIONS

Capillary electrophoresis of PCR products from frozen and FFPE tissue is suitable for detecting clonal TCRgamma gene rearrangements. It is important, however, to correlate the results with conventional morphological and immunohistochemical studies.

Expression of CD56 antigen in Langerhans cell histiocytosis associated with T-lymphoblastic lymphoma in a same lymph node

Association of T-lymphoblastic lymphoma (LBL) and Langerhans cell histiocytosis (LCH) in the same lymph node is very rare. Herein, we report such two cases with expression of CD56 in Langerhans cells. Immunohistochemically, lymphoblasts were positive for anti-polyclonal CD3 antibody, CD34, CD7, CD99, and terminal deoxynucleotidyl transferase. LCH cells were positive for anti-S100 protein, CD1a, CD4, CD56, and CD68. Although those two populations were separated topographically, many histiocytes intermingled with lymphoblasts in the paracortex and a few lymphoblasts were scattered within the intrasinusoidal sheets of histiocytes. Neither admixed eosinophils nor multinucleated giant cells were observed. The pathogenetic mechanism of CD56 expression in LCH associated with LBL is discussed.

Hepatosplenic γδ T-cell lymphoma

AIM: To investigate the clinicopathologic characteristics, immunophenotype and TCR gene rearrangements of hepatosplenic T-cell lymphoma in eight Chinese patients.

METHODS: Eight Chinese patients with hepatosplenic γδ T-cell lymphomas were studied. Hematoxylin-eosin-stained slides and clinical histories were reviewed. We also carried out immunohistochemical staining for CD3, CD4, CD8, CD20, CD43, CD56, CD79a, UCHL-1, and TCR γδ. Rearrangements of TCR gamma and delta chain genes were also studied.

RESULTS: The spleens were enlarged and the cut surfaces were homogeneous and red-purple in color without identifiable gross lesions or enlarged hilar lymph nodes. Histologically, lymphoma cells infiltrated the cords of Billroth and often packed the sinuses. Liver biopsy showed lymphoma cell infiltrations in the sinusoids, and three cases showed involvements of the portal tracts. Immunohistochemically lymphoma cells were positive for CD3, CD43, and CD56 in all cases. Four of eight cases were positive for CD8, and all cases were negative for CD4 (6/6). Monoclonal rearrangements of TCR γ gene were demonstrated by PCR analysis in five out of the eight cases. TCR δ gene rearrangements were detected in six out of the eight cases, which demonstrated single bands on PAGE gel, and the amplification products in two cases were confirmed by sequencing.

CONCLUSION: The clinicopathology of hepatosplenic γδ T-cell lymphoma in Chinese patients is similar to what was previously reported except that the splenomegaly is not so massive, and CD8 is positive.

Rapid detection of clonal T-cell receptor-beta gene rearrangements in T-Cell lymphomas using the LightCycler-polymerase chain reaction with DNA melting curve analysis

Various molecular methods have been developed to diagnose clonal T-cell receptor (TCR) gene rearrangements in clinical samples. Most polymerase chain reaction strategies for detecting clonal TCR gene rearrangements rely on either gel or capillary electrophoresis. However, a cumbersome manual transfer step separates amplification from analysis. Recently, we developed a novel polymerase chain reaction assay using the LightCycler system to detect clonal immunoglobulin heavy chain gene rearrangement. In the current study, we extend this work to include the TCR. We report that clonal TCR-beta (TCR-beta) gene rearrangements can be detected in less than 1 hour after preparing the DNA by measuring DNA melting immediately after amplification in a single closed capillary tube. We retrospectively studied 52 fresh-frozen tissue samples from patients clinically suspected of T-cell malignancy. A clonal TCR-beta gene rearrangement was detected in 14 samples by DNA melting curve analysis. When DNA melting was compared to the gold standard methods of Southern blot or denaturing gradient gel electrophoresis, it achieved a sensitivity equal to 71% and a specificity equal to 94%. We also compared melting curve analysis and polyacrylamide gel electrophoresis: melting curve analysis reached a sensitivity equal to 100% and a specificity equal to 97%. We conclude that DNA melting curve analysis in the LightCycler system has potential for clinical use as a new, ultra-fast method for the initial diagnosis of clonal TCR-beta gene rearrangements.

CD4+CD56+ lineage negative hematopoietic neoplasm: so called blastic NK cell lymphoma

Blastic natural killer (NK) cell lymphoma is a rare neoplasm characterized by blastoid tumor cells expressing CD4 and CD56, with predominant skin involvement. Although this tumor has been regarded as a neoplasm related to NK cell, recent studies suggested that it is derived from plasmacytoid dendritic cells, but not from NK cell. Herein we report 4 cases of CD4+CD56+ lineage marker-blastic NK cell lymphomas with a review of literatures. The patients were 3 men and one woman. Three of them were young (17, 18, and 22 yr old). Three patients had skin lesions, at initial presentation in two patients and during the course of disease in other patient. Histologically, tumors consisted of monotonous medium to large blastoid cells showing no necrosis, angiocentric growth or epidermotrophism. All four tumors were CD4+ and CD56+. Three expressed CD68 antigen. Lineage specific markers for B- and T cell were negative. All tumors did not express myeloperoxidase. T-cell receptor gene rearrangement, EBV, CD13 and CD33 were negative. In one patient, tumor cells arranged in Homer-Wright type pseudorosette and expressed terminal deoxynucleotidyl transferase(TdT). Despite the standard lymphoma chemotherapy, the tumors, except one lost during follow-up, progressed and relapsed. The patients died 8-60 months after diagnosis.

Assessment of T-cell Clonality via T-cell Receptor-γ Rearrangements in Cutaneous T-cell–Dominant Infiltrates Using Polymerase Chain Reaction and Single-stranded DNA Conformational Polymorphism Assay

Discerning the pathologic significance of cutaneous T-cell infiltrates can pose a diagnostic challenge for dermatopathologists. Reactive conditions such as drug-associated lymphomatoid hypersensitivity and lymphomatoid lupus erythematosus can demonstrate lymphoid atypia and a phenotype resembling cutaneous T-cell lymphoma (CTCL). Further, lymphoid dyscrasias such as pityriasis lichenoides chronica, large plaque parapsoriasis, and atypical pigmentary purpura confuse the picture because they not only mimic CTCL but also represent prelymphomatous states with inherent malignant potential. Although the emergence of a dominant clone has been considered a clue indicative of a T-cell dyscrasia, there are reports concerning the identification of monoclonality in biopsies of reactive lymphoid infiltrates. We have conducted a modified single-stranded DNA conformational polymorphism (SSCP) assay using paraffin-embedded, formalin-fixed tissue on 92 T-cell-rich biopsies to determine the relative specificity and sensitivity of this methodology. In addition, laser capture microdissection (LCM) was performed on 22 of the 92 samples to isolate the area of interest and to compare its specificity and sensitivity with those SSCP assays performed without LCM. We found that monoclonality or oligoclonality is 86% specific for preneoplastic and neoplastic states, whereas the finding of polyclonality appears to be relatively specific for a reactive process. Some cases of reversible T-cell dyscrasia produced a molecular profile mimicking lymphoma or prelymphomatous states by virtue of monoclonality or oligoclonality. Although LCM appears to improve the sensitivity for detecting preneoplastic conditions, the relative specificity appears to be the same as that encountered with routine SSCP.

The role of molecular studies in lymphoma diagnosis: a review

Lymphoma classification is based on a multiparametric approach to diagnosis, in which clinical features, morphology, immunophenotype, karyotype and molecular characteristics are important to varying degrees. While in most cases, a diagnosis can be confidently established on the basis of morphology and immunophenotype alone, a small proportion of diagnostically difficult cases will rely on molecular studies to enable a definitive diagnosis. This review discusses the various molecular techniques available including Southern blotting (SB), polymerase chain reaction (PCR), fluorescence in situ hybridisation (FISH)--including multicolour-FISH/spectral karyotyping and comparative genomic hybridisation--and also gene expression profiling using cDNA microarray technology. Emphasis is given to the analysis of antigen receptor gene rearrangements and chromosomal translocations as they relate to lymphoma diagnosis and also in the setting of minimal residual disease (MRD) detection and monitoring. Laboratories performing these tests need to have expertise in these areas of testing, and there is a need for greater standardisation of molecular tests. It is important to know the sensitivity and specificity of each test as well as its limitations and the pitfalls in the interpretation of results. Above all, results of molecular testing should never be considered in isolation, and must always be interpreted in the context of clinical and other laboratory data.

Investigation of T-cell receptor-γ gene rearrangement in gastrointestinal lymphomas by PCR-SSCP analysis

AIM: To analyze the characterization of T-cell receptor-γ (TCR-γ) gene rearrangement in the gastrointestinal lymphomas and evaluate the value of PCR-SSCP analysis in gastrointestinal lymphomas investigation.

METHODS: TCR-γ gene rearrangement segments of gastrointestinal lymphomas were cloned and sequenced. Single clone plasmid and mixed clone plsamids were subsequently submitted to PCR-SSCP analysis to investigate the relationship between the number of amplified clones and band patterns of the amplified products. The PCR products of TCR-γ gene rearrangement of 40 gastrointestinal lymphomas were electrophoresed on agarose gels and the positive cases on agarose gels were studied by SSCP analysis.

RESULTS: The sequencing showed that TCR-γ gene rearrangement of the gastrointestinal lymphomas included functional gene and pseudogene with extensive variety in the junctional regions. In SSCP analysis, the number of the single-stranded bands was about two times of the number of amplified clones, and double-stranded band became broad with the increased number of the amplified clones. Thirteen of the 25 B- cell gastrointestinal lymphomas and 14 of the 15 gastrointestinal T-cell lymphomas were positive detected on agarose gel electrophoresis. Of the positive cases detected by SSCP analysis, 3 B-cell lymphomas and 13 T-cell lymphomas showed positive bands. The other cases showed only smears. The rearranged pattern included 13 monoallelic gene rearrangements and 3 biallelic or oligoclonal gene rearrangements.

CONCLUSION: The pattern of TCR-γ gene rearrangement in gastrointestinal lymphomas are similar to that of the nodular lymphomas. PCR-SSCP analysis for TCR-γ gene rearrangement can be applied both for adjuvant diagnosis of gastrointestinal lymphomas and analysis of the gene rearrangement pattern. The ratio of TCR-γ gene rearrangements occurred in T-cell gastrointestinal lymphomas is significantly higher than that in B-cell gastrointestinal lymphomas. The gene rearrangement pattern involves monoallelic and biallelic (or oligoclonal) gene rearrangement.

Annular lichenoid dermatitis of youth

BACKGROUND

Lichenoid dermatoses are composed of a wide spectrum of disorders with a common histopathologic interface pattern but diverse causes and pathophysiology.

OBJECTIVE

We describe a series of young patients with a peculiar annular lichenoid dermatitis, the clinical appearance of which initially suggested diagnoses of morphea, mycosis fungoides, or annular erythema.

RESULTS

The study involved 23 patients (median age 10 years; age range 5-22 years). Lesions consisted of persistent asymptomatic erythematous macules and round annular patches with a red-brownish border and central hypopigmentation, mostly distributed on the groin and flanks. Histology revealed a peculiar lichenoid dermatitis with massive necrosis/apoptosis of the keratinocytes limited to the tips of rete ridges, in the absence of dermal sclerosis and epidermotropism of atypical lymphocytes. The infiltrate was composed mainly of memory CD4(+) CD30(-) T cells with few B cells and macrophages. Analysis of T-cell receptor-gamma-chain gene rearrangement in skin biopsy specimens revealed polyclonality in all the 15 cases studied. Topical and systemic corticosteroids or phototherapy were effective in most patients with relapse after treatment withdrawal.

CONCLUSIONS

We suggest that this is a distinctive inflammatory condition, and we propose to term it "annular lichenoid dermatitis of youth."

Improved detection of clonality in cutaneous T-cell lymphomas using laser capture microdissection

BACKGROUND

The diagnosis of cutaneous T-cell lymphoma is a challenge for both the pathologist and the clinician. This is particularly true for distinguishing early-stage mycosis fungoides from dermatitis. In this clinical setting, the presence of a clonal T-cell population supports lymphoma.

METHODS

Usually, routinely processed paraffin-embedded material is available for gene rearrangement analysis, and polymerase chain reaction (PCR)-based methods to assess clonality can be performed. One drawback of this approach is that sensitivity is suboptimal in biopsy specimens in which the lymphocytic infiltrate represents only a small percentage of all cells present. Another drawback is that DNA extraction from routinely processed, paraffin-embedded tissue is a time-consuming and labor-intensive procedure which can take up to 5 days in our laboratory. To bypass these problems, we used laser capture microdissection (LCM) to obtain lymphocytic infiltrates from tissue sections of formalin-fixed, paraffin-embedded skin biopsy specimens. This approach allows for more specific PCR assessment of the lymphocytic infiltrate and for rapid DNA extraction and PCR analysis.

RESULTS

Using the LCM approach, we could demonstrate clonal T-cell receptor gamma gene rearrangements in biopsy specimens that did not show clonality using DNA extracted by conventional methods from full tissue sections. In addition, DNA extraction and PCR analysis can be performed in 11 h.

CONCLUSION

In conclusion, applying LCM to clonality analysis of cutaneous lymphocytic infiltrates is rapid and more sensitive than conventional methods, and we recommend introducing this approach into the routine diagnostic setting.

Application of laser capture microdissection to cytologic specimens for the detection of immunoglobulin heavy chain gene rearrangement in patients with malignant lymphoma

BACKGROUND

The demonstration of the monoclonality of immunoglobulin heavy chain (IgH) gene rearrangement is an indispensable method for the diagnosis of B-cell lymphoma as well as histocytochemical analysis. For the detection of IgH gene rearrangement, the extraction of DNA from a homogenous cell population is necessary. Recently, the laser capture microdissection (LCM) technique was shown to isolate specific cells from histopathologic specimens for molecular analysis. However, to the authors' knowledge the applicability of LCM to cytologic specimens has not yet been well established.

METHODS

Using LCM, a homogenous population of B-cell lymphoma cells as both histologic sections and cytologic specimens was captured, and genomic DNA was extracted from the captured cells. IgH gene rearrangement was analyzed by the polymerase chain reaction (PCR)-based single-strand conformational polymorphism (SSCP) method.

RESULTS

Genomic DNAs were extracted successfully from ethanol-fixed cytologic specimens, but cells were not captured from air-dried specimens. Using PCR-SSCP analysis, the monoclonality of the IgH gene rearrangement was detected in five cases of tissue sections among nine analyzed cases of malignant lymphoma diagnosed immunohistochemically. However, analysis of the cytologic specimens with LCM demonstrated the monoclonality of the IgH gene rearrangement in seven cases of lymphoma.

CONCLUSIONS

The results of the current study suggest that the novel application of LCM to cytologic specimens occasionally exhibits high sensitivity for the detection of IgH gene rearrangement monoclonality compared with the use of histologic sections.

Primary central nervous system lymphoma in Korea: comparison of B- and T-cell lymphomas

The great majority of primary central nervous system lymphoma (PCNSL) is known to be of B-lineage, with T-cell PCNSL (T-PCNSL) accounting for <5%. We report an unusually high incidence of T-cell lymphoma among the PCNSLs originated in a large general-care hospital in the metropolitan Seoul area. PCNSLs (n = 42) accrued from April 1995 through June 2001 were reviewed for histologic and clinical features, and immunohistochemical staining was done for CD3, CD20, CD4, CD8, Bcl-6, and CD10. Clonal rearrangements of the TCR-gamma and IgH genes were studied with semi-nested PCR in all seven cases of T-PCNSL and seven of 35 B-cell PCNSL (B-PCNSL). Formalin-fixed, paraffin-embedded specimens were used in all these studies. By immunohistochemical staining and molecular studies, seven cases (16.7%) were diagnosed as T-PCNSL, each displaying clonal rearrangement of the TCR-gamma gene, and 35 (83.3%) as B-PCNSL. Radiologically, T-PCNSL was significantly correlated with the superficial and subcortical lobar location (p <0.001), solitary mass formation (p = 0.001), presence of rim enhancement (p <0.001), and peritumoral edema (p = 0.029). Involvement of cerebrospinal fluid was observed only in B-PCNSL (n = 17) but not in T-PCNSL (p = 0.010). Histologically, T-PCNSL was characterized by a population of mixed predominantly small- and occasionally medium-sized cells (p <0.001), which were loosely scattered without forming a solid mass (p = 0.024), and perivascular infiltration was frequent (p = 0.007), in contrast to predominantly large cells of B-PCNSL, i.e., diffuse large B-cell lymphoma (DLBCL), in which the cells tended to aggregate to form monomorphous sheets (p = 0.024). In T-PCNSL, staining for CD8 was positive in five, including one with coexpression of CD4, and two were negative for CD4 and CD8. Of 24 DLBCLs tested, the pattern of Bcl-6+ tumor cells was diffusely dense, similar to that of the germinal center in nine cases (37.5%), with coexpression of CD10 in three of the nine cases. T-PCNSL accounted for 16.7% of the PCNSLs; thus, in Korea it may not be as rare as previously known. The T-PCNSL presented with certain clinical and pathologic features that were distinct from B-PCNSL and displayed preponderance of CD8 expression. DLBCL of the germinal center B-cell derivation defined by bcl-6 expression comprised 37.5% of DLBCL of the brain.

Purely follicular mycosis fungoides without mucinosis: report of two cases with review of the literature

Follicular lesions can either associate with typical patch-/plaque-type mycosis fungoides or, more rarely, be the only clinical manifestation of the disease. We describe 2 adult patients who presented with alopecia and disseminated follicular erythematous papules, and comedones and cysts, respectively. In both patients, histology showed a folliculotropic infiltrate of atypical lymphocytes that spared the epidermis, in the absence of follicular mucinosis. Molecular genetic analysis confirmed the oligo/monoclonal nature of the T-cell infiltrate. Reported cases of purely follicular mycosis fungoides without mucinosis are reviewed.

The value of molecular analysis by PCR in the diagnosis of cutaneous lymphocytic infiltrates

The diagnosis and classification of cutaneous lymphomas remain a challenge for the clinician and dermatopathologist. This diagnostic dilemma is mainly encountered in the distinction between an early malignant lymphoma and a benign reactive lymphocytic infiltrate (pseudolymphoma). Until the beginning of the 1980s, our diagnostic tools were limited to the clinical presentation, course, and histopathology in diagnosis and classification of lymphocytic infiltrates. Advances in immunology and, in particular, in molecular genetics with the introduction of the Southern blot technique and the polymerase chain reaction (PCR) have revolutionized the diagnosis of lymphocytic infiltrates by determination of clonality. In some series, more than 90% of cutaneous T-cell lymphomas have a clonal rearrangement of the T-cell receptor gamma-chain gene, as opposed to very low percentages of rearrangement in T-cell pseudolymphomas. However, the presence of clonality does not necessarily imply malignancy. Cases of pseudolymphomas, lichen planus and pityriasis lichenoides et varioliformis acuta were reported with clonal lymphocytic proliferations. Therefore, care should be exercised in the evaluation of the results of molecular analysis, and these should always be correlated with the clinical, histological and immunophenotypic picture to arrive at the correct diagnosis. It may be expected that the molecular methods for diagnosis of lymphocytic infiltrates will be improved and refined in future, and that sensitivity and specificity will increase.

Comparative evaluation of PCR-based methods for the assessment of T cell clonality in the diagnosis of T cell lymphoma

AIMS

The accurate diagnosis of T cell lymphoma often depends on the demonstration of a monoclonal T cell population in a lymphoproliferative disorder (LPD). The aim of this study was to evaluate four polymerase chain reaction (PCR)-based methods used to analyse T cell receptor (TCR) gene rearrangements in the assessment of T cell clonality.

METHODS

DNA was tested from 23 T cell neoplasms, seven B cell non-Hodgkin's lymphomas (B-NHL), three Hodgkin's lymphomas (HL), 14 benign LPD and peripheral blood from a healthy donor. TCRgamma rearrangements were assessed by McCarthy's et al. two primer set method, Benhattar's et al. linear pre-amplification method, and Chhanabhai's et aL heteroduplex method. TCRbeta D-J rearrangements were analysed by Slack's et al. method.

RESULTS

Monoclonal TCRgamma rearrangements were found in 91% (21 of 23) of T cell neoplasms using McCarthy's et al. method; in 83% (19 of 23) using Benhattar's et al. or Chhanabhai's et al. methods and monoclonal TCRbeta rearrangements were found in 43% (10 of 23) using Slack's et al. method. Monoclonality was established in all T cell neoplasms using one or more PCR methods. One follicular B-NHL had inappropriate monoclonal TCRbeta rearrangement, while the remaining B-NHL and all HL samples had no monoclonal TCRgamma or TCRbeta rearrangements. In addition to polyclonal products, one reactive lymph node had oligoclonal TCRgamma rearrangements and two others generated monoclonal products of uncertain significance. McCarthy's et al. TCRgamma method was the most sensitive in establishing T cell monoclonality, and in combination with Slack's et al. TCRbeta method, monoclonality was demonstrated in 100% of T cell neoplasms (23 of 23).

CONCLUSIONS

These data indicate that multiple primer set PCR methods should obviate a need for the more expensive and time-consuming Southern blot (SB) technique and are the preferred diagnostic molecular test for assessing T cell clonality.

Effectiveness of capillary electrophoresis using fluorescent-labeled primers in detecting T-cell receptor gamma gene rearrangements

We describe the use of fluorescent-labeled primers to analyze T-cell receptor gamma gene rearrangements (TCR gamma GR) using capillary electrophoresis in the ABI Prism 310 Genetic Analyzer. We also compare the performance with denaturing gradient gel electrophoresis (DGGE). In a single multiplex polymerase chain reaction (PCR) we amplified TCR gamma GR with primers for all known groups of variable region genes, and joining region genes described in lymphoid neoplasms. Ten reactive samples, followed by five cell lines and 25 tumor samples with 41 individual TCR gamma GR (due to many biallelic rearrangements) previously identified by DGGE, were analyzed to validate the technique. The capillary electrophoresis protocol has 92% concordance for both TCR clonal status (23 of 25) and 95% concordance in the number of individual TCR gamma GR (38 of 41) identified by DGGE. The reproducible sensitivity for detecting TCR gamma GR diluted in reactive lymphoid DNA is 2% in clinical applications. Discrimination of predominant rearrangements requires a minimum ratio of two times the height of the normal distribution of polyclonal peaks. Capillary electrophoresis can provide results within 60 minutes for each specimen after PCR is complete. Capillary electrophoresis provides a faster result than sequence-based separation methods and gives an archival electronic record. Fluorescent labeling allows the identification of both the variable and joining gene segments used in a TCR gamma GR. The effectiveness of capillary electrophoresis is similar to DGGE.

Semireannealing, single-stranded conformational polymorphism: a novel and effective tool for the diagnosis of T-cell clonality

Single-stranded conformational polymorphism (SSCP) is often used for the diagnosis of T-cell clonality in lymphoproliferative disorders. We introduce a semireannealing SSCP (SR-SSCP) protocol that is rapid, reproducible, and effective. By denaturing and reannealing the polymerase chain reaction (PCR) product before high-resolution polyacrylamide gel electrophoresis, it is possible to generate a diagnostic fingerprint for each case with clonal T-cell receptor-gamma (TCR-gamma) gene rearrangement detected after PCR with TCR-gamma specific consensus primers. Discrete and distinct denatured single-stranded DNA band profiles characterize the rearranged TCR-gamma clones. In the same gel, the clone size may be estimated in the reannealed double-stranded PCR DNA and can be assessed down to the 2% clonal T-cell population level. Eighty-four cases, including 37 T-cell neoplasms, 29 B-cell neoplasms, and 18 reactive lymph node samples were analyzed by SR-SSCP. Clonal TCR-gamma rearrangement was diagnosed in 32 out of 37 T-cell neoplasms but in none of the B-cell tumors or reactive lymph node samples corresponding to sensitivity and specificity of 86.5% and 100%, respectively. We compare the results of SR-SSCP to those obtained by capillary electrophoresis and direct sequence analysis with 100% correlation. This novel method is applicable to any system for identification and quantitation of microheterogeneity in PCR products.

Spontaneous regression of Kikuchi lymphadenopathy with oligoclonal T-cell populations favors a benign immune reaction over a T-cell lymphoma

To aid in the initial diagnosis of Kikuchi lymphadenitis and to assess whether the composition of the T cells might shed light on the pathogenesis, we used nested polymerase chain reaction tests followed by high-resolution gel electrophoresis to determine the pattern of T-cell antigen receptor rearrangement in 56 consecutive cases. Except for 1 unusual case with recurrent lymphadenopathy, none had a monoclonal beta or gamma rearrangement. Eight cases had a polyclonal pattern at both beta and gamma loci, 20 cases had a mixed polyclonal beta and oligoclonal gamma pattern, and 27 cases had an oligoclonal pattern at both loci. The high frequency of oligoclonality did not indicate an early-stage T-cell lymphoma in evolution, as confirmed by spontaneous resolution of the lymphadenopathy in all cases within 6 months. Rather, it is consistent with reports of oligoclonal T cells in a variety of immune reactions. We conclude that, in the vast majority of cases, absence of a monoclonal T-cell receptor rearrangement excludes the possibility of T-cell lymphoma, and the presence of an oligoclonal pattern implies a benign immune reaction.

Practical evaluation and management of cutaneous lymphoma

Accurate evaluation of patients with suspected or known cutaneous lymphoma requires the integration of many sources and types of information, including clinical evaluation, microscopic analysis of tissue, immunophenotyping, gene rearrangement studies, clinical staging, and longitudinal observation. Diagnoses should be based on knowledge of specific lymphoma types as described in modern classification systems. Management of patients with cutaneous lymphoma requires collaboration among dermatologists, dermatopathologists, hematopathologists, and medical, surgical and radiation oncologists. (J Am Acad Dermatol 2002;46:325-57.)

LEARNING OBJECTIVE

At the conclusion of this learning activity, participants should better understand how to evaluate and manage patients for suspected or established lymphoma of the skin. Components include the clinical history and physical examination, optimal biopsy and tissue handling, interpretation of pathology and adjunctive test results, clinicopathologic correlation, and therapy. Participants should also understand the basis for establishing a specific diagnosis of cutaneous lymphoma based on current classification and staging.

Quantitative assessment of minimal residual disease in childhood lymphoid malignancies using an allele-specific oligonucleotide real-time quantitative polymerase chain reaction

We developed an assay using a real-time quantitative polymerase chain reaction (RQ-PCR) for the quantitative assessment of minimal residual disease (MRD) in childhood lymphoid malignancies by using a consensus V-region probe combining a allele-specific oligonucleotide (ASO) reverse primer. Our strategy employs a set consisting of a consensus V-region probe, an ASO reverse primer, and a patient-specific forward primer for clonal antigen-receptor (IgH, immunoglobulin heavy chain; TCR, T-cell receptor) gene rearrangements (IgH-ASO and TCR-ASO RQ-PCR assays). The limit of detection in both assays was 5 copies of the target/10(5) cell equivalents. We tested the assays in 17 childhood malignancies (14 cases of acute lymphoblastic leukemia and 3 of non-Hodgkin's lymphoma). High correlation coefficients of the standard curves (>0.980) and PCR efficiency (>0.95) were achieved with all primer/probe sets. In 2 (12%) of the 17 patients, ASO primers could not be designed because there was no junctional N-sequence. The quantitative data suggest that the copy number of clonal antigen receptors markedly decreased after induction therapy in 15 of 17 patients and that 1 patient relapsed and died of the disease. Consensus probes make it possible to examine a large number of patients with only a limited number of probes. The strategy used for IgH-ASO and TCR-ASO RQ-PCR assays is accurate and reliable in the clinical prospective study of MRD in childhood lymphoid malignancies.

Simultaneous evaluation of T- and B-cell clonality, t(11;14) and t(14;18), in a single reaction by a four-color multiplex polymerase chain reaction assay and automated high-resolution fragment analysis: a method for the rapid molecular diagnosis of lymphoproliferative disorders applicable to fresh frozen and formalin-fixed, paraffin-embedded tissues, blood, and bone marrow aspirates

Current polymerase chain reaction (PCR) methods for the molecular diagnosis of B- and T-cell lymphomas by determination of clonality of immunoglobulin heavy chain (IgH) and T-cell receptor-gamma rearrangements and by detection of the chromosomal translocations t(14;18) and t(11;14), require several laborious and costly PCR assays for each of these diagnostic tests. We have developed a multiplex PCR assay for the simultaneous determination of B- and T-cell clonality and the detection of the chromosomal translocations t(14;18) and t(11;14) in a single reaction, using four-color fluorescence and automated high-resolution fragment analysis. The 26 primers combined in the multiplex PCR correspond to the sequences of >90% of the 69 variables and 6 join IgH genes and 100% of the T-cell receptor-gamma variables and join genes that could participate in the respective rearrangements. In addition, they detect the major and the minor breakpoint regions of the t(14;18) and the major breakpoint region of the t(11;14), and amplify the beta-globin gene as an internal control. The specificity of the multiplex PCR was confirmed by analysis of 39 T-cell lymphomas and 58 B-cell lymphomas, including 11 mantle cell lymphomas bearing the t(11;14) and 25 follicular lymphomas bearing the t(14;18), with known rearrangements and/or translocations. Fifteen samples of reactive lymphadenitis remained negative.

Hodgkin's lymphoma of T-cell type: clonal association with a CD30+ cutaneous lymphoma

The derivation of Reed-Sternberg cells in Hodgkin's lymphoma has been a subject of great interest. In most cases, Reed-Sternberg cells seem to be derived from germinal center B cells. In few sporadic cases, a T-cell origin has been shown. This article supports the concept of a T-cell derivation for rare cases of Hodgkin's lymphoma and provides evidence of a novel mechanism of pathogenesis from chronic inflammation in the skin.

Restricted killer cell immunoglobulin-like receptor repertoire without T-cell receptor gamma rearrangement supports a true natural killer-cell lineage in a subset of sinonasal lymphomas

The cellular lineage of sinonasal T/NK (natural killer) cell lymphoma remains controversial. Lineage assignment is difficult because T cells and NK cells have a similar morphology and surface markers. Consequently, the assignment must depend heavily on the status of T-cell receptor (TCR) rearrangement. A monoclonal TCR rearrangement supports a T lineage; however, a corresponding monoclonality test for NK cells has not yet been established. Each NK cell bears a distinct set of killer cell immunoglobulin (Ig)-like receptors (KIRs) that are randomly distributed over three groups. In principle, restriction of the KIR repertoire signifies a monoclonal or possibly oligoclonal NK-cell proliferation, just as Ig light-chain restriction usually indicates a monoclonal B-cell neoplasm. Using a novel group-specific reverse transcriptase-polymerase chain reaction, we found a restricted KIR repertoire in most sinonasal lymphomas (9 of 10), but only rarely in T-cell lymphomas (2 of 10) or reactive conditions involving T/NK cells (1 of 10). KIR+ sinonasal lymphomas usually lacked a monoclonal TCR-gamma rearrangement pattern, expressed another NK cell receptor, NKG2a, and were usually CD56-positve, cyclin-dependent kinase-6 (CDK6)-positive, CD44-negative, a phenotype already reported to indicate a true NK cell lineage. We conclude that, although sinonasal lymphomas have heterogeneous genotypes and phenotypes, a restricted KIR repertoire without TCR-gamma rearrangement provides preliminary support for the monoclonality hypothesis and can be used for defining a true NK-cell lineage in a subset of sinonasal lymphomas.

New insights into the applicability of T-cell receptor gamma gene rearrangement analysis in cutaneous T-cell lymphoma

BACKGROUND

Detection of clonal T-cell receptor (TCR) gamma gene rearrangement by polymerase chain reaction (PCR) based method is a marker for cutaneous T-cell lymphoma (CTCL) although it can be seen in some benign dermatoses. To determine the accuracy of histologic criteria alone as well as the adjuvant diagnostic role of TCR gene rearrangement for the diagnosis of CTCL, we studied 100 patients with cutaneous T-cell infiltrates by both histology and TCR gene rearrangement.

METHODS

The histologic features of the 100 patients were first reviewed by two independent dermatopathologists and their confidence in the diagnosis of CTCL was assigned one of four levels. Then the specimens were analyzed for TCR gene rearrangement either on paraffin-embedded or fresh-frozen tissue by PCR/denaturing gradient gel electrophoresis (DGGE).

RESULTS

The clonality was detected in 100% (15/15) diagnostic of, 84.6% (11/13) consistent with, 57.6% (19/33) suggestive of CTCL. In 9 cases TCR gene rearrangement was compared between formalin-fixed and fresh specimens of the same individual, but with different degrees of histologic confidence (no lower than suggestive). In all cases fresh specimens were positive. In 5 of the cases (2-diagnostic, 2-consistent, 1-suggestive) formalin-fixed specimens were positive as well, and in 4 cases (1-consistent, 3-suggestive) formalin-fixed specimens were negative. When TCR gene rearrangement was studied in eight cases on sequential biopsies from the same patient, the clonality was detected in only one or two biopsies in four cases in which the histologic confidence was low (suggestive or nondiagnostic). The TCR gene rearrangement study showed identical banding patterns in lesions from different clinical stages in most patients. However, we observed that in one case, oligoclonal-banding pattern was seen in initial biopsy with histopathologic consistent with CTCL, while monoclonal banding pattern in more advanced lesion.

CONCLUSIONS

Our data have demonstrated that TCR gene rearrangement studies by PCR/DGGE are consistently positive regardless of tissue fixation (formalin-fixed, paraffin-embedded vs. fresh-frozen tissue) and biopsy site when the histologic degree of confidence is very high (diagnostic). So, it may be of less importance as an adjuvant to histopathologic diagnosis for the cases with diagnostic CTCL histology. However, TCR gene rearrangement studies are particularly important in earlier cases with less conclusive histology, which provides strong confirmatory evidence of an evolving CTCL. In these cases, multiple biopsies may be required to establish the diagnosis and analysis of fresh tissue is suggested to increases the sensitivity. Moreover, our observation also suggested that some CTCL might not be monoclonal de novo, but oligoclonal instead.

Heteroduplex analysis of T-cell receptor gamma gene rearrangement as an adjuvant diagnostic tool in skin biopsies for erythroderma

BACKGROUND

Erythroderma, defined as red skin covering most of the body surface often accompanied or followed by exfoliation, is the clinical manifestation of at least six different underlying etiologies with allergic or irritant contact dermatitis, atopic/asteotic dermatitis, pityriasis rubra pilaris (PRP), psoriasis, and seborrheic dermatitis accounting for the majority of cases. Approximately 10% of cases are due to adverse drug reactions with roughly another 10% due to cutaneous T-cell lymphoma (CTCL), predominantly mycosis fungoides, or leukemia. It is clear from multiple studies that the clinical diagnosis of the underlying entity is often difficult, as these diseases can present in a very similar fashion. A skin biopsy is usually employed in this setting as a diagnostic tool. However, the histopathologic diagnosis of the underlying cause is complicated by the subtlety of the distinguishing histologic features. In this situation, an ancillary technique demonstrating the presence of a monoclonal T-cell proliferation could help to rule in or out CTCL in cases that clinically and histopathologically do not allow a definitive diagnosis.

METHODS

We retrospectively studied 25 biopsies from sixteen patients who presented to the Stanford Dermatology Clinic with erythroderma. We examined the specimens morphologically and analyzed the gamma chain of the T-cell receptor (TCR- gamma) by polymerase chain reaction (PCR) followed by heteroduplex analysis for clonality. We then correlated the results of our PCR and heteroduplex analyses with the patients' clinical outcomes.

RESULTS

Four biopsies, from three patients, contained clonal TCR-gamma rearrangements; the four biopsies, all of which were equivocal histologically, correlated to diagnoses of mycosis fungoides (MF) or Sézary syndrome (SS). Twenty-one biopsies contained polyclonal T-cell populations. Eighteen of these biopsies represent patients with inflammatory dermatoses. Three of these biopsies, all of which were taken from a single patient, correlate to a diagnosis of MF.

CONCLUSION

TCR-gamma PCR heteroduplex analysis seems to represent an important adjuvant diagnostic tool that, used in conjunction with histopathology and clinical history, could help to clarify the underlying etiology of erythroderma.

Detection of clonal T cell receptor gamma gene rearrangements in cutaneous T cell lymphoma by LightCycler-polymerase chain reaction

Cutaneous T cell lymphoma is thought to be characterized by a monoclonal T cell infiltrate in the skin that can be detected by polymerase chain reaction-based amplification of T cell receptor gamma gene rearrangements. We sought to establish a new, simple, and fast LightCycler-based real-time polymerase chain reaction assay for the detection of monoclonality in cutaneous T cell lymphoma, which was suitable for routine laboratory application. Monoclonal T cell receptor gamma gene rearrangements were detected by polymerase chain reaction with consensus primers using: (i) a thermocycler followed by polyacrylamide gel electrophoresis; (ii) a Light Cycler followed by melting curve analysis; and (iii) a LightCycler and subsequent polyacrylamide gel electrophoresis. The detection limit of monoclonal Jurkat T cells diluted in polyclonal peripheral blood mononuclear cells was: (i) 1--3% by thermocycler--polymerase chain reaction and polyacrylamide gel electrophoresis; (ii) 10% by LightCycler--polymerase chain reaction and melting curve analysis; and (iii) 1% by LightCycler--polymerase chain reaction and polyacrylamide gel electrophoresis. In skin biopsies of 22 cutaneous T cell lymphoma patients, a monoclonal or biclonal T cell infiltrate was detected in: (i) 15 of 22 (68%) by thermocycler--polymerase chain reaction and polyacrylamide gel electrophoresis; (ii) 13 of 22 (59%) by LightCycler--polymerase chain reaction and melting curve analysis; and (iii) 16 of 22 (72%) by LightCycler--polymerase chain reaction and polyacrylamide gel electrophoresis. All three techniques revealed negative results in skin biopsies from 26 patients with benign dermatitis. In conclusion, LightCycler--polymerase chain reaction and melting curve analysis is a fast, simple and specific method to detect monoclonal T cell infiltrates in cutaneous T cell lymphoma. Sensitivity of LightCycler--polymerase chain reaction and polyacrylamide gel electrophoresis is slightly higher compared with sensitivity of thermocycler--polymerase chain reaction and polyacrylamide gel electrophoresis. Melting curve analysis, however, is less sensitive compared with polyacrylamide gel electrophoresis, and in case of negative results of the melting curve analysis, it is recommended to resolve LightCycler--polymerase chain reaction samples by gel electrophoresis.

The value of clonality in the diagnosis and follow-up of patients with cutaneous T-cell infiltrates

The diagnosis of early stages of cutaneous T-cell lymphoma (CTCL) is often difficult, especially for lesions that are at the borderline between reactive and neoplastic skin T-cell infiltrates. T-cell monoclonality in these lesions is considered by some to be an important prognostic factor of neoplastic evolution, whereas others claim that clonality can also be found in benign skin infiltrates and is therefore of limited diagnostic value. To address this controversy, the authors analyzed retrospectively eight patients with lymphocytic skin lesions who progressed to CTCL, and three patients with recurrent T-cell lymphocytic infiltrates who had not developed CTCL. From a total of 65 biopsies of eight progressing patients, 32 were diagnosed as histologically malignant and 33 were diagnosed as benign or borderline. The authors found clonality by either polymerase chain reaction or Southern blot analysis in 88% of malignant and in 79% of nonmalignant lesions. None of the 37 biopsies of non-progressing patients was clonal. These results indicate strongly that the presence of monoclonality in T-cell skin infiltrates is related closely to the risk of developing CTCL. The value of clonality as a marker of malignancy is supported by the absence of T-cell clonal populations in all infiltrates from patients who had not progressed to lymphoma.

In situ determination of T-cell receptor beta expression patterns

A definitive diagnosis of T-cell lymphoma may be contingent on the rearrangement profile of the T-cell receptor. This is most accurately done by molecular analysis of the beta-chain of the T-cell receptor (TCR beta) by Southern blotting hybridization that requires unfixed tissue. We describe a reverse transcriptase in situ PCR (RT in situ PCR) method that permits the target-specific direct incorporation of the reporter nucleotide into the different transcripts that comprise the TCR beta, using paraffin-embedded, formalin-fixed tissue. Each of the 25 possible V beta segment rearrangements was documented in three lymph nodes with nonspecific lymphadenitis, with clonal expansion evident in a case of metastatic melanoma. Monoclonal expression was documented in seven tissues diagnostic of a T-cell lymphoma. We analyzed five additional tissues for which a definitive diagnosis of T-cell vs B-cell lymphoma could not be rendered on the basis of histological, immunohistological, and flow cytometric analysis. RT in situ PCR for TCR beta expression with CD3 co-labeling demonstrated which of these lesions was a B-cell-rich T-cell lymphoma. We conclude that the RT in situ PCR methodology will allow the routine determination of monoclonal vs multiclonal expression patterns of the TCR beta using archival paraffin-embedded tissues.(J Histochem Cytochem 49:139-145, 2001)

Primary effusion lymphoma in HIV-infected patients with multicentric Castleman's disease

Multicentric Castleman's disease (MCD) and primary effusion lymphoma (PEL) are two B-cell lymphoproliferative diseases associated with Kaposi's sarcoma-associated herpes virus/human herpesvirus-8 (KSHV/HHV-8). Although MCD is considered a prelymphoma state, it is not known whether a pathogenetic link exists between MCD and PEL. This paper reports the clinico-pathological features of four cases of PEL (two pericardial, one pleural, and one peritoneal) developing in the context of HIV-associated MCD. Effusions, lymph nodes, spleen, and additional tissues from three autopsies were examined for morphology/immunophenotype, search for HHV-8 DNA, and assessment of immunoglobulin heavy chain gene (IgH) configuration using polymerase chain reaction (PCR)-based techniques. MCD and PEL samples contained HHV-8 DNA. Clonal IgH rearrangements were detected only in PEL, whereas MCD tissues were polyclonal. Light-chain immunostaining confirmed B-cell clonality in PEL (two lambda, one kappa, one not tested) and polyclonality in MCD. The autopsies revealed different morphological variants of visceral KS and multi-organ atypical infiltrates exhibiting immunoblastic/plasmablastic features reminiscent of PEL morphology, with a restriction of lambda-positive cells. In two cases, using microdissection and IgH PCR analysis, multiple/discrete bands were found in the infiltrates, compatible with polyclonality/oligoclonality. The case showing an oligoclonal IgH ladder contained a rearrangement of identical junctional size to the PEL clone; however, further analysis with PEL-derived clonotypic primers and sequencing of PCR products showed no amplification and nucleotide diversity, respectively, indicating that the two B-cell populations examined were clonally unrelated. These data show that MCD and PEL may co-exist in HIV-infected patients, suggesting a relevant association between these two HHV-8-related disorders. Although a definite clonal relationship between MCD and PEL was not demonstrated, it is hypothesized that in some MCD cases, within expanded polyclonal B-cell populations secondary to HHV-8 infection, clonal expansions may occur that localize into a body cavity, i.e. PEL.

Detection of T-cell receptor-gamma gene rearrangement in lymphoproliferative disorders by temperature gradient gel electrophoresis

OBJECTIVE

Polymerase chain reaction amplification of DNA for T-cell receptor (TCR) gene rearrangement analysis is helpful in the evaluation of T-cell lymphoproliferative disorders. Detection of polymerase chain reaction products is limited by the poor resolution of bands analyzed by agarose or polyacrylamide gel electrophoresis. To improve the detection of a clonal T-cell population, we used temperature gradient gel electrophoresis (TGGE) as an alternative method for analysis of TCR gene rearrangement.

DESIGN

One hundred eighteen archival DNA samples were randomly selected based on previous Southern blot analysis results. Samples included 58 T-cell neoplasms with positivity for TCR beta gene rearrangement, 22 cases of reactive hyperplasia with germline pattern for both TCR beta and J(H), and 38 patients with B-cell lymphoma. MOLT-16, a T-cell lymphoblastic cell line, was used for the sensitivity assay. Polymerase chain reaction was performed using GC-clamped multiplex primers to amplify the TCR gamma locus and was analyzed by TGGE. The range of temperature gradients was empirically determined for optimal resolution of bands.

RESULTS

The sensitivity of TGGE was 0.1% when DNA from the MOLT-16 cell line was serially diluted with DNA from reactive lymphoid tissue. Fifty-four (93%) of 58 T-cell neoplasms with TCR beta gene rearrangements showed rearrangement patterns by TCR gamma TGGE, and only 1 of 60 samples (reactive or B-cell lymphomas) showed evidence of gene rearrangement by TGGE. Patients with T-cell neoplasm and involvement of multiple sites showed an identical migration pattern by TGGE analysis.

CONCLUSION

We demonstrate that TGGE is an effective method for analysis of TCR gene rearrangement in the evaluation of nodal and extranodal lymphoid lesions.