Detection of Monoclonal Lymphoid Cell Populations by Polymerase Chain Reaction Technology

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.

Update on erythrodermic cutaneous T-cell lymphoma: report of the International Society for Cutaneous Lymphomas

Two conferences were sponsored by the International Society for Cutaneous Lymphomas (ISCL) to gain consensus on definitions and terminology for clinical use in erythrodermic cutaneous T-cell lymphoma (E-CTCL). Three subsets of E-CTCL were defined: Sézary syndrome ("leukemic phase" E-CTCL), erythrodermic mycosis fungoides (secondary E-CTCL that develops in patients with mycosis fungoides), and E-CTCL, not otherwise defined. The hematologic criteria recommended for Sézary syndrome are intended to identify patients with a worse prognosis compared with the other E-CTCL subsets and consist of one or more of the following: (1) an absolute Sézary cell count of 1000 cells/mm3 or more; (2) a CD4/CD8 ratio of 10 or higher caused by an increase in circulating T cells and/or an aberrant loss or expression of pan-T cell markers by flow cytometry; (3) increased lymphocyte counts with evidence of a T-cell clone in the blood by the Southern blot or polymerase chain reaction technique; or (4) a chromosomally abnormal T-cell clone. For staging purposes, it is proposed that these criteria define the B2 blood rating and that the B2 rating be considered equivalent to nodal involvement.

Early mycosis fungoides: molecular analysis for its diagnosis and the absence of p53 gene mutations in cases with progression

The histological diagnosis of initial mycosis fungoides (MF) and the molecular mechanisms that are responsible for its progression and transformation to the more highly malignant variants of MF remain largely unknown. Because of the rare occurrence of these tumours, the need for snap frozen skin biopsy specimens and the difficulty to obtain suitable material for karyotypic and genotypic analysis, specific cytogenetic and molecular lesions have not yet been identified. In particular the role of known oncogenes and tumour suppressor genes, including the p53 gene, in the pathogenesis and clinical progression of MF has not been extensively investigated. The present study was carried out using the polymerase chain reaction (PCR) technique combined with temperature gradient gel electrophoresis (TGGE) to detect mutations of the p53 gene in 58 patients with MF. TGGE analysis was also used in combination with clonality analysis by means of T-cell receptor gamma (TCRG) gene rearrangement studies to distinguish parapsoriasis en plaque and initial MF from patch/plaque stage MF. More than 83% of the diagnoses of initial MF could be confirmed using PCR-TGGE analysis. However, although the sensitive TGGE analysis was used for all exons, p53 gene polymorphisms were found in 4 and p53 gene mutation in only 1 of 58 biopsy specimens. It appears unlikely that p53 gene mutations play a role in either the pathogenesis of parapsoriasis and initial MF or their progression to advanced stages of MF. However, TCRG gene rearrangement studies by means of TCR-TGGE analysis may be useful for distinguishing histologically discordant cases of initial MF.

Analysis of T-cell antigen receptor gamma chain gene rearrangement by polymerase chain reaction in combination with denaturing gradient gel electrophoresis in the differential diagnosis of cutaneous T-lymphoproliferative diseases

A polymerase chain reaction (PCR)-based strategy has been developed for analysis of clonal rearrangement of the T-cell receptor gamma gene (TCR gamma) and was shown to be useful for detection of clonal T-cell populations. In this study, we performed PCR combined with denaturing gradient gel electrophoresis (DGGE) on fresh frozen biopsy samples from 16 patients with cutaneous T-lymphoproliferative diseases in whom a definite diagnosis was difficult to make on morphological and immunohistochemical grounds alone. Ages of the patients at biopsy ranged from 28 to 81 (median 62) years, and the subjects consisted of 8 men and 8 women. They presented with erythema on the extremities in 5 cases, trunk in 7, buttock in 2, and papules on the trunk and face in one case each. Clonal rearrangement of TCR gamma was observed in 3 of 16 cases. Clinical diagnoses of these three cases were mycosis fungoides, cutaneous invasion of adult T-cell leukemia (ATL), and large granular lymphocytic leukemia (LGL) of T-cell type, respectively, but they were histologically difficult to differentiate from reactive cutaneous T-cell proliferation. The skin lesions of the LGL case worsened, and this patient died two years after biopsy. Another patient with suspected mycosis fungoides in the plaque stage died due to dissemination of tumors 22 months after biopsy. The remaining one patient with ATL survived with cutaneous lesions for over four years. Clonality was not demonstrated in the remaining 13 cases, and their clinical courses were favorable. These findings showed that demonstration of clonal TCR gamma gene rearrangement using the PCR-DGGE method is very helpful for diagnosis of cutaneous T-cell neoplasms.

Prognostic Significance of a Polymerase Chain Reaction–Detectable Dominant T-Lymphocyte Clone in Cutaneous Lesions of Patients With Mycosis Fungoides

Although mycosis fungoides (MF) is considered to be an indolent lymphoma, survival is highly influenced by TNM stage. At diagnosis, most MF patients present with early stage disease and a high probability of long-term survival. Treatment is generally directed towards skin lesions, and achievement and duration of complete responses are variable. A dominant T-cell clone is detectable in the cutaneous lesions of 60% of patients. The aim of this study was to determine whether the presence of a T-cell clonal population influences the clinical course of the disease after topical therapy. Cutaneous biopsies from 68 patients were histologically diagnosed as MF and T-cell clonality was analyzed by in vitro amplification of TCR-γ chain gene rearrangements (polymerase chain reaction γ [PCRγ]). After a median follow-up of 48 months, response to treatment was clinically assessed. Age, sex, duration of symptoms before diagnosis, type of cutaneous lesions (T stage), TNM stage, and PCRγ were evaluated as predictive factors of response to treatment in univariate and multivariate analyses. Univariate analysis demonstrated that T1 cutaneous lesions (P = .05) and PCRγ negativity (P = .007) were associated with a higher complete remission rate. Using multivariate analysis, T stage (relative risk, 3.13; P = .06) and PCRγ (relative risk, 4.4; P = .01) remained independent significant predictive parameters of response. In conclusion, T stage and cutaneous PCRγ at diagnosis are the two predictive parameters of treatment response for MF. Therefore, the cutaneous PCRγ findings should be considered in the analysis of future therapeutic trials.

© 1998 by The American Society of Hematology.

Prognostic Significance of a Polymerase Chain Reaction–Detectable Dominant T-Lymphocyte Clone in Cutaneous Lesions of Patients With Mycosis Fungoides

Although mycosis fungoides (MF) is considered to be an indolent lymphoma, survival is highly influenced by TNM stage. At diagnosis, most MF patients present with early stage disease and a high probability of long-term survival. Treatment is generally directed towards skin lesions, and achievement and duration of complete responses are variable. A dominant T-cell clone is detectable in the cutaneous lesions of 60% of patients. The aim of this study was to determine whether the presence of a T-cell clonal population influences the clinical course of the disease after topical therapy. Cutaneous biopsies from 68 patients were histologically diagnosed as MF and T-cell clonality was analyzed by in vitro amplification of TCR-γ chain gene rearrangements (polymerase chain reaction γ [PCRγ]). After a median follow-up of 48 months, response to treatment was clinically assessed. Age, sex, duration of symptoms before diagnosis, type of cutaneous lesions (T stage), TNM stage, and PCRγ were evaluated as predictive factors of response to treatment in univariate and multivariate analyses. Univariate analysis demonstrated that T1 cutaneous lesions (P = .05) and PCRγ negativity (P = .007) were associated with a higher complete remission rate. Using multivariate analysis, T stage (relative risk, 3.13; P = .06) and PCRγ (relative risk, 4.4; P = .01) remained independent significant predictive parameters of response. In conclusion, T stage and cutaneous PCRγ at diagnosis are the two predictive parameters of treatment response for MF. Therefore, the cutaneous PCRγ findings should be considered in the analysis of future therapeutic trials.

© 1998 by The American Society of Hematology.

Detection of clonal T cells in cutaneous T cell lymphoma by polymerase chain reaction: comparison of mutation detection enhancement-polyacrylamide gel electrophoresis, temperature gradient gel electrophoresis and fragment analysis of sequencing gels

Cutaneous T cell lymphomas (CTCL) can be differentiated from benign inflammatory dermatoses by the demonstration of clonal T cells in skin biopsy. As a marker of the T cell clonality, the rearrangement of the T cell receptor (TCR) genes is amplified by polymerase chain reaction (PCR) and subsequently analyzed by several electrophoresis techniques. Since the validity of this approach depends substantially on the separating capacity of the applied electrophoresis technique, we investigated in the present study the lower detection limit and the sensitivity of heteroduplex-loaded polyacrylamide gel electrophoresis on MDE (mutation detection enhancement) gels (HD-MDE PAGE), of heteroduplex-loaded temperature gradient gel electrophoresis (HD-TGGE) and fragment analysis (FA) on sequencing gels. Genomic DNA from formalin-fixed, paraffin-embedded skin biopsies of 53 CTCL specimens and 27 samples of benign dermatoses was analyzed by TCRy PCR followed by electrophoretic separation. Clonality was detected by HD-MDE PAGE in 22, by HD-TGGE in 34, and by FA in 33 of the 53 CTCL cases. Additionally, FA revealed an oligoclonal fragment profile in seven CTCL specimens. In the 27 samples from benign dermatoses, HD-MDE PAGE and HD-TGGE showed the expected polyclonal pattern in 26, and FA in 25 specimens. HD-TGGE and FA detected a clonal pattern down to a dilution of 10(3) monoclonal cells in 10(6) peripheral blood mononuclear cells (PBMC), while HD-MDE PAGE revealed a detection limit of 10(4) monoclonal cells in 10(6) PBMC. In conclusion, HD-TGGE and FA possess a higher sensitivity and lower detection limit than HD-MDE PAGE. Therefore, both former techniques are useful tools for the routine diagnostic procedure. With regard to time and cost, we recommend HD-TGGE.

Value of clonality studies of cutaneous T lymphocytes in the diagnosis and follow-up of patients with mycosis fungoides

Histological features of early mycosis fungoides (MF) can simulate numerous inflammatory lesions and histological confirmation of MF is often delayed, compared with clinical diagnosis. Recently, using molecular techniques, the detection of a dominant T-lymphocyte clone has been reported in cutaneous lesions of MF. The aim of the present study was to determine the diagnostic value of a dominant T-lymphocyte clone as assessed by PCR-DGGE in early MF. Histopathological and molecular analyses were performed on cutaneous lesions from 104 patients clinically suspected as having MF. In this population, the positive predictive value of a PCR gamma(+) was 0.86. In addition, four of six patients whose lesions were PCR gamma(+) (detectable dominant T-cell clone) but not histologically MF progressed to MF within 2-48 months. In order to evaluate the relevance of PCR gamma-DGGE in MF follow-up, serial biopsies were performed in 24 patients. In 89 per cent of cases, the presence or absence of a PCR gamma(+) was constant during the course of the disease. When present, the DGGE imprint of PCR products was case-specific. These data demonstrate the diagnostic value in MF of T-lymphocyte clonality assessed by PCR gamma-DGGE on cutaneous lesions and show that the technique can be used in MF follow-up to evaluate residual disease with high specificity.