Detection of clonal T-cell receptor gamma gene rearrangements in early mycosis fungoides/Sezary syndrome by polymerase chain reaction and denaturing gradient gel electrophoresis (PCR/DGGE)

Oligoclonal expansion of HIV-specific cytotoxic CD8 T lymphocytes in the skin of HIV-1-infected patients with cutaneous pseudolymphoma

A massive infiltration of the skin by activated CD8+ T lymphocytes involving both the dermis and the epidermis has been found in HIV-1-infected patients presenting with a chronic skin rash. We characterized the T cell receptor (TCR) BV-BJ junctional diversity of the skin-infiltrating lymphocytes (SILs) in four patients. The SILs expressed a limited set of TCRBV gene segments. Complementarity determining region 3 length analysis further emphasized their oligoclonality, suggesting that antigen stimulation might be responsible for the cutaneous T cell expansion. Furthermore, independent skin biopsies obtained from the same individual were shown to harbor distinct T cell repertoires, possibly reflecting the spatial heterogeneity of the antigenic stimuli. The CD8+ cytotoxic T lymphocyte (CTL) lines isolated from the skin rash in one patient exhibited a specific, class I MHC-restricted cytotoxic activity against HIV-1 Gag- and Pol-expressing target cells, whereas CTL lines derived from the skin lesions of a second patient were shown to be predominantly Env-specific. Taken together, these data demonstrate the infiltration of HIV-specific CTLs in the skin of HIV-infected patients, and suggest that in addition to their known role in controlling the retroviral infection, these CTLs may also be involved in the pathogenesis of cutaneous inflammatory disorders occurring during the course of HIV infection.

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.

Advances in the management of cutaneous T-cell lymphoma

This article focuses on the management of specific T-cell components of cutaneous T-cell lymphomas. Advances in the management of these lymphomas are evaluated and classified. New treatment strategies and therapies are discussed.

Detection of clonal T-cell receptor gamma chain gene rearrangements by polymerase chain reaction and denaturing gradient gel electrophoresis (PCR/DGGE) in archival specimens from patients with early cutaneous T-cell lymphoma: correlation of histologic findings with PCR/DGGE

BACKGROUND

Early stages of cutaneous T-cell lymphoma (CTCL) may be difficult to distinguish from benign inflammatory dermatoses by routine histologic examination.

OBJECTIVE

Our purpose was to determine whether clonal rearrangements of the T-cell receptor (TCR) gamma gene by polymerase chain reaction and denaturing gradient gel electrophoresis (PCR/DGGE) could be detected in the early stages of CTCL and to correlate these findings with conventional histopathology.

METHODS

A total of 39 specimens from 12 patients with CTCL were obtained. The slides were evaluated independently by three dermatopathologists, and categorized into three groups: nondiagnostic, suggestive of CTCL, and diagnostic of CTCL. Of the 39 specimens, 33 were tested by PCR/DGGE by means of GC-clamped primers for clonal rearrangement of the TCR gamma gene.

RESULTS

The histologic evaluation of the 12 cases showed a significant variation among the three dermatopathologists. The correlation of PCR/DGGE with routine histology was as follows: Clonal TCR gamma gene rearrangements were demonstrated in 73% of the specimens nondiagnostic for CTCL, 71% of those suggestive of CTCL, and 74% of those diagnostic of CTCL.

CONCLUSION

Clonal TCR gamma gene rearrangements may be detected in patients with early CTCL, even when the histologic findings are not unequivocally diagnostic. In patients with multiple biopsy specimens, identical clones were demonstrated in all rearranged samples, indicating the same neoplastic clone was present in the earliest stages of disease.

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.

Differentiation between actinic reticuloid and cutaneous T cell lymphoma by T cell receptor gamma gene rearrangement analysis and immunophenotyping

AIMS

Differentiation between actinic reticuloid and cutaneous T cell lymphoma can be extremely difficult. Demonstration of clonal T cell receptor (TCR) gene rearrangements has been suggested as a potential diagnostic criterion, but the results obtained thus far have been conflicting. This study investigated whether TCR gamma gene rearrangement analysis, using polymerase chain reaction (PCR) in combination with denaturing gradient gel electrophoresis (DGGE) and immunohistochemistry, can serve as a diagnostic criterion.

METHODS

PCR/DGGE was performed on skin, peripheral blood mononuclear cells, and/or lymph nodes of seven patients with actinic reticuloid, 11 patients with Sézary syndrome, and 15 patients with a benign form of erythroderma. The results of PCR/DGGE and Southern blot analysis of TCR beta gene rearrangements were compared. In addition, CD4:CD8 ratios in skin and peripheral blood samples were investigated.

RESULTS

Clonal T cell populations were detected in 19 of 21 samples obtained from patients with Sézary syndrome but were not detected in any of the 12 samples from patients with actinic reticuloid. Clonal T cells were detected in the peripheral blood of only one of 15 patients with a benign form of erythroderma. PCR/DGGE and Southern blot analysis gave concordant results in 28 of 29 samples. Immunophenotypic analysis demonstrated increased proportions of CD8+ T cells in skin (seven of seven cases) and peripheral blood (four of seven cases) of patients with actinic reticuloid.

CONCLUSION

The results of this study demonstrate that gene rearrangement analysis, in combination with immunohistochemistry, may be an important adjunct in differentiating between actinic reticuloid and cutaneous T cell lymphoma. In patients suspected of having actinic reticuloid, application of both techniques is recommended.

DNA extraction from formalin-fixed, paraffin-embedded tissues: protein digestion as a limiting step for retrieval of high-quality DNA

Several DNA extraction methods have been used for formalin-fixed, paraffin-embedded tissues, with variable results being reported regarding the suitability of DNA obtained from such sources to serve as template in polymerase chain reaction (PCR)-based genetic analyses. We present a method routinely used for archival material in our laboratory that reliably yields DNA of sufficient quality for PCR studies. This method is based on extended proteinase K digestion (250 micrograms/ml in an EDTA-free calcium-containing buffer supplemented with mussel glycogen) followed by phenol-chloroform extraction. Agarose gel electrophoresis of both digestion buffer aliquots and PCR amplification of the beta-globin gene tested the suitability of the retrieved DNA for PCR amplification.

Extracorporeal photochemotherapy restores Th1/Th2 imbalance in patients with early stage cutaneous T-cell lymphoma

Extracorporeal photochemotherapy (ECP) has been shown to be a potent activator of peripheral blood macrophages because it causes a marked release of macrophage-dependent proinflammatory cytokines, and it is therefore currently considered to be a safe and non-toxic immunomodulatory treatment. On this basis we studied the function of peripheral blood mononuclear cells (PBMC) in eight patients with early stage (Ib) cutaneous T-cell lymphoma (CTCL), before and 1 year after ECP, together with their clinical and histological responses. In particular we evaluated in vitro phytohaemagglutinin (PHA)-stimulated proliferation and production of interleukin-4 (IL-4) and interferon-gamma (IFN-gamma) as well as lipopolysaccharide (LPS)-induced production of IL-12. Before treatment we observed that PBMC of patients produced significantly higher levels of IL-4 and lower levels of IFN-gamma and IL-12 than those of healthy control subjects. After 1 year of ECP, IL-4, IFN-gamma and IL-12 production no longer differed from that of control subjects. Moreover, we observed a good clinical result matched by histological response. Our data confirm that early-stage CTCL patients show a predominantly type-2 immune response that might be responsible for several immunological abnormalities found in this disease. We have demonstrated that ECP reverses the T-helper type 1/T-helper type 2 (Th1/Th2) imbalance and may therefore be considered an efficient biological response modifier.

Demonstration of Frequent Occurrence of Clonal T Cells in the Peripheral Blood of Patients With Primary Cutaneous T-Cell Lymphoma

Clonal T cells have been demonstrated in skin lesions of all stages of cutaneous T-cell lymphomas (CTCLs). However, there are conflicting data regarding the CTCL stage at which dissemination of clonal cells into peripheral blood occurs. Although the multifocal occurrence of cutaneous CTCL lesions and T-cell recirculation suggest an early appearance of neoplastic cells in the blood, circulating clonal T cells have only been detected in advanced stages. We investigated their occurrence by a highly sensitive polymerase chain reaction (PCR) assay amplifying T-cell receptor γ rearrangements and subsequent heteroduplex temperature gradient gel electrophoresis (HD-TGGE) of the amplification products. Circulating clonal T cells were found in 26 of 45 patients with mycosis fungoides (MF ), six of seven with Sezary's syndrome (SS), 10 of 13 pleomorphic CTCLs, and three of four unclassified CTCLs. Corresponding skin specimens carried clonal T cells in 29 of 40 MF, three of four SS, 12 of 12 pleomorphic, and two of two unclassified CTCL patients. Except for the blood specimen of a psoriatic patient, all samples of 60 controls (psoriasis vulgaris, atopic dermatitis, and healthy volunteers) revealed polyclonal amplification products. In 30 of 32 CTCL patients carrying a clonal rearrangement in blood and skin, identity of both clones was indicated by HD-TGGE and confirmed by sequencing six of these cases. We found an unexpected high frequency of identical clonal T cells in peripheral blood and skin of CTCL patients, including early stages of MF. This supports the concept of an early systemic disease in CTCL and raises new questions concerning the pathogenesis.

Demonstration of Frequent Occurrence of Clonal T Cells in the Peripheral Blood of Patients With Primary Cutaneous T-Cell Lymphoma

Clonal T cells have been demonstrated in skin lesions of all stages of cutaneous T-cell lymphomas (CTCLs). However, there are conflicting data regarding the CTCL stage at which dissemination of clonal cells into peripheral blood occurs. Although the multifocal occurrence of cutaneous CTCL lesions and T-cell recirculation suggest an early appearance of neoplastic cells in the blood, circulating clonal T cells have only been detected in advanced stages. We investigated their occurrence by a highly sensitive polymerase chain reaction (PCR) assay amplifying T-cell receptor γ rearrangements and subsequent heteroduplex temperature gradient gel electrophoresis (HD-TGGE) of the amplification products. Circulating clonal T cells were found in 26 of 45 patients with mycosis fungoides (MF ), six of seven with Sezary's syndrome (SS), 10 of 13 pleomorphic CTCLs, and three of four unclassified CTCLs. Corresponding skin specimens carried clonal T cells in 29 of 40 MF, three of four SS, 12 of 12 pleomorphic, and two of two unclassified CTCL patients. Except for the blood specimen of a psoriatic patient, all samples of 60 controls (psoriasis vulgaris, atopic dermatitis, and healthy volunteers) revealed polyclonal amplification products. In 30 of 32 CTCL patients carrying a clonal rearrangement in blood and skin, identity of both clones was indicated by HD-TGGE and confirmed by sequencing six of these cases. We found an unexpected high frequency of identical clonal T cells in peripheral blood and skin of CTCL patients, including early stages of MF. This supports the concept of an early systemic disease in CTCL and raises new questions concerning the pathogenesis.

The value of the polymerase chain reaction in the diagnosis of cutaneous T-cell infiltrates

The distinction between reactive and neoplastic cutaneous T-cell infiltrates is difficult and requires good clinicopathologic correlation. Many cases manifest changes that are at the borderline between the two. The polymerase chain reaction (PCR) has been reported to detect monoclonality in 52-90% of cutaneous T-cell lymphomas and may be of use in the diagnosis of histologically borderline lesions. We have investigated the use of PCR in a series of borderline lesions including borderline biopsy samples from patients who subsequently developed cutaneous lymphoma. PCR amplification of T-cell receptor (TCR)-gamma chain gene was performed on formalin-fixed, paraffin-embedded tissue from 27 cases of clinically and histologically typical mycosis fungoides (MF), 22 borderline biopsy samples from 10 patients who subsequently developed MF (pre-MF), 32 clinically suspicious, histologically borderline lesions, and 31 cases of chronic dermatitis. Monoclonality was demonstrated in 16 of 27 (59%) cases of MF, 10 of 22 (50%) pre-MF biopsy samples (six of 10 patients), and six of 32 (19%) borderline biopsy samples. The same size monoclonal band was detected in pre-MF biopsy samples from six of seven patients in which a band was demonstrated in the diagnostic MF biopsy. Sequencing confirmed that the MF biopsy sample and the pre-MF biopsy sample contained the same clone. The 31 dermatitis cases gave rise to polyclonal PCR products. Monoclonality can be demonstrated using PCR in 59% of MF cases, which is comparable with other T-cell lymphomas and in up to 50% of borderline biopsy samples in patients who later develop lymphoma. Detection of T-cell monoclonality by PCR is strong evidence of an established or evolving cutaneous T-cell lymphoma.

The polymerase chain reaction in the diagnosis of early mycosis fungoides

The earliest or patch stage of mycosis fungoides may present diagnostic difficulty both clinically and pathologically. The present study of the polymerase chain reaction (PCR) as a diagnostic tool in early mycosis fungoides was therefore undertaken, using a rapid PCR method for the detection of gamma- and beta-chain T-cell receptor (TCR) gene rearrangements in routine formalin-fixed, paraffin-embedded histological sections. Forty-two biopsies were studied from 26 patients with mycosis fungoides. Twenty-three skin biopsies with a clinicopathological diagnosis of early, or patch stage, mycosis fungoides were investigated. Of these, 18 (78 per cent) showed TCR-gamma or both beta- and gamma-chain TCR gene rearrangements. TCR gene rearrangements were shown in seven of the 14 plaque stage lesions (50 per cent) and also in the single case of tumour stage disease. Where gene rearrangements were identified, these were identical in all biopsies from an individual patient, irrespective of the site of the lesion, the disease stage, or the time lapse between the biopsies. The PCR is therefore a highly sensitive technique, which can be performed on routine pathological material, in cases where the diagnosis of early mycosis fungoides cannot be made with certainty on conventional histopathological and immunohistochemical grounds.

A realistic approach to the sensitivity of PCR-DGGE and its application as a sensitive tool for the detection of clonality in cutaneous T-cell proliferations

The practical value of the detection of clonality within the T-cell receptor gamma locus by polymerase chain reaction for the diagnosis of cutaneous T-cell lymphomas is well known. However, studies dealing with this subject so far, with special emphasis on the sensitivity of the technique in comparison to, for example, Southern blotting have used mixtures of DNA in various concentrations instead of using mixtures of the cells involved, which would reflect the in vivo situation in a more realistic scope. The purpose of this study was therefore to determine the sensitivity and the limitations of the PCR assay by dilution experiments, using mixtures of cells. Furthermore we studied its applicability to cutaneous T-cell proliferative disorders. Two clonal T-cell lines (MyLa and Jurkat) served as positive control. Dilutions of MyLa cells, cultured normal human keratinocytes and peripheral blood mononuclear cells from lymphoma negative volunteers were used to assess the sensitivity of the PCR-DGGE assay. Skin samples from 4 patients with cutaneous T-cell lymphoma, 1 lesional lymph node, 2 blood samples from a patient with Sézary syndrome and 4 lymphoma-negative tissue samples were analysed. Two samples were uncertain for diagnosis of lymphoma. The PCR-DGGE assay consisted of a 2-round nested PCR with consensus primers within the TCR-gamma locus followed by electrophoretic separation of the product along a denaturing urea/formamide gradient gel. PCR-DGGE sensitivity was, to our knowledge, for the first time investigated for mixtures of lymphocytes (clonal and polyclonal) and keratinocytes. Clonal T-cells were detected in a concentration between 1-0.1% in keratinocytes, whereas the sensitivity was generally lower upon dilution in peripheral blood mononuclear cells or in a mixture of keratinocytes and peripheral blood mononuclear cells. Nevertheless, T-cell clonality was detected in 2 blood samples of a patient with Sézary syndrome, which were negative by Southern blot analysis. The crucial point of this work was the new approach to establish the sensitivity of the PCR-DGGE, in a way which more closely mimics the condition of clinical specimens. Instead of mixing and amplifying DNA extracted from clonal T-cell lines and polyclonal bone marrow cells, we amplified DNA from clonal and polyclonal cells which had been mixed in various ratios before DNA extraction. Polymerase chain reaction in conjunction with denaturing gradient gel electrophoresis is a sensitive and versatile molecular tool for the assessment of clonality of suspect cutaneous lesions. The determination of sensitivity using DNA extracted from premixed cells more closely corresponds to the actual test situation when testing skin samples.

Persistent pigmented purpuric dermatitis and mycosis fungoides: simulant, precursor, or both? A study by light microscopy and molecular methods

Mycosis fungoides (MF) can present with purpuric lesions, and rare patients who seemed to have persistent pigmented purpuric dermatitis (PPPD) have developed MF. We recently encountered two patients referred to our cutaneous lymphoma clinic who had PPPD rather than MF and two others who appeared to have both conditions, leading us to explore the histologic similarities of these diseases. We examined specimens from 56 patients with PPPD to determine the frequency of MF-like histologic configurations, namely, the psoriasiform lichenoid, psoriasiform spongiotic lichenoid, and atrophic lichenoid patterns. We also noted the degree of spongiosis, epidermotropism, papillary dermal fibrosis, lymphocytic atypia, and epidermal hyperplasia, the number of extravasated erythrocytes and siderophages, and the distribution of lymphocytic infiltrate within the epidermis. In 29 of 56 patients, there were patterns typically seen in MF. PPPD can feature lymphocytes aligned along the epidermal side of the dermoepidermal junction, with few necrotic keratinocytes, as can MF. Papillary dermal edema occurred frequently in PPPD but not in MF, while lymphocytes in MF but not PPPD had markedly atypical nuclei and had ascended into the upper spinous layer. Given these similarities, we tested for clonality of the T-cell population using a polymerase chain reaction assay for gamma-chain rearrangements. Clonal populations were present in three of three and one of two specimens from patients with both PPPD and MF, but also in 8 of 12 specimens typical of lichenoid patterns of PPPD. These findings raise the possibility that the lichenoid variants of PPPD are biologically related to MF.

The dynamic interplay of malignant and benign T cells in cutaneous T-cell lymphoma

Cutaneous T-cell lymphoma is a malignancy of functional, tissue-specific T cells. Many characteristics of the disease can be explained by virtue of the ability of the malignant cell population to actively participate in the host's immunologic network. Various aspects of this dynamic interplay between malignant and benign T cells are discussed, including impact on diagnosis, staging, and therapy.

Failure to detect human T-lymphotropic virus type-I proviral DNA in cell lines and tissues from patients with cutaneous T-cell lymphoma

Previous molecular studies investigating the presence of HTLV-I proviral DNA in cell lines and tissue samples of patients with cutaneous T-cell lymphoma (CTCL) have reported a detection rate ranging from 0-92%. Despite the lack of epidemiologic data linking HTLV-I infection with CTCL, the molecular data still invite speculation regarding the precise role of HTLV-I in the pathogenesis of CTCL. To determine the detection rate of HTLV-I proviral DNA among CTCL patients referred to our medical center, we analyzed Epstein-Barr virus-transformed cell lines established from peripheral blood of seven CTCL patients and 43 tissue samples from 22 patients with different stages of disease. Genomic DNA was polymerase chain reaction-amplified with primers within the HTLV-I tax gene region. Amplification products were probed with nested oligonucleotide probes by Southern blot analysis. No HTLV-I proviral sequences were detected in the samples (0/50). Using HTLV-I/II pol primers, no HTLV-I pol gene sequences were detected. In tissues from one patient, HTLV-II pol and tax gene sequences were detected; however, HTLV-II proviral integration was not detected by Southern blot analysis of the genomic DNA. Our data suggest: (i) HTLV-I does not appear to be a primary etiologic agent in CTCL; and (ii) HTLV-II pol and tax gene sequences can be detected in a minority of CTCL patients, but this does not necessarily imply an etiologic role.

Evidence against a role for human T-cell lymphotrophic virus type I (HTLV-I) in the pathogenesis of American cutaneous T-cell lymphoma

We used a standard polymerase chain reaction (PCR)/Southern blot assay (sensitivity > 10(-5)) to detect human T-cell lymphotrophic virus type I (HTLV-I) proviral pX, pol, and env genes in the lesional skin of 42 American patients with cutaneous T-cell lymphoma (CTCL). As in some prior reports using similar methods, a variable proportion of PCR tests were positive (seven of 42 for pX, three of 42 for pol, and two of 37 for env), resulting in an overall positive test rate of 12 of 121 (10%). To determine the significance of these positive test results, we performed several additional studies. D1S80 polymorphism analysis of CTCL cases and HTLV-I PCR analysis of non-CTCL dermatosis controls showed no evidence that positive PCR tests resulted from sample mislabeling, gross HTLV-I contamination, or human endogenous retroviruses. We then modified the standard PCR assay to incorporate ultraviolet (UV) light to destroy low-level PCR contamination. With this modified assay (sensitivity > 10(-5)), only three of 12 previously positive cases were still positive, suggesting that the earlier positives were due to trace contamination of PCR reagents or trace contamination of sample DNA. This interpretation was also supported by: (i) a match between pX and pol sequences cloned from one PCR-positive specimen and the MT4-positive control, (ii) our inability to confirm HTLV-I in any PCR-positive case using genomic dot blotting (sensitivity > 10(-2)), and (iii) negative PCR results when new samples from two of the remaining positive cases were analyzed. Finally, we used our modified UV/ PCR/Southern blot assay to test an additional 28 cases of American CTCL for pX. All of them were negative. Although these studies of 70 cases of American CTCL do not exclude the possibility that another virus is involved in the pathogenesis of this disease, they provide strong evidence against a role for HTLV-I. Furthermore, they emphasize the need for special strategies to control for false-positive PCR tests that can result from even trace levels of contamination with viral DNA. As a consequence, associations between diseases and viruses should be viewed skeptically if they are based primarily on conventional PCR data.

HLA-DR5 and DQB1*03 class II alleles are associated with cutaneous T-cell lymphoma

Cutaneous T-cell lymphoma (CTCL) may present with eczematous lesions, mycosis fungoides (MF), or as exfoliative erythroderma with circulating atypical cells, Sezary syndrome (SS). The "malignant" T cells are epidermotropic and clonal, but whether they respond to antigen stimulation is unknown. Because CD4+ lymphocytes recognize antigen presented by histocompatibility locus antigen (HLA) class II molecules, and HLA association have been found in autoimmune skin diseases, we determined by allele-specific oligonucleotide typing whether HLA-DR or DQ alleles were associated with CTCL and its two variants MF (n = 47) and SS (n = 23). Phenotypic frequencies were compared by chi-square and Fisher exact test, and p values were corrected independently for either 12 DR or 15 DQ alleles. HLA-DR5, previously associated with MF, was significantly increased in all 70 CTCL patients (31.5%) versus controls (11%) (uncorrected p value [Pnc] = 0.000038, odds ratio [OR] = 3.9, 1.9 < OR < 8.1), in MF patients (34%) (Pnc = 0.000047, OR = 3.62, 1.9 < OR < 10), and in SS patients (26%) (Pnc = 0.03, OR = 3, 0.9 < OR < 9.3). HLA-DQB1*03 alleles (0301, 0302, and 0303) were increased in 72% of all CTCL patients versus 49% of controls (corrected p value [Pc] = 0.014, OR = 2.7, 1.4 < OR < 5.1), in SS (82%) (Pc = 0.05, OR = 4.7, 1.4 < OR < 5), and in MF (67%) (Pnc = 0.024, OR = 2.15, 1 < OR < 4.5). DQB1*0502 was strongly increased in SS patients (Pc = 0.045, OR = 7.75, 1.25 < OR < 48). Although HLA-DQB1*0603 and HLA-DR6 (1301, 1302, and 1402) were decreased in all groups, the decreases were not statistically significant. These data suggest that certain HLA-DRB and DQB1 alleles, also associated with other T-cell-mediated skin diseases, may participate in the pathogenesis of or susceptibility to CTCL.

T-cell receptor beta variable region (V beta) usage in cutaneous T-cell lymphomas (CTCL) in comparison to normal and eczematous skin

Cutaneous T-cell lymphomas (CTCL) are a heterogeneous group of lymphoproliferative disorders. We investigated the variable region (V beta) of the T-cell receptor (TCR) repertoire in CTCL and compared it to the V beta repertoire in normal and eczematous skin. We used a panel of 21 anti-V beta antibodies and investigated 84 biopsies of 71 CTCL patients (4 parapsoriasis en grandes plaques (PA), 1 lymphomatoid papulosis, 29 mycosis fungoides (MF), 13 Sezary syndrome (SS), 1 CD8+ CTCL, 11 pleomorphic CTCL (PLEO), 12 CTCL nor classified). Six biopsies of normal skin and 6 of eczematous skin lesions served as controls. We determined the frequency of the V beta in normal and inflamed skin and compared it to the percentage of the respective V beta in the malignant clone of the CTCL patients. The percentage of the V beta positive CD4+ cells in relation to the total number of T cells in normal skin and inflamed skin differed from the distribution of the V beta families in the peripheral blood mononuclear cells (PBMC). Out of 71 CTCL cases, the clone was identified in 23 (32%). We identified the following clones: 1 V beta 3.1 (16MF), 7 V beta 5.1 (1 CD8+ CTCL, 1 CTCL not classified, 1 MF, 1 PA, 3 SS), 1 V beta 6.7 (1 SS), 7 V beta 8.1/8.2 (2 CTCL not classified, 1 PLEO, 2 MF, 2 SS), 1 V beta 12.1 (1 PLEO), 3 V beta 17.1 (2 CTCL not classified, 1 MF), 2 V beta 22.1 (1 CTCL not classified, 1 MF), 1 TCR delta (SS). The frequency of the malignant clone V beta usage corresponded well to the repertoire of V beta in eczematous skin but not to the repertoire in PBMC. In 6 patients, the malignant clone was mainly localized in the epidermis. In 17 cases, the clone-specific cells were distributed in epidermis and dermis equally. A retrospective analysis showed that preferential epidermal homing of the clone was associated with a non-aggressive clinical course. The V beta usage of CTCL and eczema suggests a special cutaneous microenvironment which might be co-created by certain (bacterial?) superantigens. A preferential epidermal homing of the clone might have prognostic implications.

Detection of low-level tumor cells in allergic contact dermatitis induced by mechlorethamine in patients with mycosis fungoides

Two patients with histologically proven mycosis fungoides, a malignancy of phenotypically mature T cells, received a topical challenge with mechlorethamine to areas of clinically uninvolved skin to exclude possible hypersensitivity reactions to this chemotherapeutic agent. In both patients, allergic contact dermatitis (ACD) developed at the sites of the application and resolved completely after withdrawal of mechlorethamine. The lesions were biopsied and analyzed for the presence of clonal T-cell receptor (TCR)-gamma gene rearrangements using two polymerase chain reaction (PCR)-based assays involving denaturing gradient gel electrophoresis (PCR/DGGE) and ribonuclease protection analysis (PCR/RPA). The former method has a clonal detection threshold of 10(-3)-10(-2), while the latter has a sensitivity of 10(-5). In both cases, the ACD lesions were polyclonal by PCR/DGGE. In contrast, PCR/RPA detected tumor-specific TCR-gamma gene rearrangements in these same lesions. This indicates that the ACD lesions contained tumor cells at a density within the 10(-5)-10(-2) range. Analysis of peripheral blood mononuclear cells from both patients failed to detect the malignant clone and showed the same result as blood from four normal individuals. The normal skin from one skin patient also lacked detectable TCR-gamma gene rearrangements. These results indicate that mycosis fungoides tumor are present within ACD lesions induced in mycosis fungoides patients and that this phenomenon does not appear to be due to the ubiquitous presence of detectable levels of these tumor cells in the blood or skin. These findings might be explained by nonspecific recruitment of malignant T cells to sites of local inflammation mediated by non-neoplastic antigen-specific T cells. Alternatively, they might be due to the local proliferation of very rare tumor cells in apparently normal skin in response to cytokines generated during the ACD reaction. In either case, the present study offers evidence that the malignant cells in myosis fungoides retain at least some capability of responding in vivo to physiologic stimuli.

Multiparametric image cytometry in mycosis fungoides

Eighteen cases of early mycosis fungoides were compared with 18 cases of eczematous dermatitis by multiparametric image cytometry. A minimum of 100 lymphocytes was measured in each case. A large number of measurements was acquired for each lymphocyte, characterizing nuclear DNA content, area, shape, and texture. There were significant differences between the two groups, especially in nuclear DNA content and texture. These differences allowed the two groups of nuclei to be distinguished with 78% accuracy. The two groups of lesions were distinguished with 94% accuracy, using neural network analysis.

Chronic cutaneous lupus erythematosus mimicking mycosis fungoides

Mycosis fungoides, which is characterized by a malignant infiltrate of T lymphocytes involving the epidermis, can be confused with other inflammatory skin diseases. We report the case of a patient with skin lesions containing an infiltrate of atypical lymphocytes with epidermotropism. This patient's condition was initially diagnosed as mycosis fungoides. Repeated biopsy samples had the histologic features of chronic cutaneous lupus erythematosus. The patient had a strongly positive antinuclear antibody response and the clinical lesions responded to hydroxychloroquine, however, and these findings led to an altered diagnosis. Other disorders that either clinically or histologically mimic mycosis fungoides are reviewed, and the diagnostic evaluation of patients in whom mycosis fungoides is suspected is summarized. Chronic cutaneous lupus erythematosus should be added to the list of diseases that can mimic mycosis fungoides.

The polymerase chain reaction in the demonstration of monoclonality in T cell lymphomas

AIMS

To evaluate polymerase chain reaction (PCR) amplification of T cell receptor (TCR) beta and gamma chain genes as a means of demonstrating monoclonality in T cell lymphomas using histological samples; to compare the performance of PCR with Southern blot analysis.

METHODS

TCR-beta, TCR-gamma and immunoglobulin heavy chain (IGH) genes were analysed using PCR in 55 cases of T cell lymphoma (28 frozen tissue and 27 paraffin wax embedded samples), diagnosed using morphological and immunohistochemical criteria. The 28 frozen samples were subjected to Southern blot analysis using TCR-beta, TCR-gamma and IGH gene probes. Twenty five B cell lymphomas and 21 non-neoplastic lymphoid tissue samples were used as controls.

RESULTS

Using TCR-beta PCR, monoclonality was detected in 24 (44%) of 55 T cell lymphomas compared with 43 (78%) of 55 using TCR-gamma PCR and in 82% with both techniques. Five (9%) of 55 T cell lymphomas were IGH PCR positive. None of the non-neoplastic lymphoid control samples were PCR positive. All B cell lymphomas showed a polyclonal pattern with TCR-beta PCR while a single B cell lymphoma was positive using TCR-gamma primers. With TCR-beta PCR, a monoclonal result was seen in 12 (43%) of 28 frozen samples of T cell lymphoma, compared with 23 (82%) of 28 using Southern blot analysis. With TCR-gamma PCR, 19 (68%) of 28 frozen tissue samples were positive, compared with 26 (93%) of 28 using Southern blot analysis. A single case showed IGH rearrangement by Southern blot analysis.

CONCLUSION

TCR-gamma PCR should be the method of choice for analysis of clonality in paraffin wax embedded sections of lymphoproliferative lesions, as TCR-beta PCR has a high false negative rate. Southern blot analysis remains the most successful technique when sufficient fresh tissue samples and resources are available.

Lymphocyte activation in cutaneous T-cell lymphoma

Cutaneous T-cell lymphoma (CTCL) is a neoplasm of CD4+ T cells that includes mycosis fungoides and its leukemic variant, Sezary syndrome. The phenotype of CTCL cells and their predilection for localizing in the skin and regional lymph nodes indicate that CTCL is a neoplasm of mature, memory helper T cells belonging to the skin-associated lymphoid tissue. Experimental evidence suggests that the mechanisms of lymphocyte activation in CTCL may involve both T-cell receptor-dependent and -independent pathways. Furthermore, recent studies of the consequences of this activation have yielded several important findings. First, a dominant T-cell clone is generally present in CTCL specimens, including the earliest histologically diagnosable cutaneous patch lesions. Second, some cases of apparent chronic dermatitis harbor dominant T-cell clones. Such cases, known as "clonal dermatitis," have been observed to develop into overt CTCL. This suggests that patients with clonal dermatitis may be at increased risk for subsequent CTCL. Third, diseases associated with CTCL, such as lymphomatoid papulosis, large-cell lymphoma, and Hodgkin disease, arise as subclones of the original CTCL tumor and thereby share its clone-specific T-cell receptor gene rearrangements. Development of these secondary lymphoproliferative disorders appears to involve somatic mutations leading to deregulation of lymphoid activation/proliferation pathways. Fourth, CD8+ tumor-infiltrating lymphocytes present within lesions of CD4+ CTCL express a phenotype consistent with activated, major histocompatibility complex-restricted, cytotoxic T-cell differentiation. They tend to be more plentiful in early-stage disease and their proportion appears to correlate positively with improved survival, suggesting that they may exert an anti-tumor host response.

Lymphomatoid papulosis and associated cutaneous lymphoproliferative disorders exhibit a common clonal origin

Determination of the clonal relationship among multiple lymphoproliferative disorders occurring in individual patients has been hampered by dependence on molecular biologic techniques that require analysis of advanced lesions containing high tumor clone densities to isolate dominant, clonal antigen-receptor gene rearrangements. Polymerase chain reaction/denaturing gradient gel electrophoresis (PCR/DGGE) involves the amplification of T-cell receptor (TCR)-gamma gene rearrangements followed by their electrophoresis in denaturing gradient gels. This method detects dominant TCR-gamma gene rearrangements at tumor clone densities as low as 0.1%, making this assay suitable for analysis of early as well as late lesions. Using this approach, we analyzed skin lesions of lymphomatoid papulosis and either CD30+ large-cell lymphoma or early patch/plaque mycosis fungoides that developed in three patients. In each case, the dual specimens exhibited an identical band pattern by PCR/DGGE analysis, suggesting a common clonal origin. To confirm this clonal relationship, the dominant TCR-gamma gene rearrangements were eluted, amplified, cloned, and sequenced. In each case, they showed identical junctional sequences. These findings are significant for several reasons: 1) they demonstrate the common clonal origin of lymphomatoid papulosis and CD30+ large-cell lymphoma or mycosis fungoides occurring in individual patients; 2) they confirm that co-migrating PCR/DGGE bands exhibit identical nucleotide sequences; and 3) they provide a method for determining the sequence of a tumor-derived TCR-gamma gene rearrangement in early lesions containing a low tumor clone density. This latter feature should allow the prospective molecular staging of early cutaneous lymphoproliferative disorders.

Molecular staging of cutaneous T-cell lymphoma: evidence for systemic involvement in early disease

Biopsies of various tissues from eight patients with confirmed cutaneous T-cell lymphoma were analyzed for lymphomatous involvement using V-J junctional sequences in rearranged T-cell receptor-gamma genes as specific molecular markers for the malignant clone. The patients included one stage IA, one stage IB, and six stage IVA. Twenty-five specimens were analyzed including 14 skin, five lymph node, four blood, and two bone-marrow samples. Ten skin samples and four lymph node samples were histologically positive for lymphoma. The other specimens were morphologically uninvolved. An assay involving polymerase chain reaction (PCR) amplification of T-cell receptor-gamma gene rearrangements and denaturing gradient gel electrophoresis was used to identify the tissue specimen containing the greatest tumor clone density in each case. This specimen was then used to generate a tumor-specific RNA probe that was used to molecularly stage each patient by means of an assay involving PCR gene amplification and RNase protection analysis (PCR/RPA). This assay detected malignant cells in all available biopsies, including morphologically uninvolved extracutaneous tissue samples (two blood, one lymph node, and one bone marrow) obtained from the two patients in pathologic stage I. Microscopic examination and the less sensitive PCR/denaturing gradient gel electrophoresis technique failed to detect lymphomatous involvement in 11 (44%) and eight (32%) of these 25 specimens, respectively. We conclude that molecular biologic staging using PCR/RPA is able to demonstrate morphologically occult dissemination of cutaneous T-cell lymphoma in early disease. In addition, PCR/RPA may be able to monitor tumor response to therapy and detect early recurrence of malignant lymphomas during clinical remission.

Temperature gradient gel electrophoresis for analysis of a polymerase chain reaction-based diagnostic clonality assay in the early stages of cutaneous T-cell lymphomas

By means of a multiplex polymerase chain reaction (PCR) we amplified rearranged T-cell receptor gamma chain genes to detect monoclonality in 370 formalin-fixed skin biopsy specimens, showing histological features of parapsoriasis or mycosis fungoides. PCr products were analyzed by temperature gradient gel electrophoresis (TGGE). We selected 20 positive cases for use in a comparison of this technique with conventional agarose and polyacrylamide gel electrophoresis (PAGE). With TGGE the T-cells had shown monoclonality in 272 of the 370 cases; with agarose electrophoresis they did so in only 5 of the 20 selected cases and with PAGE in 16. Where multiple biopsy specimens from the same patient were analyzed, PCR products showed identical rearrangement patterns in TGGE. TGGE is an efficient technique that works on routine material and can help to verify a histological diagnosis of cutaneous T-cell lymphoma.