Demonstration of clonal disease in early mycosis fungoides

Duration of symptoms does not correlate with results of T-cell gene rearrangement studies in patients evaluated for cutaneous T-cell lymphoma

OBJECTIVES

We aimed to determine if clonality on T-cell gene rearrangement studies correlated with duration of cutaneous symptoms in patients with skin disease who are being evaluated for cutaneous T-cell lymphoma (CTCL). Specifically, our goal was to determine if symptom duration could help better optimize sample selection for T-cell gene rearrangement studies.

METHODS

Biopsies were reviewed from patients within both general dermatology clinic and CTCL specialty clinic for clonality results in relation to disease duration.

RESULTS

We did not find an association between duration and clonality in any group.

CONCLUSIONS

The yield of T-cell gene rearrangement studies is similar between shorter and longer duration of disease implying that there is not an optimal duration range in which T-cell gene rearrangement studies are more likely to give a positive result.

Histopathologic Features of Early (Patch) Lesions of Mycosis Fungoides

The histologic diagnosis of early mycosis fungoides (MF) is one of the most vexing problems in dermatopathology. We reviewed the histopathologic features of 745 biopsy specimens from 427 patients (male:female = 277:150; median age, 52 years; range, 3-95 years) with early (patch) lesions of MF collected from the lymphoma database of the Department of Dermatology of the Medical University of Graz (Austria). In all patients, the diagnosis was established by clinicopathologic correlation. The most common histopathologic pattern consisted of a band-like or patchy lichenoid infiltrate admixed with coarse bundles of collagen in the superficial dermis. Epidermotropism of lymphocytes was observed in most cases in one or more forms (single lymphocyte epidermotropism, 22%; basilar lymphocytes, 23%; Pautrier's microabscesses, 19%; "haloed" lymphocytes, 40%; disproportionate exocytosis, 17%; pagetoid epidermotropism, 3%). In 4% of cases, epidermotropism was completely missing. Atypical lymphocytes were present only in 9% of cases. Features of interface dermatitis were observed in 59% of cases. Other unusual findings were the presence of necrotic keratinocytes (23%), melanophages (8%), and extravasated erythrocytes (4%). In 28 patients, two or more biopsies taken on the same day at different body sites showed different histopathologic aspects, underlying the protean features of MF even in a single patient at a given time. Our study expands previous observations on histopathologic features of early lesions of MF. Although sometimes the histopathologic features are not diagnostic, they should be considered consistent with MF and do not rule out the diagnosis.

Evidence for Restricted Vβ Usage in the Leukemic Phase of Cutaneous T Cell Lymphoma

Antibodies directed against the beta chain of the T cell receptor (anti-Vbeta antibodies) are useful to identify the Vbeta repertoire of T cells in various diseases and to quantify numbers of Vbeta-bearing T cells. The goals of this study were to identify Vbeta+ cases of leukemic phase cutaneous T cell lymphoma (CTCL) and to compare the percentage of positive calls with other measures of blood tumor burden, i.e., lymphocyte subsets with a CD4+CD7- and CD4+CD26- phenotype and Sezary cell counts. Thirty-three of 49 (67%) cases of leukemic CTCL reacted with an anti-Vbeta antibody. When combined with reports from the literature, the frequency of Vbeta5 (probably Vbeta5.1) usage was relatively high when compared with Vbeta2 that is also frequently expressed by normal CD4+ T cells. The percentage of Vbeta+ cells correlated to the percentage of CD4+CD7- and CD4+CD26- cells for cases in which the neoplastic cells were deficient in expression of CD7 and CD26, respectively, but not the Sezary cell count. We hypothesize that the increased Vbeta5.1 usage in CTCL may be the result of depletion of Vbeta2 and other Vbeta-bearing T cells by staphylococcal superantigens prior to neoplastic transformation, resulting in a relative increase in the frequency of Vbeta5.1 usage in CTCL.

Polyclonal expansion of T cells with the TCR Vbeta type of the tumour cell in lesions of cutaneous T-cell lymphoma: evidence for possible superantigen involvement

The involvement of superantigens in the pathology of cutaneous T-cell lymphomas (CTCL) has been suggested before, but without unequivocal evidence for superantigen activity in the patients. Seeking evidence for superantigen activity we analysed clones and microdissected single cells isolated from the epidermis of early-stage lesions of a CTCL patient for their T-cell receptor (TCR) V beta expression and TCR V gamma gene rearrangements. The vast majority of these T cells expressed the TCR V beta family type of the tumour. From their TCR gamma gene rearrangements, however, these cells were polyclonal. The tumour cell clone accounted for about 60% of these cells, about 40% were of heterogeneous origin. This dominance of a single V beta family in the polyclonally expanded dermal T-cell populations implies superantigen activity in the CTCL lesions.

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.

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.

Malignant and normal T cells show random use of T-cell receptor alpha chain variable regions in patients with cutaneous T-cell lymphoma

Cutaneous T-cell lymphoma (CTCL) is a malignancy of mature T lymphocytes, most of which express alpha/beta type T-cell receptors (TCRs). The cause of CTCL is unknown, but hypotheses postulating chronic stimulation of TCRs by superantigen or by a leukemogenic virus have been proposed. Either mechanism might produce bias in the TCR variable (V) region types used by the malignant cells. To determine if TCR alpha use is restricted in CTCL, we used reverse transcription and the polymerase chain reaction to determine V alpha and V beta usage by malignant cells purified from the peripheral blood of leukemic patients with CTCL. Usage of alpha chain V region segments appeared totally random; malignant lymphocytes isolated from each of six patients used different V alpha regions. As has been previously reported, no bias was found in beta chain V region usage either. In addition to productive (in frame) TCR V region mRNAs in malignant cells from each patient, we detected non-productive (out of frame) beta chain transcripts in these cells in two of six patients, and non-productive alpha chain transcripts in five of six. Residual normal peripheral blood lymphocytes from these patients showed a random, polyclonal or oligoclonal pattern of V region usage. We conclude that there is no bias in V region usage in CTCL, making it unlikely that interactions between superantigen or virus and the TCR V regions play a role in the pathogenesis of CTCL.

Assessment of an anti-T-cell receptor variable region antibody panel in cutaneous T-cell lymphoma

Using a panel of seven commercially available monoclonal antibodies directed against specific sites of the T-cell receptor variable region, we have studied the staining patterns in 15 biopsies from 11 patients with cutaneous T-cell lymphoma (CTCL), and in five patients with benign lymphocytic infiltrates. Eight of the 11 patients with CTCL showed staining of the majority of lymphocytes with either V beta 8 alone (n = 3), V beta 12 alone (n = 2) or with both V beta 8 and V beta 12 (n = 3). None of the biopsies from patients with benign dermatoses showed staining of the majority of lymphocytes with any of the antibodies.