T-cell lymphoma cell lines (HUT102 and HUT78) established at the National Cancer Institute: history and importance to understanding the biology, clinical features, and therapy of cutaneous T-cell lymphomas (CTCL) and adult T-cell leukemia-lymphomas (ATLL)

Efforts at the National Cancer Institute to generate continuous in vitro cultures from patients with mycosis fungoides and the Sezary syndrome, neoplasms with a mature T-helper phenotype, led to the establishment of two cell lines, HUT78 and HUT102. Further characterization of these cell lines led to the identification of the first human retrovirus, HTLV-1, in the HUT102 cells, and the clinical description of the syndrome of HTLV-1 associated acute T-cell leukemia/lymphoma; the serum antibody test to screen for this virus was developed from the serum of the patient from whom the cell line was derived. The HUT78 cell line was pivotal in the identification and characterization of the HIV retrovirus in that a subclone, H9, proved to be permissive for replication of HIV in vitro. Propagation of HIV in vitro in H9 cells allowed for the development of immunological reagents to screen blood supplies for the presence of the virus. Further biologic and molecular studies of these lines have led not only to a better understanding of the underlying diseases but also to the development of rational therapeutic approaches.

The clonal nature of circulating Sezary cells

To determine if circulating Sezary cells can be classified as reactive or neoplastic based on the ability to detect the presence or absence of clonal T-cell receptor beta chain (TCR-beta) gene rearrangements by Southern blot analysis, we evaluated the peripheral blood of 25 patients: 11 patients with Sezary syndrome (SS), 11 with benign inflammatory dermatoses (BID), and three normal controls. Three of 11 patients with SS, with Sezary counts ranging from 14% to 52%, did not demonstrate any clonal TCR-beta gene rearrangements in the peripheral blood, despite a TCR-beta rearrangement by Southern blot analysis in the skin. Ten of 11 BID patients and all normal controls showed no evidence of a TCR-beta gene rearrangement in the peripheral blood. However, one patient with psoriasis demonstrated a TCR-beta gene rearrangement in the peripheral blood. The TCR-beta gene rearrangement detected in this patient, confirmed with polymerase chain reaction (PCR) amplification of the TCR-gamma gene rearrangement, did not correlate with the presence of circulating Sezary cells or the increased risk of neoplasia. Our results indicate that circulating Sezary cells may be monoclonal (neoplastic) or polyclonal (reactive), as defined by TCR gene rearrangement studies. Circulating Sezary cells in SS may be reactive in nature and not accurately reflect the actual tumor burden in the peripheral blood. The presence of circulating Sezary cells or the presence of a clone of cells defined by TCR-beta gene rearrangement in the peripheral blood is not limited to neoplastic disease processes.

Expression of c-myc oncoprotein in chronic T cell leukemias

T cell clones in patients with ataxia telangiectasia (AT) and T cell prolymphocytic leukemia (T-PLL) have identical chromosome abnormalities, namely inv(14)(q11q32), t(14;14)(q11;q32) and t(X;14)(q27;q11). In T-PLL and AT developing T cell leukemia, the above abnormalities occur frequently together with trisomy for 8q. We postulated that the additional abnormalities of chromosome 8, where the c-myc oncogene is mapped to 8q24, may play a role in the development of overt leukemia. DNA analysis using the CD1A c-myc probe did not reveal rearrangements of the c-myc gene by Southern blotting. We have used a monoclonal antibody for the c-myc protein to investigate the level of expression in 11 patients with T-PLL and two with Sezary cell leukemia and compared it with levels seen in normal lymphocytes. Significantly higher levels were observed in patients compared with controls (P < 0.0001). The highest levels of c-myc were seen in eight cases with trisomy for 8q resulting from an i(8q). One patient was investigated before and after treatment. In the active state, c-myc showed a level of 64.36 units (range 20-200). After treatment a residual population of malignant cells showed a c-myc level of 155 (range 90-280). This study suggests that the increased expression of c-myc as a result of trisomy for 8q may have a role in the pathogenesis of de novo T-PLL and T cell leukemia supervening AT and that there may be a correlation between c-myc levels and resistance to therapy.

[Cytogenetic abnormalities in seven patients with the Sezary syndrome]

The cytogenetic studies performed on 7 patients diagnosed of Sezary's syndrome are reported. The chromosomal study was made after 72 hours of culture of phytohaemagglutinin-stimulated peripheral blood. The 7 patients had abnormal karyotypes, the numeral alterations involving chromosomes 10 and 13, whereas the structural abnormalities affected chromosomes 1, 2, 4, 6 and 14. The large-cell variant has been associated with tetraploidy and the small-cell variant with diploidy, but this fact was not confirmed in the present series.

Detection of clonal T-cell receptor gamma gene rearrangements with the use of the polymerase chain reaction in cutaneous lesions of mycosis fungoides and Sézary syndrome

BACKGROUND AND DESIGN

We used the amplification of junctional V (variable)-J joining sequences of the rearranged T-cell receptor gamma (TCR gamma) genes by polymerase chain reaction for rapid and sensitive detection of a clonal T-cell population in a total of 51 skin specimens obtained from 45 patients with mycosis fungoides, five patients with Sézary syndrome, and 29 patients with chronic inflammatory dermatoses.

RESULTS

A clonal TCR gamma gene rearrangement was present in all tumors (3/3, 100%) and in most infiltrated plaques (16/22, 73%) and erythrodermas (10/12, 83%). In the patch stage, a clonal subset was found in more than half of the cases (8/14, 57%), whereas no clonality was observed in the controls. We also amplified the V-J sequences of the Igh locus coding for the heavy chain of immunoglobulins, without evidence of clonal rearrangement. These data were compared with those from in situ immunophenotypic analysis. Moreover, by using the same assay with successive dilutions of standard clonal T-cell DNA, a semiquantitative study of the T-cell clone was carried out in some cases. The highest ratios of clonal DNA were observed in advanced stages.

CONCLUSIONS

These data validate polymerase chain reaction V gamma-J gamma as a rapid, sensitive tool that can be used in the routine analysis of clonality in cutaneous lesions of mycosis fungoides and in the early diagnosis of mycosis fungoides and Sézary syndrome. Semiquantitative studies suggest that the malignant T-cell clone follows a selective process during the course of the progressive form of mycosis fungoides.

Chromosome aberrations, spontaneous SCE, and growth kinetics in PHA-stimulated lymphocytes of five cases with Sézary syndrome

Cytogenetic studies of five patients with Sézary syndrome (SS) revealed clonal chromosome aberrations in all cases. In one patient, a del(8)(p21) was the sole abnormality, whereas the remaining cases had karyotypes with multiple chromosome changes. In three SS cases with hypodiploid chromosome numbers, structural rearrangements affecting regions 10q22-24 and 12p11-13, and aberrations leading to loss of material from 17p were found concurrently. Bands 14q11 and 14q32 were involved in structural rearrangements in one case each. Our results and review of 51 published previously SS cases that were analyzed with banding techniques indicate that the chromosomes most frequently involved in structural changes were chromosomes 1 and 2 (in 43% of cases), 6 (in 38%), 17 (in 34%), 14 (in 27%), 11 (in 25%), 13 (in 21%), and 9 (in 20%). In particular, the breakpoints tended to aggregate at 1p11, 1p36, 2p11-24, 6q, 9q, 11q, 13q11-14, 14q11, 14q32, and in the pericentric region of chromosome 17. The most common numerical change was loss of chromosome 10, detected in 32% of SS cases. In our studies of three SS cases, sister chromatid exchange frequencies were significantly higher in comparison to the normal control. Cell cycle kinetics analysis revealed that the cell cycle time in the malignant cells was significantly longer than in lymphocytes of normal individuals.

Expression of V beta gene segments by Sezary cells

The T-cell receptor V beta repertoire expressed by Sezary cells was determined in a series of 16 patients whose samples have been shown to contain a majority of tumor cells. By using anti-V beta monoclonal antibodies, polymerase chain reaction analysis of expressed V beta, and, in selected cases, nucleotide sequencing, we have shown that the expressed V beta segments belong to five V beta families (V beta 5, V beta 6, V beta 8, V beta 13, and V beta 18), which contain a large fraction of the T-cell receptor V beta repertoire and do not share significant similarities in complementary determining region 4. V beta segments from these five families were also found to be strongly expressed by CD4 + CD7- peripheral blood cells obtained by fluorescence-activated cell sorting from two healthy donors. The diversity of the V beta repertoire expressed by Sezary cells appears to be similar to that expressed by circulating non-neoplastic T cells. These data do not support the hypothesis that a common superantigen is involved in the initiation of this form of cutaneous T-cell lymphoma.

Appearance of isochromosome 18q can be associated with in vitro immortalization of human T lymphocytes

T lymphocytes cultured from a skin biopsy specimen of a patient with atopic dermatitis developed isochromosome 18q concomitant to escape from replicative senescence. Furthermore, two T-cell lines established from patients with cutaneous T-cell lymphoma also developed isochromosome 18q during continuous growth. The results indicate that a pathway leading to immortalization of human T lymphocytes could involve genes located at chromosome 18.

Localization of clonal T cells to the epidermis in cutaneous T-cell lymphoma

BACKGROUND

Mycosis fungoides (MF) is a form of cutaneous T-cell lymphoma (CTCL) characterized by progression of clonal, epidermotropic T cells with the proliferative (Ki-67+) T-cell fraction primarily confined to the epidermis in early CTCL.

OBJECTIVE

Our purpose was to determine whether the malignant clone (recognized by its clonal T-cell receptor [TCR] rearrangement) might also be localized to the epidermal compartment by differential Southern blot analysis.

METHODS

A rapid heat-saline technique was used to separately isolate epidermal and dermal DNA from 11 patients with CTCL (1 with disease in the pre-MF stage, 4 with patch-stage MF, 3 with plaque-stage MF, 1 with tumor-stage MF, 1 with Sézary syndrome, and 1 with non-MF peripheral T-cell lymphoma). Whole and heat-saline separated 6 mm biopsy specimens (obtained from the same lesion) were analyzed by standard Southern blotting with 5 to 10 micrograms of DNA digested with BamHI, HindIII, or EcoRI in each case. Filters were probed with a 32P-labeled TCR-C beta complementary DNA. Skin compartment localization of TCR-C beta rearrangement was compared with results of diagnostic immunophenotyping and expression of proliferating cell nuclear antigen.

RESULTS

DNA yields were as follows: from the whole specimens, 14.5 to 62.5 micrograms; from epidermal sheets, 2 to 42.5 micrograms; and from the dermis specimens, 2.5 to 25.5 micrograms. Whole and separated specimens from one patient with plaque-stage disease, three with patch-stage disease, and one patient with pre-MF disease revealed no rearrangement. Six patients had detectable gene rearrangements in the whole specimen by Southern blot; four of six had identical rearrangements in only the epidermal fragment (including the Sézary syndrome biopsy specimen) and not the dermis. The other two patients had only dermal TCR-C beta rearrangement. No relation was seen between immunophenotype or proliferating cell nuclear antigen expression and the localization of TCR-C beta rearrangements. However, the degree of epidermotropism significantly correlated with the presence of TCR-C beta rearrangements in the epidermal sheets.

CONCLUSION

This study demonstrates that the malignant clone in CTCL can be localized to the epidermal compartment in most cases in which a TCR rearrangement is detectable and that these clones are associated with epidermal proliferation of lymphocytes. This technique of differential epidermal versus dermal Southern analysis for TCR rearrangement may improve sensitivity by helping to distinguish reactive from malignant T-cell populations in future studies of the pathogenesis of CTCL.

Combined immunophenotyping and karyotyping in peripheral T cell lymphomas demonstrating different clonal and nonclonal chromosome aberrations in T helper cells

Combined immunophenotyping and karyotyping was performed in seven cases of peripheral T cell lymphoma with complex aberrant clones. Various lymphocytic cell populations entered mitosis, whereas all aberrant cells belonged to the T helper/inducer cell population. Lymphomas with the same recurrent chromosome aberrations, i.e. inversion inv(14)(q11q32.1) and isochromosome i(8)(q10), had a very similar immunophenotype. The aberrant cells in these cases expressed CD3+, CD4+, CD7+, CD45RO+. The immunophenotypic similarity is underlined in one case of T prolymphocytic leukemia, in whom the aberrant cells lost the CD8 antigen originally present, during cultivation with PHA. In one case of Sézary's syndrome, two or possibly even three different clones as well as nonclonal aberrations were identified within the T (helper/inducer) cell population, providing further evidence that chromosomal instability is a characteristic feature of cutaneous T cell lymphoma.

Cytogenetic studies in five patients with Sézary syndrome

A cytogenetic study was performed in five patients with Sézary syndrome. Metaphases were obtained from a phytohemagglutinin-stimulated lymphocyte culture. The five patients showed abnormal karyotypes. The chromosomes preferentially involved in numerical aberrations were chromosomes 10 (monosomy) and 13 (monosomy); involved in structural changes were chromosomes 1, 2, 4, 6, and 14. In our series, all patients showed progression of the disease.

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)

We used a gene amplification strategy to analyze T-cell receptor (TCR) gene rearrangements in 185 specimens, including mycosis fungoides/Sezary syndrome (MF/SS), other cutaneous neoplasms, inflammatory dermatoses, reactive lymphoid tissues, and normal skin. Genomic DNA was extracted from lesional tissues and rearrangements of the TCR-gamma chain gene were amplified using the polymerase chain reaction (PCR) with primers specific for rearrangements involving V gamma 1-8 or V gamma 9 gene segments. The resulting PCR products were then separated according to their nucleotide sequence as well as size by denaturing gradient gel electrophoresis (DGGE). Dominant clonal TCR-gamma gene rearrangements were detected in 61 of 68 MF/SS cases by PCR/DGGE. This sensitivity of 90% compared to a sensitivity of only 59% when dominant clonality was sought in 17 of these same cases by Southern blot analysis of TCR-beta gene rearrangements. This difference in sensitivity was greatest in early, minimally infiltrated skin lesions. PCR/DGGE was also more sensitive than Southern blot analysis for detecting peripheral blood involvement in two cases of early MF. Among 12 additional specimens of suspected MF/SS, nine (75%) showed clonal TCR-gamma gene rearrangements by PCR/DGGE including six of eight cases with a previously confirmed diagnosis of MF/SS and three of four cases without prior known MF/SS. Among 105 non-MF/SS specimens, dominant TCR-gamma gene rearrangements were detected in only six cases (6%). Four were diagnosed as chronic dermatitis and two were diagnosed as cutaneous lymphoid hyperplasia. We conclude that the large majority of MF/SS cases, including patch phase disease, possess dominant clonal TCR-gamma gene rearrangements. PCR/DGGE is more sensitive than Southern blot analysis for detecting dominant clonality and staging disease in patients with a confirmed diagnosis of MF/SS. However, because PCR/DGGE is sensitive enough to detect dominant TCR-gamma gene rearrangements in a subset of patients with chronic dermatitis, it cannot be used as the sole criterion for establishing a diagnosis of T-cell lymphoma. As with other molecular biologic clonality assays, clinicopathologic correlation is essential. Nevertheless, the detection of dominant clonality in some cases of histologically nonspecific dermatitis allows the identification of a previously unrecognized subset of patients, i.e., those with "clonal dermatitis." It will be important to determine the long-term risk of MF/SS among these patients because our study indicated that MF/SS can sometimes present with lesions indistinguishable from clonal dermatitis.

Cytogenetic findings in cell lines from cutaneous T-cell lymphoma

Cytogenetic analysis of some patients with CTCL demonstrates the presence of more than one cytogenetically aberrant clone in a given patient. These findings lead us to suggest that CTCL is defined by a family of "genotraumatic" T cells. A genotraumatic T cell, unlike a normal T lymphocyte, is defined by its ability to develop clonal, cytogenetically visible chromosome aberrations. Based on this hypothesis, an investigation was performed in detail of cell lines from the plaques and blood of a patient with MF. Several genotraumatic T cells could be demonstrated. Of particular interest was the establishment of two continuous T-cell lines from a single plaque. Both genotraumatic T-cell lines were genetically unstable, and multiple and complex chromosome aberrations could be demonstrated in both cell lines, suggesting that two potentially malignant T-cell clones exist in a single plaque. It is proposed that CTCL is defined by a family of genotraumatic T cells and is thus, in principle, oligoclonal or polyclonal. All genotraumatic T cells may be considered cancer prone because of their ability to develop clonal chromosomal aberrations. A genotraumatic T cell is per se not malignant, but owing to its genetic instability, it may develop into a tumor cell. This could explain how an apparent benign disorder, CTCL, occasionally may progress into malignant lymphoma.

HTLV-1-like particles and HTLV-1-related DNA sequences in an unambiguous case of Sèzary syndrome

An unambiguous case of Sèzary syndrome associated with the presence of unusual retroviral infection markers is described. The blood smear showed 15% typical Sèzary cells but also rare atypical lymphocytes with convoluted nuclei, evocative of characteristic adult T-cell leukemia (ATL) flower cells. However, the patient did not present any clinical or biological manifestations of ATL, and human T-cell leukemia virus type 1 (HTLV-1) serology was consistently negative. After being cultured for 4 months, peripheral blood mononuclear cells (PBMC) produced typical type C retrovirus-like particles with budding forms strongly resembling HTLV-1 virions. The producer cells did not express HTLV-1-specific antigens detectable by indirect immunofluorescence (IIF). Southern blotting of uncultured PBMC DNA, submitted to digestion with the restriction enzymes PstI and SacI, and hybridized with a full genomic HTLV-1 probe, showed the presence of specific homologous sequences, absent in all of the healthy donor control PBMC DNAs. These HTLV-1-like sequences presented a restriction enzyme pattern distinct from that of the HTLV-1 prototype genome and of other HTLV-1 proviruses studied up to now. Polymerase chain reaction (PCR) with highly conserved HTLV-1 derived pol and env primers was consistently negative with the patient's DNA. All these results taken together suggest that our patient carries a retroviral agent partially homologous to, but probably different from HTLV-1. The possibility is discussed that this type of retroviral agent might be associated with a subtype of cutaneous T-cell lymphoma (CTCL) represented by a typical Sèzary syndrome with a very low percentage of ATL-like flower cells in the blood smear.

Aneuploid malignant T cells from a patient with Sézary syndrome can be visualized by in situ hybridization

BACKGROUND AND DESIGN

Enumeration of malignant cells in Sézary syndrome often relies on the identification of the Sézary cell nucleus. This morphologic method is, however, nonspecific and unreliable in the enumeration of the proportion of malignant lymphocytes in peripheral blood of patients with Sézary syndrome. Malignant lymphocytes of patients with mycosis fungoides and Sézary syndrome are often characterized by multiple chromosome aberrations. Herein, we demonstrate that fluorescent in situ hybridization can visualize and accurately enumerate malignant aneuploid mononuclear cells in a patient with Sézary syndrome.

RESULTS

Fluorescent in situ hybridization demonstrated that 90% of the mononuclear cells in the patient with Sézary syndrome showed numerical aberrations for both chromosome 7 and X, a figure confirmed by flow cytometry.

CONCLUSION

Fluorescent in situ hybridization may be a valuable tool to visualize and enumerate aneuploid tumor cells in patients with cutaneous T-cell lymphoma.

A possible role for the Ras-related Rab2 protein in the immunological events associated with hematological malignancies

The Rab branch of the Ras-related guanine nucleotide (GTP/GDP)-binding proteins currently includes at least thirty related members which are involved in the intracellular vesicular transport along the secretory and endocytic pathways in eukaryotic cells. We have demonstrated the overexpression of the Rab2 protein in peripheral blood mononuclear cells from patients exhibiting Sézary syndromes and other lymphoid and myeloid malignancies. Several lines of evidence suggest that the Rab2 overexpression can be related not to leukemic cells but to a subset of peripheral lymphocytes with a CD2+ phenotype. Our results provide strong evidences for the implication of a small GDP/GTP binding protein in immunological events associated with neoplastic states. The precise cellular population involved in this process remains to be determined.

Expression and Role of Integrin Receptors in Sézary Syndrome

The potential role of integrins in the epidermotropism of the atypical lymphocytes of Sézary syndrome was studied by monitoring the expression of alpha and beta chains and their major ligands in skin biopsies and peripheral blood cells in patients at different progression stages. Most mononuclear cell integrins were also detected on infiltrating cells including the leukocyte complex CD11/CD18, alpha 4 beta 1, and their ligands, ICAM-1 and VCAM-1. Conversely, alpha 6 and beta 4 were present only in epidermal basal cells. Mononuclear infiltrates of SS were positive for both alpha 3 and alpha 5 chains, whereas in inflammatory cutaneous diseases only alpha 5 was expressed, indicating that a major feature of Sézary cells is the unique expression of alpha 3 beta 1. Significant changes of alpha 3 beta 1 were monitored in the follow-up of Sézary patients and correlated with the results of the therapy. The heterodimer alpha 1 beta 1 was absent from mononuclear cells except in one case. Among matrix molecules, laminin and type IV collagen displayed a pattern similar to that of the controls, whereas fibronectin and tenascin deposition were apparently increased. Circulating Sézary cells, both at diagnosis and during follow-up, were alpha 3 and alpha 5 negative and failed to acquire these adhesion molecules after mitogenic stimulation. We propose that the expression of alpha 3 beta 1 is a distinguishing feature of skin-infiltrating Sézary cells and may be related to their epidermotropism. It could also be adopted as an additional parameter of the progression and therapeutic stage of Sézary syndrome.

Overexpression of the ras-related rab2 gene product in peripheral blood mononuclear cells from patients with hematological and solid neoplasms

The rab2 gene product belongs to the rab branch of the ras-related GTP-binding protein family. The rab2 gene mRNA analysis in 70 tumor samples from various origins showed no obvious difference between malignant tissues and their normal counterparts. However, an over-expression has been observed at the RNA or protein levels in peripheral blood mononuclear cells from the nine patients with Sézary syndromes studied. Subsequent investigations in mycosis fungoides and solid tumor patients allowed us to link these high protein levels to immune reactive rather than to malignant cells. Circulating monocyte and lymphocyte populations from cancer patients are under analysis to correlate the Rab2 protein overexpression to a peculiar subset of cells.

Application of a multiprobe RNase protection assay and junctional sequences to define V beta gene diversity in Sezary syndrome

Nineteen patients with mycosis fungoides/Sezary syndrome (MF/SZ), a malignancy of the mature helper T-cell phenotype (CD4+TCR alpha beta+), were screened for clonotypic V beta expansions in peripheral blood with a multiprobe RNase protection assay. A different predominant V beta gene was identified in 9 of 14 patients with high peripheral blood CD4/CD8 ratios, whereas 4 of these patients showed T-cell expansions expressing V beta genes other than those included in the assay. In contrast, five patients with few, if any, malignant cells in the circulation had V beta expression levels similar to that in normal peripheral blood. A unique V-D-J sequence was found for each highly expressed V beta gene, thereby documenting monoclonality of the expanded T-cell populations. Polymerase chain reaction (PCR) primers specific for the D-J beta junction accurately identified the corresponding malignant clonotype in peripheral blood. The diverse TCR V beta gene usage found in these MF/SZ patients suggests that T-cell receptor (TCR) specificity has no bearing on this disease.

T-cell receptor variable region gene expression in cutaneous T-cell lymphomas

The cutaneous T-cell lymphomas (CTCL) are a group of diseases characterized by malignant proliferations of CD4 positive T-cells having monoclonally rearranged T-cell receptor (TCR) genes. A recent study using monoclonal antibodies to two TCR beta-chain variable (V) region gene products showed preferential expression of the V beta 8 gene product in these tumors. The finding of predominant usage of a single V beta gene would imply that selection by antigen is important in the etiology of these tumors. We have studied eight cases of cutaneous T-cell lymphoma and one cell line derived from a patient with mycosis fungoides/Sezary syndrome, using an extended panel of antibodies to V region gene products. Contrary to the previous report, in our study expression of the V beta 8 gene product by tumor cells was not observed in any of the cases of CTCL or in the tumor cell line studied; preferential use of any of the variable region genes recognized by the antibodies in the panel was not observed.

Cytogenetic findings in terminal large cell transformation in a case of Sézary syndrome

A long-lasting case of Sézary syndrome, whose chromosomal pattern had been repeatedly investigated during a follow-up period of several years, was studied in the terminal transforming phase, which took place more than 5 years after the initial diagnosis. To the best of the authors' knowledge, this appears to be the first instance of cytogenetic studies carried out in a large cell transformation of cutaneous T-cell lymphoma. The results clearly indicate that the atypical large cells seen in the transforming phase were clonally derived from the pre-existing cerebriform cells. Newly detected relevant cytogenetic findings were: a) drop of tumor cell ploidy from hypotetraploid to hypotriploid, with striking chromosomal imbalance; b) additional structural aberrations of chromosomes 2 and 7, which had been already preferentially involved in the earlier phases, and involvement of the previously unaffected chromosomes 1, 3, and X; and c) presence in 100% of the abnormal metaphases of a large HSR on the long arm of chromosome 17.

T-cell receptor gene rearrangement analysis: cutaneous T cell lymphoma, peripheral T cell lymphoma, and premalignant and benign cutaneous lymphoproliferative disorders

T-cell receptor gene rearrangement analysis is a useful technique to detect clonality and determine lineage of lymphoid neoplasms. We examined 103 patients with mycosis fungoides, Sézary syndrome, peripheral T cell lymphoma, potentially malignant lymphoproliferative disorders including pre-Sézary syndrome, large plaque parapsoriasis, lymphomatoid papulosis and follicular mucinosis, and various benign inflammatory infiltrates. A clonal rearrangement was detected in skin samples in 20 of 24 patients with mycosis fungoides and in peripheral blood samples in 19 of 21 patients with Sézary syndrome. A clonal population was also detected in seven of eight cases classified as peripheral T cell lymphoma. The potentially malignant dermatoses tended to have clonal rearrangement, with the exception of large plaque parapsoriasis, and further follow-up is needed to correlate clonality with the disease course. These studies demonstrate the value of molecular genetics as an adjunct to morphology in the examination of patients with cutaneous lymphoproliferative disease.

Analysis of beta, gamma, and delta T-cell receptor genes in mycosis fungoides and Sezary syndrome

The authors have analyzed the configuration of immunoglobulin (Ig) and beta, gamma and delta T-cell receptor (TCR) genes in DNA extracted from skin, lymph nodes, and peripheral blood mononuclear cells obtained from 41 patients with mycosis fungoides (MF), 14 patients with Sezary syndrome, and 13 patients with benign inflammatory dermatoses. No discrete rearranged bands (DRB) were detected in patients with inflammatory dermatoses. In tissue DNA from 19 patients with MF DRB were detected with beta and gamma, but not delta TCR probes. Only one patient with MF had a rearrangement of gamma and delta with germ line beta TCR genes. In 13 patients multiple biopsies were analyzed and DRB, when present, were identical in different lesions from individual patients. In three patients analysis of DNA from dermatopathic lymph nodes did not reveal DRB. Analysis of peripheral blood DNA from 24 patients revealed a discrete rearrangement of the gamma TCR gene in four patients and both beta and gamma genes in four additional patients. In MF DRB were detected more frequently with advancing stage of disease in tissues (P less than 0.01) but not in peripheral blood (P equals 0.36). Of 14 patients with Sezary syndrome, eight had DRB in peripheral blood DNA with both beta and gamma probes and in three of these patients identical DRB were also detected in DNA from skin biopsy samples. In contrast, DRB were not detected in the peripheral blood of the other six patients. In both MF and Sezary syndrome there was no restricted usage of particular V gamma genes. These results indicate that in MF (1) T-cell clones can be detected in skin biopsy specimens from the majority of patients with early stage disease, (2) gamma delta T-cell clones are only rarely found, and (3) TCR gene analysis can detect T-cell clones in the peripheral blood with a greater degree of specificity than conventional light microscopic study. In Sezary syndrome these studies also suggest that a subset of patients have a polyclonal population of circulating atypical lymphoid cells. In addition these patients appear to have a better prognosis than those with monoclonal disease.