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PubMed1993

Defining the extent and nature of cytogenetic events in prostatic adenocarcinoma: paraffin FISH vs. metaphase analysis.

A comparative study of primary prostatic tumors utilizing conventional metaphase analysis of prostate tumor cultures and fluorescence in situ hybridization (FISH) analysis of paraffin-embedded tissue sections revealed significant differences in type and extent of cytogenetic aberrations. Clonal trisomy 7 was identified in two tumors by metaphase analysis of prostate cultures, but not confirmed in either case by FISH analysis. True gain of chromosome 8 was revealed by FISH analysis in malignant epithelium of four tumors but not in adjacent normal or hyperplastic glands. Neither gain nor loss of this chromosome was observed by metaphase analysis in any of the tumors. Significant monosomy and nullisomy of chromosome 10 was identified in one case by FISH, but no cells with gain or loss of chromosome 10 were observed by metaphase analysis. Significant loss of the Y chromosome was revealed in one tumor by FISH, but no cells with -Y were identified by metaphase analysis. Clonal loss of the Y chromosome was identified in two other tumors by metaphase analysis. Paraffin FISH analysis of these tumors revealed overall monosomy in both, although in one tumor there was extensive nodular loss of the Y chromosome. Paraffin FISH analysis permits identification of cytogenetic aberrations in areas identified as carcinoma (CaP), prostatic intraepithelial neoplasia (PIN), and benign prostatic hyperplasia (BPH). This technique appears more informative in defining the true extent and nature of cytogenetic aberrations in prostate cancer than metaphase analysis of prostate tumor cultures.

Adenocarcinoma↗
PubMed1989

Human T-cell lymphotropic virus type I (HTLV-I)-associated adult T-cell leukemia-lymphoma in a patient infected with human immunodeficiency virus type 1 (HIV-1).

A patient had adult T-cell leukemia-lymphoma in the unusual setting of coinfection with human immunodeficiency virus type 1 (HIV-1) and human T-cell lymphotropic virus type I (HTLV-I). The leukemic cells were CD4 positive and showed clonal genetic rearrangement of the T-cell receptor complex. Cytogenetic analysis showed three clonal karyotypic abnormalities: trisomy 3 and two translocations [t(1;15), (X;1)]. The patient was seropositive for HIV and HTLV-I; HTLV-I and HIV-1 DNA sequences were detected in peripheral blood leukocytes by the polymerase chain reaction. The HTLV-I sequences were detected in a relatively high proportion of mononuclear cells (at least 1 in 30 cells), whereas HIV-1 sequences were detected in a smaller proportion of cells (at least 1 in 3000 cells). Clinical remission was achieved after chemotherapy. There was a decrease in the proportion of HTLV-I positive mononuclear cells (at least 1 in 1000 cells), whereas the proportion of HIV-1 positive cells was relatively unchanged (at least 1 in 1000 cells). Adult T-cell leukemia-lymphoma in the setting of HIV coinfection may become increasingly common because asymptomatic retroviral coinfections are frequent.

Adult↗
PubMed2002

A T-cell receptor gamma polymerase chain reaction assay using capillary electrophoresis for the diagnosis of cutaneous T-cell lymphomas.

Detection of clonal T-cell receptor gamma rearrangements by polymerase chain reaction (TCRgamma PCR) followed by high-resolution electrophoresis has now become a valuable tool in the diagnosis of cutaneous T-cell lymphoma (CTCL). The identification of clonal TCRgamma PCR products by fluorescent fragment analysis (FFA) on a capillary DNA sequencer is described here and compared with an established hetero-duplex temperature gradient gel electrophoresis (HD-TGGE). Of 55 CTCL derived lesional skin samples, clonality was obtained in 46 samples by FFA (83.6%) and in 45 samples by HD-TGGE (81.8%). Of 35 control skin specimens from various nonmalignant dermatoses, two samples (pityriasis lichenoides chronica) showed clonality by both methods, one sample (chronic dermatitis) only by FFA. The sensitivity of FFA was established using three clonal T-cell lines and peripheral blood mononuclear cells. The detection limit for clonal material was approximately 1% to 2.5% in mixtures of DNA and 1% to 3% in cell dilutions. For cell dilution series, we confirmed a linear correlation between the clonal/polyclonal peak-size ratios and the portion of clonal cells up to about 10%. Thus, the initial ratio between mono-and polyclonal template is correctly displayed by FFA within that concentration range. In conclusion, FFA on capillary DNA sequencer is a well-suited separation technique in TCRgamma PCR-based clonality analysis also exhibiting quantitative properties.

Clone Cells↗
PubMed1999

Detection of T cell receptor beta (TCRB) gene rearrangement patterns in T cell malignancies by Southern blot analysis.

Reliable detection of clonal T cell receptor beta (TCRB) gene rearrangements is essential for clonality assessment of suspect T cell proliferations. Since no appropriate Southern blot probes were available, we developed a new set of optimized TCRB gene probes. The TCRBJ1 and TCRBJ2 probes are positioned just downstream of the Jbeta1 and Jbeta2 gene segments, respectively, and can be used for detection of both incomplete Dbeta-Jbeta and complete Vbeta-Jbeta rearrangements, whereas the TCRBD1U and TCRBD2U probes upstream of the Dbeta segments can be used to confirm incomplete Dbeta-Jbeta rearrangements. Less frequently occurring Vbeta-Dbeta rearrangements can easily be detected via the downstream TCRBD1 and TCRBD2 probes. Although both EcoRI and HindIII are appropriate restriction enzymes to be used in combination with all these probes, false-positivity due to partial digestion of the EcoRI site in the Jbeta2-Cbeta intron has to be excluded via the TCRBC probe. Application of the TCRB probes in a large series of nearly 200 T cell malignancies revealed clonal rearrangements in all immature and mature TCR alphabeta+ T cell malignancies, in the vast majority of TCR gammadelta+ T cell acute lymphoblastic leukemias (T-ALL) (approximately 95%) and even in most CD3- T-ALL (approximately 80%). TCRB gene rearrangement patterns differed between the various categories of T cell malignancies. An increased frequency of complete Vbeta-Jbeta1 rearrangements was observed in TCR alphabeta+ T-ALL as compared to CD3- and TCR gammadelta+ T-ALL (33% vs 16% and 11%, respectively), and also incompletely rearranged V-D, D-D, or D-J alleles in the beta2 region occurred more frequently in TCR alphabeta+ cases than in CD3- and TCR gammadelta+ T-ALL (27% vs 15% and 18%, respectively). Furthermore, in comparison to TCR alphabeta+ T-ALL, less Vbeta-Jbeta1 and more Vbeta-Jbeta2 rearrangements were detected in mature TCR alphabeta+ T cell malignancies. The occurrence of the different types of TCRB rearrangement patterns has implications for PCR-based clonality assessment and for PCR-based detection of minimal residual disease via TCRB gene analysis. For instance, focussing on the beta2 region of T-ALL will allow detection of rearrangements in 70%, 75%, and 90% of CD3-, TCR gammadelta+, and TCR alphabeta+ cases, respectively. Therefore the here-described results will facilitate the design of the most appropriate primer sets for PCR analysis of TCRB gene rearrangements at the DNA level.

Blotting, Southern↗
PubMed2005

Analysis of a uropathogenic Escherichia coli clonal group by multilocus sequence typing.

Although many strain typing methods exist for pathogenic Escherichia coli, most have drawbacks in terms of resolving power, interpretability, or scalability. For this reason, multilocus sequence typing (MLST) is an appealing alternative. However, its applicability to different pathogens in specific epidemiologic contexts is not well understood. Here, we applied a previously established MLST method based on housekeeping genes to a well-characterized collection of uropathogenic E. coli isolates to compare the discriminatory ability of this procedure with that of enterobacterial repeat intergenic consensus (ERIC2) PCR, serogrouping, and pulsed-field gel electrophoresis (PFGE). Among 45 E. coli isolates studied, 17 different multilocus sequence types (ST) were identified. One MLST group (designated ST69 complex) was comprised of 22 isolates, all belonging to uropathogenic and bacteremic E. coli strains previously defined as clonal group A (CgA) by ERIC2 PCR. The ST69 strains contained five different serogroups and 14 PFGE types. ERIC2 PCR CgA strains belonging to different MLST groups were also identified. Interestingly, one cow E. coli isolate, previously shown by PFGE to be closely related to a human uropathogenic CgA strain, was found to cluster with the ST69 strains. All of the other animal and environmental CgA isolates had different MLST profiles. The discriminatory power of this MLST method based on housekeeping genes appears to be higher than that of ERIC2 PCR but lower than that of PFGE for epidemiologic study of uropathogenic E. coli.

Animals↗
PubMed2003

Clonality and malignancy. PCR assays for the diagnosis of clonal B- and T-cell proliferations: potentials and pitfalls.

The discrimination between lymphomas and reactive lymphoproliferations is difficult or even impossible in a proportion of cases by means of histology and additional immunhistochemistry alone. Therefore, the analysis of the clonality of the rearranged immunoglobulin genes and T-cell receptor genes, respectively, is often employed as an additional diagnostic tool. This analysis is based on the fact that the tumor cells of lymphomas harbor identically (clonally) rearranged antigen receptor genes whereas reactive lymphoproliferations consist of cells with differently (polyclonally or oligoclonally) rearranged antigen receptor genes. Initially Southern blot analysis was used to determine the presence of clonal lymphoid cell populations. Meanwhile polymerase chain reaction (PCR) is the method of choice because of its higher sensitivity and its applicability to DNA extracted from formalin-fixed tissues. Although this PCR approach appears to be simple, there are many pitfalls, which can lead to false negative or false positive results. In a diagnostic setting, these false clonality results could give rise to a wrong final diagnosis and, as a consequence, to the performance of an inadequate therapy. The reasons for the non-detectability of clonal B-cell or T-cell populations or for the detection of false clonality (e.g. clonal rearrangement pattern in the absence of a lymphoma) are manifold. In the following the most frequent reasons are discussed and recommendations are given to avoid false negative and false positive results.

B-Lymphocytes↗
PubMed1998

Amelogenin dosage compensation in carcinoma of colon, lung, liver and kidney, is not a marker of clonality in males.

The analysis of patterns of X-chromosome inactivation is becoming increasingly utilized as a marker of clonal composition of tissues from women. To date, however, no analogous system has been found for the study of clonality in tissue from men. In the current study, the methylation patterns for portions of the amelogenin genes are tested, which are encoded on both the X- and Y-chromosome (AMGX and AMGY). The polymerase chain reaction (PCR) was used to amplify portions of AMGX and AMGY from genomic DNA of carcinomas of the colon, lung, liver and kidney, as well as from matched normal somatic tissues. The amplification target included Alu I methylation sensitive restriction endonuclease sites as well as a 189 bp sequence which is present in AMGX but is absent in AMGY. Polymerase chain reaction amplification of AMGX and AMGY was successful using genomic DNA from both tumour and normal control tissue in 24 of the 26 cases. Pretreatment of genomic DNA with Alu I blocked amplification of AMGX in all cases from both normal tissue and tumour. This indicates that AMGX and AMGY undergo a non-random pattern of methylation in both normal tissues and in tumours, precluding their use as a marker of clonality. Methylation of Alu I sites in AMGY suggests that the amelogenin genes undergo dosage compensation, which raises the possibility that the expression of amelogenin is not restricted to the development of the tooth bud but may also play some other role in various tissues of the body.

Adenocarcinoma↗
PubMed2006

Phenotypic variation during cloning procedures: analysis of the growth behavior of clonal cell lines.

The production of recombinant protein from mammalian cells is a key feature of the biotechnology industry. However, the generation of recombinant mammalian cell lines is still largely performed on an empirical basis and there are many potential areas for enhancement. We have shown previously that despite two rounds of limiting dilution cloning (LDC) of recombinant cell lines, there remained a high degree of heterogeneity in the resulting cell lines. We suggested that a rapid phenotypic drift occurred with these cells. It was unclear if this was a consequence of the added burden of production of a recombinant protein, the selection procedures, or merely an inherent feature of cell growth in culture. To address this, we have subjected untransfected (parental) cells to three successive rounds of LDC and monitored the growth properties of the resultant cells. The results show that despite repeated rounds of cloning, it was not possible to obtain phenotypically similar cell lines. We also demonstrated that this phenotypic drift is not due to gross changes in the protein p27, a key regulators of the cell cycle. Although cells with a range of growth properties were observed even after three rounds of cloning, the variation in growth patterns between cell lines decreased after cloning. Hence, we suggest that by cloning it may be possible to generate untransfected cells, which have particular growth properties. Starting with a well-defined population of parental cells may aid in the subsequent generation of tranfectants with desired growth properties.

Animals↗
PubMed1989

Molecular analysis of original antigenic sin. I. Clonal selection, somatic mutation, and isotype switching during a memory B cell response.

To determine how the memory B cell population elicited to one epitope might be used in immune responses to other, structurally related epitopes, we explored the phenomenon of original antigenic sin. Strain A/J mice reproducibly respond to immunization with p-azophenylarsonate (Ars) by production of anti-Ars antibodies encoded predominantly by a single VH gene segment (VHIdCR). The structural analogue of Ars p-azophenylsulfonate (Sulf) fails alone to elicit such V regions, but can do so in A/J mice previously immunized with Ars, providing a means to specifically examine B cells capable of responding secondarily to a crossreactive antigen (i.e., memory cells). VHIdCR-expressing hybridomas were derived from the Ars-primed, Sulf-boosted original antigenic sin response of A/J mice at various times after Ars priming, and the properties of the antibodies they express and the structure of the genes encoding these antibodies were characterized. The data obtained support the following conclusions: (a) The Ars-induced memory B cell population capable of being crossreactively stimulated by Sulf is largely formed from a small fraction of all B cells participating in the anti-Ars primary response that express somatically mutated V regions; (b) the antibody repertoire and clonal composition of this population are stable over long periods of time; (c) memory B cells are capable of clonal expansion in the absence of a high rate of V gene somatic mutation; (d) the activation requirements for clonal selection of memory, versus naive B cells appear to differ; and (e) a major fraction of Ars-induced memory B cells express either IgM or IgG3 prior to and during the initial stages of the sin response.

Animals↗
PubMed1985

Clonal stability and heterogeneity of hybridomas: analysis by multiparameter flow cytometry.

Flow cytometry of cellular DNA and RNA content was employed to determine DNA ploidy, proliferation, and RNA content of hybridoma cultures shortly after cell fusion and sequentially thereafter. The parental mouse myeloma cell line P3UI was characterized by tetraploid DNA content, S-phase 50%, and high RNA, the parental mouse spleen cells by diploid DNA content, low proliferation, and low RNA content. Hybridoma cultures studied as early as 21 days after fusion were found to contain the sum of the parental cells' DNA content (hexaploid), or if less, more than that of the myeloma parental cells. Only one clone of 35 tested was shown to be hexaploid and the rest hypertetraploid or hyperpentaploid. Hybrid cell cultures were frequently found to contain a variable mixture of unfused parental cells. The high proliferation of hybridoma cells determined by flow cytometry indicates that these cells would eventually overgrow the parental cells. Flow cytometry also enabled an accurate estimation of the effect of various doses of dexamethasone added to HAT medium immediately after cell fusion on hybridoma formation. Cultures treated with 10(-5) mM of the hormone had a higher DNA ploidy than cultures grown in the presence of 10(-3) mM dexamethasone. No parental cells were observed in the hybridoma cultures studied with this hormone. Sequential DNA/RNA measurements of hybridoma clones showed a decrease in DNA ploidy over time with high dexamethasone doses and a minimal increase or no change with low hormone dose. Flow cytometry is suggested to be a useful technique for evaluating the effects of various agents on DNA ploidy and proliferation and on stability of fused cells.

Animals↗
PubMedDate not supplied

Clonal structure of Trypanosoma cruzi Colombian strain (biodeme Type III): biological, isoenzymic and histopathological analysis of seven isolated clones.

The clonal structure of the Colombian strain of Trypanosoma cruzi, biodeme Type III and zymodeme 1, was analyzed in order to characterize its populations and to establish its homogeneity or heterogeneity. Seven isolated clones presented the basic characteristics of Biodeme Type III, with the same patterns of parasitemic curves, tissue tropism to skeletal muscle and myocardium, high pathogenicity with extensive necrotic-inflammatory lesions from the 20th to 30th day of infection. The parental strain and its clones C1, C3, C4 and C6, determined the higher levels of parasitemia, 20 to 30 days of infection, with high mortality rate up to 30 days (79 to 100%); clones C2, C5 and C7 presented lower levels of parasitemia, with low mortality rates (7.6 to 23%). Isoenzymic patterns, characteristic of zymodeme 1, (Z1) were similar for the parental strain and its seven clones. Results point to a phenotypic homogeneity of the clones isolated from the Colombian strain and suggest the predominance of a principal clone, responsible for the biological behavior of the parental strain and clones.

Animals↗
PubMed1994

In situ hybridization analysis of lymphoproliferative disorders. Assessment of clonality by immunoglobulin light-chain messenger RNA expression.

Determination of clonality in B-cell lymphomas is a useful diagnostic adjunct. In situ hybridization (ISH) for the detection of kappa and lambda mRNAs has the potential to overcome some common specimen-related limitations in clonal assessment. Tritium-labeled antisense cRNA probes directed at conserved segments of the constant regions of the kappa and lambda mRNAs were used in an autoradiographic method to detect B-cell clonality. Using these probes, we analyzed 103 formalin-fixed, paraffin-embedded biopsy samples, and the results were subsequently compared to available immunophenotypic (all cases) and genotypic (50 cases) data. Of 103 samples, 82 (80%) had adequate RNA preservation as determined by actin RNA signals, and 73 (89%) of the 82 cases demonstrated concordant clonality assignment by both ISH and immunophenotyping. The remaining nine cases showed a specific form of discordance in that each exhibited no protein (Ig) expression but had evidence of mRNA immunoglobulin light-chain expression. Forty-five (90%) of 50 cases evaluated for immunoglobulin and T-cell receptor beta-gene rearrangements demonstrated concordant results with respect to clonality assignment by ISH. Thus, ISH demonstrates adequate sensitivity with respect to traditional methods of clonality assessment. However, its practical utility awaits the development of nonradioactive detection methods with adequate sensitivity to improve turnaround time.

Gene Rearrangement↗
PubMed2001

Denaturing HPLC for identification of clonal T-cell receptor gamma rearrangements in newly diagnosed acute lymphoblastic leukemia.

BACKGROUND: Denaturing HPLC (DHPLC) can be used to screen DNA for known and unknown mutations. We describe a novel, HPLC-based method for discrimination among polyclonal, oligoclonal, and/or clonal T-cell receptor gamma (TCR-gamma) rearrangements in samples from children with newly diagnosed acute lymphoblastic leukemia. METHODS: TCR rearrangements were PCR amplified from initial leukemic samples and, after heteroduplex-induction, the clonality status of each product was evaluated. To attain this, we used DHPLC on a high-resolution micropellicular matrix. Running conditions were established by melting-curve analysis of known clonal and polyclonal products and melting-point prediction software. Elution profiles were studied at 50 degrees C (native) and, to achieve optimal separation, at different column temperatures between 56 and 64 degrees C. RESULTS: For VgammaI-Jgamma1.3/2.3 rearrangements, an analysis temperature of 60 degrees C with a linear triethylammoniumacetate-acetonitrile gradient separated clonal bands from the polyclonal background amplification. Less than 15% clonal PCR product was detectable in mixtures of initial leukemic cell DNA and polyclonal DNA. Biallelic rearrangements produced two sharp peaks. Clonality of PCR products from 100 initial leukemic samples was completely identified in all investigated cases. CONCLUSIONS: Heteroduplex analysis with standardized DHPLC conditions simplifies the detection of unknown clonal or polyclonal TCR rearrangements in newly diagnosed leukemias. Clonal targets for detection of minimal residual disease are available after a short, automated analysis of PCR amplified rearrangements.

Base Sequence↗
PubMed1986

[Rearrangements of immunoglobulin and T-cell-antigen receptor genes as diagnostic markers in lymphatic neoplasms].

During recent years cloning of the genes encoding the immunoglobulin (Ig) and T-cell (TCR) antigen receptor has made it possible to analyze clonal expansions of B- or T-cells at the molecular level. We here describe the usefulness of the Ig- and TCR-gene rearrangements in selected cases of malignant lymphoma. In contrast to all other cases investigated, one non-Hodgkin's lymphoma (NHL) exhibited the infrequent phenomenon of oligoclonality, i.e. three distinct B-cell clones were discerned by Southern blot analysis. Detection of clonal TCR- and Ig-gene rearrangements unequivocally documented bone marrow involvement in four of eight NHL-patients, where conventional histologic and cytologic examination remained inconclusive. As expected, analysis of bone marrow DNA revealed clonal Ig-gene rearrangements in three cases with clear histologic evidence of bone marrow infiltrations by the NHL. In one case of a patient with acute mixed lymphoid-myeloid lineage leukemia a previously identified clonal Ig-gene rearrangement vanished after successful chemotherapy. Analysis of Ig- and TCR-gene rearrangements promises to be a very useful diagnostic tool in selected cases of lymphoid neoplasia.

Acute Disease↗
PubMed1996

Cytogenetic studies on fine-needle aspiration samples from osteosarcoma and Ewing's sarcoma.

The preoperative multidrug chemotherapy of osteosarcoma and Ewing's sarcoma patients requires a reliable diagnosis. There are several advantages with obtaining the diagnosis by fine-needle aspiration (FNA) and cytologic examination. Although cytologic criteria have been defined, adjunctive methods such as cytogenetic analysis are valuable to support the diagnosis. We have cytogenetically analyzed FNAs from 18 primary bone sarcomas (six osteosarcomas and 12 Ewing's sarcomas). Two of the osteosarcomas showed abnormal, complex karyotypes seen in most highly-malignant osteosarcomas. Seven Ewing's sarcoma aspirates displayed abnormal karyotypes; five of these had the characteristic 11;22 translocation, and in one of these cases molecular genetic analysis revealed the hybrid EWS/FLI1 transcript. Since only two of six osteosarcomas showed clonal changes, chromosomal analysis of FNAs from suspected osteosarcoma seems to be of limited value, but may in some cases support the diagnosis of high-grade malignancy. In Ewing's sarcomas, however, the finding of an 11;22 translocation was valuable and strongly supported the cytologic diagnosis. As shown in one case, the material obtained by FNA is sufficient for cytologic, cytogenetic, and molecular genetic analysis.

Adolescent↗
PubMed1994

An alternative approach to the assessment of gamma delta T-cell clonality in celiac disease intestinal lesions through cDNA heteroduplex analysis of T-cell receptor VJ junctions.

We have investigated the clonality of the gamma delta T lymphocytes infiltrating the intestinal mucosa of CD patients and control subjects by means of a simple and powerful method based on the heteroduplex analysis of the TCR VJ junctions. Each V-specific TCR chain, amplified either from fresh biopsy material or intestinal T-cell-line cDNA, is denatured and renatured to allow the random reshuffling of the various strands carrying different junctional sequences, coamplified in the same reaction. The mismatched chains (heteroduplexes) are separated from the matched ones (homoduplexes) through polyacrylamide gel electrophoresis, and whenever one or more T-cell clones are emerging over the polyclonal background, discrete bands are visible by ethidium-bromide staining. Through this method, we have estimated the diversity of the V delta 1-3 chains and a newly described V gene (V delta 8) whose homologue in mice is abundantly expressed in gamma delta iLs. We demonstrate that the well-documented expansion of V gamma 1+ gamma delta lymphocytes in the jejunum of CD patients is polyclonal. Overall, the heteroduplex analysis on fresh intestinal and peripheral blood lymphocytes from both healthy and affected subjects shows a polyclonal pattern of all the V delta+ subsets. In contrast, most intestinal T-cell lines produce oligoclonal patterns, suggesting a dramatic in vitro selection effect. The cell expansion in culture is generally not required for the TCR heteroduplex analysis, which can therefore be applied to rapidly monitor the T-cell response in a variety of physiologic and autoimmune reactions, substituting the standard approach of TCR cloning and multiple VJ sequencing.

Adolescent↗
PubMed2003

Improved sensitivity of T-cell clonality detection in mycosis fungoides by hand microdissection and heteroduplex analysis.

BACKGROUND: The presence of a dominant T-cell clone is an important diagnostic criterion in cutaneous T-cell lymphomas (CTCLs) and in atypical T-cell cutaneous infiltrates. Procedures based on polymerase chain reaction (PCR) are the most sensitive to detect clonality, but heteroduplex analysis is less sensitive than other methods such as denaturing gradient gel electrophoresis. OBJECTIVE: To assess whether a gross hand microdissection of the superficial (papillary) portion of the dermal infiltrate may improve the sensitivity of T-cell clonality detection by PCR-heteroduplex analysis in CTCL. SETTING: Regional university hospital (secondary or tertiary referral center). Patients A total of 29 patients with a definite diagnosis of mycosis fungoides based on typical histologic and immunophenotypic features were selected with patch (16) or plaque (13) stages. MAIN OUTCOME MEASURES: Assessment of T-cell clonality by PCR amplification of the T-cell receptor gamma chain followed by heteroduplex analysis using DNA extracted from the entire biopsy specimen and after gross microdissection of the subepidermal bandlike dermal infiltrate. RESULTS: T-cell clonality was demonstrated in 24 of 29 cases when hand microdissection was used compared with 16 of 29 cases with DNA analysis from entire biopsy specimens; thus, hand microdissection resulted in a sensitivity improvement of approximatively 50%. CONCLUSIONS: Hand microdissection substantially improves the detection of a T-cell clone in CTCL when using a PCR-heteroduplex analysis and could be used routinely in the clinical evaluation of T-cell infiltrates. Importantly, the microdissection method was found to be more useful for the detection of T-cell clones in early patch stages of CTCL than in plaque-stage disease.

Clone Cells↗