T-cell receptor gene rearrangement studies as a diagnostic tool in lymphoproliferative skin diseases

The growth of our knowledge in T-cell biology, in particular the molecular biology of the T-cell receptor (TCR), has provided a means to molecularly characterize lymphoproliferative diseases of the skin based on the presence or absence of a clonal population of T lymphocytes. TCR gene rearrangement studies, by Southern blot analysis, have aided the investigative dermatologist in gaining insights into the pathogenesis and clonal evolution of lymphoproliferative skin diseases. In addition, the application of TCR gene rearrangement studies as a diagnostic aid in the evaluation of lymphoproliferative skin diseases has been introduced into clinical dermatology. Despite its enormous research value, TCR gene rearrangement studies presently have limited applications as an independent diagnostic tool. However, as our knowledge and experience grows and as the application of new techniques provides us with greater detection sensitivity and specificity, the diagnostic utility of TCR gene rearrangement studies will be enhanced.

Erythroderma and marked atypical lymphocytosis mimicking cutaneous T-cell lymphoma probably caused by phenobarbital

A 56-year-old man had been treated with phenobarbital seven weeks prior to admission. One month after initiation of administration of phenobarbital, fever, skin rash and lymphadenopathy occurred. Nine days later, marked atypical lymphocytosis, eosinophilia and hepatic injury was noticed. The histology of the biopsied skin was indistinguishable from lymphoma. CHOP-therapy was started but the patient was followed without further treatment because of polyclonal T-lymphocytosis. Afterward, clinical and hematologic improvement ensued and he has been well until now, 52 months later. The marked T-lymphocytosis observed in this case is probably a lymphoid leukemoid reaction secondary to hypersensitivity to phenobarbital.

Combined proliferating cell nuclear antigen and morphometric analysis in the diagnosis of cutaneous lymphoid infiltrates

AIMS

To evaluate the use of morphometry in the diagnosis of benign and malignant cutaneous lymphoid infiltrates; and to determine whether the sensitivity of detection of cutaneous T cell lymphoma (CTCL) could be improved by selectively measuring cells expressing proliferating cell nuclear antigen (PCNA).

METHODS

44 archival biopsy specimens were studied. These included cases of CTCL, non-specific chronic dermatitis, lichen planus and lupus erythematosus. PCNA was identified using a standard immunohistological technique. Reactive cells were identified using automatic colour discrimination, and the size and shape were determined interactively. Similar measurements were made on the total dermal lymphocyte population.

RESULTS

There was no significant difference between the proportions of PCNA reactive cells in any of the diseases studied. The PCNA positive lymphocytes in CTCL were larger than those in lupus erythematosus and lichen planus and were more irregular in shape than those in chronic dermatitis. Differences were also seen in the total lymphocyte population. Plotting cell size and shape(fcircle) for PCNA cells together allowed CTCL to be differentiated from the inflammatory disorders with a sensitivity of 80% and a specificity of 93%. This was better than could be achieved using measurements made on the total cell population.

CONCLUSIONS

This technique can be partly automated and could be useful in the differential diagnosis of cutaneous lymphoid infiltrates. The result are also of some interest in the further understanding of patterns of cell proliferation in skin associated lymphoid tissue.

Immunohistological study of skin involvement in Kikuchi’s disease

Five patients with histiocytic necrotizing lymphadenitis (Kikuchi's disease) with erythematous or popular skin lesions were studied. All patients healed naturally within a few months like the patients with no skin involvement. Histological findings for the skin lesions mimicked cutaneous malignant lymphoma. The infiltrated mononuclear cells usually demonstrated positive reactions for Ki-M1p (20-63%), lysozymes (13-54%), MT-1 (18-64%), UCHL-1 (22-39%) and LN2 (17-36%). OPD-4 and L26 positive cells were few in number. These results suggest that the infiltrated cells in a Kikuchi's disease skin lesion are composed of the same components as the affected lesion in the lymph node.

Phenytoin-induced pseudolymphoma. A report of a case and review of the literature

We report a patient with phenytoin-induced pseudolymphoma mimicking cutaneous T-cell lymphoma (CTCL). Despite withdrawal of phenytoin, there was persistence of the cutaneous eruption and lymphadenopathy. Southern blot analysis of immunoglobulin and T-cell receptor genes was therefore used to assess whether there was a clonal lymphoid expansion. However, no rearrangement of the beta T-cell receptor gene or immunoglobulin heavy-chain gene was detected in tissue DNA from skin and lymph nodes. One year later the patient became asymptomatic, although he is still at risk of developing a true malignant lymphoma in the future, a condition known as pseudo-pseudolymphoma. It is suggested that genotypic studies may help in the initial diagnosis and the subsequent management of such patients.

Generalized nodular cutaneous pseudolymphoma associated with phenytoin therapy. Use of T-cell receptor gene rearrangement in diagnosis and clinical review of cutaneous reactions to phenytoin

The first reported case of phenytoin-induced generalized nodular cutaneous pseudolymphoma without symptoms of the phenytoin hypersensitivity syndrome is presented. Despite the malignant histologic appearance of the dermal infiltrate, T-cell receptor gene rearrangement studies did not demonstrate monoclonality. The cutaneous nodules resolved within 2 weeks after discontinuation of phenytoin therapy. The literature is reviewed with regard to the spectrum of cutaneous reactions to phenytoin and particularly with regard to the occurrence of lymphoma, pseudolymphoma, and phenytoin hypersensitivity syndrome. We suggest the use of T-cell receptor gene rearrangement studies in similar situations of phenytoin hypersensitivity syndrome and lymphadenopathy. A brief period of discontinuation of the drug will demonstrate the regression associated with benign lymphoproliferation and will forestall needless treatment.

Correlations of unique clinical, immunotypic, and histologic findings in cutaneous gamma/delta T-cell lymphoma

Cutaneous T-cell lymphoma is a malignancy of T cells that express a clone-specific heterodimer T-cell receptor for antigen. The second recognized case of an epidermotropic malignancy of T-cells expressing gamma/delta T-cell receptor-expressing cells is reported. The immunophenotype of the malignant T-cells was CD3+, CD2+, CD7+, gamma/delta T-cell receptor+, CD4-, CD8-, and alpha/beta T-cell receptor-. The clinical features were remarkable for extreme epidermotropism with a scant dermal lymphomatous infiltrate. Profound keratinocyte necrosis occurred in areas of malignant skin infiltrates. Despite cutaneous lesions covering more than 50% of the skin surface of the patient, no adenopathy or splenomegaly was detected. The intense epidermotropism of this patient's gamma/delta T-cell receptor-expressing cells and the putative cytolytic properties of CD4- CD8- gamma/delta contributed to the destruction of epidermis. Remission was induced with a combination of electron beam and extracorporeal photochemotherapy.

Cutaneous T-cell lymphoma: utility of antibodies to the variable regions of the human T-cell antigen receptor

BACKGROUND

The clonotypic 90 kd Ti heterodimer of the human T-cell antigen receptor is composed of two distinct chains (alpha beta or rarely tau delta) that result from the recombination of variable (V), constant, joining, and, in the case of beta chains, additional diversity regions.

OBJECTIVE

The variable region expression of human cutaneous T-cell lymphoma (CTCL) was studied.

METHODS

Biopsy specimens from 13 patients with CTCL (7 plaque, 3 tumor stage, 3 Sézary syndrome) were examined immunohistochemically by a panel of seven commercially available monoclonal V-region antibodies.

RESULTS

Two patients had significant anti-V-region staining. One patient with Sézary syndrome had two lesions, subjected to biopsy 4 months apart, that reacted with beta V5(a), a specificity previously documented by flow cytometry of leukemic cells. A patient with plaque-stage CTCL, negative for T-cell gene rearrangement by Southern blot, demonstrated reactivity with beta V5(c) largely limited to epidermotropic lymphocytes.

CONCLUSION

Panels of V-region antibodies should be useful reagents for diagnosis and follow-up of CTCL.

A multidisciplinary approach to the diagnosis of cutaneous T-cell lymphomas

The cutaneous T-cell lymphomas (CTCLs) comprise a spectrum of non-Hodgkin lymphomas with a predilection for the skin. This heterogeneous group of CTCLs include the prototypic CTCL mycosis fungoides (MF) and the recently described Ki-1+ lymphomas. MF is notoriously difficult to diagnose in its early stages. The histologic appearance of early MF is indistinguishable from that of chronic dermatitis. The limitations of light microscopy in the diagnosis of the CTCLs have led to the development of other diagnostic laboratory techniques. The best approach to the diagnosis of the CTCLs is a multidisciplinary one and should include ultrastructural morphometry, immunophenotyping, immunogenotyping, and histologic evaluation whenever possible. It is the purpose of this overview to point out the strengths and weaknesses of each of these techniques and, together with clinical input, to provide a comprehensive and rational approach to patient care.

Use of antibodies against the variable regions of the T-cell receptor alpha/beta heterodimer for the study of cutaneous T-cell lymphomas

Recent studies have suggested that antibodies against the variable (V) regions of the T-cell antigen receptor (TCR) may be used as markers for clonality and malignancy in T-cell infiltrates. We have investigated this by examining biopsy samples from 45 patients with cutaneous T-cell lymphomas (CTCL) for reactivity with seven antibodies against different V-gene families on the TCR alpha/beta heterodimer, i.e. ICI (V beta 5a), W112 (V beta 5b), OT145 (V beta 6a), 16G8 (V beta 8a), S511 (V beta 12a), F1 (V alpha 2a) and LC4 (alpha beta Va). Serial biopsies were available in 13 patients and a total of 62 samples were studied. The neoplastic cells in five cases were positive for either V beta 5 (one case), V beta 6 (one case), V beta 8 (two cases) or V beta 12 (one case). In the remaining 40 cases, no staining was seen of the neoplastic cells. These findings indicate that while antibodies against the TCR V-regions may be used as clonotypic markers for certain T-cell neoplasms, there is as yet not a sufficient number of anti-TCR V-region antibodies available for the routine diagnosis of these conditions.

Central nervous system involvement by cutaneous T cell lymphoma

Central nervous system disease in cutaneous T cell lymphoma is uncommon and is usually not considered in standard therapeutic regimens. We report three patients who had cutaneous T cell lymphoma with involvement of the central nervous system and review the cases of 28 such patients reported in the literature. Potential risk factors, the reliability of various diagnostic tests, and potential therapeutic modalities are discussed.

Differential diagnosis of cutaneous large cell lymphomas using monoclonal antibodies reactive in paraffin-embedded skin biopsy specimens

We studied a large panel of monoclonal antibodies reactive on routinely processed paraffin-embedded tissue to determine their sensitivity and specificity in the diagnosis of 35 primary cutaneous large cell lymphomas of B- (n = 14) and T-cell origin (n = 21). The findings show that differentiation between clinically relevant subgroups can be obtained by a small panel of antibodies including L26, MB2, LN1, MT1, UCHL1, and Ber-H2. Pitfalls in the use of the reagents are discussed.

Molecular diagnosis of cutaneous T-cell lymphoma: polymerase chain reaction amplification of T-cell antigen receptor beta-chain gene rearrangements

The goal of our study was to molecularly diagnose CTCL, by cloning the T-cell antigen receptor beta chain (TCR-beta) gene rearrangement from the malignant T cells of a patient with Sézary syndrome, in order to generate a specific oligonucleotide probe capable of detecting CTCL cells through polymerase chain reaction (PCR) amplification. Total RNA isolated from peripheral blood lymphocytes was reverse transcribed and resultant first strand cDNA was PCR amplified utilizing a concensus primer to the TCR-beta variable region (V beta) and a 3' primer to the TCR-beta constant region (C beta). PCR reaction products were subcloned into a plasmid vector and sequenced. Sequence analysis revealed that the patient's in-frame TCR-beta gene rearrangement utilized V beta 6.4, D beta 1.1, J beta 2.2, and C beta 2.1 gene segments. Oligo-primers to V beta 6.4 and J beta 2.2 were utilized to PCR amplify genomic DNA taken from the patient's blood and involved skin. Screening the amplified DNA with an oligo-probe specific for the patient's V-D-J junctional sequences resulted in the detection of the patient-specific sequences. No sequences were detected from DNA from other malignant or benign infiltrates. Thus, we have defined a "molecular fingerprint" specific for a patient's malignant T-cells and can molecularly diagnose CTCL through PCR amplification.