Benign Inflammatory Dermatoses Research Articles

Low CD7 expression in benign and malignant cutaneous lymphocytic infiltrates: experience with an antibody reactive with paraffin-embedded tissue.

Loss of CD7 expression by neoplastic lymphocytes is considered a distinguishing characteristic of mycosis fungoides (MF) and cutaneous T-cell lymphoma. Reports to date examining for the CD7 immunophenotype in MF have been performed on fresh-frozen tissue. In this study, we used a paraffin-reactive antibody directed against CD7 to determine its range of expression in MF and to compare these results with those in controls. Examining 22 cases of MF and 61 controls, we found minimal CD7 expression by lymphocytes in MF and in a few cases of benign inflammatory dermatosis (BID). The lowest mean CD7 counts (as a percentage of total lymphocytes) were found in MF (patch stage: 5% +/- 5%, range: 0-10; plaque and tumor stages: 15% +/- 5%, range: 5-25), and these counts were significantly lower than those for BID (35% +/- 20%, range: 5-80; p = 0.001). By logistic regression analysis, low CD7 expression (<10% lymphocytes labeling) had sensitivity and positive predictive values of 80% and 72%, respectively, and specificity and negative predictive values of 93% and 96%, respectively, for the diagnosis of patch stage MF. False-positive results were found for spongiotic dermatitis. Moreover, spongiotic dermatitides exhibited a progressive decrease in mean CD7 counts from acute to subacute to chronic stages (50% versus 35% versus 30%, respectively). In conclusion, minimal CD7 expression is a specific finding for MF. Benign inflammatory infiltrates can also show low CD7 expression, however, which rarely matches that of patch stage MF. Progressive loss of CD7 expression in BID is the likely consequence of expansion of antigen-selected CD3+CD4+CD7- T cells. These inflammatory CD4+CD7- T cells may represent the physiologic counterpart to the neoplastic lymphocyte of MF.

A new monoclonal anti-CD7 antibody reactive on paraffin sections.

CBC.37 monoclonal antibody (mAb) was generated using balb/c mice immunized with CEM T cell line. It was selected because of its strong reactivity on T lymphocytes on paraffin tissue sections. The anti-CD7 specificity of CBC.37 mAb was assessed by immunohistochemistry, cross-blocking, and cross-immunoprecipitation experiments using CBC.37 and the anti-CD7 mAb DK24. CBC.37 mAb immunoprecipitated a 40-kDa protein. Cross-blocking and cross-immunoprecipitation experiments demonstrated that the two antibodies recognized the same molecule. Immunostaining of a large number of reactive lymph nodes and B and T cell lymphomas confirms that CBC.37 mAb was directed against T cells. As expected, on reactive lymph nodes the staining pattern was comparable to that of CD3. Among the 110 T cell lymphomas examined, all T lymphoblastic lymphomas were positive (15+/15; 100%). As a result of the frequent loss of CD7 antigen, only 25+/95 (26%) of peripheral T cell neoplasms were found to be positive for CBC.37. A marked reduction in the number of CBC.37-positive T cells was observed in 7 of the 60 cases of benign inflammatory dermatoses studied (approximately 12%). CBC.37 was unreactive with all healthy and neoplastic non-lymphoid samples examined. Because the lack of CD7 expression in T cell lymphomas is of diagnostic value, CBC.37 mAb in association with other anti-T cell antibodies working on paraffin sections could be of particular value in asserting the diagnosis of T cell lymphomas in routine histopathology.

Reassessment of Lymphocytic Atypia in the Diagnosis of Mycosis Fungoides

The manifestations of mycosis fungoides in its early stage may mimic clinically and histologically those of many benign inflammatory dermatoses. Therefore, the diagnosis of mycosis fungoides remains a major challenge for dermatologists and dermatopathologists. For many years, it has been proposed that atypical lymphocytes within the epidermis constitute one of the diagnostic features in mycosis fungoides. Presence of dermal atypical lymphocytes remains controversial as a diagnostic criterion. We reassessed the feasibility of applying lymphocytic atypia within epidermis and dermis as diagnostic criteria discriminating between mycosis fungoides and spongiotic dermatitis. Thirty cases of mycosis fungoides and 30 cases of spongiotic dermatitis were retrieved from archival hematoxylin and eosin-stained histologic sections. Punch biopsy sections were examined by light microscopy; epidermal and dermal lymphocytes were photographed at 1000 × (oil immersion). A total of 92 ektachrome slides (35 mm) were developed, coded, and ordered randomly. For each slide, cells were interpreted as typical or atypical lymphocytes by seven pathologists. Atypical epidermal lymphocytes were judged to be present in 9 ± 2 out of 16 (56%) cases of mycosis fungoides photographed as compared with 8 ± 3 out of 16 (50%) in spongiotic dermatitis. Dermal lymphocytic atypia was thought to be present in 14 ± 6 out of 30 (47%) patients with mycosis fungoides. Thirteen ± 6 out of 30 (43%) patients with non-mycosis fungoides also displayed dermal lymphocytic atypia. No statistical significance was observed in these comparisons (t test, P > .05). Furthermore, atypia of lymphocytes was deemed to be present in 41, 38, 59, 70, 23, 47, and 40 out of 92 slides examined by the investigators, suggesting that observer variation is a very significant factor in our present study. We conclude that it is not possible to distinguish mycosis fungoides from spongiotic dermatitis merely based on lymphocytic atypia within epidermis or dermis.

Comparison of T-lymphocyte proliferation in canine epitheliotropic lymphosarcoma and benign lymphocytic dermatoses.

The lesions of patch/plaque cutaneous T-cell lymphosarcoma (CTCL) are similar to many benign inflammatory dermatoses, both histopathologically and clinically. In humans, attempts to develop a simple, reliable immunophenotypic technique to differentiate between the malignant and benign dermatoses have been unsuccessful. The purpose of our study was to determine, using a proliferating cell nuclear antigen (PCNA)/CD3 double immunolabelling technique of paraffin-embedded sections, if the rate of T-cell proliferation in canine CTCL was greater than that of other diseases with non-neoplastic lymphocyte epitheliotropism. We selected cases of patch/plaque (PP) and tumour stage CTCL, erythema multiforme (EM) and cutaneous lupus erythematosus (CLE). We did not find a significant difference in the rate of T-cell proliferation in the epithelia nor the superficial dermis between PP-CTCL and EM. Whereas epithelial T-cell proliferation is significantly higher in PP-CTCL than CLE, it is not diagnostically useful because of overlap in the labelling indices.

Detection of TCR-gamma gene rearrangements in early mycosis fungoides by non-radioactive PCR-SSCP.

Early mycosis fungoides (MF) can mimic numerous benign inflammatory dermatoses on routine histological examination. In this study, a recently developed non-radioactive polymerase chain reaction-single strand conformational polymorphism (PCR-SSCP) technique was used to assess T-cell clonality in paraffin-embedded skin biopsies clinically and pathologically suspicious for early MF. Non-radioactive PCR-SSCP is a simple, sensitive, reproducible and rapid procedure requiring minimal instrumentation. DNA was extracted from 22 skin biopsies of 20 patients with suspected patch stage MF and 15 skin biopsies of inflammatory dermatoses. V gamma1-8, V gamma9, V gamma10, V gamma11 and J gamma1/J gamma2 consensus primers were used for T-cell receptor (TCR)-gamma gene rearrangement amplification. PCR products were analyzed by non-radioactive SSCP. Clonal TCR-gamma gene rearrangements were detected in 17 of 22 (77%) suspected MF specimens. Clonal SSCP banding patterns were different among individual patients. In addition, identical banded patterns were demonstrated in serial skin biopsies from the same patient. No dominant T-cell clones were found in the inflammatory dermatoses studied. Therefore, non-radioactive PCR-SSCP is a useful molecular diagnostic tool for assessment of T-cell clonality in paraffin-embedded specimens suspicious for early MF. The SSCP imprint of PCR products is specific for each TCR-gamma gene rearrangement, and may be used to evaluate concurrent/recurrent disease in individual patients.

Immunophenotyping and T-cell receptor γ gene rearrangement analysis as an adjunct to the histopathologic diagnosis of mycosis fungoides

Background: The histopathologic diagnosis of mycosis fungoides (MF) may be difficult. Objective: Our purpose was to evaluate the role of immunophenotyping and T-cell receptor (TCR) gene rearrangement studies as an adjunct to the histopathologic diagnosis of MF. Methods: Immunohistochemical studies with antibodies to CD4, CD5, CD7, and CD8 and TCR γ gene rearrangement analysis with a polymerase chain reaction were performed on fresh-frozen material of patients with “classic” histology of MF, “inconclusive” histology, and benign inflammatory dermatoses. Results: Clonal TCR γ gene rearrangements were found in 11 of 16 (69%) of classic MF cases, in 3 of 19 (16%) of inconclusive cases, and in none of the 12 inflammatory dermatoses cases ( P < .05 and P < .001, respectively). Only the mean CD7 counts were statistically significantly different between these 3 groups (MF < inconclusive < inflammatory). Conclusion: Inconclusive histology is probably a heterogeneous group in which CD7 counts and TCR γ gene rearrangement studies might help to differentiate the MF cases from the benign cases. (J Am Acad Dermatol 1998;39:554-9.)

Subcutaneous granuloma annulare: radiologic appearance.

Granuloma annulare is an uncommon benign inflammatory dermatosis characterized by the formation of dermal papules with a tendency to form rings. There are several clinically distinct forms. The subcutaneous form is the most frequently encountered by radiologists, with the lesion presenting as a superficial mass. There are only a few scattered reports of the imaging appearance of this entity in the literature. We report the radiologic appearance of five cases of subcutaneous granuloma annulare. The radiologic images of five patients (three male, two female) with subcutaneous granuloma annulare were retrospectively studied. Mean patient age was 6.4 years (range, 2-13 years). The lesions occurred in the lower leg (two), foot, forearm, and hand. MR images were available for all lesions, gadolinium-enhanced imaging in three cases, radiographs in four, and bone scintigraphy in one. Radiographs showed unmineralized nodular masses localized to the subcutaneous adipose tissue. The size range, in greatest dimension on imaging studies, was 1-4 cm. MR images show a mass with relatively decreased signal intensity on all pulse sequences, with variable but generally relatively well defined margins. There was extensive diffuse enhancement following gadolinium administration. The radiologic appearance of subcutaneous granuloma annulare is characteristic, typically demonstrating a nodular soft-tissue mass involving the subcutaneous adipose tissue. MR images show a mass with relatively decreased signal intensity on all pulse sequences and variable but generally well defined margins. There is extensive diffuse enhancement following gadolinium administration. Radiographs show a soft-tissue mass or soft-tissue swelling without evidence of bone involvement or mineralization. This radiologic appearance in a young individual is highly suggestive of subcutaneous granuloma annulare.

Detection of clonal T-cell receptor γ 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) g 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 γ 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 γ 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 γ 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.(J Am Acad Dermatol 1998;38:453-60.)

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.

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.

Thy-1 and T-Cell Receptor Antigen Expression in Mycosis Fungoides and Benign Inflammatory Dermatoses

We have studied human Thy-1 and T-cell receptor (TCR) antigen expression in mycosis fungoides and benign inflammatory dermatoses. The study included 24 biopsy specimens from 21 patients with mycosis fungoides (nine patch stage from eight patients, 13 plaque stage from 11 patients, and two tumor stage from two patients), six specimens from five patients with premycotic parapsoriasis (pre-mycosis fungoides), three specimens from three patients with lichen planus, 11 specimens from 11 patients with lupus erythematosus, 13 specimens from 13 patients with dermatitis, six specimens from six patients with drug eruptions, nine normal skin specimens from nine subjects, and three specimens from three patients with small plaque (benign) parapsoriasis. Immunoperoxidase studies using the avidin-biotin complex technique on serial frozen sections were performed. Primary antibodies were anti-human Thy-1, anti-alpha heterodimer of the TCR, anti-beta heterodimer of the TCR, and anti-delta heterodimer of the TCR. An extensive dendritic network of Thy-1+ cells was seen in all cases of mycosis fungoides. Epidermotropic cells were Thy-1 negative, and Thy-1 was expressed perivascularly in normal individuals and patients as previously reported. Epidermal gamma/delta cells were seen only in mycosis fungoides, where up to 60% of the epidermal lymphocytes expressed this TCR. The increased numbers of Thy-1 and gamma/delta T cells in mycosis fungoides were statistically significant when compared with normal skin or benign inflammatory dermatoses. The role of these dendritic dermal Thy-1+ cells and epidermal gamma/delta T cells in mycosis fungoides is unclear. The significant numbers of these potentially immunomodulating cells that were seen suggest that they are involved in the pathogenesis of mycosis fungoides.

Characterization of factor XIIIa positive dermal dendritic cells in normal and inflamed skin.

The immunocytochemical identification and characterization of indigenous dermal dendritic cells (dermal dendrocytes) using a rabbit polyclonal antibody to clotting enzyme factor XIII subunit A (FXIIIa) was carried out on normal and inflamed human cutaneous tissue. The immunophenotype of FXIIIa positive dendritic cells was analysed with a panel of 18 monoclonal antibodies using immunoperoxidase and double immunofluorescence staining techniques. The antibody against FXIIIa detected highly dendritic dermal cells located particularly in the upper reticular and papillary dermis. Double fluorescence microscopy showed that FXIIIa positive cells were bone marrow derived (HLe-I+) and co-expressed monocyte, macrophage or antigen presenting cell markers (HLA-DR+, LFA-I+, HLA-DQ+, OKM5+, Mo I+, Mono-I+, Leu M3+). No labelling was obtained with cell markers for Langerhans cells (CDI), T lymphocytes (CD2), granulocytes (LeuMI) fibroblasts (Te7), intercellular adhesion molecule-I (ICAM-I) or endothelial cells (Factor VIII related antigen). Gamma interferon induced increased expression of HLA-DR and co-expression of ICAM-I on FXIIIa+ dermal dendritic cells in normal skin in organ culture. Moreover, in benign inflammatory dermatoses such as atopic eczema and psoriasis there was an increased number of FXIIIa+, DR+, ICAM-I+ cells in the upper dermis and foci of FXIIIa+ cells in the epidermis closely associated with lymphocytes. FXIIIa positive cells in human skin represent a specific population of bone-marrow dermal dendritic cells, distinct from Langerhans cells, that share some features common to mononuclear phagocytes (monocyte/macrophages). In addition, the detection of HLA-DQ on 48% of FXIIIa+ cells and the lack of OKMI in combination with high OKM5 expression suggests an antigen-presenting cell phenotype.

T cell subset heterogeneity in a series of patients with mycosis fungoides and Sézary syndrome

The diagnostic value of the identification of T cell subsets in skin biopsies from a series of eight patients (clinical stages I-IV) with cutaneous T cell lymphoma (6 with mycosis fungoides and 2 with Sézary syndrome) was determined with an indirect immunoperoxidase technic using commercially available monoclonal anti-T lymphocyte antibodies. Each patient had a mixture of helper and suppressor T cells within both the dermis and the epidermis, although helper T cells predominated approximately 2:1 over suppressor cells in all except two patients. This pattern is not appreciably different from that reported in benign inflammatory dermatoses. One patient with Sézary syndrome who had had an unusually protracted course was found to have a greater number of suppressor cells than helper cells within the epidermis. We conclude that the in situ identification of T cell subsets adds little, if any, diagnostic sensitivity to standard histopathologic methods in cutaneous T cell lymphoma.

Characterization of T-Cell Subpopulations in Skin and Peripheral Blood of Patients with Cutaneous T-Cell Lymphomas and Benign Inflammatory Dermatoses

Using a series of monoclonal antibodies, the distribution of T-cell subpopulations in the skin and peripheral blood was investigated in 21 patients with a cutaneous T-cell lymphoma and 14 patients with benign inflammatory dermatoses, histologically characterized by a bandlike mononuclear infiltrate, e.g., atopic dermatitis, chronic eczema, and lichen planus. In Sezary's syndrome the large majority of the neoplastic cells, both in the skin and the peripheral blood, reacted with Leu-1, Leu-3a, OKT3, OKT4, and TA-1 antisera (T helper/inducer phenotype). The cutaneous infiltrates in mycosis fungoides showed a predominance of Leu-3a + , OKT4 + cells (T helper/inducer phenotype), varying numbers of Leu-2a + , OKT8 + cells (T cytotoxic/suppressor phenotype), and, in contrast to Sezary's syndrome, not only large numbers of nondendritic HLA-DR + cells (probably activated T-cells) but also many dendritic nonlymphoid cells expressing HLA-DR and/or OKT6 antigens, which presumably represent cells of the Langerhans cell/interdigitating reticulum cell series. However, the number of HLA- DR + cells in the peripheral blood was not increased. In the advanced stages of mycosis fungoides a loss of certain T-cell antigens (Leu-1, OKT3, and/or Leu-3a and OKT4) was observed both in the skin and peripheral blood. The distribution of T-cell subsets, OKT6 + and HLA-DR + cells in the skin and peripheral blood of patients with atopic dermatitis and chronic eczema was similar as compared to the early stages of mycosis fungoides. These results indicate that the monoclonal antibodies used in the present study have limited value in discriminating between the early stages of mycosis fungoides and benign inflammatory dermatoses. However, the loss of reactivity with some of these anti-T-cell anti-sera in patients with well-established mycosis fungoides may have prognostic significance.

Production of Sézary-like Cells From Normal Human Lymphocytes

The present study was designed to determine if lymphocytes from healthy humans could be stimulated to assume the morphologic appearance of Sézary-like cells. Lymphocyte-rich populations of cells were incubated for 72 hours with pokeweed mitogen and phytohemagglutinin, both potent cellular mitogens. With light microscopy, differential cell counts performed on 0.5mu epoxy resin-embedded sections showed that 5% to 11% of the lymphocytes had cerebriform nuclei, and were designated as Sézary-like cells. The morphological results were confirmed by electron microscopy. Production of Sézary-like cells from stimulated, normal, human lymphocytes suggests that cells with cerebriform nuclei may represent reactive lymphocytes, and may explain their presence in benign inflammatory dermatoses.