CD7-positive Sézary syndrome with a Th1 cytokine profile

Phenotypical Markers, Molecular Mutations, and Immune Microenvironment as Targets for New Treatments in Patients with Mycosis Fungoides and/or Sézary Syndrome

Primary cutaneous lymphomas encompass a wide spectrum of rare lymphoproliferative disorders originating in the skin, among which, mycosis fungoides (MF) is the most common subtype. The treatment of this disease is based on skin-directed therapies eventually in association with biologic response modifiers in the early phases, whereas in patients with the advanced stages, several therapeutic strategies can be used including mono and/or polychemotherapy and bone marrow transplantation. In recent years, the identification of specific markers (phenotypical, immunological, and molecular) has led to the development of several studies (including two randomized phase III trials). The results of these studies are modifying our therapeutic strategy toward a personalized treatment approach in which the clinical characteristics of the patients and tumor-node-metastasis-blood stage are considered together with the expression of specific markers (i.e., a CD30-positive expression for the use of brentuximab vedotin). This review will provide a comprehensive scenario of the main phenotypical, molecular, and immunological markers related to MF pathogenesis and disease evolution, which could represent the target for the development of innovative effective treatments in this disease.

Alopecia universalis associated with impaired interleukin-4 production and low serum IgE level

A 17-year-old female presented with alopecia universalis, which appeared following widespread eczematous dermatitis. An immunohistochemical study demonstrated that CD8(+) T cells infiltrated into hair follicles with satellite cell necrosis of keratinocytes. The precedence of the autosensitization dermatitis suggested that T cells concerned with the eczematous reaction also attacked hair follicles, or alternatively, that those T cells sequentially activated another population of cytotoxic T cells. We found that she had a continuously low level of serum IgE (<1 units/ml), and this abnormality urged us to investigate interleukin (IL)-4 production of T cells. Although the patient had a normal number of CD4(+) T cells, the production of IL-4, but not IL-10, was profoundly impaired as assessed by a reverse transcriptase polymerase chain reaction analysis, suggesting the possible relationship between the baldness and IL-4 reduction. The autoimmune hair loss might occur via activation of cytotoxic T cells and Th(1) cells as a result of a relief from IL-4 control.

SC5 mAb represents a unique tool for the detection of extracellular vimentin as a specific marker of Sezary cells

Circulating malignant Sézary lymphocytes result from a clonal proliferation of memory/activated CD4(+)CD45RO(+) T lymphocytes primarily involving the skin. Recently, the CD158k/KIR3DL2 cell surface receptor has been identified to phenotypically characterize these cells. We previously described a mAb termed SC5 that identifies an unknown early activation cell membrane molecule. It is expressed selectively by T lymphocytes isolated from healthy individuals upon activation, and by circulating Sézary syndrome lymphocytes. In addition, we found that SC5 mAb was reactive with all resting T lymphocytes once permeabilized, indicating that SC5 mAb-reactive molecule might present distinct cellular localization according to the T cell activation status. In this study, we show for the first time that SC5 mAb recognizes the intermediate filament protein vimentin when exported to the extracellular side of the plasma membrane of viable Sézary malignant cells. We demonstrate that SC5 mAb is unique as it reacts with both viable malignant lymphocytes and apoptotic T cells. As vimentin is also detected rapidly at the cell membrane surface after normal T lymphocyte activation, it suggests that its extracellular detection on Sézary cells could be a consequence of their constitutive activation status. Finally, as a probable outcome of vimentin cell surface expression, autoantibodies against vimentin were found in the sera of Sézary syndrome patients.

Treatment with IFN-γ increases serum levels of Th1 chemokines and decreases those of Th2 chemokines in patients with mycosis fungoides

BACKGROUND

Interferon-gamma (IFN-gamma) is used for the treatment of mycosis fungoides, which is a Th2 neoplasm with elevation of serum Th2 chemokines. Although therapeutic effectiveness of IFN-gamma is caused at least partly by augmented activity of cytotoxic T cells against the tumor cells, its modulation on chemokine production remains unknown.

OBJECTIVE

Alterations in the serum levels of Th1 chemokines, IP-10 and MIG, and Th2 chemokines, TARC and MDC, were examined in mycosis fungoides patients treated with recombinant IFN-gamma.

METHODS

Four patients with mycosis fungoides received intravenous injections of IFN-gamma for 14 or 28 days. On day 0, 7, 14, and 28, sera were obtained from the patients, and the concentrations of TARC, MDC, IP-10, and MIG were measured by ELISA, along with the percentages of peripheral blood Th1 and Th2 cells.

RESULTS

Whereas the levels of TARC and MDC were decreased by IFN-gamma treatment, those of IP-10 and MIG were increased. In particular, the increment of MIG was remarkable. No substantial change of Th1 or Th2 cell number was observed.

CONCLUSION

In IFN-gamma treatment as well as other therapies, TARC may serve as a marker for the disease activity of mycosis fungoides. The dramatic elevation of MIG by IFN-gamma suggests the strong dependency of MIG production on IFN-gamma and the participation of MIG in skin-infiltration of tumoricidal cytotoxic T cells.

Leukoderma associated with Sézary syndrome: a rare presentation

We describe a patient with Sézary syndrome who was initially seen with the rare occurrence of both generalized erythroderma and extensive leukoderma of his lower limbs. Apart from the absence of melanocytes in the leukodermic skin, histopathologic features of both areas were identical, showing an infiltrate of atypical lymphocytes with epidermotropism. This form of Sézary syndrome-associated leukoderma is clinically distinguishable from hypopigmented mycosis fungoides in which hypopigmented lesions are the sole manifestation of the cutaneous T-cell lymphoma.

Unique therapeutic effects of the Japanese-Chinese herbal medicine, Sairei-to, on Th1/Th2 cytokines balance of the autoimmunity of MRL/lpr mice

Sairei-to, one of the Japanese-Chinese herbal medicines has been used for the treatment of various diseases, especially collagen disease and edema in nephrotic syndrome. However, the mechanism of the therapeutic effects remains uncertain. Therefore, we investigated the immunological changes of skin, kidney, spleen cells and serum in autoimmune-prone MRL/lpr, MRL/n and C57BL/6J mice treated with Sairei-to. In MRL/lpr mice treated with Sairei-to, the improvement of proteinuria, reduction in the number of hematoxylin bodies in kidney, and reduced serum levels of blood urea nitrogen were observed. These results indicate that Sairei-to can improve or inhibit the progression of lupus nephritis. The proportion of CD19 and the serum levels of IgG1, which is one of the pathogenesis of lupus dermatoses and lupus nephritis, were significantly reduced in Sairei-to-treated MRL/lpr mice. Therefore, it is suspected that the B cell function was suppressed by Sairei-to. In addition, CD4/8 ratio in spleen cells and the degree of lymphoproliferation in MRL/lpr mice also decreased. Interestingly, IL-4 producing spleen cells were increased significantly by ELISPOT assay, and IFN-gamma mRNA expressions were reduced in Sairei-to-treated MRL/lpr mice. Regarding the Th balance, an imbalance towards Th1 predominance may play a significant role in MRL/lpr mice, and the Th1 axis was suppressed and the Th2 axis became predominant in Sairei-to-treated MRL/lpr mice. On the other hand, Th2 cell type immunoglobulins (IgG1) were suppressed. These results suggested that Sairei-to is potential for impairing shifted Th1/Th2 balance and hypergammaglobulinemia resulting in therapeutic effects.

Variable CD7 expression on T cells in the leukemic phase of cutaneous T cell lymphoma (Sézary syndrome)

CD7, a molecule normally expressed on 90% of normal CD4+ T cells, is often deficient on the malignant T cells of cutaneous T cell lymphoma. To investigate the clinical and biologic implications of CD7 expression, blood lymphocytes from 42 patients with the leukemic phase of cutaneous T cell lymphoma (CD4/CD8 ratio of 10 or more with evidence of a T cell clone in the blood) were analyzed for level of expression of CD7 by flow cytometry. CD7 expression by cells did not clearly segregate into two distinct subgroups that are either CD7 positive or CD7 negative as generally thought; however, nine of 17 patients with a predominantly CD4+CD7+ tumor population on early studies became CD4+CD7- over time whereas the converse situation was not observed. In addition, of three patients with evidence of large tumor cells in the blood coexisting with smaller cells, discordant CD7 expression was observed in one instance. In lymph node specimens, the percentage of cells expressing CD7 and other T cell markers did not correlate with histologic evidence of involvement. CD7 expression on blood lymphocytes also did not correlate with patients' survival nor to serum IgE levels or blood eosinophil counts, a finding suggesting that this marker does not identify functional cell subsets that produce serum interleukin-4 or -5, respectively. We speculate that the level of CD7 expression on malignant T cells may be the effect of sustained antigen stimulation in vivo analogous to what has been proposed to occur with normal T cells during aging.

Crosstalk between tumor T lymphocytes and reactive T lymphocytes in cutaneous T cell lymphomas

We have established several tumor T cell lines, both from the skin and from the blood of a patient with an MHC class II-/class I+, CD4+ cutaneous T cell lymphoma (CTCL). These cell lines, like the initial tumor cells, had a CD3+CD4+CD8- phenotype. We also isolated two cytotoxic T lymphocyte clones from the tumor site of this CTCL patient. These clones displayed a CD4+CD8dim+ (TC5) and CD4+CD8- (TC7) phenotype and mediated a specific MHC class I-restricted cytotoxic activity toward noncultured tumor cells and autologous tumor cell lines. Despite surface expression of Fas on tumor cells and Fas-L induction on TC5 and TC7 cell membrane after coculture with autologous tumor cells, the CD4+ CTL clones did not use this cytotoxic mechanism to lyse their specific target. TC7 used a granzyme/perforin-dependent pathway, whereas TC5 used a TRAIL-dependent mechanism. Quantitative analysis of cytokine mRNA expression indicated that while the tumor cells displayed a Th2-type profile, the CTL clones expressed Th1-type cytokines. Preincubation of TIL clones with autologous tumor cells in a short-term culture induced their activation and subsequent amplification of the Th1-type response, which indicates a direct contribution of the malignant cells in the Th1/Th2 imbalance. However, we found that tumor cells produced high amounts of TGF-beta, which could explain the inhibition of a specific antitumor immune response. Another mechanism to avoid the host immune response was the expression of CD158a, CD158b, p70, and CD94/NKG2A inhibitory receptors by tumor-specific lymphocytes. Finally, we present recent data on new antigen structures expressed both by long-term CTCL lines and uncultured tumor cells.

CD4(+)CD7(-) T cells compose the dominant T-cell clone in the peripheral blood of patients with Sézary syndrome

BACKGROUND

Absence of CD7 antigen expression in T cells defines a subset of normal CD4(+) CD45RO(+) CD45RA(-) memory cells and is furthermore observed in Sézary syndrome (SS).

OBJECTIVE

Our purpose was to identify circulating T-cell clones in patients with SS and to elucidate whether the dominant T-cell clones express the CD7 antigen.

METHODS

Peripheral blood lymphocytes of patients with SS were analyzed by two-color flow cytometry using antibodies to the V beta region of the T cell receptor (TCR) in combination with an antibody to CD7. In addition, T cells were analyzed for TCR-gamma gene rearrangement by polymerase chain reaction (PCR) techniques.

RESULTS

Clonal T-cell expansion was detected in 7 patients with SS by immunostaining of the TCR V beta regions. PCR analysis confirmed the presence of dominant T cell clones. Double-immunostaining revealed that in each case cells of the clonal V beta TCR rearrangement homogeneously express the CD4(+)CD7(-) phenotype. Furthermore, CD4(+)CD7(-) cells express the CD15s antigen but lack expression of CD26 and CD49d.

CONCLUSION

Expansion of clonal T cells strongly correlates with the expansion of CD4(+)CD7(-) T cells in 7 tested patients with SS. This supports our model that a subset of late differentiated, normal CD4(+)CD7(-) memory T cells may represent the physiologic counterpart of Sézary cells. Monitoring of circulating T cells with the CD4(+)CD7(-)CD15s(+)CD26(-)CD49d(-) phenotype proved to be useful for the identification of clonal T cells in patients with SS.

Nonerythrodermic, leukemic variant of cutaneous T-cell lymphoma with indolent clinical course: Th2-type tumor cells lacking T-cell receptor/CD3 expression and coinfiltrating tumoricidal CD8 T cells

As typically represented by Sézary syndrome, the leukemic form of cutaneous T-cell lymphoma (CTCL) mostly exhibits erythroderma. A patient with CTCL had slowly developing skin tumors as well as chronic leukemia. The tumor cell was CD4+ CD7- Th2 cells lacking T-cell receptor/CD3 complex and persistently occupied 27% to 48% of peripheral blood lymphocytes. In skin tumors, only 13% of tumor-infiltrating lymphocytes were malignant cells and substantial numbers of nonmalignant CD4+ or CD8+ T cells and B cells coinfiltrated. CD8+-infiltrating T cells had cytotoxic activity against the malignant T cell. Our case demonstrates the existence of the leukemic form of CTCL presenting with skin manifestation other than erythroderma and parapsoriatic patches. The nonerythrodermic feature and indolent course may be associated with the lack of T-cell receptor/CD3 expression and coinfiltration of a high percentage of nontumor lymphocytes, including tumoricidal CD8+ T cells.

Sarcoidal tissue reaction in Sézary syndrome

Sézary syndrome (SS) is an erythrodermic and leukemic variant of cutaneous T-cell lymphoma (CTCL). Occasionally, the histology of CTCL exhibits evidence of a granulomatous infiltrate in the skin. A case of SS that showed epithelioid granulomas resembling sarcoidosis in the skin and lymph nodes is presented. The clinical course of this patient has been relatively indolent.

Cutaneous T cell lymphoma reactive CD4+ cytotoxic T lymphocyte clones display a Th1 cytokine profile and use a fas-independent pathway for specific tumor cell lysis

We have previously described two cytotoxic T lymphocyte clones isolated from lymphocytes infiltrating a human major histocompatibility complex class II-/class I+, CD4+ cutaneous T cell lymphoma. These clones displayed a CD4+CD8dim+ (TC5) and CD4+ CD8- (TC7) phenotype and mediated a specific major histocompatibility complex class I-restricted cytotoxic activity toward Cou-LB autologous tumor cell line. Our studies were performed to elucidate the mechanism involved in T-cell-clone-mediated cytotoxicity and to determine the cytokine profile of both the lymphoma cell line and specific cytotoxic T lymphocyte clones. The results indicate that, despite surface expression of Fas receptor on Cou-LB and Fas ligand induction on TC5 and TC7 cell membranes, the CD4+ cytotoxic T lymphocyte clones do not use this cytotoxic mechanism to lyse their specific target. The TC7 clone uses instead a granzyme-perforin-dependent pathway. Furthermore, quantitative analysis of Th1 and Th2 cytokine mRNA expression in the cutaneous T cell lymphoma cell line as well as in TC5 and TC7 clones indicated that, whereas the tumor cells display a Th2-type profile (interleukin-4, interleukin-6, and interleukin-10), the cytotoxic T lymphocyte clones express Th1-type cytokines (interferon-gamma, granulocyte macrophage colony stimulating factor, and interleukin-2). In addition, preincubation of the tumor-infiltrating lymphocyte clones with autologous tumor cells induced their activation and subsequent amplification of the Th1-type response. These results indicate a direct contribution of the malignant cells in the Th1/Th2 imbalance observed frequently in cutaneous T cell lymphoma patients and suggest their potential role in depressed cell-mediated immunity. Identification of CD4+ Th1-type cytotoxic T lymphocyte clones, the tumor antigen they recognize, and optimization of their cytokine expression profile should be useful for the design of new immunotherapy protocols in cutaneous T cell lymphoma.

Treatment of T lymphocytes with 8-methoxypsoralen plus ultraviolet A induces transient but biologically active Th1-skewing cytokine production

8-Methoxypsoralen plus ultraviolet A light is suggested to shift T lymphocytes from Th2 to Th1 cells. To clarify this issue, we examined the effects of 8-methoxypsoralen/ultraviolet A on the expression/production of cytokines in peripheral blood mononuclear cells from normal subjects and a Sézary syndrome patient. 8-Methoxypsoralen/ultraviolet A augmented the expression of mRNAs for interferon-gamma and interleukin-2 and reduced those for interleukin-4 and interleukin-10. It seems that this enhancement of Th1 cytokines is caused by increment of cytokine production by Th1 cells but not by conversion of Th2 cells to produce Th1 cytokines. The number of interferon-gamma-secreting lymphocytes was markedly increased in 8-methoxypsoralen/ultraviolet A-treated peripheral blood mononuclear cells 20 h after treatment, whereas that of Th2 cytokine-producing cells was decreased. Accordingly, the amount of interferon-gamma was elevated in culture supernatants from 8-methoxypsoralen-phototreated peripheral blood mononuclear cells, whereas interleukin-4 was significantly reduced. This enhanced production of interferon-gamma, however, was found only until 3 d after 8-methoxypsoralen phototreatment and was declined by 5 d after treatment. Finally, 8-methoxypsoralen/ultraviolet A treatment of T cells regulated their ability to induce keratinocyte CD54 expression. Our results show that 8-methoxypsoralen/ultraviolet A has a transient but biologically active Th1-skewing action in human T cells, suggesting that 8-methoxypsoralen/ultraviolet A exerts a beneficial therapeutic effect on Th2-mediated or Th2-malignant diseases.

Cytokines and cutaneous T-cell lymphomas

Cytokines are considered to be of major importance for the pathogenesis of cutaneous T-cell lymphomas (CTCL). Their impact may result from autocrine, paracrine or endocrine effects. Several investigations demonstrated the overexpression of different cytokines in different CTCL entities. Interestingly, stage-dependent shifts in the cytokine pattern have been observed in mycosis fungoides (MF). There is evidence that the abnormal cytokine expression in CTCL might be responsible for tumor progression, resulting from an enhanced proliferation of the malignant cells and/or the depression of the anti-tumor immune response. Moreover, cytokine loops might explain phenomena like the epidermotropism of malignant cells or eosinophilia and increased plasma levels of IgE, which are present in advanced stages of CTCL. Analysis of the cytokine pattern in CTCL might give the basis for direct therapeutic intervention into the cytokine network as a new therapeutic approach. In this review, the current knowledge regarding cytokines in CTCL is summarized.

Prognostic factors in Sézary syndrome: a multivariate analysis of clinical, haematological and immunological features

BACKGROUND

Sézary syndrome (SS) prognostic factors are not well defined because of the rarity of this disease. The specific goal of this prospective study was to assess by multivariate analysis the predictive value with respect to survival of a series of clinical, haematological and immunological parameters taken at SS diagnosis.

PATIENTS AND METHODS

A cohort of 62 SS patients diagnosed and followed since 1975 was examined, and 51 were included in the multivariate analysis model.

RESULTS

The median survival time was 31 months (range: 1 month-15.7+ years), and the five-year survival rate 33.5%. The following variables were found by univariate analysis to be associated with a poor prognosis at the time of SS diagnosis: previous history of mycosis fungoides (P = 0.013), high number of circulating leukocytes (P = 0.001), Sézary cells (SC) (P < 0.001) and CD4+ cells (P < 0.001), presence of large circulating SC (P < 0.001), above normal range LDH serum levels (P = 0.015), presence of PAS-positive inclusions in the cytoplasm of circulating SC (P < 0.001), high CD4/CD8 ratio (P = 0.004) and a CD7 negative circulating SC phenotype (P < 0.001). Among them, the stepwise multivariate analysis selected as adverse independent prognostic factors: PAS-positive cytoplasmic inclusions (P = 0.001), CD7 negative phenotype (P = 0.018) and presence of large circulating SC (P = 0.045).

CONCLUSIONS

Two low-/high-risk groups have been singled out on the basis of the risk index. Patients with no or one adverse prognostic feature(s) (risk index < or = 1; n = 31) share a slow disease course and a relatively favorable prognosis (five-year survival: 58%); on the other hand, patients with 2 or 3 adverse prognostic feature (risk index > 1; n = 20) are characterized by an aggressive disease course not modifiable by traditional therapies (five-year survival: 5%).

Tumour-specific cytotoxic T lymphocyte activity in Th2-type Sézary syndrome: its enhancement by interferon-gamma (IFN-gamma) and IL-12 and fluctuations in association with disease activity

Sézary syndrome (SzS) is the leukaemic variant of cutaneous T cell lymphoma (CTCL), whose malignant T cells are of the Th2 type in most cases. In this study we investigated the tumouricidal activity of cytotoxic T lymphocytes (CTL) present in peripheral blood of a patient with Th2-type SzS, focusing on the effect of IL-2, IFN-gamma and IL-12 on their cytotoxic activity, and the relationship between their lytic capacity and the patient's clinical course. At four different time points during a 2-month clinical period, CD4+CD7- Sézary cells and CD8+ cells were separated from the patient's circulating cells. CD8+ cells were cultured with chemically attenuated, purified Sézary cells in the presence of IL-2 to develop specific cytotoxicity. The CD8+ cells thus cultured exhibited lytic activity against autologous Sézary cells. Concomitant addition of IFN-gamma or IL-12 exerted a synergistic cytolytic effect with IL-2 on the tumour cells. Cytotoxicity inhibition studies using MoAbs revealed that the cytotoxicity operated in MHC class I-, CD8- and alphabeta T cell receptor-dependent manners. Furthermore, eight CD8+ T cell clones generated from cultured CD8+ cells exhibited a strong cytotoxicity against Sézary cells in an MHC class I-restricted fashion. During the clinical course, the activity of generated CTL and the number of CD8+ cells were inversely correlated with disease activity as assessed by the serum level of lactate dehydrogenase. These findings suggest that CTL down-regulate the growth of malignant T cells in this long-standing disease. Since Th2 cytokines such as IL-4 down-modulate CTL activity, CTL are assumed to be usually suppressed in SzS, whose malignant T cells are of Th2 type. It is likely that the administration of IFN-gamma normalizes this Th2-skewing state, activates CTL, and thus exerts the therapeutic effectiveness in the treatment of CTCL.

Interferons in dermatology. Present-day standard

Since the first clinical trials in the early 1980s with recombinant interferon, it was possible to show for a variety of indications that cytokines, especially interferons, at certain doses and at respective intervals, when applied in combination with other pharmaceutical compounds open new powerful therapeutic possibilities. Worldwide, recombinant interferon is licensed, especially in dermato-oncology, for the indication of HIV-associated Kaposi's sarcoma, cutaneous T-cell lymphoma, and recently for adjuvant therapy of high-risk malignant melanoma. Recombinant interferon is at present not licensed for dermatologic indication (septic granulomatosis). At the end of our century the indication spectrum for interferons as monotherapy and as combination therapy will undoubtedly be extended. Larger and controlled studies will prove the importance of interferons in dermato-oncology as well as in inflammatory and infectious dermatoses. The combination of interferons with standard therapies will surely be of the utmost importance in dermatotherapy.

Sézary syndrome, T-helper 2 cytokines and accessory factor-1 (AF-1)

Mycosis fungoides and the Sézary Syndrome are characterized by clonal accumulation of well differentiated T-helper memory cells in the skin and, in the case of the Sézary Syndrome, also in the blood and lymph nodes. Well known immunological abnormalities in patients with MF and SS include reduced delayed type hypersensitivity, decreased proliferation upon stimulation with mitogens of the peripheral blood mononuclear cells, elevated IgE or IgA serum levels and eosinophilia. These abnormalities can be explained by the predominance of T-helper 2 cytokines. Clonal T-lymphocytes purified from the peripheral blood of SS patients transcribe mainly IL-10 and IL-5. They can be CD7 positive or negative. These clonal T cells express the accessory factor-1 (AF-1) or Interferon gamma receptor beta-chain that is essential for Interferon gamma signalling. These results imply perspectives for new therapeutical approaches, such as IL-12 or chimeric fusion proteins.

Th2 cytokine mRNA expression in primary cutaneous CD30-positive lymphoproliferative disorders: successful treatment with recombinant interferon-gamma

Primary cutaneous CD30 (Ki-1)+ large cell lymphoma (KiL) and lymphomatoid papulosis (LyP) type A are collectively termed as primary cutaneous CD30-positive lymphoproliferative disorders. We examined the cytokine profile of skin-infiltrating cells and the therapeutic efficacy of recombinant interferon-gamma (rIFN-gamma) in primary cutaneous KiL and LyP type A. By reverse transcriptase-polymerase chain reaction, mRNAs for interleukin-4 (IL-4) and IL-10 were detected in the dermis of skin lesions in all cases (three cases of KiL and four cases of LyP). In addition, tissue from one KiL patient transcribed IL-2 and IFN-gamma messages, and one LyP patient showed IL-2 mRNA. In contrast, normal skin from ten healthy donors contained mRNA for IL-2 or IFN-gamma, or both, but not for IL-4. Before the therapeutic trial of rIFN-gamma, the response of skin lesions was assessed by a predictive skin test with local injection of rIFN-gamma (0.5 x 10(6) Japan Reference Units [JRU; 1 JRU roughly corresponds to 4 NIH units]) for 3 consecutive days in two KiL and two LyP patients. Numbers of skin-infiltrating CD30+ cells were decreased, and transcription of mRNA for IL-4 and IL-10 was downregulated after the skin test in one KiL and two LyP cases. One KiL patient showed no histologic response or change in mRNA expression. In the therapeutic trial, rIFN-gamma (total doses of 1.2-4.0 x 10(7) JRU) was administered intravenously (n = 2) or locally (n = 2). In three patients who responded to the skin test, the lesions were objectively improved and the numbers of skin-infiltrating CD30+ cells were markedly decreased after the therapeutic trial. No improvement was observed in one KiL patient who did not respond to the skin test. These findings suggest that the skin-infiltrating CD30+ cells in KiL and LyP have a Th2 cytokine profile and raise the possibility that the administration of rIFN-gamma improves the conditions by inhibiting cytokine mRNA transcription and proliferation of CD30+ cells.