Soluble CD30 correlates with clinical but not subclinical renal allograft rejection.

Soluble CD30 (sCD30) has been proposed as a promising noninvasive biomarker for clinical renal allograft rejection, but its diagnostic characteristics regarding detection of subclinical rejection have not been assessed. We investigated sCD30 in 146 consecutive kidney allograft recipients under tacrolimus-mycophenolate-based immunosuppression having 250 surveillance biopsies at 3 and 6 months as well as 52 indication biopsies within the first year post-transplant. Allograft histology results were classified as (i) acute Banff score zero or interstitial infiltrates only, (ii) tubulitis t1, (iii) tubulitis t2-3 and (iv) isolated vascular compartment inflammation. sCD30 correlated well with the extent of clinical (P < 0.0001), but not subclinical tubulointerstitial rejection (P = 0.06). To determine diagnostic characteristics of sCD30, histological groups were assigned to two categories: no relevant inflammation (i.e. acute Banff score zero and interstitial infiltrates only) versus all other pathologies (tubulitis t1-3 and isolated vascular compartment inflammation). For clinical allograft inflammation, AUC was 0.87 (sensitivity 89%, specificity 79%; P = 0.0006); however, for subclinical inflammation, AUC was only 0.59 (sensitivity 50%, specificity 69%; P = 0.47). In conclusion, sCD30 correlated with clinical, but not subclinical renal allograft rejection limiting its clinical utility as a noninvasive rejection screening biomarker in patients with stable allograft function receiving tacrolimus-mycophenolate-based immunosuppression.

CD30+ lymphoproliferative disorders of the skin: still an open question.

CD30+ lymphoproliferative disorders of the skin represent a well-defined spectrum of primary cutaneous T-cell lymphomas. They include lymphomatoid papulosis and cutaneous anaplastic large-cell lymphoma which are characterized by the common expression of the CD30 antigen, but different clinical, histological and molecular features. Recent progress in the pathobiology and identification of therapeutic targets has contributed to our current understanding of this peculiar group of cutaneous lymphoproliferative disorders. The characteristic features of this group of cutaneous lymphoproliferative disorders are reviewed with particular emphasis to their diagnosis and treatment strategies.

Interference of the CD30-CD30L pathway reduces atherosclerosis development.

OBJECTIVE: Costimulatory molecules tightly control immune responses by providing positive signals that promote T-cell activation or by transducing inhibitory signals that limit T-cell responses. CD30 and CD30L are members of the tumor necrosis factor receptor superfamily and are involved in the activation and proliferation of T and B cells, which have been implicated in the initiation and progression of atherosclerosis. In the present study, we thus aimed to determine the role of the CD30-CD30L pathway in the development of atherosclerosis. METHODS AND RESULTS: Western-type diet-fed low-density lipoprotein receptor-deficient mice were treated with an anti-CD30L antibody for 8 weeks, which resulted in a reduction of atherosclerotic lesion formation in the aortic root by 35%. Reduced numbers of adventitial CD3(+) T cells were found in anti-CD30L-treated mice, whereas no differences were observed in collagen and macrophage content of the atherosclerotic lesions. B-cell and mast cell responses were also not affected on anti-CD30L treatment. Interestingly, splenocyte proliferation was reduced by 53%, whereas T-cell numbers were concomitantly reduced in anti-CD30L-treated mice compared with control mice. These data thus indicate that the CD30-CD30L pathway solely exerts its function via inhibition of T-cell responses. CONCLUSIONS: In the present study, we are the first to show that interruption of the CD30-CD30L pathway reduced initial atherosclerosis development by modulating T-cell function.

Notch is an essential upstream regulator of NF-κB and is relevant for survival of Hodgkin and Reed-Sternberg cells.

A major pathogenetic mechanism in classical Hodgkin lymphoma (cHL) is constitutive activation of canonical nuclear factor-κB (NF-κB) p50/p65 signaling, controlling lymphoma cell proliferation and survival. Recently, we demonstrated that aberrant Notch1 activity is a negative regulator of the B cell program in B cell-derived Hodgkin and Reed-Sternberg (HRS) cells. Despite abundant evidence for a complex context-dependent cross talk between Notch and NF-κB signaling in hematopoietic cells, it is unknown whether these pathways interact in HRS cells. Here, we show that Notch-signaling inhibition in HRS cells by the γ-secretase inhibitor (GSI) XII results in decreased alternative p52/RelB NF-κB signaling, interfering with processing of the NF-κB2 gene product p100 into its active form p52. As a result, expression of Notch and NF-κB target genes is reduced, and survival of HRS cells is impaired. Stimulation of alternative NF-κB signaling in the Hodgkin cell line L540cy by activation of the CD30 receptor rescued GSI-mediated loss of cell viability and apoptosis induction. Our data reveal that Notch is an essential upstream regulator of alternative NF-κB signaling and indicate cross talk between both the pathways in HRS cells. Therefore, we suggest that targeting the Notch pathway is a promising therapeutic option in cHL.

In vitro soluble CD30 levels in patients with chronic stable coronary artery disease.

The CD30 antigen seems to play a costimulatory role in maintaining the physiological balance between T-helper (Th)1/Th2 immune responses. In this study, plasma and in vitro soluble CD30 (sCD30) secretion was investigated in patients with coronary artery disease (CAD) as a plausible marker of dysregulated immune response.Twenty one patients with angiographically confirmed CAD and 31 healthy controls took part in this study. The levels of the activation marker sCD30 were determined in plasma and phytohaemagglutinin (PHA)-stimulated and unstimulated peripheral blood mononuclear cell cultures by ELISA. Plasma sCD30 levels did not differ significantly between the patients and controls. However, spontaneous sCD30 secretion was significantly lower in patients with CAD compared to controls (p < 0.001). The soluble CD30 levels were significantly increased in the supernatant of PHA-stimulated PBMCs compared to unstimulated cultures in both groups of patients and controls (p < 0.001). PHA-stimulated sCD30 secretion was found to be lower in patients compared to controls; however, the difference was not statistically significant. Plasma sCD30 levels were not statistically different in patients with chronic stable CAD, a well-known Th1-mediated disease, compared to controls; whereas decreased spontaneous and PHA-stimulated sCD30 secretion in patients with CAD might indicate the progressive shift towards a Th1 immune response.

Association of a novel functional promoter variant (rs2075533 C>T) in the apoptosis gene TNFSF8 with risk of lung cancer--a finding from Texas lung cancer genome-wide association study.

Published genome-wide association studies (GWASs) have identified few variants in the known biological pathways involved in lung cancer etiology. To mine the possibly hidden causal single nucleotide polymorphisms (SNPs), we explored all SNPs in the extrinsic apoptosis pathway from our published GWAS dataset for 1154 lung cancer cases and 1137 cancer-free controls. In an initial association analysis of 611 tagSNPs in 41 apoptosis-related genes, we identified only 10 tagSNPs associated with lung cancer risk with a P value<10(-2), including four tagSNPs in DAPK1 and three tagSNPs in TNFSF8. Unlike DAPK1 SNPs, TNFSF8 rs2181033 tagged other four predicted functional but untyped SNPs (rs776576, rs776577, rs31813148 and rs2075533) in the promoter region. Therefore, we further tested binding affinity of these four SNPs by performing the electrophoretic mobility shift assay. We found that only rs2075533T allele modified levels of nuclear proteins bound to DNA, leading to significantly decreased expression of luciferase reporter constructs by 5- to -10-fold in H1299, HeLa and HCT116 cell lines compared with the C allele. We also performed a replication study of the untyped rs2075533 in an independent Texas population but did not confirm the protective effect. We further performed a mini meta-analysis for SNPs of TNFSF8 obtained from other four published lung cancer GWASs with 12 214 cases and 47 721 controls, and we found that only rs3181366 (r2=0.69 with the untyped rs2075533) was associated to lung cancer risk (P=0.008). Our findings suggest a possible role of novel TNFSF8 variants in susceptibility to lung cancer.

Primary cutaneous and systemic anaplastic large cell lymphoma: clinicopathologic aspects and therapeutic options.

Anaplastic large cell lymphoma (ALCL) is a biologic and clinically heterogenous subtype of T-cell lymphoma. Clinically, ALCL may present as localized (primary) cutaneous disease or widespread systemic disease. These two forms of ALCL are distinct entities with different clinical and biologic features. Both types share similar histology, however, with cohesive sheets of large lymphoid cells expressing the Ki-1 (CD30) molecule. Primary cutaneous ALCL (C-ALCL) is part of the spectrum of CD30+ lymphoproliferative diseases of the skin including lymphomatoid papulosis. Using conservative measures, 5-year disease-free survival rates are > 90%. The systemic ALCL type is an aggressive lymphoma that may secondarily involve the skin, in addition to other extranodal sites. Further, systemic ALCL may be divided based on the expression of anaplastic lymphoma kinase (ALK) protein, which is activated most frequently through the nonrandom t(2;5) chromosome translocation, causing the fusion of the nucleophosmin (NPM) gene located at 5q35 to 2p23 encoding the receptor tyrosine kinase ALK. Systemic ALK+ ALCLs have improved prognosis compared with ALK-negative ALCL, although both subtypes warrant treatment with polychemotherapy. Allogeneic and, to a lesser extent, autologous stem cell transplantation play a role in relapsed disease, while the benefit of upfront transplant is not clearly defined. Treatment options for relapsed patients include agents such as pralatrexate (Folotyn) and vinblastine. In addition, a multitude of novel therapeutics are being studied, including anti-CD30 antibodies, histone deacetylase inhibitors, immunomodulatory drugs, proteasome inhibitors, and inhibitors of ALK and its downstream signaling pathways. Continued clinical trial involvement by oncologists and patients is imperative to improve the outcomes for this malignancy.

Soluble CD30: a biomarker for evaluating the clinical risk versus benefit of IFNbeta1A treatment in multiple sclerosis patients.

Aberrant redox regulation occurs in immune and neurological pathologies, hence targeting the pathways involved in the regulation of the redox system could provide further insights into these diseases and open up new avenues for therapy. Soluble (s) CD30 is of key clinical importance in this respect, as its levels reflect the functionality of the CD30 receptor (CD30R), the specific lymphocyte receptor for thiol disulfide/oxidoreductase thioredoxin 1 (Trx1) which is known to regulate important immune and neurological processes. Increased levels of sCD30 appear to be a common element of oxidative stress, immunological alterations and neurological deficit, therefore these increases could be used as a clinical biomarker and target for therapy. We targeted sCD30 in our study of dendritic cell (DC) regulation of the T helper (Th) cell network in multiple sclerosis (MS) patients, as abnormalities in T regulatory (Treg)/Th1/Th17 pathways contribute to the pathogenesis of this immunological/neurological disease. DC profiles in Treg/Th1/Th2/Th17-types of cytokine production in culture supernatants were used as they determine the type of Th differentiation. Our results show that sCD30 levels increase significantly in MS patients, reflecting the disruption in the regulation of the Treg/Th1/Th17 cell network. A fall in the level of soluble CD30, induced by IFNbeta1a therapy, opposed the increase of neurological deficit through increasing IL10 and TGFbeta levels, thus re-establishing network homeostasis but only when this was accompanied by an increase in IL12p70 levels. Since IL12p70 cytokine production is regulated by Trx1, our results indicate that redox system alterations may be the cause of IFNbeta1a therapeutic inefficacy. We conclude that an increase in the level of IL10, TGFbeta and IL12p70 and a fall in the level of sCD30 represent a means of evaluating the clinical risk/benefit of IFNbeta1a treatment.

NK cells protect secondary lymphoid tissue from cytomegalovirus via a CD30-dependent mechanism.

The pathogenic outcomes of viral infection are often reminiscent of a dysfunctional immune system. Thus, cytomegalovirus (CMV) causes disruption of the lymphoid architecture and the functionality of lymphocytes, both of which are features of CD30 deficiency. It was therefore plausible that CD30 might interfere with CMV infection. The present study identifies CD30 as an inducible NK-cell receptor critical for innate immunity against CMV. Expression of CD30 integrates survival signals to NK cells that allow them to prevent viral spread and subsequent disintegration of secondary lymphoid tissue. Deficiency in CD30 results in exaggerated NK cell death and complete abrogation of the lymphoid architecture. Our data define the necessity of NK cells for protection of secondary lymphoid organs and describe a mechanism by which this protection is conferred.

Synergistic OX40 and CD30 signals sustain CD8+ T cells during antigenic challenge.

Prior to acquiring a memory phenotype, antigen-activated CD8(+) T cells need to expand and then undergo a contraction phase. Utilizing two different antigenic stimuli, we provide evidence that the tumor necrosis factor receptors OX40 and CD30 integrate synergistic signals during the expansion phase to help maintain CD8(+) effectors. Thus, double deficiency in OX40 and CD30 leads to CD8(+) cell loss during expansion after immunization either with OVA or with murine CMV. Following their contraction, OX40- and CD30-deficient CD8(+) T cells persist normally in CMV-infected mice. In contrast, persistence after OVA challenge is dependent on OX40 and CD30. Collectively, our data define the important role of both OX40 and CD30 during CD8(+) T-cell activation, and show that long-term CD8 persistence after contraction is regulated not only by stimulatory receptors but also by the nature of the antigen or how the antigen is presented.

Different role of CD30 in the development of acute and chronic airway inflammation in a murine asthma model.

CD30 is a costimulatory molecule of the TNF receptor superfamily, expressed on activated T and B cells. Previously, we have shown in a murine asthma model the crucial role of CD30 signaling for the development of this Th2-cell-mediated disease. In the present study, we investigated the role of CD30 in the maintenance of the immune response. In contrast to the acute model, in the chronic model CD30(-/-) mice developed a severe asthma-like phenotype with eosinophilic inflammation and high serum IgE levels. Collagen content, ECM protein deposition and proliferation of smooth muscle cells as signs for airway remodeling were equally increased in both CD30(-/-) and WT mice. Reduced expression of the costimulatory molecule OX40 on CD3(+) T cells in the acute and up-regulation in the chronic model indirectly supported a compensatory role of OX40 for CD30 signaling. In accordance, application of agonistic OX40 antibody restored the asthma phenotype in CD30(-/-) mice in the acute model, whereas chronic airway inflammation was reduced in the presence of an inhibitory anti-OX40 ligand antibody. These data demonstrate that the crucial role of CD30 signaling in the development of acute asthma may be taken over by other costimulatory molecules like OX40 after long-term exposure to the antigen.

T lymphocytes coexpressing CCR4 and a chimeric antigen receptor targeting CD30 have improved homing and antitumor activity in a Hodgkin tumor model.

For the adoptive transfer of tumor-directed T lymphocytes to prove effective, there will probably need to be a match between the chemokines the tumor produces and the chemokine receptors the effector T cells express. The Reed-Stemberg cells of Hodgkin lymphoma (HL) predominantly produce thymus- and activation-regulated chemokine/CC chemokine ligand 17 (TARC/CCL17) and macrophage-derived chemokine (MDC/CCL22), which preferentially attract type 2 T helper (Th2) cells and regulatory T cells (Tregs) that express the TARC/MDC-specific chemokine receptor CCR4, thus generating an immunosuppressed tumor environment. By contrast, effector CD8(+) T cells lack CCR4, are nonresponsive to these chemokines and are rarely detected at the tumor site. We now show that forced expression of CCR4 by effector T cells enhances their migration to HL cells. Furthermore, T lymphocytes expressing both CCR4 and a chimeric antigen receptor directed to the HL associated antigen CD30 sustain their cytotoxic function and cytokine secretion in vitro, and produce enhanced tumor control when infused intravenously in mice engrafted with human HL. This approach may be of value in patients affected by HL.

A novel role of CD30L/CD30 signaling by T-T cell interaction in Th1 response against mycobacterial infection.

A CD30 ligand (CD30L, CD153) is a type II membrane-associated glycoprotein belonging to the TNF family. To illustrate the potential role of CD30L in CD4(+) Th1 cell responses, we investigated the fate of Ag-specific CD4(+) T cells in CD30L-deficient (CD30L(-/-)) mice after Mycobacterium bovis bacillus Calmette-Guérin (BCG) infection. The number of bacteria was significantly higher in organs of CD30L(-/-) mice than in wild-type (WT) mice 4 wk postinfection. The numbers of purified protein derivative- or Ag85B-specific-IFN-gamma-producing-CD4(+) T cells in spleen, lung, or peritoneal exudate cells were significantly fewer in CD30L(-/-) mice than in WT mice. During the infection, CD30L was expressed mainly by CD44(+)CD3(+)CD4(+) T cells but not by CD3(+)CD8(+) T cells, B cells, dendritic cells, or macrophages. Costimulation with agonistic anti-CD30 mAb or coculturing with CD30L-transfected P815 cells restored IFN-gamma production by CD4(+) T cells from BCG-infected CD30L(-/-) mice. Coculturing with CD30L(+/+)CD4(+) T cells from BCG-infected WT mice also restored the number of IFN-gamma(+)CD30L(-/-)CD4(+) T cells. When transferred into the CD30L(+/+) mice, Ag-specific donor CD30L(-/-) CD4(+) T cells capable of producing IFN-gamma were restored to the compared level seen in CD30L(+/+) CD4(+) T cells on day 10 after BCG infection. When naive CD30L(+/+) T cells were transferred into CD30L(-/-) mice, IFN-gamma-producing-CD4(+) Th1 cells of donor origin were normally generated following BCG infection, and IFN-gamma-producing-CD30L(-/-)CD4(+) Th1 cells of host origin were partly restored. These results suggest that CD30L/CD30 signaling executed by CD30(+) T-CD30L(+) T cell interaction partly play a critical role in augmentation of Th1 response capable of producing IFN-gamma against BCG infection.

A critical role of CD30 ligand/CD30 in controlling inflammatory bowel diseases in mice.

BACKGROUND & AIMS: A CD30-ligand (CD30L) is a 40-kilodalton, type II membrane-associated glycoprotein belonging to the tumor necrosis factor family. Serum levels of soluble CD30 increased in inflammatory bowel diseases (IBD), suggesting that CD30L/CD30 signaling is involved in the pathogenesis of IBD. In this study, we investigated the role of CD30L in oxazolone (OXA)- and trinitrobenzene sulfonic acid (TNBS)-induced colitis in CD30L knockout (KO) mice. METHODS: Colitis was induced by OXA or TNBS in CD30LKO mice with BALB/c or C57BL/6 background, respectively, and diverse clinical signs of the disease were evaluated. Cytokine production from lamina propria T cells of the colon was assessed by enzyme-linked immunosorbent assay. Anti-interleukin (IL)-4 monoclonal antibody (mAb) or agonistic anti-CD30 mAb was inoculated in mice with colitis induced by OXA or TNBS. RESULTS: CD30LKO mice were susceptible to OXA-induced colitis but resistant to TNBS-induced acute colitis. The levels of T helper cell 2 type cytokines such as IL-4 and IL-13 in the LP T cells were significantly higher, but the levels of interferon gamma were lower in OXA- or TNBS-treated CD30LKO mice than in wild-type mice. In vivo administration of agonistic anti-CD30 mAb ameliorated OXA-induced colitis but aggravated TNBS-induced colitis in CD30LKO mice. CONCLUSIONS: These results suggest that CD30L/CD30 signaling is involved in development of both OXA- and TNBS-induced colitis. Modulation of CD30L/CD30 signaling by mAb could be a novel biologic therapy for IBD.

Critical synergy of CD30 and OX40 signals in CD4 T cell homeostasis and Th1 immunity to Salmonella.

CD30 and OX40 (CD134) are members of the TNFR superfamily expressed on activated CD4 T cells, and mice deficient in both these molecules harbor a striking defect in the capacity to mount CD4 T cell-dependent memory Ab responses. This article shows that these mice also fail to control Salmonella infection because both CD30 and OX40 signals are required for the survival but not commitment of CD4 Th1 cells. These signals are also needed for the survival of CD4 T cells activated in a lymphopenic environment. Finally, Salmonella and lymphopenia are shown to act synergistically in selectively depleting CD4 T cells deficient in OX40 and CD30. Collectively these findings identify a novel mechanism by which Th1 responses are sustained.

TNF family ligands define niches for T cell memory.

Immunological memory is a critical feature of the adaptive immune system and the underlying principal behind vaccination. The mechanisms that maintain memory T cell survival between the initial and subsequent encounter with antigen remain incompletely defined. Although the cytokines IL-15 and IL-7 are important in memory T cell homeostasis, additional signals by way of TNFR family members are required for maximal maintenance of T cell memory. Here we propose a unifying model in which subsets of TNF family ligands distinguish the competitive niches for maintenance of CD4 versus CD8 T cell memory. Understanding the unique 'memory niches' defined by TNF family ligand expression will provide new insights into the mechanisms of memory T cell maintenance.

A novel role of CD30/CD30 ligand signaling in the generation of long-lived memory CD8+ T cells.

Memory CD8+ T cells can be divided into two subsets, central memory (T(CM)) and effector memory (T(EM)) CD8+ T cells. We found that CD30, a member of the TNFR-associated factor (TRAF)-linked TNFR superfamily, signaling is involved in differentiation of long-lived CD8+ T(CM) cells following Listeria monocytogenes infection. Although CD8+ T(EM) cells transiently accumulated in the nonlymphoid tissues of CD30 ligand (CD153-/-) mice after infection, long-lived memory CD8+ T(CM) cells were poorly generated in these mice. CCR7 mRNA expression was down-regulated in CD8+ T cells of the spleen of CD153-/- mice in vivo and the expression was up-regulated in CD8+ T(EM) cells by anti-CD30 mAb cross-linking in vitro. These results suggest that CD30/CD30 ligand signaling plays an important role in the generation of long-lived memory CD8+ T cells at least partly by triggering homing receptors for T(CM) cells.

Aberrant NF-kappaB2/p52 expression in Hodgkin/Reed-Sternberg cells and CD30-transformed rat fibroblasts.

Overexpression of CD30 and constitutive nuclear factor-kappaB (NF-kappaB) activation are hallmarks of the malignant Hodgkin Reed-Sternberg (H-RS) cells. Previous investigations have demonstrated that both proliferation and survival of H-RS cells require constitutive NF-kappaB activity, which is comprised of the p50 and RelA subunits. We report here enhanced expression of NF-kappaB2/p52 and RelB-containing NF-kappaB DNA-binding activity in Epstein-Barr virus-negative H-RS cells. Kinetic studies revealed that a proteasome inhibitor MG132 induced p100 accumulation with reduced p52 expression in H-RS cells, suggesting proteasome-dependent processing of p100. In addition, treatment with a protein synthesis inhibitor cycloheximide rapidly downregulated inhibitor of NF-kappaB (IkappaB) kinase activity in H-RS cells. We also demonstrate that overexpression of CD30 in rat fibroblasts at levels comparable to those in H-RS cells results in constitutive IkappaB kinase activation, proteasome-dependent p100 processing, and NF-kappaB-dependent cell transformation. Our results thus indicate that CD30 triggers the noncanonical NF-kappaB activation pathway, and suggest that deregulated CD30 signaling contributes to the neoplastic features of H-RS cells.

Impaired recall of CD8 memory T cells in immunologically privileged tissue.

Foreign Ags that enter immunologically privileged sites such as the eye, brain, and testis persist for an extended period of time, whereas the same Ags are rapidly eliminated at conventional sites. Immune privilege, therefore, provides unwanted refuge for pathogens and tumor cells but is beneficial for the survival of allogeneic grafts. In this study, we asked whether memory T cells can eliminate foreign Ags deposited at an immunologically privileged site by studying CD8 memory T cell-mediated rejection of pancreatic islet allografts placed either in the testis (a privileged organ) or under the kidney capsule (a nonprivileged site) of diabetic mice. We found that CD8 memory T cells reject intratesticular grafts at a significantly slower rate than the rejection of intrarenal grafts. Delayed graft rejection in the testis was not due to reduced homing or proliferation of memory T cells but due to their increased apoptosis at that site. Apoptosis was mediated by the combined actions of two TNFR family members that are up-regulated on activated memory T cells, Fas, and CD30. Therefore, memory T cells survey immunologically privileged tissues but are subject to the immunosuppressive mechanisms present at these sites.

Signal transduction in anaplastic large cell lymphoma cells (ALCL) mediated by the tumor necrosis factor receptor CD30.

Expression of the cytokine receptor CD30 is a characteristic feature of anaplastic large cell lymphoma (ALCL). Reports regarding CD30-mediated signaling in ALCL cells are highly controversial, especially with respect to the regulation of cell survival. In this study, we stimulated 6 ALCL-derived cell lines with immobilized anti-CD30 antibody. CD30-induced cell death was investigated by Western blot and FACS analysis. CD30-dependent cell proliferation and activation was analyzed by applying the trypan blue exclusion method and a luciferase-based ATP assay. The expression of cell cycle relevant proteins and the activation of mitogen-activated protein (MAP) kinases were also examined. We demonstrated that activation of CD30 did not lead to the cleavage of pro-caspase-3. FACS analysis confirmed that in all examined cells cell death was not mediated by CD30. Cell growth was strongly inhibited in 2 of the 6 cell lines and restrained cell growth was accompanied by expression of the cell cycle inhibitor p21(WAF1/CIP1). Furthermore, stimulation of CD30 led to the activation of the p38 MAP kinase but not of the extracellular signal-regulated kinase (ERK) or the jun N-terminal kinase (JNK). Interestingly, activation of CD30 induced a strong synergistic reduction of cell activity, if the p38 MAP kinase activity was blocked by SB203580. The aim of the study was to elucidate CD30-induced signaling in different ALCL-cells. Our results suggest that CD30-mediated apoptosis is not a common feature in this cell type and that p38 MAP kinase is involved in CD30-mediated singal transduction.