Cutaneous malignant lymphomas

Vaccination of patients with cutaneous T-cell lymphoma using intranodal injection of autologous tumor-lysate-pulsed dendritic cells

Cutaneous T-cell lymphoma (CTCL) is a lymphoproliferative skin disease with limited therapeutic options. Ten CTCL patients were treated with once-weekly intranodal injection of 1 x 106 mature monocyte-derived dendritic cells (DCs) pulsed with 100 microg/mL tumor lysate protein equivalent and keyhole limpet hemocyanin (50 microg/mL). Tumor-specific delayed-type hypersensitivity (DTH) reactions developed in 8 of 8 patients challenged with tumor-lysate-pulsed DCs and in 3 of 8 patients challenged with tumor lysate alone. Three of 5 patients showed significant tumor-lysate-specific increases of in vitro peripheral blood lymphocyte proliferation coinciding with increased interferon-alpha (IFN-alpha) production. Five of 10 (50%) patients had objective responses. Four patients had partial responses (PRs). Two are still in PR, and the other 2 patients had a mean PR duration of 10.5 months. One patient had a complete response (CR) for 19 months that is ongoing. The remaining 5 patients had progressive disease. In the 5 responder patients, 6.8 +/- 1.4 vaccinations were necessary to induce an objective clinical response. Response was associated with low tumor burden. Continuation of vaccinations with new tumor lysate derived from progressive lesions reinduced treatment responses in 2 patients in PR. Selected patients had massive infiltration of CD8+ and TIA+ cytotoxic T cells at the site of regressing lesions and molecular remission after therapy. Intranodal injection of autologous tumor-lysate-pulsed DCs is well-tolerated and achieves immunologic and objective clinical responses in selected CTCL patients.

Tumor-specific antigens in cutaneous T-cell lymphoma: expression and sero-reactivity

Cutaneous T-cell lymphoma (CTCL) is a heterogeneous group of extra-nodal non-Hodgkin lymphomas with primary manifestation in the skin with poor treatment options in the advanced stages. As basis for future immune-therapeutic strategies we have investigated the possible expression of tumor-specific targets in CTCL focusing mainly on so-called cancer-germline genes. cDNAs derived from 20 CTCL tissues and 4 CTCL cell lines were tested with 15 gene-specific and 4 gene family-specific primers by RT-PCR and confirmative Northern blotting. The most frequently detected mRNAs were LAGE-1 (55% with only partial coexpression of the splicing variants), cTAGE-1 (35%), MAGE-A9 (27%) and the GAGE-3-7 group (35%). Furthermore, we could detect NY-ESO-1 (21%) and a MAGE-A subgroup (15%), whereas sub-specification of the latter proved absence of MAGE-A1, -A2, -A3, -A6 and -A12. SCP-1 was found in only one specimen and a several antigens could not been detected in any tumor tissue or cell line (MAGE-B, GAGE-1,2,8 and all 4 RAGE genes). 90% of all CTCL samples were positive for at least 1 of the frequent mRNAs in RT-PCR (LAGE-1, NY-ESO-1, cTAGE-1, MAGE-A9, or GAGE-3to7). Using a secondary SEREX approach we could detect sero-reactivity in sera of CTCL patients against recombinant cTAGE-1 (10/29), GAGE (3/19), MAGE-A1 (1/18), -A3 (1/18), -A6 (2/18) and -A9 (4/18) protein, but not against LAGE-1a, MAGE-A4b or MAGE-A12 protein (n = 19). We conclude, that certain cancer-germline genes can be detected frequently in CTCL and are able to elicit a systemic immune response. These candidate genes might therefore be promising targets for immunotherapeutic interventions in CTCL.

Engagement of ILT2/CD85j in Sézary syndrome cells inhibits their CD3/TCR signaling

Extensive phenotype analysis of cutaneous T-cell lymphoma (CTCL) malignant cell lines revealed surface expression of receptors usually not detected on normal circulating CD4(+)CD45RO(+) lymphocytes. We previously found that CTCL malignant cells express the killer cell immunoglobulinlike receptor (KIR) KIR3DL2/CD158k, whereas they fail to express the other KIRs. In the present study, we report for the first time that the CD85j/immunoglobulin (Ig)-like transcript 2 (ILT2) receptor is found on Sézary cell lines and on circulating Sézary malignant CD4(+) cells, while it is hardly detectable on circulating CD4(+) lymphocytes from healthy individuals. We demonstrate that ILT2 is functional on CTCL cells, as its triggering leads to the recruitment of Src homology 2 domain-containing tyrosine phosphatase (SHP-1) and to the specific inhibition of CTCL malignant cell proliferation induced by CD3/T-cell receptor (TCR) stimulation. Interestingly, we found that separated CD4(+)ILT2(+) circulating malignant Sézary cells are less susceptible to anti-CD3 monoclonal antibody (mAb)-induced cell death than autologous CD4(+)ILT2(-) lymphocytes. Therefore, the resistance to apoptosis of Sézary cells may result from distinct mechanisms including cytokine-induced high levels of bcl-2 and specific expression of inhibitory receptors involved in lymphocyte survival.

Phage display particles expressing tumor-specific antigens induce preventive and therapeutic anti-tumor immunity in murine p815 model

The efficacy of phage display particles expressing tumor antigen P1A35-43 in inducing protective and therapeutic anti-tumor immune responses were studied. A protective immune response against a lethal progressive P815 mastocytoma tumor cell challenge was established after subcutaneous injection of phage display particles. Furthermore, the vaccine suppressed growth of pre-existing tumors. Immunization with the hybrid phage particles elicited P1A(35-43) specific CTL responses and a Th1-dominated immune response with phage particle-specific secretion of IFN-gamma but not IL-4. Our results indicate that phage display particles might be a useful vaccine form for tumor-associated antigen epitopes in tumor immunotherapy.

Serological detection of cutaneous T-cell lymphoma-associated antigens

Cutaneous T-cell lymphomas (CTCL) are a group of skin neoplasms that originate from T lymphocytes and are difficult to treat in advanced stages. The present study is aimed at the identification of tumor-specific antigens from a human testis cDNA library using human sera known as the SEREX (serological identification of recombinantly expressed genes) approach. A cDNA library from normal testicle tissue was prepared and approximately 2 million recombinants were screened with sera from Sézary Syndrome and Mycosis fungoides patients. A total of 28 positive clones belonging to 15 different genes/ORFs were identified, including five hitherto unknown sequences. Whereas control sera did not react with most clones, 11-71% sera from CTCL patients were reactive against the identified clones. Expression analysis on 28 normal control and 17 CTCL tissues by reverse transcription-PCR (RT-PCR) and Northern blotting revealed seven ubiquitously distributed antigens, six differentially expressed antigens (several normal tissues were positive), and two tumor-specific antigens that were expressed only in testis and tumor tissues: (i) A SCP-1-like sequence, which has already been detected in various tumors, has been found in one CTCL tumor and four sera of CTCL patients reacted with various SCP-1-like clones and (ii) a new sequence named cTAGE-1 (CTCL-associated antigen 1) was detected in 35% of CTCL tumor tissues and sera of 6/18 patients reacted with this clone. The present study unravels CTCL-associated antigens independent of the T-cell receptor. The SCP-1-like gene and cTAGE-1 were shown to be immunogenic and immunologically tumor-specific and may therefore be candidates for immunotherapy targeting CTCL.