Early reduction of serum TARC levels may predict for success of ABVD as frontline treatment in patients with Hodgkin Lymphoma.

BACKGROUND: Many efforts have been made to predict prognosis of newly diagnosed Hodgkin Lymphoma (HL) patients. Objective of this study was to investigate the association between early reduction of Thymus and Activation-Regulated Chemokine after the first ABVD cycle (TARC-1) and prognosis of HL patients. METHODS: Serum samples of 116 HL patients were collected at baseline, after every ABVD cycle and during follow-up. The 99th centile of TARC distribution in a group of 156 independent healthy subjects (800pg/ml) was considered as cut-off for discriminating between abnormal and normal TARC values. FINDINGS: 101 patients out of 116 had baseline TARC above 800pg/ml (median value 27515pg/ml (IQR, 11001-68139)) and were the object of this analysis. TARC-1 significantly decreased to a median value of 556pg/ml (IQR, 378-977pg/ml). TARC-1 values below 800pg/ml were associated with success of therapy (p=0.0003) and PET-2 negativity (p=0.001). TARC-1≤800pg/ml identified a population with a significantly higher 5-years PFS in the whole cohort (90.1% vs 55.6%; p<0.0001) and in both subgroups of advanced (p=0.003) and early stage patients (p=0.021). At multivariable analysis, TARC-1 was significant independent predictor of PFS (p=0.0035). INTERPRETATION: Early reduction of TARC serum levels can predict success of treatment, being associated with achievement of interim PET-2 negative and favorable long-term outcome in HL patients receiving ABVD as front-line therapy.

Late onset of hepatitis B virus reactivation following hematopoietic stem cell transplantation: successful treatment with combined entecavir plus tenofovir therapy.

Prophylaxis with lamivudine (LAM) is recommended for hepatitis B core antibody-positive allogenic hematopoietic stem cell transplant (HSCT) recipients, but the optimal timing for the institution and duration of the prophylaxis is still unknown. Furthermore, considering the high rate of mortality associated with hepatitis B virus reactivation (HBV-R), the most potent and long-term effective antiviral regimen should be considered. We report here a case of late onset of HBV-R after a long-term prophylaxis with LAM in a patient who underwent HSCT for non-Hodgkin lymphoma and who was successfully treated with a combination antiviral regimen including entecavir and tenofovir disoproxil fumarate.

Water load test before and after PPI therapy in patients with gastro-oesophageal reflux disease.

BACKGROUND: Patients with gastro-oesophageal reflux disease may complain of epigastric pain, bloating, early satiety, epigastric fullness, epigastric burning, nausea and vomiting. AIMS: To evaluate the symptoms in response to gastric distension and its relationship to a therapeutic course in patients with gastro-oesophageal reflux disease using the water load test, compared to healthy controls. METHODS: Thirty gastro-oesophageal reflux disease patients with grade A oesophagitis (studied before and after 4 weeks of therapy with esomeprazole, 40 mg per day) and 15 patients with reflux-related symptoms demonstrated at wireless pH monitoring (non-erosive reflux disease) were compared to 30 healthy volunteers. RESULTS: Patients with grade A oesophagitis and with reflux-related symptoms ingested significantly lower water volumes than did controls, before onset of fullness, without statistically significant difference between erosive or non-erosive gastro-oesophageal reflux disease; this variable improved in patients after treatment. Nausea scores were higher basally in patients, pre- and post-therapy, and improved after therapy. Thirty-minute fullness and bloating scores improved after therapy in all gastro-oesophageal reflux disease patients compared to controls and pre-therapy. In all pre-treatment patients, a significant correlation was found only with epigastric fullness; after treatment, there was no significant relationship between the water load and the symptom scores. CONCLUSIONS: In patients with reflux-related symptoms, with or without grade A oesophagitis, the water load test is frequently abnormal, suggesting an altered gastric function. This could explain the incomplete resolution of symptoms after treatment in some patients, and should lead to additional studies aimed at exploring gastric function in gastro-oesophageal reflux disease patients.

Is pseudomelanosis coli a marker of colonic neuropathy in severely constipated patients?

AIMS: To study relationships between the number of pseudomelanosis coli cells and that of colonic enteric neurons and interstitial cells of Cajal, which are significantly reduced compared with controls in severely constipated patients. Pseudomelanosis coli is frequent in patients using anthraquinone laxatives. It is not known whether the prolonged use of these compounds damages the enteric nervous system in constipated patients. PATIENTS AND METHODS: The relationship between the number of pseudomelanosis coli cells and that of colonic enteric neurons (as well as that of apoptotic enteric neurons) and of interstitial cells of Cajal was assessed by histological and immunohistochemical methods in 16 patients with chronic use of anthraquinone laxatives undergoing surgery for severe constipation unresponsive to medical treatment. No relationship was found between the number of pseudomelanosis coli cells and that of enteric neurons (and that of the apoptotic ones), nor of interstitial cells of Cajal, in either the submucosal or the myenteric plexus. CONCLUSION: The use of anthraquinone laxatives, leading to the appearance of pseudomelanosis coli, is probably not related to the abnormalities of the enteric nervous system found in severely constipated patients.

Treatment with botulinum toxin of octo-nonagerians with oesophageal achalasia: a two-year follow-up study.

BACKGROUND: Treatment of oesophageal achalasia with intrasphincteric injections of botulinum toxin has proved to be a successful alternative treatment modality. However, little is known about its long-term effects in very old patients. AIM: To evaluate the effects of such treatment in octo-nonagerians during a 2-year follow-up period. PATIENTS AND METHODS: Thirty-three patients with idiopathic oesophageal achalasia (range 81-94 years) entered the study. After basal evaluation and screening procedures, 100 U of botulinum toxin was injected at the lower oesophageal sphincter, and the procedure was repeated 1 month later. Data were collected at baseline and were compared after 1 and 2 years following the procedure. RESULTS: Seventy-eight per cent of patients were considered responders at 1 year and 54% were considered responders at 2 years. The weight gain at the end of the follow-up period was 2 (0-3) kg. No significant relationship was found between baseline lower oesophageal sphincter pressure and symptoms score after 1 and 2 years of follow-up; moreover, no major complications of botulinum toxin therapy were reported. CONCLUSION: Treatment of very old achalasic patients with botulinum toxin is safe, effective and yields good quality of life in a substantial proportion of these subjects.

Simultaneous transduction of B7-1 and IL-2 genes into human melanoma cells to be used as vaccine: enhancement of stimulatory activity for autologous and allogeneic lymphocytes.

In order to construct an immunogenic cellular vaccine, we transduced three HLA-A*0201 human melanoma lines, selected for expression of classes I and II HLA, adhesion molecules and the T cell-defined melanoma antigens Melan/MART-1, gp100 and tyrosinase, with both interleukin-2 (IL-2) and B7-1 genes by the use of a polycistronic retroviral vector. The lines were selected to share only the HLA-A*0201 allele to avoid generation of strong alloreactivity in case of their multiple in vivo use in HLA-A*0201 + patients. Phenotypic and functional analysis of B7-1-IL2 transduced melanoma lines in comparison with B7-1 transduced and/or parental untransduced counterparts were then carried out. Tumor cells expressing either B7-1 or both genes did not change their original antigenic profile. From a functional point of view, expression of both genes in melanoma lines: (1) improved the response of anti-melanoma cytotoxic T lymphocytes (CTL) over singly transduced or untransduced melanoma cells when subthreshold levels of MHC-peptide complexes were expressed by melanoma cells; (2) conferred a distinct advantage in the ability to stimulate cytotoxicity and interferon-gamma release by autologous and/or HLA-A*0201-compatible allogeneic lymphocytes; (3) allowed the generation of a high number of specific CTL by in vitro stimulation of lymphocytes of HLA-A*0201-melanoma patients. Thus, B7-IL2 gene-transduced melanoma lines appear to display a high immunogenicity and could be used as vaccine in melanoma patients.

Human heat shock protein 70 peptide complexes specifically activate antimelanoma T cells.

Members of the heat shock protein 70 (HSP70) family display a broad cellular localization and thus bind a repertoire of chaperoned peptides potentially derived from proteins of different cellular compartments. In this report, we show that HSP70 purified from human melanoma can activate T cells recognizing melanoma differentiation antigens in an antigen- and HLA class I-dependent fashion. HLA class I-restricted anti-melanoma T cells were susceptible to MHC-restricted, HSP70-dependent stimulation, indicating that HSP70 complexed peptides were able to gain access to the class I HLA presentation pathway. In addition, MHC matching between the melanoma cells used as a source of HSP and the responding T cells were not required, indicating that HSP70 activation may occur across MHC barriers. Besides the MHC-restricted and peptide-dependent activation pathway, HSP70 with no endogenous complexed peptides or HSP70 purified from antigen-negative cells was also able to induce IFN-gamma release by antimelanoma T cells by a MHC-independent mechanism. In this case, however, higher doses of HSP70 were required. The capacity to activate class I-restricted, antitumor T cells as well as antigen-presenting cells, together with the finding that the HSP70 chaperoned peptide repertoire includes melanoma-shared epitopes, holds promise for a HSP70-based cancer vaccine.

Gene therapy in melanoma.

The identification of genes involved in different biologic functions and in the pathogenesis of diseases has paved the way to the possibility of either interfering with the role of such genes or replacing them in somatic cells in case of loss, which may occur in some genetic diseases or cancer. Such progress has been accomplished thanks to advances in molecular biology and applied technology that allow the transport and insertion of genes into recipient cells by viral or physical vectors as well as the inhibition of gene transcription by antisense oligonucleotides. Methods have also been devised to transfer genes not only in vitro but also in vivo, although this latter approach is still limited owing to poor selectivity and targeting of most vectors when given systemically. Viral and physical vectors have been employed; each of these vectors has distinct advantages and disadvantages, and, therefore, the appropriate vector should be selected according to the therapeutic system involved (1). Retro viral vectors have been used largely for their ability to selectively transfect proliferating cells, a feature that can be advantageous in case one wishes to target only proliferating tumor cells. Owing to the heterogeneous proliferation rate in different parts of a tumor, however, it could be desirable, under some circumstances, to be able to target even the fraction of nonproliferating tumor cells. This can now be obtained by the use of lentivirus (2) or by switching to the use of adenoviruses that can target both dividing and quiescent cells but also induce unwanted inflammmatory reactions from the host.

Type I consensus interferon (CIFN) gene transfer into human melanoma cells up-regulates p53 and enhances cisplatin-induced apoptosis: implications for new therapeutic strategies with IFN-alpha.

In this study, we describe the effects produced by the retroviral transduction of human type I consensus IFN (CIFN) coding sequence into the 8863 and 1B6 human melanoma cell lines, derived from a metastatic and a primary human melanoma, respectively. Melanoma cell lines producing approximately 103 IU/ml of IFN were obtained. Interestingly, cisplatin treatment of IFN-producing 8863 and 1B6 melanoma cells resulted in a three- to four-fold increase in the percentage of apoptotic cells with respect to similarly treated parental or control-transduced cell cultures. A similar effect, although less intense, was caused by cultivation of parental melanoma cells in the presence of exogenous CIFN. The increased susceptibility of the IFN-producing melanoma cell lines to cisplatin-induced apoptosis was associated with an IFN-dependent accumulation of p53, which also correlated with a decrease in Bcl-2 expression. Addition of exogenous CIFN to parental melanoma cells resulted in similar although weaker modulations of p53 and Bcl-2 expression. Cisplatin administration to nude mice bearing 3-day-old IFN-producing 8863 tumors resulted in complete tumor regression, while only a partial tumor inhibition was observed upon cisplatin treatment of mice bearing parental or control-transduced 8863 tumors. Starting the cisplatin treatment 7 days after tumor cell injection still resulted in a stronger inhibition of tumor growth in the mice bearing IFN-producing 8863 tumors as compared with parental tumor-bearing mice. A comparable therapeutic effect was obtained after repeated peritumoral administration of 103 IU of exogenous CIFN and cisplatin treatment. Interestingly, a spontaneous tumor regression was observed in nude mice injected with IFN-producing 1B6 cells, in contrast to the progressive tumor growth occurring in mice receiving a similar inoculum of the parental or control-transduced 1B6 melanoma cells. Repeated peritumoral administration of 103 IU of exogenous CIFN to mice bearing parental 1B6 tumors caused only a transient inhibition of tumor growth. These results indicate that type I IFN gene transfer is an effective approach for suppressing the tumorigenic phenotype of human melanoma cells and for increasing the efficacy of anticancer drugs. These observations, together with our previous findings showing the importance of IFN-alpha-T cell interactions in the generation of an antitumor response in mouse models, underline the interest of using type I IFN in gene therapy strategies for the treatment of human melanoma.

Vaccination of melanoma patients with interleukin 4 gene-transduced allogeneic melanoma cells.

A human melanoma line genetically modified to release interleukin 4 (IL-4) was utilized to immunize advanced melanoma patients in order to elicit or increase a specific anti-melanoma immune response, which may affect distant lesions. Twelve metastatic melanoma patients were injected subcutaneously at least three times with 5 x 10(7) IL-4 gene-transduced and irradiated allogeneic melanoma cells per dose. Both systemic and local toxicities were mild, consisting of transient fever and erythema, swelling, and induration at the vaccination site. Two mixed but not complete or partial clinical responses were recorded. To assess the immune response of vaccinated patients, both serological and cell-mediated activities were evaluated. Antibodies to alloantigens could be detected in 2 of 11 patients tested. Mixed tumor-lymphocyte cultures were performed, utilizing autologous and allogeneic HLA-A2-matched melanoma lines as simulators and targets. A significant increase in IFN-gamma release was detected in 7 of 11 cases when postvaccination lymphocytes were stimulated by the untransduced allomelanoma cells. However, induction of a specific recognition of autologous melanoma cells by PBLs was obtained after vaccination in only one of six cases studied. This response involved the melanoma peptide Melan-A/MART-1(27-35) that was recognized in an HLA-A2-restricted fashion. These results indicate that vaccination with allogeneic melanoma cells releasing IL-4 locally can expand a T cell response against antigen(s) of autologous, untransduced tumor, although in a minority of patients.

Novel HLA-Cw8-restricted T cell epitopes derived from tyrosinase-related protein-2 and gp100 melanoma antigens.

The identification of T cell epitopes presented by alternative HLA-B and -C alleles may provide a means to counteract the tumor escape mechanism based on the selection of tumor cells no longer susceptible to HLA-A-restricted T cell recognition. Several T cell clones and lines were obtained from T lymphocytes purified from melanoma-infiltrated or noninfiltrated lymph nodes of a patient who remained disease free 8 yr after surgery. Selected T cells recognized the autologous melanoma as evaluated by direct cytolysis and production of cytokines. These effectors were directed against the tyrosinase-related protein-2 (TRP-2) and gp100 melanoma epitopes restricted by HLA-Cw8. The nonamer and decamer peptides containing the sequence ANDPIFVVL (residues 387-395) of TRP-2 and the octamer, nonamer, and decamer peptides containing the sequence SNDGPTLI (residues 71-78) of gp100 reconstituted the epitope for TRP-2- and gp100-specific T cell lines and clones, respectively. However, only the nonameric form of TRP-2 and the nonameric and octameric forms of gp100 were able to induce peptide-specific T cells recognizing the autologous tumor in an HLA-class I-restricted fashion from PBMC of the melanoma patient studied. Together these data indicate that HLA-Cw8 can restrict the recognition of gp100 and TRP-2 epitopes by CTL, and that such peptides could stimulate a patient's PBL, suggesting that these Ags could have contributed to a systemic immunity against melanoma.

A superagonist variant of peptide MART1/Melan A27-35 elicits anti-melanoma CD8+ T cells with enhanced functional characteristics: implication for more effective immunotherapy.

In the present study, we show that a singly substituted peptide derived from the epitope MART1(27-35) and containing a Leu in position 1 (LAGIGILTV; 1L) behaves as a superagonist by in vitro inducing specific T cells with enhanced immunological functions. 1L-specific CTLs can be raised from peripheral blood of HLA-A2+ melanoma patients more efficiently than T cells specific for the cognate peptide. These T cells show a greater sensitivity to native MART1(27-35) when compared with CTL variable raised to parental peptide from the same patients. More importantly, anti-1L but not anti-native T cells display high levels of interferon gamma production at early time points, and readily secreted interleukin-2 in response to native epitope endogenously presented by melanoma cells. Additionally, anti-1L T cells are insensitive to the inhibitory effects of MART1(27-35) natural analogues that antagonize the lytic response of CTLs raised to the cognate peptide. Analysis of T-cell receptor variable beta usage suggests that the native and 1L peptides stimulate different components of the MART1(27-35)-reactive T cell population. These data provide rationale to the use of superagonist analogues of tumor antigens for inducing in vivo immunization potentially able to overcome tumor immune escape and mediate a more significant control of tumor growth.

Human melanoma-reactive CD4+ and CD8+ CTL clones resist Fas ligand-induced apoptosis and use Fas/Fas ligand-independent mechanisms for tumor killing.

Tumor cells have been shown recently to escape immune recognition by developing resistance to Fas-mediated apoptosis and acquiring expression of Fas ligand (FasL) molecule that they may use for eliminating activated Fas+ lymphocytes. In this study, we report that tumor-specific T lymphocytes isolated from tumor lesions by repeated in vitro TCR stimulation with relevant Ags (mostly represented by normal self proteins, such as MART-1/Melan A and gp100) can develop strategies for overcoming these escape mechanisms. Melanoma cells (and normal melanocytes) express heterogeneous levels of Fas molecule, but they result homogeneously resistant to Fas-induced apoptosis. However, CD4+ and CD8+ CTL clones kill melanoma cells through Fas/FasL-independent, granule-dependent lytic pathway. In these lymphocytes, Ag/MHC complex interaction with TCR does not lead to functional involvement of FasL, triggered, on the contrary, by T cell activation with nonspecific stimuli such as PMA/ionomycin. Additionally, melanoma cells express significant levels of FasL (detectable on the cell surface only after treatment with metalloprotease inhibitors), although to a lesser extent than professional immune cells such as Thl clones. Nevertheless, antimelanoma CTL clones resist apoptosis mediated by FasL either in soluble form or expressed by Thl lymphocytes or FasL+ melanoma cells. These results demonstrate that CD4+ and CD8+ antimelanoma T cell clones can be protected against Fas-dependent apoptosis, and thus be useful reagents of immunotherapeutic strategies aimed to potentiate tumor-specific T cell responses.

The susceptibility to natural killer cell-mediated lysis of HLA class I-positive melanomas reflects the expression of insufficient amounts of different HLA class I alleles.

NK cells selectively lyse tumor cells which do not express one or more MHC class I alleles. The ability to discriminate between self normal or tumor cells is due to the expression of MHC class I-specific killer inhibitory receptors (KIR). In the present study we analyzed melanoma cell lines which were highly susceptible to NK cell-mediated lysis in spite of the expression of a complete set of HLA class I alleles. Quantitative analysis of the HLA class I expression using allele-specific monoclonal antibodies (mAb) revealed a down-regulation of all HLA class I molecules. Treatment of melanoma cells with IFN-gamma resulted in up-regulation of all HLA class I alleles that was paralleled by the acquisition of resistance to lysis. That resistance to lysis reflected the up-regulation of HLA class I molecules was revealed by the finding that mAb-mediated masking of either KIR or their HLA class I ligands completely restored the melanoma cell lysis. These results were obtained by the use of selected NK cell clones derived either from allogeneic or autologous donors. In addition, similar results were obtained using in vitro expanded autologous NK cell populations. Our data indicate that NK cells can lyse not only melanoma cells which have lost the expression of one or more HLA class I alleles but also cells expressing a decreased amount of class I molecules.

Evaluation on serum 2'-5'oligoadenylate synthetase (2'-5'oligoAS) and beta 2 microglobulin (B2M) in patients with nodal metastases from cutaneous malignant melanoma treated with rIFN-alpha 2A.

UNLABELLED: IFN-alpha is a promising adjuvant agent in patients with regional melanomatous metastases (stage IIIB). The aim of this study was to verify whether serum evaluation of the interferon induced proteins 2'-5'oligoAS and B2M can predict the clinical response to rIFN-alpha 2A therapy. PATIENTS AND METHODS: Forty-two patients who had undergone radical dissection of nodal metastases were evaluated. All patients received adjuvant rIFN-alpha 2A (3 million units s.c. three times weekly) for 3 years or until progression. The patients were followed for a medium period of 43 months (range 19-46). During follow-up 22 of the 42 patients had disease progression. In all patients blood samples were obtained before starting adjuvant therapy and after 1 and 6 months of therapy with rIFN-alpha 2A. 2'-5' oligoAS and B2M were measured by radioimmunoassay. RESULT: During the first month of adjuvant therapy with rIFN-alpha 2A the serum levels of 2'- 5' oligoAS increased 10-fold, and this trend was maintained in the following 6 months. Similar results were obtained for B2M serum levels. However, we did not find any significant difference in AS and B2M serum levels between responders and non-responders. CONCLUSION: Our results, therefore, indicate that AS and B2M are markers of the biological activity of administered IFN but that they have little efficacy in predicting the clinical outcome of the treated patients.

Immunogenicity of the ALLAVGATK (gp100[17-25]) peptide in HLA-A3.1 melanoma patients.

A T cell line recognizing autologous and allogeneic HLA-A3.1 melanomas was obtained from a disease-free melanoma patient (patient 15392). By transfection of a tumor cDNA library and in vitro sensitization experiments, the ALLAVGATK gp100/Mel17-derived peptide was found to be the epitope recognized by this melanoma-specific T cell line. The role of the ALLAVGATK peptide in the systemic immune response to melanoma of this patient was evaluated. When pulsed on the autologous peripheral blood mononuclear cells, the ALLAVGATK peptide generated tumor-specific HLA-A3-restricted T lymphocytes and a single restimulation in vitro was sufficient to raise gp100-specific T lymphocytes, indicating a high frequency of epitope-specific T cells. gp100-specific T cells were also induced from T lymphocytes purified from tumor-invaded lymph nodes (tumor-associated lymphocytes, TAL). TAL-derived effectors displayed lower peptide affinity and lower tumor recognition than effectors elicited from peripheral blood lymphocytes (PBL). To further evaluate its immunogenicity, ALLAVGATK was used to stimulate PBL derived from six additional HLA-A3.1 melanoma patients and seven healthy donors. After 7 weeks of peptide stimulation in vitro the generation of anti-gp100 and tumor-specific T cell lines was achieved in one out of the six patients analyzed. Taken together these data indicate that an in vivo priming leading to a systemic immunity against gp100 in HLA-A3 melanoma patients may occasionally occur and that the immunogenicity of ALLAVGATK peptide in melanoma patients is comparable to that of other HLA-A2-restricted epitopes derived from gp100/Mel 17 protein.

Effectiveness of a dental preventive program on plaque index results in 8-year-old children of Bergamo, Italy.

The study presents the results of a preventive program based on a children's book and carried out in the elementary schools of Bergamo, Italy. The book was published to improve 8-year-old schoolchildren's knowledge of primary dentition, dental plaque, nutrition, oral hygiene, fluoride and regular dental visits. The study was experimental. A total of 440 schoolchildren were selected to test the effectiveness of the book. They were divided into four groups: two groups underwent the training program and the other two were control groups. Measurements were made using the Quigley-Hein index before and after the program. A significant difference reduction of the plaque index of -0.6 was observed (P < 0.005).

T-cell recognition of melanoma antigens and its therapeutic applications.

During the last few years, tumor immunology has gained impetus due to the molecular definition of T-cell-recognized antigens and the mechanisms of such recognition, antigen processing, and presentation. To date, the majority of the identified melanoma antigens are shared among different melanomas and some are also expressed in tumors of different histology. However, unique antigens expressed solely by the melanoma autologous to the T-cell used for their characterization were also found. The identification of the immunogenic peptides, the minimal target entity required for T-cell recognition, has provided novel reagents for the development of peptide-based immunotherapy. These findings, together with the understanding of requirements for T-lymphocyte recognition and activation, allow the design of new therapeutic protocols. In addition, the large body of data now available on the fine mechanism of antigen processing and presentation have revealed not only the role of the MHC molecules but also that of other intracellular proteins, such as transporter associated with antigen processing-1 and -2 and proteosome-related molecules. These findings suggest that, in order to select patients eligible for vaccination, the expression of the MHC allele involved in T-cell recognition, the profile of tumor antigens, and the status of the antigen-processing system should be carefully evaluated in tumors cells of prospective patients. In this review, some of the basic concepts of immune recognition and the current view of melanoma tumor antigens recognized by T-lymphocytes will be discussed along with the potential application of these findings in designing new therapeutic strategies.

Multiple melanoma-associated epitopes recognized by HLA-A3-restricted CTLs and shared by melanomas but not melanocytes.

The molecular characterization of melanoma-associated Ags allowed the definition of several HLA class I-presented peptides recognized by T cells. However, no HLA-A3.1-restricted melanoma epitopes have been identified to date. To gain insight into the HLA-A3.1-restricted T cell epitope repertoire of human melanoma, we analyzed the immunologic reactivity of CTLs isolated from tumor-involved or tumor-free lymph nodes in two HLA-A3.1+ melanoma patients. Three CTL lines, clonal or highly oligoclonal in their TCR composition, and two CTL clones were selected for HLA class I-restricted lysis of the autologous tumor and then tested for the recognition of HLA-A3+ and HLA-A3- normal or neoplastic cells of the melanocyte lineage. One CTL recognized a unique HLA-A3.1-restricted Ag expressed only by the autologous tumors, while all the other CTLs defined three HLA-A3.1 epitopes shared by melanomas, but not by melanocytes. Moreover, the epitopes of two CTL lines with different specificity were reconstituted by nonoverlapping fractions of HLA-A3+ melanoma-derived peptides resolved by reverse phase-HPLC, indicating that distinct naturally processed peptides were specifically recognized on melanoma cells in association with HLA-A3.1 molecules. These novel lineage-unrelated HLA-A3.1-restricted melanoma epitopes do not derive from MAGE, BAGE, or GAGE gene families, as evaluated by the COS-7 transfection assay. Our data show that CTLs may recognize HLA-A3.1-class 1 complexes presenting melanoma (but not melanocyte)-associated epitopes that are either unique to a given patient's tumor or that are shared between multiple melanomas.

Differences in frequency distribution of HLA-A2 subtypes between North American and Italian white melanoma patients: relevance for epitope specific vaccination protocols.

Cytotoxic T lymphocytes (CTL) associated in vivo with tumor regression recognize the product of nonmutated genes expressed by most melanoma cells as peptides bound to human leukocyte antigen (HLA) molecules. Multiple HLA-A*0201 restricted peptides derived from melanoma associated antigens (MAA) have been described, and peptide-based vaccination protocols against melanoma are being developed worldwide for the treatment of HLA-A2 melanoma patients based on the assumption that most serologically typed HLA-A2+ individuals will be suitable for such vaccinations. Serologic typing of HLA-A2, however, encompasses a family of at least 17 related alleles recognized by molecular typing techniques and differing at one or more functional residues of the HLA class I molecule. We have recently shown that naturally occurring single-residue variants of HLA-A*0201 are responsible for significant differences in CTL response to MAA-peptide stimulation. Existing data for HLA-A*02 subtype frequencies among whites (who are most affected by melanoma) derive from analyses of Northern European and North American populations that are of similar heritage and predict an exceedingly rare (< 5%) frequency of non-HLA-A*0201 alleles. Melanoma however, affects other white populations in which the prevalence of HLA-A*02 alleles could be more variable. This study was done to identify HLA-A*02 subtypes and their prevalence in two ancestrally different white melanoma populations. HLA-A*02 subtype frequencies were compared by polymerase chain reaction between serologically HLA-A2+ melanoma patients referred for treatment to the Istituto Nazionale Tumori of Milan (n = 93), Italy or the National Cancer Institute, Bethesda, MD, U.S.A. (n = 100). This analysis demonstrated differences in subtype specificity and distribution between the two populations, with a significantly higher percentage of non HLA-A*0201 subtypes in the Italian population. Only 2% of serologically HLA-A2+ Northern American white melanoma patients did not express HLA-A*0201. In contrast, 15% of HLA-A2+ Italian patients were not HLA-A*0201 (p2 value = 0.001). As allele-specific/peptide-based vaccination protocols are presently pursued at several institutions, a proportion of patients might be inappropriately enrolled basing their eligibility on serologically defined HLA-typing.