Essential oils: what is the clinical tolerance in asthmatic patients?

Essential oils in air-spray form are being more and more used for several purposes, even by allergic and asthmatic patients. Available data on the potentially dangerous effects of volatile organic compounds and terpenes contained in essential oils are scarce, and sometimes difficult to compare. Through the present work, we evaluated the clinical tolerance of asthmatic patients exposed to compounds emitted by an essential oils spray, and compared previous and new data available in the scientific literature, focusing on the aspects that may influence clinical results.

Low end-tidal CO2 as a real-time severity marker of intra-anaesthetic acute hypersensitivity reactions.

BACKGROUND: Prompt diagnosis of intra-anaesthetic acute hypersensitivity reactions (AHR) is challenging because of the possible absence and/or difficulty in detecting the usual clinical signs and because of the higher prevalence of alternative diagnoses. Delayed epinephrine administration during AHR, because of incorrect/delayed diagnosis, can be associated with poor prognosis. Low end-tidal CO2 (etCO2) is known to be linked to low cardiac output. Yet, its clinical utility during suspected intra-anaesthetic AHR is not well documented. METHODS: Clinical data from the 86 patients of the Neutrophil Activation in Systemic Anaphylaxis (NASA) multicentre study were analysed. Consenting patients with clinical signs consistent with intra-anaesthetic AHR to a neuromuscular blocking agent were included. Severe AHR was defined as a Grade 3-4 of the Ring and Messmer classification. Causes of AHR were explored following recommended guidelines. RESULTS: Among the 86 patients, 50% had severe AHR and 69% had a confirmed/suspected IgE-mediated event. Occurrence and minimum values of arterial hypotension, hypocapnia and hypoxaemia increased significantly with the severity of AHR. Low etCO2 was the only factor able to distinguish mild [median 3.5 (3.2;3.9) kPa] from severe AHR [median 2.4 (1.6;3.0) kPa], without overlap in inter-quartile range values, with an area under the receiver operator characteristic curve of 0.92 [95% confidence interval: 0.79-1.00]. Among the 41% of patients who received epinephrine, only half received it as first-line therapy despite international guidelines. CONCLUSIONS: An etCO2 value below 2.6 kPa (20 mm Hg) could be useful for prompt diagnosis of severe intra-anaesthetic AHR, and could facilitate early treatment with titrated doses of epinephrine. CLINICAL TRIAL REGISTRATION: NCT01637220.

Anaphylactic bronchospasm during general anesthesia is not related to asthma.

In the general population, a history of asthma (HA) is associated with a higher risk of mortality of anaphylactic shock (AS), but it is unknown whether this association remains valid for intra-operative AS. The goal of this retrospective study was to investigate whether a HA was associated with a higher risk of bronchospasm during intra-operative AS. We analyzed 106 patients (January 2009-December 2012) with intra-operative AS: 57% of them had a confirmed IgE-mediated reaction and 27% had a HA. On logistic regression, the only factor statistically associated with bronchospasm was a neuromuscular blocking drug, with both IgE- or non-IgE-mediated reactions. These results suggest that the mechanisms of bronchospasm in AS may be different from those of asthma and that, in the presence of bronchospasm during anesthesia, AS should be considered to be the most likely cause.

Macrophage-stimulating protein polymorphism rs3197999 is associated with a gain of function: implications for inflammatory bowel disease.

Crohn's disease and ulcerative colitis, the two main types of inflammatory bowel disease (IBD), were reported to be associated with a variety of genetic polymorphisms. A subset of these polymorphisms was identified in both diseases and only three of them were found in primary sclerosing cholangitis (PSC). rs3197999 (Arg689Cys) located in the MST1 gene is one of the most convincingly replicated IBD/PSC-associated polymorphisms but its functional consequences have not been investigated, yet. We expressed both MST1 gene variants (Arg(689) (MSP(wt)) and Cys(689) (MSP(mut)) in a eukaryotic cell system and compared their stimulatory effects on macrophage-like THP-1 cells. Except for the rate of apoptosis that remained unchanged, MSP(mut) significantly increased the stimulatory effect of MSP (macrophage-stimulating protein) on chemotaxis and proliferation by THP-1 cells, indicating a gain of function associated with the Arg689Cys exchange. A broad set of evidence reported previously suggests that pro-inflammatory changes in macrophage function have a major role in the initiation of the inflammatory process in IBD and PSC. Therefore, the gain of function observed with rs3197999 in MST1 might provide a cellular mechanism for the consistent association of this polymorphism with an increased risk for IBD and PSC.

Desloratadine improves quality of life and symptom severity in patients with allergic rhinitis.

BACKGROUND: Desloratadine is associated with decreased signs and symptoms and improved nasal airflow in multiple clinical trials in patients with allergic rhinitis (AR). The effect of desloratadine on quality of life (QOL) in AR has not been widely reported to date. We compared the effects of desloratadine and placebo on QOL in seasonal AR using validated, disease-specific measures. METHODS: This was a multicenter, double-blind, randomized, parallel-group study of desloratadine 5 mg or placebo daily for 2 weeks in patients with symptomatic seasonal AR. QOL was assessed at baseline and at day 14 using the Rhinoconjunctivitis Quality of Life Questionnaire (RQLQ). AR signs/symptoms and the global response to therapy were measured at baseline and at day 14; signs/symptoms were also rated AM/PM in patient diaries. Adverse events (AE) were recorded. RESULTS: Overall 234 patients received desloratadine and 249 received placebo. At day 14 desloratadine was associated with a significantly larger improvement from baseline in the mean total RQLQ score vs placebo (P = 0.0003). Desloratadine also led to significant improvements from baseline in all RQLQ sub-domains (P < or = 0.043). At day 14 significant decreases from baseline were noted in the desloratadine group for total nasal (P = 0.0003), total non-nasal (P = 0.001) and total symptoms scores (P = 0.0001). Morning AR symptoms were significantly decreased in the desloratadine group after 1 day of treatment. Desloratadine was well tolerated, with an AE rate similar to placebo. CONCLUSION: Significant reductions in signs and symptoms of AR with desloratadine treatment were accompanied by improved disease-specific QOL measures.

MHC class II tetramer guided detection of Mycobacterium tuberculosis-specific CD4+ T cells in peripheral blood from patients with pulmonary tuberculosis.

Novel diagnostic tools are needed to diagnose latent infection and to provide biologically meaningful surrogate markers to define cellular immune responses against Mycobacterium tuberculosis (MTB). Interferon gamma-based assays have recently been developed in addition to the more than 100-year-old tuberculin skin test (TST) for the immune diagnosis of MTB in blood. The advent of soluble MHC/peptide tetramer molecules allows to objectively enumerate antigen-specific T cells. We identified novel MHC class II-restricted MTB epitopes and used HLA-DR4 tetrameric complexes to visualize ex vivo CD4(+) T cells directed against the antigens Ag85B and the 19-kDa lipoprotein, shared between MTB and other Mycobacterium species, and CD4(+) T cells which recognize the MTB-associated ESAT-6 antigen. MTB-reactive CD4(+) T cells reside predominantly in the CD45RA(+) CD28(+) and CD45(-) CD28(+) T-cell subset and recognize naturally processed and presented MTB epitopes. HLA-DR4-restricted, Ag85B or ESAT-6-specific CD4(+) T cells show similar dynamics over time in peripheral blood mononuclear cells (PBMC) when compared with CD8(+) T cells directed against the corresponding HLA-A2-presented MTB epitopes in patients with pulmonary MTB infection and subsequent successful therapy. This was not found to be true for T-cell responses directed against the 19-kDa lipoprotein. The dissection of the cellular immune response in M. tuberculosis infection will enable novel strategies for monitoring MTB vaccine candidates and to gauge CD4(+) T cells directed against MTB.

Changes in airway inflammation following nasal allergic challenge in patients with seasonal rhinitis.

BACKGROUND: Seasonal allergic rhinitis could predispose to the development of chronic bronchial inflammation as observed in asthma. However, direct links between nasal inflammation, bronchial inflammation and airway responsiveness in patients with seasonal allergic rhinitis and without asthma are not fully understood. The aim of this study was to analyse the changes induced by allergic nasal challenge outside the pollen season in airway responsiveness and bronchial inflammation of patients with seasonal allergic rhinitis. METHODS: Nine patients were evaluated after either grass pollens or placebo nasal challenge in a randomized cross-over double-blinded trial. Nasal parameters were recorded hourly and airway responsiveness was assessed by methacholine challenge. Cytological examinations and cytokine measurements were performed in nasal lavage and induced sputum. Eosinophil activation was investigated by eosinophil-cationic protein expression and secretion. RESULTS: Airway responsiveness was increased after allergic nasal challenge. Total eosinophils and eosinophils expressing eosinophil-cationic protein were increased in induced sputum after allergic nasal challenge. Both eosinophil number and eosinophil-cationic protein concentration in induced sputum were correlated to methacholine responsiveness. CONCLUSIONS: These results suggest that eosinophils participate to the bronchial inflammation in patients with seasonal allergic rhinitis following allergic nasal challenge outside the pollen season and might explain changes in airway responsiveness.

Association of bronchial hyperresponsiveness and lung function with C-reactive protein (CRP): a population based study.

BACKGROUND: C-reactive protein (CRP), a marker of systemic inflammation, is a powerful predictor of adverse cardiovascular events. Respiratory impairment is also associated with cardiovascular risk. Although some studies have found an inverse relationship between lung function and markers of systemic inflammation, only one study has reported a relationship between lung function and CRP levels. In contrast, little is known about the relationship between bronchial hyperresponsiveness (BHR) and systemic inflammation. The association between lung function and CRP and between BHR and CRP has been investigated. METHODS: As part of the European Community Respiratory Health Survey follow up study serum CRP levels, forced expiratory volume in 1 second (FEV(1)), and BHR to methacholine (>/=20% decrease in FEV(1) to <4 mg methacholine) were measured in 259 adults aged 28-56 years free of cardiovascular disease or respiratory infection. RESULTS: Mean (SD) FEV(1) (adjusted for age, sex, height, and smoking status) was lower in subjects with a high CRP level (high tertile) (3.29 (0.44) l/s v 3.50 (0.44) l/s; p<0.001) and BHR was more frequent (41.9% v 24.9%; p = 0.005) than in subjects with lower CRP levels (low+middle tertiles). Similar results were obtained when the potential confounding factors were taken into account. Similar patterns of results were found in non-smokers and in non-asthmatic subjects. CONCLUSIONS: Increased CRP levels are strongly and independently associated with respiratory impairment and more frequent BHR. These results suggest that both respiratory impairment and BHR are associated with a systemic inflammatory process.

Definition of the HLA-A2 restricted peptides recognized by human CD8+ effector T cells by flow-assisted sorting of the CD8+ CD45RA+ CD28- T cell subpopulation.

In response to antigenic stimulation, naive MHC-class I restricted and antigen-specific CD8+ CD45RA+ CD28+ T cells undergo clonal expansion, differentiate into CD8+ CD45RO+ memory T cells and convert to CD8+ CD45RA+ CD28- T cells displaying potent immune effector functions upon re-encounter with the nominal antigen. We show that the effector CD8+ CD45RA+ CD28- T cell subset is expanded in peripheral blood lymphocytes (PBL) from patients with human papilloma virus (HPV)+ cervical lesions as well as in PBL from patients with pulmonary tuberculosis. Flow-cytometric cell sorted CD8+ CD45RA+ CD28- and CD8+ CD45RA+ CD28- T cells were tested for recognition of HLA-A2 restricted peptides derived either from the human papillomavirus (HPV)16-E7 gene product, or from M. tuberculosis antigens. Mostly CD8+ CD45+ CD28- T cells define antigen/peptide-specific and MHC-restricted responses. These data were confirmed in PBL from patients with tuberculosis using HLA-A2 tetramer-complexes loaded with a peptide from the M. tuberculosis Ag85b antigen by flow cytometry. The sorting of this T cell subset enables to determine the fine specificity of CD8+ effector T cells without the need for in vitro manipulation.

Longitudinal analysis of the T-cell receptor (TCR)-VA and -VB repertoire in CD8+ T cells from individuals immunized with recombinant hepatitis B surface antigen.

Recent studies have suggested that vaccination induces alterations in the T cell receptor (TCR) repertoire. We investigate the diversity of the TCR repertoire after immunization with a recombinant hepatitis B surface vaccine in seven healthy subjects in CD8+ T cells in peripheral blood lymphocytes. Cellular immune responses were monitored over time by sorting CD8 T cells followed by TCR-VA and -VB complementarity determining region 3 (CDR3) analysis. Frequency of individual VB families was determined by flow cytometry. TCR-VA/VB repertoires obtained from CD8+ T cells drawn after vaccination were compared to the TCR repertoire determined prior to vaccination. Monoclonal TCR transcripts could be detected exclusively in CD8+, but not in CD4+ T cells. Such monoclonal TCR transcripts were either stable in some individuals, or could only be detected at certain time points after vaccination. Sorting of monoclonal TCR-VB3+ T cells, which constituted up to 5% of the CD8+ T cell population from one individual, revealed that this T cell clone recognizes an epitope provided by the recombinant hepatitis B vaccine presented by MHC-class I on autologous antigen-presenting cells. Examination of the structural anatomy, defined by the TCR, and the frequency of T cells responding to the immunizing antigen may be helpful to provide surrogate markers to monitor cellular immune responses induced by protein antigens utilized for vaccination.

Improved assessment of T-cell receptor (TCR) VB repertoire in clinical specimens: combination of TCR-CDR3 spectratyping with flow cytometry-based TCR VB frequency analysis.

Antigen-specific T-cell responses may be described by combining three categories: (i) the specificity and effector functions of a T-cell population, (ii) the quantity of T-cell responses (i.e., the number of responding T cells within the CD4/CD8 population), and (iii) the "quality" of T cells (defined by the T-cell receptor [TCR] structure). Several methods to measure T-cell responses are now available including evaluation of T-cell precursors using limiting dilution, the enzyme-linked immunospot assay, ex vivo TCR variable (v)-segment analysis determined by flow cytometry, and TCR-CDR3 length analysis (spectratyping), as well as identification of peptide-specific T cells using major histocompatibility complex (MHC) class I tetramers containing appropriate peptides. Until now, only a limited set of MHC-peptide complexes have been available as tetramer complexes. We demonstrate that CD8(+) or CD4(+) T cells in patients with cancer can be molecularly defined using a combination of spectratyping (TCR structure and "molecular composition") plus the implementation of an antibody panel directed against 21 individual VB TCR chains ("quantity" of T-cell families). This approach is instrumental in defining and comparing the magnitudes of CD4(+) or CD8(+) T-cell responses over time in individual patients, in comparing the TCR VA and VB repertoire in different anatomic compartments, and in comparing the TCR VA-VB diversity with that in normal healthy controls. This method provides the means of objectively defining and comparing the TCR repertoire in patients undergoing vaccination protocols and underlines the necessity to calibrate the TCR-CDR3 analysis with a qualitative assessment of individual TCR VB families.

Antigen-driven T-cell selection in patients with cervical cancer as evidenced by T-cell receptor analysis and recognition of autologous tumor.

We characterized the T-cell receptor (TCR) repertoire in freshly harvested tumor lesions, in short-term-expanded CD4(+) tumor infiltrating lymphocytes (TIL) as well as in CD4(+) and CD8(+) peripheral blood lymphocytes (PBL) from three patients with cervical cancer. Skewing of the T-cell repertoire as defined by measuring the length of the complementarity-determining region 3 (CDR3) of the TCR VA and VB chains was observed in CD8(+) PBL, in freshly harvested tumor tissue, as well as in CD4(+) TIL. Comparative analysis of the TCR repertoire revealed unique monoclonal TCR transcripts within the tumor lesion which were not present in PBL, suggesting selection of TCR clonotypes due to antigenic stimulation. TCR repertoire analysis of the short-term (7-day) CD4(+) TIL lines revealed that the TCR composition is markedly different from that in CD4(+) PBL or in the freshly harvested tumor tissue. Only one-third of CD4(+) TIL lines showed HLA-DR-restricted recognition of autologous tumor cells as defined by cytolysis. These data provide support for the antigen-driven selection of T cells within cervical cancer lesions and suggest that analysis of the TCR repertoire may aid in obtaining an objective description of the immune response in patients with cervical cancer who are undergoing epitope-based immunotherapy.

Does living on a farm during childhood protect against asthma, allergic rhinitis, and atopy in adulthood?

Recent studies of children suggest that factors encountered in a farm environment might protect against the development of allergy. However, it remains uncertain whether living on a farm in childhood is associated with a decreased risk of atopic diseases in adulthood. We analyzed data from 6,251 randomly selected adults 20 to 44 yr of age participating in the European Community Respiratory Health Survey (ECRHS). Subjects answered a detailed questionnaire and underwent specific IgE measurements to five allergens. After adjustment for potential confounders, including pet exposure in childhood, number of siblings, severe respiratory infection in childhood, and parental history of allergy, living on a farm in childhood was associated with a reduced risk of atopic sensitization in adulthood (OR = 0.76, CI 95% = 0.60-0.97). Compared with other adults, those who had lived on a farm as a child were less frequently sensitized to cat (OR = 0.63, CI 95% = 0.41-0.96) and to Timothy grass (OR = 0.68, CI 95% = 0.50-0.94), and were at lower risk of having nasal symptoms in the presence of pollen (OR = 0.80, CI 95% = 0.64-1.02). The protective effect of farming environment in childhood observed in this population-based sample of young adults provides evidence in favor of the hypothesis that environmental factors encountered in childhood may have a lifelong protective effect against the development of allergy.

Reduced pulmonary function is associated with central arterial stiffness in men.

The association of impaired pulmonary function with cardiovascular morbidity and mortality has been reported in several prospective studies. The nature of this association and the mechanisms underlying it are unknown. Both atherosclerosis and central arterial stiffness might be involved. We recently reported, in a 4-yr longitudinal study, that reduced lung function predicts the development of carotid atherosclerotic plaques. In the present study, we report the associations of aortic stiffness with lung function measurements. One hundred and ninety-four men, aged 30 to 70 yr and free of coronary heart disease, who volunteered for a standard health examination were included. FEV(1) and FVC were used to assess lung function. Aortic stiffness was estimated from the carotid-femoral pulse-wave velocity (PWV), which increases proportionally with an increase in aortic stiffness. PWV was significantly and negatively associated with FEV(1) and FVC (partial correlation coefficients adjusted for age and height: -0.27 [p < 0.001] and -0.24 [p < 0.001], respectively). For every 1 SD increase in PWV (2.5 m/s), FEV(1) decreased by 195.2 +/- 50.1 ml (p < 0.001) in an age- and height-adjusted analysis. The corresponding decrease in FVC was 190.4 +/- 55.0 ml (p < 0.001). Further adjustment for cardiovascular risk factors (weight, smoking habits, hypercholesterolemia, diabetes, and hypertension) did not markedly alter these results. In addition, negative associations of PWV with lung function measurements were observed within each category of cardiovascular risk factors. This study suggests that reduced pulmonary function is independently associated with aortic stiffness in men. The interrelations between pulmonary and vascular alterations should be thoroughly investigated.

Human leucocyte antigen-A2 restricted and Mycobacterium tuberculosis 19-kDa antigen-specific CD8+ T-cell responses are oligoclonal and exhibit a T-cell cytotoxic type 2 response cytokine-secretion pattern.

CD8+ T cells can be grouped into two different types of secretory T lymphocytes, based on the cytokine-secretion pattern upon antigen exposure: those with a T-cell cytotoxic type 1 response (Tc1), which secrete interferon-gamma (IFN-gamma), or those with a T-cell cytotoxic type 2 response, which secrete interleukin (IL)-4 and IL-10. We examined the CD8+ T-cell response directed against an immunodominant human leucocyte antigen (HLA)-A2-presented peptide derived from a 19-kDa Mycobacterium tuberculosis-associated antigen. T cells were examined by functional analysis and by T-cell receptor (TCR) complementarity-determining region 3 (CDR3)-spectratyping, which defines the complexity of a T-cell response. T-cell stimulation with the immunodominant VLTDGNPPEV epitope yielded a Tc2 (IL-4) cytokine-secretion pattern and resulted in oligoclonal expansion of TCR-variable beta chain (VB) families, which differed from patient to patient. Generation of T-cell clones corroborated the notion that the CD8+ T-cell response directed against the HLA-A2-presented VLTDGNPPEV epitope leads to a Tc2 cytokine-secretion pattern in CD8+ T cells, as defined by IL-4 and granulocyte-macrophage colony-stimulating factor (GM-CSF) release. Characterization of the cytokine-secretion profile in HLA-A2/VLTDGNPPEV-tetramer sorted T cells from patients with active tuberculosis supported this observation: peptide-specific T cells from three of three patients secreted IL-4 and only one of three patients produced IFN-gamma in response to the nominal target epitope. Permutation of this T-cell epitope may aid to elicit a qualitatively different CD8+ T-cell response in patients with M. tuberculosis infection.

Effect of cetirizine on bronchial hyperresponsiveness in patients with seasonal allergic rhinitis and asthma.

Although H1 antihistamine compounds (H1) are highly effective in the treatment of allergic rhinitis (AR), their role in the treatment of asthma is still controversial. Because a strong association between AR and bronchial hyperresponsiveness (BHR) has been reported, this study was designed to assess the effect of a new H1 anti histamine, cetirizine (C), on nonspecific BHR in patients with AR. Twelve patients were included in a double-blind, crossover, placebo-controlled trial. All patients had positive skin tests for common allergens and showed BHR to inhaled methacholine after specific nasal allergenic challenge. After a washout period of 1 week to ensure the stability of the BHR, the patients received, by crossover randomization, C 10 mg daily or placebo (P) for 2 weeks. After each treatment period, BHR and nasal blocking index (NBI) were measured 1 and 6 h after nasal challenge. Bronchial responsiveness was expressed as methacholine PD20, the provocation dose of methacholine causing a 20% decrease in FEV1. Measurements were then performed after 2 weeks of C and after 2 weeks of P. Baseline values of PD20 (median) measured before challenge showed no difference after cetirizine or after placebo (1.36 mg). Results 1 h after allergen did not show significant differences between C (methacholine PD20=0.522 mg) and placebo (methacholine PD20=0.455 mg). By contrast, 6 h after challenge, methacholine PD20 was 0.918 mg for C and 0.483 mg for P (P=0.042). Similarly, NBI showed no change between C and P 1 h after challenge, whereas the difference was significant 6 h after challenge (P=0.011 ). These data demonstrate a protective nasal effect of C against BHR measured 6 h after nasal allergen challenge in patients with AR. They suggest that C may be useful in patients with asthma associated with AR.

Quality of life in allergic rhinitis and asthma. A population-based study of young adults.

Quality of life has been found to be impaired both in patients with asthma and in patients with allergic rhinitis, but the relative burden of these diseases has not been investigated. We analyzed answers to the SF-36 questionnaire from 850 subjects recruited in two French centers participating in the European Community Respiratory Health Survey, a population-based study of young adults. Both asthma and allergic rhinitis were associated with an impairment in quality of life. However, 78% of asthmatics also had allergic rhinitis. Subjects with allergic rhinitis but not asthma (n = 240) were more likely than subjects with neither asthma nor rhinitis (n = 349) to report problems with social activities, difficulties with daily activities as a result of emotional problems, and poorer mental well-being. Patients with both asthma and allergic rhinitis (n = 76) experienced more physical limitations than patients with allergic rhinitis alone, but no difference was found between these two groups for concepts related to social/mental health. As asthma was not found to further impair the quality of life in subjects with allergic rhinitis for concepts related to mental disability and well-being, and as subjects with asthma often also suffer from allergic rhinitis, further studies on quality of life in asthma should ensure that the impairment in quality of life attributed to asthma could not result from concomitant allergic rhinitis.

Human papillomavirus type 33 E7 peptides presented by HLA-DR*0402 to tumor-infiltrating T cells in cervical cancer.

Several characteristics make human papillomavirus (HPV) amenable to vaccination. Anti-HPV-directed vaccines are based on the observation that HPV E6 and E7 oncoproteins are constitutively expressed in HPV-positive cervical cancer and may serve as tumor rejection antigens. Five HPV types (16, 18, 31, 33, and 45) account for 80% of cervical cancer. Until now, the type of immune response capable of mediating an effective antitumor response has not been defined. In order to define the anticancer-directed immune response in situ, we characterized CD4(+) and CD8(+) sorted T cells from peripheral blood lymphocytes, freshly harvested tumor tissue, and tumor-infiltrating lymphocytes (TIL) from a patient with cervical cancer. The HLA-DR-restricted CD4(+) T-cell receptor VB16-, VA10-, VA21-, and VA22-positive CD4(+) T-cell line derived from TIL recognizes autologous HLA-DR*0402(+) (HPV33(+)) cervical cancer cells, as determined by gamma interferon secretion. Testing of different peptides spanning the E7 gene revealed that the HPV33(73-87) peptide ASDLRTIQQLLMGTV represents the immunodominant epitope which can also be presented by the DR*0401 allele to TIL. Such major histocompatibility complex class II-presented peptides represent attractive candidates to augment T-cell responses directed against autologous tumor cells.

Clonal expansion of Melan A-specific cytotoxic T lymphocytes in a melanoma patient responding to continued immunization with melanoma-associated peptides.

Peptides derived from human tumor antigens have been used in a number of clinical trials to induce specific immune responses against autologous tumors in cancer patients. Although favorable clinical results were observed in single patients, immune responses correlating with tumor regression were either not detected or in case of responses, the T-cell specificity was difficult to demonstrate. In this study, we analyzed antigen-specific T-cell responses induced in the skin and in peripheral blood lymphocytes (PBL) in an HLA-A2-positive melanoma patient. The patient showed major regression of metastatic melanoma under continued immunization with peptides derived from the melanocyte differentiation antigens Melan A/MART-1, tyrosinase and gp100/Pmel17. Based on the identification of different T-cell receptor (TCR) families reactive with Melan A/MART-1, we have demonstrated that i.d. immunization with peptides alone leads to oligoclonal expansion of Melan A/MART-1-specific cytotoxic T lymphocytes (CTL), detectable in local delayed-type hypersensitivity (DTH) reactions and PBL. A monoclonal expansion of a Melan A/MART-1-specific TCR VB 16 CTL was reproducibly observed after in vitro stimulation with Melan A/MART-1 peptides. The same TCR VB 16 CTL clone was detected in skin biopsies taken from vitiligo areas. Our findings provide strong evidence for the effective induction of specific T-cell responses to Melan A/MART-1 by i.d. immunization with peptide alone, which accounts for dermal depigmentation, specific cytotoxicity against Melan A/MART-1-expressing melanoma cells and clinical tumor regression.