Occupational protein contact dermatitis from lettuce

Identification of a 17 kDa protein that is a potentially novel antigen of lettuce-associated respiratory allergy in farmers

BACKGROUND

We have identified and reported a novel antigen, nonprotein-specific secreted EP1-like glycoprotein (51 kDa), for lettuce-related respiratory allergy.

OBJECTIVE

We aimed to identify a novel antigen for lettuce-related respiratory allergy that is different from epidermis-specific secreted EP1-like glycoprotein.

METHODS

Immunoblotting was performed using an immunoglobulin E-specific antibody. The antigen-antibody reaction was confirmed by means of enzyme-linked immunosorbent assaying. LC-MS/MS analysis was carried out to detect a novel protein found in sera from 3 of 13 patients with lettuce-related respiratory allergy. Finally, we purified a novel protein from Escherichia coli.

RESULTS

Immunoblotting assays showed common bands of 17 kDa in the sera of 3 of 13 patients. An enzyme-linked immunosorbent assay confirmed that the patient sera reacted with lettuce latex juice. A 17 kDa protein band that showed antigenic reactivity in 3 of 13 patient sera was identified as a kirola-like protein by LC-MS/MS. In addition, although we purified this protein, we failed to show the inhibitory effect.

CONCLUSION

A 17 kDa protein that is a potentially novel antigen of lettuce-associated respiratory allergy was identified. In further studies, we will focus on purifying this novel protein to diagnose lettuce allergy.

Contact dermatitis

Contact dermatitis (CD) is among the most common inflammatory dermatological conditions and includes allergic CD, photoallergic CD, irritant CD, photoirritant CD (also called phototoxic CD) and protein CD. Occupational CD can be of any type and is the most prevalent occupational skin disease. Each CD type is characterized by different immunological mechanisms and/or requisite exposures. Clinical manifestations of CD vary widely and multiple subtypes may occur simultaneously. The diagnosis relies on clinical presentation, thorough exposure assessment and evaluation with techniques such as patch testing and skin-prick testing. Management is based on patient education, avoidance strategies of specific substances, and topical treatments; in severe or recalcitrant cases, which can negatively affect the quality of life of patients, systemic medications may be needed.

Occupational respiratory allergy to lettuce in lettuce farmers

BACKGROUND

Lettuce-associated respiratory allergy has never been reported before. The aim of this study was to clarify the clinical condition of lettuce-associated respiratory allergy and to identify the lettuce antigen which induces allergic symptoms.

METHODS

We distributed questionnaires to 1168 lettuce farmers and performed medical examinations in those who exhibited respiratory symptoms related to occupational exposure to lettuce. We analysed specific IgE-binding proteins in the sera of patients through immunoblotting analysis and determined molecular characterization of the IgE-binding bands using liquid chromatography-mass spectrometry.

RESULTS

A total of 932 farmers (80%) responded to the questionnaire. Of those, 7% exhibited lettuce-associated respiratory symptoms, during harvesting and packaging. Thirteen patients were diagnosed with allergy to lettuce and agreed to undergo further examinations. The percentage of activated basophils in these patients was significantly higher compared with that reported in negative controls (P < .05). Lettuce-specific IgE (ImmunoCAP® ) and skin prick testing was positive in 46% and 62% of patients, respectively. Notably, occupational lettuce-allergic asthma was detected in one patient through specific bronchial provocation testing. The IgE-binding bands recognized in the sera of >50% of patients were identified as epidermis-specific secreted glycoprotein EP1-like (51 kDa).

CONCLUSION

The present analysis identified a novel lettuce allergen. This allergen may have clinically useful applications, such as specific IgE testing and allergen-specific immunotherapy.

Lettuce contact allergy

Lettuce (Lactuca sativa L.) and its varieties are important vegetable crops worldwide. They are also well-known, rarely reported, causes of contact allergy. As lettuce allergens and extracts are not commercially available, the allergy may be underdiagnosed. The aims of this article are to present new data on lettuce contact allergy and review the literature. Lettuce is weakly allergenic, and occupational cases are mainly reported. Using aimed patch testing in Compositae-allergic patients, two recent Danish studies showed prevalence rates of positive lettuce reactions of 11% and 22%. The majority of cases are non-occupational, and may partly be caused by cross-reactivity. The sesquiterpene lactone mix seems to be a poor screening agent for lettuce contact allergy, as the prevalence of positive reactions is significantly higher in non-occupationally sensitized patients. Because of the easy degradability of lettuce allergens, it is recommended to patch test with freshly cut lettuce stem and supplement this with Compositae mix. As contact urticaria and protein contact dermatitis may present as dermatitis, it is important to perform prick-to-prick tests, and possibly scratch patch tests as well. Any person who is occupationally exposed to lettuce for longer periods, especially atopics, amateur gardeners, and persons keeping lettuce-eating pets, is potentially at risk of developing lettuce contact allergy.

Protein contact dermatitis--case report

Protein contact dermatitis is a skin condition not well known and underdiagnosed by dermatologists, resulting from an IgE-mediated allergic reaction. Clinically it presents as a chronic hand and/or forearms eczema of occupational origin, especially in professionals who work as food handlers. Epicutaneous tests are negative, and to diagnose this condition it is necessary to perform immediate-type allergy tests. The most sensitive and practical is the prick-by-prick test with food that the patient refers to cause intense itching after immediate skin contact. Treatment is symptomatic, and it is mandatory to avoid the responsible allergen, wearing plastic gloves and even sometimes leaving the workplace for symptom resolution.

Lettuce anaphylaxis: identification of a lipid transfer protein as the major allergen

BACKGROUND

Allergy to plant-derived foods is associated with birch pollinosis in central and northern Europe. Symptoms elicited are usually limited to the oropharyngeal system. By contrast, in the Mediterranean area, allergy to the same foods manifests more frequently with systemic reactions caused by nonspecific lipid transfer proteins (nsLTP), independently of an associated pollinosis.

OBJECTIVE

We sought to investigate the pattern of immunoglobulin E (IgE) binding protein bands implicated in lettuce allergy, in particular the presence of an nsLTP.

METHODS

Consecutive lettuce allergic patients were selected. Determination of serum-specific IgE, immunoblot, and inhibition experiments were performed in order to study the pattern of IgE binding proteins and the potential cross-reactivity to pollens. Inhibition studies with recombinant allergens were conducted to identify the lettuce allergens. The major allergen was subjected to N-terminal amino acid sequencing.

RESULTS

Fourteen patients were diagnosed as being allergic to lettuce. All were sensitized to Platanus pollen. Ten of them showed specific IgE to a lettuce protein of 9-kDa. The IgE binding to this protein was completely inhibited by the cherry-LTP and peach extract. The N-terminal sequence of the 9-kDa protein showed a high degree of amino acid sequence identity to other nsLTPs. A clear partial cross-reactivity was observed between lettuce-LTP and Platanus-pollen extract.

CONCLUSIONS

An LTP has been demonstrated to be a major allergen in patients suffering from lettuce allergy.

Occupational protein contact dermatitis and paronychia from natural rubber latex

Protein contact dermatitis (PCD) is a chronic recurrent dermatitis caused by contact with a proteinaceous material. PCD may also present as paronychia. Here a case of PCD and paronychia from natural rubber latex (NRL) is presented. The correct diagnosis would not have been established if prick testing with NRL had not been performed. This case shows that contact allergy presenting as dermatitis may occur despite negative patch test results. PCD from NRL may be relatively common, although very few cases have been published. This is probably due to the fact that the term contact urticaria is so closely connected to NRL that automatically all cases of type I allergy to NRL are considered contact urticaria, although the clinical picture is a dermatitis, i.e. PCD.

Compositae dermatitis

Compositae dermatitis is an allergic contact dermatitis. The most important allergens in the Compositae family are sesquiterpene lactones (SL), which are present in the oleoresin fraction of leaf, stem, flower and possibly pollen. Compositae dermatitis is most frequently seen in middle-aged and elderly people in patterns reflecting airborne or direct contact with the allergens. The pattern typically starts in summer and disappears in the autumn or winter. Repeated exposure over many years may lead to a chronic and, at times, a disseminated pattern. Seasonal variation does not occur in occupational Compositae dermatitis. In addition to the classically described airborne pattern of face, 'V' of neck, hands and forearms, hand dermatitis is now recognized to be an equally common presentation. This variability of clinical features, and the frequent occurrence of atopic dermatitis and contact allergy to one or more compounds, highlights the need for routine patch testing with sesquiterpene lactone mix 0.1% (Thermal, Hamburg, Germany), combined with aimed patch testing with Compositae plants and extracts. Avoidance of the plants and plant extracts of this large family can be difficult due to its widespread occurrence in flower, herb and vegetable gardens, urban and rural weed population and native vegetation. Importantly, Compositae plant extracts are present in many cosmetics, shampoos, herbal creams and ingested herbal remedies and tonics.

Study of a case of hypersensitivity to lettuce (Lactuca sativa)

BACKGROUND

Allergic reactions to lettuce (Lactuca sativa) are not too frequent and few cases of systemic adverse reactions after its ingestion have been described.

OBJECTIVE

We report a case of clinical sensitization to lettuce on a patient who presented mucocutaneous manifestations after its ingestion, with positive skin tests, histamine release test and serum specific-IgE to lettuce. The allergens responsible for this sensitization were also characterized by means of SDS-PAGE immunoblotting.

MATERIALS AND METHODS

We performed skin tests, histamine release test, serum specific IgE determination and CAP inhibition with lettuce and mugwort (Artemisia vulgaris) extracts. An aqueous and enriched lettuce (from loose leaf type) extract was subjected to SDS-PAGE immunoblotting for determination of its IgE-binding components.

RESULTS AND CONCLUSIONS

CAP inhibition showed antigenic community between lettuce and mugwort. Four protein bands from the lettuce extracts with molecular weights of 50, 43, 39 and 16 kDa exhibited IgE-binding properties.

Occupational dermatitis in Danish gardeners and greenhouse workers (III). Compositae-related symptoms

The clinical part of the study aimed at describing epidemiological and diagnostic aspects of occupational Compositae dermatitis. Patch testing with the sesquiterpene lactone (SL) and Compositae mixes, feverfew extract and supplementary allergens in 250 selected gardeners showed Compositae allergy in 25, 17 females and 8 males. 24 were possibly occupationally sensitized. The mean age was lower and the preponderance of women higher compared to classical Compositae dermatitis, and the distribution and course of the dermatitis most often did not differ from other occupational plant dermatoses. The Compositae mix detected 2x as many as the SL mix, and the overall detection rate with both was 76%, making aimed patch testing necessary. Chrysanthemum (Dendranthema), marguerite daisy (Argyranthemum frutescens) and lettuce (Lactuca sativa) were frequent sensitizers. Occupational type I allergy to Compositae comprised sensitization to Gerbera, chrysanthemum, lettuce, Senecio cruentus and Aster. Among 1657 respondents in the questionnaire part of the study, 824 had worked with Compositae, and 160 (19%) reported occupational Compositae-related symptoms of skin and mucous membranes. Possible risk factors for the development of these were assessed in a stepwise logistic regression model and a history of childhood eczema, hay fever and duration of exposure were significantly associated with Compositae-related irritant and allergic symptoms in both sexes.