Flow-based basophil activation test in immediate drug hypersensitivity. An EAACI task force position paper

Diagnosing immediate drug hypersensitivity reactions (IDHRs) can pose a significant challenge and there is an urgent need for safe and reliable tests. Evidence has emerged that the basophil activation test (BAT), an in vitro assay that mirrors the in vivo response, can be a complementary test for many drugs. In this position paper, members of Task Force (TF) "Basophil activation test in the evaluation of Drug Hypersensitivity Reactions" from the European Academy of Allergy and Clinical Immunology (EAACI) present the data from a survey about the use and utility of BAT in IDHRs in Europe. The survey results indicate that there is a great interest for using BAT especially for diagnosing IDHRs. However, there are still main needs, mainly in the standardization of the protocols. Subsequently consensus-based recommendations were formulated for: (i) Technical aspects of BAT in IDHRs including type of sample, management of drugs, flow cytometry protocols, interpretation of the results; and (ii) Drug-specific aspects that should be taken into account when performing BAT in relation to betalactams, neuromuscular blocking agents, fluoroquinolones, chlorhexidine, opioids, radio contrast media, chemotherapeutics, biological agents, nonsteroidal anti-inflammatory drugs, COVID vaccine, and excipients. Moreover, aspects in the evaluation of pediatric population have also been considered. All this indicates that BAT offers the clinician and laboratory a complementary tool for a safe diagnostic for IDHRs, although its place in the diagnostic algorithm depends on the drug class and patient population (phenotype, geography, and age). The standardization of BAT is important for generalizing this method beyond the individual laboratory.

50 Jahre Universitäts-Hautklinik am Biederstein in München

Die Klinik und Poliklinik für Dermatologie und Allergologie am Biederstein der Technischen Universität München (TUM) wurde 1969 in Betrieb genommen und feiert daher im Jahr 2019 ihr 50-jähriges Bestehen. Die Ursprünge dieser Klink gehen aber wie an vielen Orten auf ältere Versorgungsstrukturen zurück. Anlässlich des 50-jährigen Bestehens soll dieser Artikel die Entwicklung und aktuelle Ausrichtung der Klinik illustrieren und dabei auch die Wertschätzung für unsere Vorgänger ausdrücken, die sich auf den verschiedenen Positionen für unsere Patienten eingesetzt und so die Basis für eine erfolgreiche Klinik in Krankenversorgung, Forschung und Lehre geschaffen haben. Die Klinik und Poliklinik für Dermatologie und Allergologie am Biederstein gehört zum Universitätsklinikum, dem Klinikum rechts der Isar, der Technischen Universität München (TUM), sie selbst liegt jedoch links der Isar, im schönen Schwabing unweit des Englischen Gartens. Sie ist eine von 3 Hautkliniken in München, die im Rahmen der Münchner Dermatologischen Gesellschaft (MDG e. V.) regelmäßig Fortbildungen ausrichten. Die MDG am Biederstein wird sich im Jahr 2019 neben der Fortbildung auch dem Jubiläum dieser Klinik widmen.

Die Klinik als universitäre Einrichtung umfasst den Bereich medizinische Versorgung mit 74 Betten auf 4 Stationen, einen ambulanten Bereich mit einer großen Poliklinik für Allgemein- und Privatpatienten (jährlich mehr als 60 000 Patientenbesuche), den Bereich Forschung mit verschiedenen Forschungsgruppen und großen Laboratorien sowie den Bereich Lehre, Weiter- und Fortbildung. Ein Schwerpunkt in der klinischen Versorgung und in der Forschung war bereits zur Zeit der Gründung der Klinik 1969 die Allergologie. Weiterhin bestehen Schwerpunkte im Bereich der entzündlichen Hauterkrankungen, der Dermatoonkologie, der Dermatoinfektiologie, der Dermatochirurgie und der Wundversorgung. Die Klinik hat das Comprehensive Allergy Center der Technischen Universität München (ACTUM) und EU-Exzellenz-Zentrum für Allergie auf den Weg gebracht und ist Teil der Krebszentren Comprehensive Cancer Center München der Technischen Universität München (CCC MünchenTUM) und des Comprehensive Cancer Center München (CCCM). Pro Semester werden etwa 450 Studenten im Rahmen von Vorlesungen, Seminaren und Praktika betreut. Neben Kongressen wie der Jahrestagung der Arbeitsgemeinschaft Dermatologische Forschung (ADF) im Jahr 2019 oder der European Society for Dermatological Research (ESDR) im Jahre 2016 richten die Klinik und der Lehrstuhl regelmäßige Fortbildungsveranstaltungen im Rahmen des Biedersteiner Symposiums, des Biedersteiner Kolloquiums und der MDG aus.

Aktuelle Bedeutung der dermatologischen Röntgentherapie

Die dermatologische Röntgentherapie hat mit neuen Geräten wieder eine langfristige Perspektive. Auch deshalb ist es wichtig, diejenigen Indikationen für eine Röntgentherapie im Bereich der Dermatologie und deren Stellenwert im therapeutischen Kanon herauszustellen. Die Therapie kann vom spezialisierten Dermatologen eingesetzt werden bei gutartigen Hauterkrankungen wie Keloiden (v. a. postoperativ), in den frühen Stadien des M. Dupuytren, des M. Ledderhose und der Induratio penis plastica. Bei den Präkanzerosen werden sehr gute Erfolgsraten bei der Lentigo maligna erreicht, wobei die Therapie bei älteren Patienten auch als Primärtherapie eingesetzt werden kann. Eine Strahlentherapie für Basalzellkarzinome, Plattenepithelkarzinome und Lentigo-maligna-Melanome kommt dann infrage, wenn lokal nicht in sano resezierbare Tumoren vorliegen, Patienten inoperabel sind oder eine Einwilligung zur Operation nicht gegeben wird. Sowohl die Mycosis fungoides wie auch das Kaposi-Sarkom sind strahlungssensible Tumoren, bei denen die Radiotherapie primär oder adjuvant zur Lokalkontrolle erfolgreich einsetzbar ist. Aufgrund dieser Einsatzmöglichkeiten werden Kenntnisse im Bereich der dermatologischen Röntgenweichstrahltherapie vermittelt, um Patienten diese erfolgreichen Behandlungen bei entsprechender Indikation anbieten zu können.

Alpha-gal is a possible target of IgE-mediated reactivity to antivenom

BACKGROUND

Antivenoms are mammalian immunoglobulins with the ability to neutralize snake venom components and to mitigate the progression of toxic effects. Immediate hypersensitivity to antivenoms often occurs during the first administration of these heterologous antibodies. A comparable clinical situation occurred after introduction of cetuximab, a chimeric mouse-human antibody, for cancer treatment. The carbohydrate epitope galactose-alpha-1,3-galactose, located on the Fab region of cetuximab, was identified as the target responsible for IgE reactivity.

OBJECTIVE

To investigate whether serum IgE antibodies directed to the α-gal epitope are associated with hypersensitivity to equine antivenoms.

METHODS

Antivenoms were screened for α-gal epitopes via immunoblot and in comparison with cetuximab and pork kidney by IgE reactivity assays. Basophil activation tests were used to investigate reactivity to antivenoms in samples from 20 patients with specific IgE antibodies to α-gal and 10 controls. Additional IgE detection, IgE inhibition, ImmunoCAP inhibition, and skin prick tests were performed using samples from selected patients.

RESULTS

Both antivenoms and cetuximab induced positive skin prick test results in patients with sIgE to α-gal. Alpha-gal epitopes were detected by immunoblotting on antivenoms. Measurements of IgE reactivity and ImmunoCAP inhibition indicated that the antivenoms contained lower α-gal contents than cetuximab. Deglycosylation assays and IgE inhibition tests confirmed that IgE-mediated reactivity to antivenom is associated with α-gal. Antivenoms, pork kidney, and cetuximab activated basophils from patients with IgE to α-gal.

CONCLUSION

Alpha-gal is a potential target of IgE-mediated reactivity to equine antivenom and a possible cause of the high incidence of hypersensitivity reactions during the first application of equine antivenom.

Application of recombinant antigen 5 allergens from seven allergy-relevant Hymenoptera species in diagnostics

BACKGROUND

Hymenoptera stings can cause severe anaphylaxis in untreated venom-allergic patients. A correct diagnosis regarding the relevant species for immunotherapy is often hampered by clinically irrelevant cross-reactivity. In vespid venom allergy, cross-reactivity between venoms of different species can be a diagnostic challenge. To address immunological IgE cross-reactivity on molecular level, seven recombinant antigens 5 of the most important Vespoidea groups were assessed by different diagnostic setups.

METHODS

The antigens 5 of yellow jackets, hornets, European and American paper wasps, fire ants, white-faced hornets, and Polybia wasps were recombinantly produced in insect cells, immunologically and structurally characterized, and their sIgE reactivity assessed by ImmunoCAP, ELISA, cross-inhibition, and basophil activation test (BAT) in patients with yellow jacket or Polistes venom allergy of two European geographical areas.

RESULTS

All recombinant allergens were correctly folded and structural models and patient reactivity profiles suggested the presence of conserved and unique B-cell epitopes. All antigens 5 showed extensive cross-reactivity in sIgE analyses, inhibition assays, and BAT. This cross-reactivity was more pronounced in ImmunoCAP measurements with venom extracts than in sIgE analyses with recombinant antigens 5. Dose-response curves with the allergens in BAT allowed a differentiated individual dissection of relevant sensitization.

CONCLUSIONS

Due to extensive cross-reactivity in various diagnostic settings, antigens 5 are inappropriate markers for differential sIgE diagnostics in vespid venom allergy. However, the newly available antigens 5 from further vespid species and the combination of recombinant allergen-based sIgE measurements with BAT represents a practicable way to diagnose clinically relevant sensitization in vespid venom allergy.

To remember: Radiotherapy - a successful treatment for early Dupuytren's disease

Dupuytren's disease (DD) is a common fibroproliferative condition of the hand which tends to cause progressive digital flexion contracture. Therapeutic strategies to treat the disease include radiotherapy, injections of collagenase clostridium histolyticum, needle fasciotomy and extended surgical intervention dependent on involvement and duration of the disease. We have reviewed the literature with the aim to assess the conditions and effects of radiotherapy in DD. In early stages of the disease, radiotherapy resulted in regression of symptoms/a lack of progression found on average in 40% (range 10-85%)/81% (range 50-100%) of the patients with recurrence rates of only 12-31% after long-term follow-up (>4 years). These results proved to be significantly better than in the untreated patients with natural course of the disease (about 50% progression after a follow-up of 5-6 years). Long-term side-effects (skin dryness) are observed on average in one quarter of the patients, but are well tolerated. Local occurrence of malignancies has not been reported yet. Due to severe functional impairment leading to individual suffering and the high economic burden, treatment of DD in early stages is necessary and radiation therapy represents an effective, safe and economic treatment option.

Two galactose-α-1,3-galactose carrying peptidases from pork kidney mediate anaphylactogenic responses in delayed meat allergy

BACKGROUND

Serum IgE antibodies directed at galactose-α-1,3-galactose (α-Gal) are associated with a novel form of delayed anaphylaxis occurring upon consumption of red meat or innards. Pork kidney is known as the most potent trigger of this syndrome, but the culprit allergens have not yet been identified. The aim of this study was the identification and characterization of pork kidney proteins mediating delayed anaphylactic reactions through specific IgE to α-Gal.

METHODS

A cohort of 59 patients with specific IgE to α-Gal was screened by immunoblot for IgE-reactive proteins in pork kidney. Proteins were identified by peptide mass fingerprinting. Isolated proteins were assayed in ELISA and ELISA inhibition, basophil activation and skin prick test.

RESULTS

Several IgE-binding proteins of high molecular weight (100- >200 kDa) were detected in pork kidney extracts by immunoblot using patient sera and an anti-α-Gal antibody. Two major IgE-binding proteins were identified as porcine angiotensin-I-converting enzyme (ACE I) and aminopeptidase N (AP-N). Reactivity of patient sera and anti-α-Gal antibody to both proteins was abolished by carbohydrate oxidation. The α-Gal IgE epitopes were resistant to heat denaturation. Pork kidney extract, isolated ACE I, and AP-N were able to activate patient basophils and elicit positive responses in skin prick tests.

CONCLUSION

Two cell-membrane proteins carrying α-Gal epitopes were identified in pork kidney. For the first time, isolated meat proteins were shown to induce basophil activation in patients with delayed anaphylaxis to red meat providing further confirmation for the clinical relevance of these α-Gal-carrying proteins.

The clinical utility of basophil activation testing in diagnosis and monitoring of allergic disease

The basophil activation test (BAT) has become a pervasive test for allergic response through the development of flow cytometry, discovery of activation markers such as CD63 and unique markers identifying basophil granulocytes. Basophil activation test measures basophil response to allergen cross-linking IgE on between 150 and 2000 basophil granulocytes in <0.1 ml fresh blood. Dichotomous activation is assessed as the fraction of reacting basophils. In addition to clinical history, skin prick test, and specific IgE determination, BAT can be a part of the diagnostic evaluation of patients with food-, insect venom-, and drug allergy and chronic urticaria. It may be helpful in determining the clinically relevant allergen. Basophil sensitivity may be used to monitor patients on allergen immunotherapy, anti-IgE treatment or in the natural resolution of allergy. Basophil activation test may use fewer resources and be more reproducible than challenge testing. As it is less stressful for the patient and avoids severe allergic reactions, BAT ought to precede challenge testing. An important next step is to standardize BAT and make it available in diagnostic laboratories. The nature of basophil activation as an ex vivo challenge makes it a multifaceted and promising tool for the allergist. In this EAACI task force position paper, we provide an overview of the practical and technical details as well as the clinical utility of BAT in diagnosis and management of allergic diseases.

GSTM1, GSTT1 and GSTP1 gene polymorphism in polymorphous light eruption

BACKGROUND

Polymorphous light eruption (PLE) is the most common chronic and idiopathic photodermatosis. PLE is assumed to represent an immunological hypersensitivity reaction to a radiation-induced cutaneous antigen involving reactive oxygen species (ROS) on the basis of a genetic predisposition. Among others, cellular protection against ROS is provided by glutathione S-transferases (GSTs). Different variants of the GST enzymes may influence the activity and efficiency of detoxification and biotransformation of unknown UV-induced skin-antigens and other factors that may play an important role in the pathogenesis of PLE.

METHODS

In this study the relationship between isoenzymes of the GST genes GSTM1, GSTT1 and GSTP1 and possible protective or predisposing effects on PLE was examined in 29 patients and 144 controls. Diagnosis of PLE was based on the presence of characteristic clinical features.

RESULTS

No association between the functional polymorphisms of the GST gene family and PLE was found. Prevalence of certain GST isoenzymes or polymorphisms in patients with PLE did not differ from healthy controls.

CONCLUSION

Our data do not support prevalence of GST isoenzymes or polymorphisms as a protective effect against PLE. Especially a higher carrier frequency of GSTP1 Val(105) as a protective factor against PLE which has been published before could not be proved. The GST genotypes GSTM1, GSTT1 and GSTP1 (including SNPs) seem to have no relevant association with PLE.

European S3-guidelines on the systemic treatment of psoriasis vulgaris

Of the 131 studies on monotherapy or combination therapy assessed, 56 studies on the different forms of phototherapy fulfilled the criteria for inclusion in the guidelines. Approximately three-quarters of all patients treated with phototherapy attained at least a PASI 75 response after 4 to 6 weeks, and clearance was frequently achieved (levels of evidence 2 and 3). Phototherapy represents a safe and very effective treatment option for moderate to severe forms of psoriasis vulgaris. The onset of clinical effects occurs within 2 weeks. Of the unwanted side effects, UV erythema from overexposure is by far the most common and is observed frequently. With repeated or long-term use, the consequences of high, cumulative UV doses (such as premature aging of the skin) must be taken into consideration. In addition, carcinogenic risk is associated with oral PUVA and is probable for local PUVA and UVB. The practicability of the therapy is limited by spatial, financial, human, and time constraints on the part of the physician, as well as by the amount of time required by the patient. From the perspective of the cost-bearing institution, phototherapy has a good cost-benefit ratio. However, the potentially significant costs for, and time required of, the patient must be considered.

Efficacy of UVA1 phototherapy in 230 patients with various skin diseases

OBJECTIVE

Investigation of the efficacy of ultraviolet (UV) A1 phototherapy on atopic eczema, scleroderma, granuloma annulare, urticaria pigmentosa, prurigo nodularis, lichen sclerosus et atrophicus, T-cell lymphoma, keratosis lichenoides chronica, chronic urticaria and some rare, sclerosing skin diseases.

METHODS

The data of 230 patients treated with low-dose, medium-dose and high-dose UVA1 therapy during 6 years were retrospectively analysed. The mean single dose (J/cm(2)), the mean number of irradiations and the mean total dose (J/cm(2)) were evaluated. The efficacy of phototherapy was assessed by a grading scale and the number of patients was given in percentage for each group.

RESULTS

Good therapeutic effects of UVA1 therapy were shown in patients with atopic eczema, scleroderma, lichen sclerosus et atrophicus, keratosis lichenoides chronica, prurigo nodularis and with cutaneous T-cell lymphoma. Positive effects in some patients were seen in the urticaria pigmentosa and granuloma annulare group, no change to slight improvement was seen in most of the patients with rare, sclerosing skin diseases and no effect was seen in the chronic urticaria group.

CONCLUSION

Besides topical and systemic therapy, UVA1 radiation is a good option of treatment in various skin diseases. It is one of the first-line treatments for several sclerotic diseases and it often improves pruritus considerably.

Adjuvant treatment of atopic eczema: assessment of an emollient containing N-palmitoylethanolamine (ATOPA study)

BACKGROUND

For long-term management of atopic eczema, the use of skin care creams is recommended, but effectiveness of this treatment is not well established.

OBJECTIVE

The objective of this study was to yield data on the skin care properties of a cream with a unique lamellar matrix containing N-palmitoylethanolamine (PEA) and to assess quality-of-life variables in patients with mild to moderate atopic eczema.

SETTING

In this multinational, multicentre, observational, non-controlled, prospective cohort study, patients between 2 and 70 years of age were enrolled. All patients were supplied with the study product sufficient for treatment over the entire study period. Outcome was followed in periods between 3 and 7 days and 4 and 6 weeks after study start. Data were gathered from doctor reports and patient self-assessments via patient questionnaires.

RESULTS

Data from 2456 patients entered the database. The mean examination intervals were 6 days for the 3- to 7-day period and 38 days for the 4- to 6-week period. At study end, intensities of erythema, pruritus, excoriation, scaling, lichenification and dryness were significantly reduced with a combined score reduction of 58.6% in the entire population (57.7% in adults > 12 years and 60.5% in children </= 12 years) according to doctors' reports. Patients reported a reduction of pruritus on visual analogue scales from 4.9 +/- 2.6 to 2.7 +/- 2.4 6 days after treatment start and a further reduction to 2.0 +/- 2.3 at study end (P < 0.001 each). Likewise, sleep quality improved significantly during the study period. Earlier-used topical corticosteroids were omitted by 56% of all patients (53.4% in adults and 62.5% in children) at study end, and the average weekly application rate decreased by 62% from 7.9 +/- 6.0 to 3.0 +/- 5.1 (P < 0.001). The tolerance was assessed as very good or good in 92% of cases by both patients and doctors.

CONCLUSION

This study showed substantial relief of objective and subjective symptoms of atopic eczema after regular skin care with the study cream. The patient-related effectiveness (decline of pruritus and loss of sleep) indicated a gain in quality of life in these patients. The reduced use of topical corticosteroids is important in view of safety and pharmacoeconomic implications in the treatment of atopic eczema.

Domestic allergens and endotoxin in three hospitals offering in-patient rehabilitation for allergic diseases in the alpine mountain climate of Bavaria - The AURA study

Endotoxins and allergens represent the major relevant contents of the atmospheric bioaerosol with regard to the triggering and exacerbation of allergic diseases. In this study, mattress concentrations of endotoxin and indoor allergens were measured in three hospitals in the alpine climate of Bavaria and in adjacent homes. Dust was collected from each of 10 mattresses according to a standardized protocol, and endotoxin was analyzed with the Limulus Amebocyte Lysate (LAL) test, indoor allergens Der p 1, Der f 1 and Fel d 1 were analyzed by ELISAs. The concentration of endotoxin in the mattresses did not differ significantly between different cities. The percentiles of endotoxin were significantly higher in hospitals than in homes. The concentrations of mite allergens (Der p 1 and Der f 1) in the dust were significantly lower in all hospitals than in homes. There was no significant difference of mite allergens between different time points. The concentrations of Fel d 1 were significantly higher in the autumn than in the summer (median: 1376 vs. 478ng/g). No significant differences of Fel d 1 were found between hospitals and homes or between different hospitals. As Fel d 1 concentrations reached levels at which cat allergic patients can experience symptoms, efforts had to be made to reduce the concentrations of Fel d 1 especially in hospitals. In contrast, mite allergens were low in hospitals, which can be clinically beneficial for patients with mite allergies.

Evidence for a new low-lying resonance state in 7He

Low-lying resonance states in 7He(6He+n), formed after fragmentation reactions of a 227 MeV/nucleon 8He beam on a carbon target, have been studied. Coincidences between 6He nuclei and neutrons, corresponding to the one-neutron knockout channel in 8He, were selected. The relative energy spectrum in the 6He+n system shows a structure, which is interpreted as the 7He ( Ipi = 3/2(-)) ground state, unbound with 0.43(2) MeV relative to the 6He+n system and a width of Gamma = 0.15(8) MeV overlapping with an excited ( Ipi = 1/2(-)) state observed at 1.0(1) MeV with a width of Gamma = 0.75(8) MeV.

Demonstration of olaquindox phototoxicity in vitro

Olaquindox is an oral anti-bacterial agent used as an additive to animal food. It is known to cause photosensitization in pig breeders, probably due to a photoallergic mechanism. Also, olaquindox was found to be phototoxic in animal experiments. We have evaluated the phototoxic properties of olaquindox in vitro with a photohemolysis test using different light sources. Irradiation with a source rich in ultraviolet A (UVA) and, to a lesser degree, with a lamp emitting mainly visible light induced photohemolysis, which depended on the concentration of olaquindox and the radiation dose. Exposure to radiation rich in UVB caused no olaquindox-dependent hemolysis. The absorption spectrum of olaquindox changed prominently after irradiation, indicating photodegradation of the compound.

Viral culture and p24 antigenemia of human immunodeficiency virus (HIV)-infected individuals correlated with antibody profiles determined with recombinant polypeptides of all HIV-1 open-reading frames

The association between viral activity and antibody profiles was investigated in 202 individuals infected by the human immunodeficiency virus (HIV) grouped according to their Walter Reed clinical stage. Each study group was subdivided into subjects positive or negative for markers of active viral replication: presence of serum p24 antigen and viral culture. In Western blots using recombinant antigens, sera of HIV-positive individuals with positive viral markers had a significantly lower antibody reactivity to several viral proteins than did individuals without viral markers. Noticeably, proteins of the gag (p24, p17) and env (gp120, COOH-terminal part of gp41) open-reading frames revealed a decreased reactivity. The antibody response to the regulatory proteins revealed no or poor association with viral activity in the host. The results suggest that seroreactivity is mainly influenced by factors reflecting the viral activity of an HIV-infected individual, while the clinical stage of the patient is less important. Especially, reductions in antibodies against gp120 and p17 were useful markers associated with increased viral activity.

Expression of human immunodeficiency virus (HIV) in naturally infected peripheral blood mononuclear cells: comparison of a standard co-culture technique with a newly developed microculture method

Peripheral blood mononuclear cells (PBMCs) from 29 patients infected with human immunodeficiency virus (HIV) were cultured by two different methods. One was the standard co-culture technique, the other a newly developed microculture method. In this assay 10(6) PBMCs were cultivated in 250 microliters medium, no activating agents or allogeneic cells were present. P24 antigen production measured by this method was found in 7 out of 11 PBMC cultures of patients in the Walter Reed (WR) stage 1 or 2, whereas only 4 samples were positive by the co-culture procedure. Cultures from patients in the later stages of the disease (WR 5/6) showed a higher p24 production by the co-culture method than by the microculture assay. It is assumed that rapidly growing HIV strains can be better assessed by the co-culture method which may select for these strains. P24 expression can be more easily obtained by the microculture technique even in cases where slowly replicating strains may be present. In conclusion, results from the microculture procedure described may be a useful supplementation to findings observed by the co-culture method.

Ultraviolet A inhibits histamine release from human peripheral leukocytes

Irradiation of human peripheral leukocytes with ultraviolet A (UVA) induced a significant and dose-dependent reduction of anti-IgE or Ca-ionophore-stimulated histamine release without consistent influence upon C5a-induced release reactions. This effect was equally demonstrable in atopics and controls. In the presence of the radical scavenger superoxide dismutase, the UVA-induced inhibition of anti-IgE-induced histamine release was abolished. Under the conditions used, UVB exposure did not result in relevant changes of in vitro histamine release.