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Derk P Bruynzeel

Publications and source records attributed to Derk P Bruynzeel.

10 recordsLinked to original sources
PubMed2006

Mercaptobenzothiazole or the mercapto-mix: which should be in the standard series?

Mercaptobenzothiazole (MBT) compounds are well known contact allergens. To detect rubber allergic patients we use both MBT (2% in petrolatum) and a mercapto-mix with 4 constituents of 0.5% each in our standard series. In this article the EECDRG presents data of in total 32,475 consecutive tested patients attending the respective contact dermatitis clinics from 11 centres in Europe to determine if the mix and MBT detected the same allergic patients. We found 327 patients positive to the mix or MBT, or to both. 261 were positive to the mix and 254 to MBT. MBT was negative in 73 patients who were positive to the mix. If the mix had not been in the standard series, on average 22% of patients allergic to a mercapto-compound would have been missed, for MBT this would have been on average 20%. All clinics would have missed a significant number of positive reactions if both compounds had not been tested. We conclude, that both the mercapto mix and MBT are required in the standard series.

Benzothiazoles↗
PubMed2006

Intrinsic characteristics of contact and respiratory allergens influence production of polarizing cytokines by dendritic cells.

Type 1 and type 2 cytokines are primary mediators in contact allergy and aeroallergen-mediated disorders, respectively. For both types of disease, dendritic cells (DCs) are pivotal in initiating immune hyperresponsiveness. We studied whether contact and respiratory allergens possess intrinsic capacities to polarize DC towards DC1 and DC2 functions, independent of environmental factors. Human monocyte-derived DCs were exposed to the positive controls [type 1: lipopolysaccharide (LPS) + interferon-gamma; type 2: LPS + prostaglandin E(2)], contact allergens [2,4-dinitrochlorobenzene (DNCB), oxazolone (OXA), and nickel sulfate (NiSO(4))], and respiratory allergens [trimellitic anhydride (TMA) and the protein allergen derived from Dermatophagoides pteronyssinus (Der p1)]. The polarizing potentials of the allergens on DCs were determined by the secretion of type 1 [tumour necrosis factor-alpha (TNF-alpha), CXCL10, and interleukin (IL)-12p70] and type 2 (IL-10) cytokines. The contact allergens, DNCB and OXA, induced strict type 1 DC polarization, whereas the respiratory allergens, TMA and Der p1, showed strict type 2 DC polarization. The contact allergen, NiSO(4), induced both DC1 (TNF-alpha and CXCL10 production) and DC2 (decreased IL-12p70/IL-10 ratio) features. These results support the view that allergens have an intrinsic capacity to skew immune responses at the DC level, irrespective of local factors such as those determined by cutaneous or mucosal epithelial microenvironments.

Allergens↗
PubMed2005

Airborne irritant contact dermatitis due to synthetic fibres from an air-conditioning filter.

We describe 8 cases of occupational airborne irritant contact dermatitis in intensive care unit (ICU) employees caused by synthetic (polypropylene and polyethylene) fibres from an air-conditioning filter. Not until a workplace investigation was conducted, was it possible to clarify the unusual sequence of events. High filter pressure in the intensive care air-conditioning system, maintained to establish an outward airflow and prevent microorganisms from entering the ward, probably caused fibres from the filter to become airborne. Upon contact with air-exposed skin, fibres subsequently provoked skin irritation. Test periods in the ICU with varying filter pressures, in an attempt to improve environmental conditions, led to even higher filter pressure levels and more complaints. The sometimes-very-low humidity might have contributed to development of skin irritation. The fact that most patients recovered quickly after treatment with emollients and changing the filters made it most likely that the airborne dermatitis was of an irritant nature.

Adult↗
PubMed2005

Improved detection of allergen-specific T-cell responses in allergic contact dermatitis through the addition of 'cytokine cocktails'.

The gold standard for the diagnosis of allergic hypersensitivity is skin patch testing with the suspected allergens. This diagnostic tool, however, has distinct disadvantages, and therefore the development of alternative or complementary in vitro tests is of great importance. In this study, we evaluate the applicability of an in vitro test method, as developed earlier for nickel allergy, to detect allergen-specific T cells in the blood of patients allergic to frequent sensitizers (chromate, cobalt, paraphenylenediamine, fragrances and chloromethyl-isothiazolinone). Peripheral blood mononuclear cells (PBMCs) of allergic patients and healthy controls were cultured in the absence or presence of allergen. Additionally, type 1 (IL-7 and IL-12) or type 2 (IL-7 and IL-4) stimulating cytokines were added; after 6-day proliferation, IFN-gamma and IL-5 secretions were determined. Without the addition of cytokines, consistent allergen-induced proliferation was observed in PBMCs of nickel-allergic patients only. By contrast, the addition of type 1 or type 2 stimulating cytokines resulted in a significantly enhanced allergen-specific proliferation for all allergens tested (sensitivity increased from 26 to 43% or 38%, respectively, P < 0.05). In these cultures, allergen-induced IFN-gamma and IL-5 secretion was also significantly increased, compared to healthy controls (P < 0.05, for IFN-gamma sensitivity 79%, specificity 93%; for IL-5 sensitivity 74%, specificity 81%). In conclusion, these results demonstrate an increased proliferative capacity and cytokine production by allergen-specific T cells from allergic patients, but not of healthy individuals upon stimulation with allergens in combination with type 1 or 2 skewing cytokines. The present data warrant further exploration of the application of this test to a broader set of allergens.

Adult↗
PubMed2004

Comparison of oral psoralen-UV-A with a portable tanning unit at home vs hospital-administered bath psoralen-UV-A in patients with chronic hand eczema: an open-label randomized controlled trial of efficacy.

OBJECTIVE: To study whether oral psoralen-UV-A (PUVA) with a portable tanning unit at home is as effective as hospital-administered bath PUVA in patients with chronic hand eczema. DESIGN: Open-label randomized controlled trial, with a 10-week treatment period and an 8-week follow-up period. SETTING: Two university hospital dermatology departments in the Netherlands, specializing in hand eczema. PATIENTS: One hundred fifty-eight patients with moderate to severe chronic hand eczema (more than 1 year in duration). INTERVENTIONS: Oral PUVA using methoxsalen capsules and a simple portable commercial facial tanning unit, or hospital-administered bath PUVA with trioxsalen. MAIN OUTCOME MEASURES: The primary outcome was clinical assessment by a hand eczema score (evaluation of desquamation, erythema, vesiculation, infiltration, fissures, itch, and pain, each on a 4-point scale) after 10 weeks of treatment. The secondary outcome was hand eczema score at 8 weeks of follow-up, after completion of treatment. The tertiary outcome was travel cost and time off work. RESULTS: Both groups showed a comparable and substantial decrease in hand eczema score (meaningful clinical improvement). This decrease was maintained during the follow-up period. Patients treated with oral PUVA at home had lower travel costs and less time off work. CONCLUSIONS: Oral PUVA at home has a clinically relevant efficacy, similar to that of hospital-administered bath PUVA. This effect was maintained during an 8-week follow-up period. It resulted in lower travel costs and less time off work.

Administration, Oral↗
PubMed2004

Increased CCL27-CCR10 expression in allergic contact dermatitis: implications for local skin memory.

Allergic contact dermatitis (ACD) is a T-cell-mediated disease in which expression of a distinct repertoire of chemokines results in the recruitment of effector T cells into the skin. While it is becoming clear which chemokines and receptors determine the development of ACD, the mechanisms involved in the retention of T cells in the skin after resolution of inflammation are still unknown. Unravelling these mechanisms will help us to understand local skin memory as observed in retest reactivity and flare-up reactions. This study was designed to evaluate the role of chemokine-chemokine receptor interactions in local T-cell retention. The results show that expression of the CCR10 targeting ligand CCL27 is not only increased during inflammation, but also remains increased several weeks after clinical responsiveness to patch testing. In parallel with increased CCL27 expression, an increased number of infiltrating cells could still be detected in skin that, clinically, had returned to normal 21 days after patch testing. These persisting cells were characterized as CD4+ cells expressing CCR10, while no CD8+ CCR10+ cells could be detected. The presence of these cells is most likely an allergen-mediated effect, as increased levels of CCL27 and CCR10 could not be detected 21 days after initiating an irritant contact dermatitis reaction. In contrast to CCL27, increased expression of CXCL9, CXCL10, and CXCL11 could only be observed during the clinically inflammatory phase of ACD. In conclusion, local CCL27-mediated retention of CCR10+ CD4+ T cells in sites previously challenged by ACD could be responsible for phenomena such as local skin memory observed in retest reactions and flare-up reactions in which the presence of persisting T cells results in an accelerated inflammatory response upon renewed allergen challenge.

CD4-Positive T-Lymphocytes↗
PubMed2002

Assessment of contact allergen cross-reactivity by retesting.

At former allergic contact dermatitis reaction sites retesting causes augmented hyper-reactivity, characterized by an accelerated onset within a few hours. This expression of 'local skin memory' has been ascribed to locally persisting allergen-specific effector/memory T cells. To verify this hypothesis, we investigated whether accelerated retest reactivity also occurs with cross-reactive allergens. Guinea pigs were immunized with either or both 2,4-dinitrochlorobenzene (DNCB) and 2-hydroxyethyl methacrylate (HEMA), and primary skin tests to these and cross-reactive methacrylic compounds were performed 12-21 days later. Subsequently, new skin tests were conducted 3 weeks later both at the former test ('retest') and contralateral, non-pretreated test ('control') sites, and skin test readings started 2 h later. Retest reactivity was evaluated by comparing retest and contralateral control reactions. Both contact sensitizers, HEMA and DNCB, induced strong retest reactivity, peaking at 4-6 h. Fully allergen-specific retest reactivity was observed when primary skin tests had been postponed until 21 days after immunization, most probably reflecting loss of accumulation of irrelevant allergen-primed T cells at that time. As hypothesized, retesting with various methacrylate congeners at primary HEMA, but not DNCB, skin test sites showed early hyperreactivity strengths in line with those observed earlier in conventional cross-reactivity studies. These results, therefore, support the view that local skin memory exhibits allergen specificity through residual allergen-primed T cells. Because the retesting procedure is readily applicable in clinical practice, it provides a tool not only for confirmation of doubtful contact allergic skin reactions, but also for distinguishing between true cross-reactivity and coincident multiple sensitization in man.

Allergens↗