Assessment of psychological aspects during systemic provocation tests in patients with pseudoallergic drug reactions

BACKGROUND

Basic mechanisms of pseudoallergic drug reactions as well as a possible role of the psyche are currently unknown.

OBJECTIVE

Examination of psychological status and reactions during diagnostic provocation tests in patients with previous pseudoallergic reactions to drugs.

SUBJECTS AND METHODS

Ten inpatients, admitted for provocation tests, were studied in a double-blind, placebo-controlled setting, with inventories of anxiety and depression being measured at baseline and psychological reactions and symptoms being recorded daily by patients and the attending physician.

RESULTS

Patients reported more than twice as many symptoms as the physician, independent of the type of exposure. While the basic psychological profile of the patients was normal, anxiety trait and state values were high during testing, with a significant increase depending on whether the patients thought they had received a drug or a placebo. Similarly, frequency of symptoms was dependent on the patients' perception of the type of exposure.

CONCLUSION

These findings demonstrate a high level of anxiety during systemic provocation tests in patients with previous pseudoallergic drug reactions, raising serious questions as to the diagnostic validity of the routine application of this testing.

EAACI/GA2LEN/EDF guideline: management of urticaria

This guideline is the result of a consensus reached during a panel discussion at the second International Consensus Meeting on Urticara, Urticaria 2004, a joint initiative of the EAACI Dermatology Section and GA2LEN. Urticaria has a profound impact on the quality of life, and effective treatment is therefore required. The recommended first line treatment are nonsedating H1 antihistamines. They have proven to be effective in double-blind controlled studies, but dosages increased up to fourfold over the recommended doses may be necessary. However, for different urticaria subtypes and in view of individual variation in the course of the disease and response to treatment, additional or alternative therapies may be required. Immunosuppressive drugs like cyclosporin A and corticosteroids are not recommended for long-term treatment due to unavoidable severe adverse effects. This guideline was, in addition, accepted by the European Dermatology Forum (EDF) and formally approved by the European Union of Medical Specialists (UEMS).

EAACI/GA2LEN/EDF guideline: definition, classification and diagnosis of urticaria

This guideline is the result of a consensus reached during a panel discussion at the 2nd International Consensus Meeting on Urticaria, Urticaria 2004, a joint initiative of the European Academy of Allergology and Clinical Immunology Dermatology Section and the European Union (EU)-funded network of excellence, GA2LEN. It covers the definition and classification of urticaria, taking into account the recent progress in identifying causes, eliciting factors and pathomechanisms of this disease. We have outlined useful diagnostic approaches for different subtypes of urticaria. This guideline was, in addition, accepted by the European Dermatology Forum (EDF) and was formally approved by the European Union of Medical Specialists (UEMS).

Differential expression of angiotensin receptors in human cutaneous wound healing

BACKGROUND

Angiotensin AT1 and AT2 receptors are expressed in human skin. Furthermore, AT2 receptors have been reported to be upregulated during tissue repair and remodelling in various noncutaneous human tissues.

OBJECTIVES

Detection of alterations in angiotensin II receptor expression during wound healing in human skin.

METHODS

Three models were employed. (i) Primary human keratinocytes were razor scraped in culture flasks and alterations in the expression of angiotensin receptor mRNA determined by semiquantitative reverse transcription-polymerase chain reaction for 1-12 h thereafter. (ii) Early wound healing (48 h after cutting) was studied in punch biopsies from human skin ex vivo by means of immunohistochemical staining using polyclonal antibodies against the AT1 or AT2 receptor. (iii) In vivo wound healing was studied in sections of human cutaneous scars by immunohistochemistry to determine receptor expression early (2 days) and late (2 weeks-3 months) after surgery.

RESULTS

In all experimental settings, an upregulation of both receptor subtypes was noticed after wounding. Immunohistochemically stained skin sections showed a stronger expression of AT2 than of AT1 receptors within the area of scarring. Enhanced receptor expression was detectable as early as 24 h after injury and lasted for up to 3 months.

CONCLUSIONS

From these data, we conclude that angiotensin AT1 and AT2 receptors are upregulated in human cutaneous wounds, giving further support to the concept that angiotensin II plays a role even at an early stage during cutaneous wound healing.

Gene expression and regulation of transcription factor activator protein-2 alpha in human mast cells

BACKGROUND

The transcription factor activator protein (AP)-2 regulates cell-type specific gene expression during development and differentiation, but its role in mast cell development has so far not been explored.

METHODS

Gene expression and regulation of AP2 was assessed in normal skin, diseases with increased mast cell numbers, and in vitro models of mast cell differentiation.

RESULTS

AP-2alpha-protein was not detectable in normal skin but in mastocytoma lesional mast cells. AP-2alpha-mRNA and -protein were also detected in leukemic mast cells (HMC-1), in the adherent fraction of peripheral blood (PBMC) and umbilical cord blood mononuclear cells (CBMC), and AP-2alpha-mRNA at low levels in isolated-purified mast cells. During culture with fibroblast supernatants or SCF, AP-2alpha-mRNA was de novo expressed in KU812-cells, maintained at about the same level in PBMC and CBMC, and upregulated in HMC-1-cells. On extended culture, a down-regulation was noted at mRNA and/or protein levels. In contrast, tryptase expression increased in all cells throughout culture, as did c-Kit in normal cells, whereas in both leukemic cell lines, c-Kit was maintained unchanged at about the same level.

CONCLUSIONS

These findings suggest a continuous activation of AP-2alpha in mastocytomas and mast cell leukemia and its transient upregulation during c-Kit dependent early steps of normal mast cell differentiation.

Retinoic acid inhibits CD40 plus IL-4 mediated IgE production through alterations of sCD23, sCD54 and IL-6 production

BACKGROUND

All-trans retinoic acid (ATRA) inhibits IgE synthesis from anti-CD40 plus IL-4 stimulated human B lymphocytes.

OBJECTIVE

To study the underlying mechanisms, we examined here molecules which are known to have an impact on IgE production, namely CD23, CD54 and IL-6.

METHODS

Human anti-CD40 plus IL-4 stimulated B cells were cultured in the absence and presence of ATRA (10(-6)-10(-10) M). ELISAs were performed to determine soluble (s) CD23 and sCD54, IL-6 and IgE-levels. CD23 and CD54 surface expression were determined by flow cytometric analysis. Semiquantitative-RT-PCR was employed to analyse IL-6, CD23 and CD54 mRNA expression.

RESULTS

ATRA induced a dose-dependent increase of percent CD23 (3.4 fold) or CD54 (1.6 fold) positive B cells. At the mRNA level, this was reflected by a modest increase of CD54 mRNA (46.5 +/- 15.8%) only. By contrast, levels of sCD54 were decreased dose-dependently in the presence of ATRA (56.6 +/- 7.6%). Cytokine analysis showed that IL-6 secretion was significantly inhibited by ATRA (53.6 +/- 0.6%) and also IL-6 mRNA synthesis was reduced (66.3 +/- 11.6%). The observed inhibition of IgE production mediated by ATRA was significantly reversed to 90.5 +/- 12% by the addition of 100 pg/mL recombinant IL-6.

CONCLUSIONS

ATRA interferes through several pathways with the anti-CD40 plus IL-4 mediated B cell activation, namely IL-6, CD23 and CD54.

Prior immunisation of patients with malignant melanoma with vaccinia or BCG is associated with better survival. An European Organization for Research and Treatment of Cancer cohort study on 542 patients

There is increasing evidence that infections and vaccinations play an important role in the normal maturation of the immune system. It was therefore of interest to determine whether these immune events also affect the prognosis of melanoma patients. A cohort study of 542 melanoma patients in six European countries and Israel was conducted. Patients were followed up for a mean of 5 years and overall survival was recorded. Biometric evaluations included Kaplan-Meier estimates of survival over time and Hazard Ratios (HRs), taking into account all known prognostic factors. During the follow-up between 1993 and 2002, 182 of the 542 patients (34%) died. Survival curves, related to Breslow's thickness as the most important prognostic marker, were in accordance with those observed in previous studies where the cause of death was known to be due to disseminated melanoma. In a separate analysis of patients, vaccinated with vaccinia or Bacille Calmette-Guerin (BCG), HRs and the corresponding 95% Confidence Intervals (CIs) were 0.52 (0.34-0.79) and 0.69 (0.49-0.98), respectively. Joint analyses yielded HRs (and 95% CIs) of 0.55 (0.34-0.89) for patients vaccinated with vaccinia, 0.75 (0.30-1.86) with BCG, and 0.41 (0.25-0.69) with both vaccines. In contrast, infectious diseases occurring before the excision of the tumour had little, or, at the most, a minor influence on the outcome of the melanoma patients. These data reveal, for the first time, that vaccination with vaccinia in early life significantly prolongs the survival of patients with a malignant tumour after initial surgical management. BCG vaccination seems to have a similar, although weaker, effect. The underlying immune mechanisms involved remain to be determined.

Mast cells and vasculature in atopic dermatitis--potential stimulus of neoangiogenesis

BACKGROUND

Atopic dermatitis skin lesions are characterized by inflammatory changes and epithelial hyperplasia requiring angiogenesis. As mast cells may participate in this process via bidirectional secretion of tissue-damaging enzymes and pro-angiogenic factors, the present study aimed to assess the occurrence and possible function of mast cells in the papillary dermis and in epidermal layers of atopic dermatitis lesions.

METHODS

Semi-thin and serial sections in combination with immunohistochemistry, histochemistry and proliferating cell nuclear antigen (PCNA)-activity assays were used and related to epidermal thickness and targeted gene expression studies.

RESULTS

Mast cells were located in the papillary dermis and migrated through the basal lamina into the epidermis of atopic dermatitis lesions. An increased PCNA-activity in cells of superficial epidermal layers indicated an activation of keratinocytes and stimulation of endothelial growth. Only approximately 30% of the papillary mast cells stained with the tryptase were toluidin-blue-positive, and approximately 80% were chymase positive. A high number of mast cells expressed c-kit. Most papillary and epidermal mast cells were localized close to endothelial cells. Vascular expression of endoglin (CD105) demonstrated neoangiogenic processes. Mast cells stimulation led to the expression of proangiogenic factors. Also, gene expression of tissue-damaging factors such as matrix metalloproteinases was increased.

CONCLUSIONS

These data suggest that in atopic dermatitis, mast cells are abundantly localized close to and within the epidermis where they may stimulate neoangiogenesis. Via the new vessels, inflammatory cells, together with complement components and antibodies, can be transported to the epidermis to aid in the defense against environmental antigens and to maintain chronic inflammation.

The transcription factor profile of human mast cells in comparison with monocytes and granulocytes

Expression profiles of mRNAs and proteins for various transcription factors were determined for human skin mast cells (sMCs), leukemic HMC-1 MCs, monocytes and granulocytes. By quantitative RT-PCR, sMCs expressed lower levels of c-fos, PU.1, C/EBPalpha, and C/EBPepsilon than monocytes and granulocytes, but higher levels of MITF, SCL, GATA-1 and GATA-2. At the protein level, MITF, SCL, GATA-2, Elf-1 and c-fos were clearly detectable in sMCs. With the exception of c-fos, these proteins were absent or expressed only slightly in monocytes and granulocytes. The expression of NF-E2p45, GATA-1, PU.1, Ets-1, C/EBPalpha and C/EBPepsilon was below the detection limit in sMCs, but detectable in other myelocytes. The high expression of SCL and GATA-2 in sMCs is reminiscent of stem cells. The absence of C/EBPvarepsilon in sMCs, but strong expression in HMC-1, suggests it may impair MC maturation. In summary, mature human MCs can be characterized as C/EBPalpha(low), C/EBPvarepsilon-, PU.1(low), GATA-1(low), GATA-2+, SCL+, MITF(high).

Crossreacting IgG antibodies against fox mite antigens in human scabies

Scabies continues to be an important parasitic disease of mammals. There remain, however, major gaps in the understanding of the human host immune response, and a simple diagnostic test is lacking. In contrast to human mites, red fox mites (Sarcoptes scabiei var. vulpis) can be collected easily and have been used, due to crossreactivity, for enzyme-linked immunosorbent assay (ELISA) studies in dogs and pigs. We wanted to investigate the possibility that crossreactivity might also exist for the human mite, and determined titers against fox mite antigens by ELISA in 41 patients with scabies. Specific IgG was significantly higher in patients with scabies than in healthy controls (P=0.01). The sensitivity was, however, only 48%, although it increased slightly during treatment (P=0.86). A positive correlation was also noted between disease duration and severity of infestation (r=0.5), with specific IgG titers increasing in parallel with severity of symptoms (P=0.01). Patients with symptomatic scabies for more than 4 weeks had furthermore significantly higher IgG titers than patients with a shorter duration of disease (P=0.007). In conclusion, these findings demonstrate IgG antibodies in human scabies that crossreact with fox mite antigens, thus encouraging the search for improved ELISAs with more specific mite antigens to produce a more sensitive detection system for scabies in humans.

Muckle-Wells syndrome: clinical and histological skin findings compatible with cold air urticaria in a large kindred

BACKGROUND

Muckle-Wells syndrome is a rare familial disease with autosomal dominant inheritance, characterized by cold sensitivity and polyarthralgias since childhood, with possible later development of nerve deafness and renal amyloidosis. The nature of the skin manifestations is, however, not well characterized.

OBJECTIVES

To clarify the nature of cutaneous cold sensitivity in patients with Muckle-Wells syndrome by studying clinical aspects and histological features.

METHODS

Eighteen members of a family with Muckle-Wells syndrome and the recently identified mutation of the CIAS1 gene at locus 260 of chromosome 1q44 were available for study. Examination included a thorough history, physical examination and a battery of laboratory tests. In two brothers, standard cold contact and cold air provocation tests were performed, as were biopsies from normal and lesional skin.

RESULTS

All affected family members reported an increased sensitivity to cold, dampness or changes in temperature, and most had arthritis and conjunctivitis. Eight had developed hearing loss, four renal involvement, and amyloid deposits were found in three of five patients in whom rectal biopsies were performed. Laboratory tests showed leucocytosis and elevated C-reactive protein, but no serum cold agglutinins and cryoglobulins. Skin eruptions, with weals of 0.2-3 cm, lasted from 5 to 24 h and were associated with local itching or pain as well as fever, malaise and chills. On cold provocation of two patients, lesions could be reproduced by cold air, but not by contact with an ice cube or cold water. On histology, there was increased vasodilatation, marked infiltration with neutrophils and monocytes/macrophages, and increased expression of beta 2 integrins in lesional vs. normal skin. Numbers of mast cells as well as expression of interleukin-3 and tumour necrosis factor-alpha were unchanged.

CONCLUSIONS

Cold-induced skin lesions in Muckle-Wells syndrome represent typical generalized cold air/wind inflammatory reactions, as also observed in familial cold urticaria. Microscopic features are similar to those observed in other types of urticaria.

Dithranol in an Emulsifying Oil Base (Bio-Wash-Oil) for the Treatment of Psoriasis of the Scalp

On the scalp, dithranol has been studied in only a few trials. The dithranol molecule that contains both hydrophilic and lipophilic centers can be incorporated into detergents and allows easy removal from hair. This property has led to the incorporation of dithranol in an emulsifying oil base (bio-wash-oil). The formulation has been used routinely for more than two decades in East Germany. We reexamined the efficacy and safety of dithranol in bio-wash-oil and compared it to dithranol embedded in crystalline monoglycerides (Micanol) in patients with psoriasis of the scalp. In a prospective, parallel group study, 64 patients attending a day-care clinic were randomly allocated to 3 treatment groups: (1) dithranol in bio-wash-oil; (2) Micanol cream, and (3) Micanol cream in bio-wash-oil. Treatment was carried out for 3 weeks and results assessed using a modified Psoriasis Area and Severity Index score. Dithranol in bio-wash-oil resulted in a reduction in the score of 34% on day 7 and 57% on day 14. This was significantly better than in groups 2 and 3, as were the overall response and patients' assessment at the end of treatment (p < 0.05). Dithranol in a bio-wash-oil is an effective, well-tolerated and low-priced treatment in psoriasis of the scalp.

Miliaria crystallina in an intensive care setting

Drop-like, transient blisters of miliaria crystallina may develop with focal intensity of heat within the skin, such as occurs in tropical climates or during febrile episodes. Miliaria crystallina develops due to a transient poral closure of the sweat duct opening, resulting in obstruction of free flow of eccrine sweat and retention in a vesicle below the skin surface. Dual cholinergic and adrenergic sweat gland innervation is influenced by a variety of medications used in intensive care patients. We present two febrile intensive care patients in whom enhanced alpha-adrenergic stimulation of sweat gland myoepithelia may have led to miliaria crystallina.

Evidence for altered mast cell proliferation and apoptosis in cutaneous mastocytosis

BACKGROUND

Mastocytosis presents as a focal or generalized increase of mast cells, particularly in the skin, but also in other organs. Activating mutations of KIT (formerly c-kit), the receptor of the mast cell growth factor stem cell factor (SCF), appear to play a key role in the pathogenesis of sporadic adult onset mastocytosis. However, these mutations are not present in childhood-onset and familial mastocytosis and also fail to explain the heterogeneity of adult-onset disease. Other factors such as prolonged survival of mast cells may therefore participate in causing and modulating the pathological increase of mast cells in mastocytosis.

OBJECTIVES

To examine the expression of proliferation and apoptosis markers in the mast cells of cutaneous mastocytosis lesions in order to gain further insight into the pathogenesis of mastocytosis.

METHODS

Lesional cutaneous biopsies from eight infants with solitary mastocytomas, five children with multiple mastocytomas, 11 children with generalized urticaria pigmentosa, 12 adults with urticaria pigmentosa, and skin from seven normal controls were used in this study. Serial sections were stained with toluidine blue to quantify mast cell numbers and with antibodies against the proliferation marker Ki67 protein, the tumour suppressor protein p53, and the inhibitor of cyclins and cyclin-dependent kinases p21WAF1/CIP1, using the alkaline phosphatase antialkaline phosphatase technique. The terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-biotin nick end labelling (TUNEL) method was used to assess apoptosis.

RESULTS

Cutaneous mast cell counts were significantly increased in all patient sections, particularly in childhood lesions, and similarly, a small but significant increase of proliferation was found in the lesional mast cells of all patients. Enhanced mast cell numbers and proliferation was associated with a significant decrease of TUNEL staining, particularly in mastocytomas. p53 expression was highly variable, with an overall significant increase in all patient skin mast cells, whereas p21 expression was barely observed at all.

CONCLUSIONS

These findings further support the concept that an imbalance of mast cell proliferation and apoptosis is prevalent in mastocytosis lesions that may account in part for the increased focal mast cell accumulation in this condition.

Impact of vaccinations and infectious diseases on the risk of melanoma--evaluation of an EORTC case-control study

A significant correlation between a reduced risk of melanoma and BCG and vaccinia vaccination in early childhood or infectious diseases later in life has already been reported from the FEBrile Infections and Melanoma (FEBIM) multicentre case-control study. This correlation is further evaluated in this study based on 603 incident cases of malignant melanoma and 627 population controls in six European countries and Israel by means of a joint analysis of the influence of vaccinations and infectious diseases. In addition, the previously unconsidered impact of influenza vaccinations is evaluated for the whole study population. The strong effects of the frequently given BCG and vaccinia vaccinations in early childhood, as well as of uncommon previous severe infectious diseases, were apparently not cumulative. With the Odds Ratio (OR) being set at 1 in the absence of vaccinations and infectious diseases, the OR dropped to 0.37 (95% Confidence Interval (CI): 0.10-1.42) when subjects had experienced one or more severe infectious diseases, associated with a fever of > 38.5 degrees C, and had not been vaccinated with BCG or vaccinia. The OR was 0.29 (CI: 0.15-0.57) in those who had had a severe infectious disease and were vaccinated with either BCG or vaccinia and 0.33 (CI: 0.17-0.65) for those with 1 or more severe infectious diseases and who had received both vaccinations. We conclude that both vaccinations as well as previous episodes of having a severe infectious disease induced the same protective mechanism with regards to the risk of melanoma. Because of a 'masking effect' by the vaccinia vaccination, the protective effect of the BCG vaccination and of certain infectious diseases against cancer has remained undetected. The vaccinations contributed more to the protection of the population than a previous episode of having an infectious disease. In view of the termination of vaccinations with vaccinia in all countries and of BCG in many of them, these findings call for a re-evaluation of vaccination strategies.

Decreased cutaneous expression of stem cell factor and of the p75NGF receptor in urticaria

BACKGROUND

Mast cells, the main effector cells in urticaria, have been reported to be increased in number in lesional and nonlesional skin of urticaria patients, but the underlying mechanisms have so far not been studied. Serum NGF has however, been reported to be increased in urticaria.

OBJECTIVES

We have therefore explored the potential involvement of known mast cell growth modulating factors in urticaria.

METHODS

Tissue sections from patients with different types of urticaria and healthy controls were studied for the immunohistochemical expression of known mast cell growth factors (stem cell factor, SCF; nerve growth factor, NGF), of the inhibitory granulocyte-macrophage colony-stimulating factor (GM-CSF), and of the corresponding receptors, using the alkaline phosphatase-antialkaline phosphatase technique.

RESULTS

Compared to skin of normal controls, staining for SCF, but not for NGF and GM-CSF, was significantly decreased in epidermis, endothelium and perivascular cells in lesional and nonlesional skin of all urticarias. On separate analysis of urticaria subtypes, decreased expression reached significance only in delayed pressure urticaria. Expression of the p75NGF receptor (p75NGFR) was also significantly decreased on endothelium and on perivascular cells of lesional and nonlesional skin in all urticarias. On evaluation of serial sections, p75NGFR expression was also decreased on c-Kit positive dermal mast cells. In contrast, expression of the NGF receptor tyrosine kinase and of the SCF and GM-CSF receptors was unchanged.

CONCLUSIONS

These findings show that SCF and p75NGFR are selectively and systemically down-regulated in the skin of urticaria patients and may represent a negative feedback to increased mast cell reactivity and proliferation.

Nine-year follow-up of a case of Grzybowski type multiple keratoacanthomas and failure to demonstrate human papillomavirus

We describe a patient with a 9-year history of generalized eruptive keratoacanthoma (KA) of the Grzybowski type whose multiple skin lesions showed steady progression, resulting in a sclerotic, mask-like facial expression and ectropion. Eleven tumour biopsies representing lesions of different stages and localizations (erupting and regressing KAs, biopsies from non-involved light-protected and light-exposed skin, dermatosclerosis and squamous cell carcinomas) were analysed for human papillomavirus (HPV) sequences using a polymerase chain reaction approach capable of detecting the majority of all presently known HPV genotypes. None of the biopsy specimens proved to be HPV-positive, although HPV was detected in weakly and heavily affected control specimens by the method applied. These findings suggest an HPV-independent aetiology of this rare type of multiple KA.

Laser-induced weal and flare reactions: clinical aspects and pharmacological modulation

BACKGROUND

Among the adverse effects of cutaneous laser therapy, weal and flare reactions immediately after treatment have received little attention, and the pathomechanisms are unclear.

OBJECTIVES

To study clinical features and possible mechanisms of laser-induced weal and flare reactions in order to identify means of possible therapeutic intervention.

METHODS

Normal skin from the inner arm of 20 volunteers was treated with an argon laser, and the size of weal and flare reactions was measured over a 60-min period. Skin biopsies were taken from four volunteers before and up to 24 h after laser treatment and examined histologically and immunohistologically. Possible underlying mechanisms were also explored using various topical or systemic pharmacological agents.

RESULTS

Wealing was noted in 19 of 20, and flare reactions in all volunteers, with peak values at 15 min. Skin biopsies showed central coagulation of the tissue, cleft formation between epidermis and dermis, normal numbers of morphologically intact mast cells on toluidine blue staining close to the lesion, and only minor upregulation of endothelial and leucocyte adhesion molecules. In agreement with these findings, pretreatment with acetylsalicylic acid, the H1-blocker loratadine and triamcinolone cream was ineffective or resulted in a non-significant reduction of weal and flare reactions. In contrast, local anaesthetics as well as neuropeptide depletion of skin with capsaicin abolished the reactions almost completely.

CONCLUSIONS

Transient weal and flare reactions in response to laser treatment occur in almost all persons and are based primarily on a neurogenic rather than a histamine- or mast cell-dependent mechanism.

Management of urticaria: a consensus report

This consensus report is the result of a panel discussion during the International Clinically Oriented ESDR Symposium Urticaria 2000. Urticaria has a profound impact on the quality of life and effective treatment is required. The most important are nonsedating H1 antihistamines. They have been proven to be effective in double-blind controlled studies, but concentrations higher than those recommended may be necessary. Due to different urticaria subtypes and the individual variation in the course of the disease and response to treatment, however, alternative therapies may be required. Immunosuppressive drugs like cyclosporine A and corticosteroids should not be used long term due to undesirable side-effects.

Mastocytosis: review of clinical and experimental aspects

Mastcytosis is a rare disease characterized by an abnormal increase of mast cells in tissues. The skin is the organ most frequently involved, but mast cells also accumulate in the bone marrow, gastrointestinal tract, lymph nodes, spleen, and liver. Recent studies suggest that activating mutations of c-kit, a protooncogene encoding for the receptor (kit) of stem cell factor, are a possible cause of some forms of mastocytosis. In addition, an increased rate of chromosomal aberrations has been found. Despite significant advances in research on mastocytosis, curative treatment is not yet available. Current management is based on avoidance of mediator-releasing triggers and symptomatic treatment.

Definition, classification, and routine diagnosis of urticaria: a consensus report

Urticaria is a well-known disease entity; however, with an increasing understanding of the molecular mechanisms involved in its pathogenesis, there is also growing evidence for a heterogeneity of urticaria. Currently it is sometimes difficult to compare divergent data reported by different centers researching urticaria due to a lack of precisely described patient populations. A consensus definition and classification of the disease and its subtypes, taking into account new developments, are therefore needed. In addition, this consensus report provides a guideline for diagnostic procedures in different subtypes of urticaria.

Adhesion molecules and cellular infiltrate: histology of urticaria

Urticarial reactions are characterized by dermal capillary dilatation and edema, associated with a variably intense mixed inflammatory infiltrate consisting of neutrophils, eosinophils, T-helper lymphocytes, and activated macrophages. Mast cell numbers are moderately increased by a factor of 2.4, in contrast to mastocytosis where numbers are much higher (5-48-fold increase). In urticarial vasculitis there is in addition endothelial damage, leukocytoclasia, and fibrin and complement deposition. The emigration of leukocytes is regulated by vasoactive and chemotactic mediators released firom mast cells, inducing a sequential upregulation of endothelial adhesion molecules (P-selectin, E-selectin, ICAM-1, and VCAM-1), of beta2-integrins on leukocytes, and of cytokines on endothelial, epithelial, and infiltrating cells. In nonlesional skin, there is also an increase of mast cells and an upregulation of endothelial adhesion molecules, probably due to molecules in the circulation of which P-selectin and TNFalpha have so far been demonstrated. Whereas these data provide a molecular basis for the understanding of variations in mast cell-dependent pathology, they underline the fact that they are not diagnostic for different types of urticaria, except for urticarial vasculitis and mastocytosis.

Human skin mast cells rapidly release preformed and newly generated TNF-alpha and IL-8 following stimulation with anti-IgE and other secretagogues

Several groups have previously reported that rodent or human leukemic mast cells produce inflammatory cytokines such as TNF-alpha and IL-8 as well as the pro-allergic cytokines IL-4, IL-5 and IL-13. Comparatively little is known, however, regarding the ability of normal human skin mast cells to secrete these factors following either IgE-dependent or IgE-independent modes of activation. We therefore investigated whether normal human skin mast cells produce these cytokines following stimulation by a variety of secretagogues. Enriched isolated skin mast cells released both TNF-alpha and IL-8 following activation with either anti-IgE, SCF, substance P, compound 48/80 or A23187. This release was dose- and time-dependent, with maximal levels being reached within 4 h of stimulation involving, in part, the secretion of preformed stores of both cytokines. In accordance with this, using lysates of highly purified (>90%) skin mast cells, we could demonstrate that both TNF-alpha and IL-8 mRNA and protein were present in both unstimulated as well as stimulated mast cells. In stark contrast to these results, no significant levels of either IL-4, IL-5 or IL-13 were detected, regardless of the secretagogue used or the period of stimulation. These results show that human skin mast cells are capable of rapidly secreting pro-inflammatory cytokines like TNF-alpha and IL-8 following IgE-dependent activation and stimulation by the neuropeptide substance P, SCF and the basic polypeptide analogue compound 48/80. In contrast to other types of human mast cells however, human skin mast cells were incapable of secreting IL-4, IL-5 or IL-13 in these settings.

Angiotensin-converting enzyme inhibitors as inducers of adverse cutaneous reactions

Since adverse effects due to angiotensin-converting enzyme (ACE) inhibitors frequently occur in cutaneous locations, this review summarizes the spectrum of expected and unexpected adverse effects of these drugs, possible associated mechanisms, and their basic functions for dermatologists. ACE inhibitors block the activity of the metalloproteinase ACE by binding to its active site, thus displacing angiotensin I and preventing its conversion to vasopressive angiotensin II. Furthermore, ACE degrades bradykinin, substance P, enkephalins and some of the reproductive peptide hormones. The overall incidence of adverse effects to ACE inhibitors is estimated at 28%, approximately half of which occurs in the skin. General reactions are first-dose hypotension, hyperkalaemia and renal failure. Cutaneous reactions comprise life-threatening angioedema, pruritus, bullous eruptions, urticaria, other generalized rashes, photosensitivity and hair loss. ACE inhibitors thus mimic a broad variety of skin diseases, why these drugs should be thought of when sudden, unexplainable skin eruptions are observed.

Effect of granulocyte macrophage colony-stimulating factor in a patient with benign systemic mastocytosis

We report the in vitro and in vivo effects of granulocyte macrophage colony stimulating factor (GM-CSF), a known inhibitor of in vitro mast cell differentiation, in a patient with benign, adult-onset systemic mastocytosis. In vitro effects of GM-CSF on bone marrow cultures before the start of treatment showed a marked inhibition of mast cell marker expression [tryptase, Kit, and high-affinity IgE receptor (FcepsilonRIalpha)] at both protein and mRNA levels. Therefore, the patient was treated with daily injections of GM-CSF for 10 weeks. After an initial improvement, increasing worsening of clinical symptoms was noted, and the patient refused further treatment. Lesional skin biopsies showed an increase of toluidine blue-positive mast cells, compared with uninvolved skin, with further significant increase after treatment. Similar results were obtained on staining for mast cell-specific tryptase and Kit, as well as for CD1a and FcepsilonRIalpha. These findings show that GM-CSF inhibits human bone marrow mast cell differentiation in vitro, and also in mastocytosis. However, GM-CSF apparently enhances recruitment of mast cell as well as dendritic cell precursors into the tissue during systemic treatment. These findings and the observed adverse clinical effects in the present patient make it unlikely that GM-CSF monotherapy will be beneficial for the treatment of mastocytosis.

Acute herpes zoster neuralgia: retrospective analysis of clinical aspects and therapeutic responsiveness

BACKGROUND

Although the efficacy of modern antiviral agents for the treatment of herpes zoster is unquestioned, their ability to affect the associated pain remains controversial.

OBJECTIVE

We have therefore evaluated the inpatient hospital records of 550 patients with herpes zoster with regard to pain-related clinical aspects and therapeutic responsiveness.

METHODS

Intensity of pain was quantified by calculating a daily pain equivalence index (PEI) on the basis of different classes of pain medication and the number of tablets used in each category.

RESULTS

The mean age of patients was 66.7 years, cranial segments were predominantly involved (55%), 64% of patients suffered from associated diseases and 77% experienced herpes-related pain. The PEI was 0.90 in the entire patient population, with significantly higher values in women and in patients with 3 or more associated diseases. It was lower in sacral and cranial nerve involvement, and it decreased rapidly in patients prior to discharge from hospital. Although there were significant differences in hospital stay between patients who received aciclovir and those who did not (mean 20.3 vs. 23.8 days), and for high- versus low-dose oral or intravenous administration, no significant differences were noted between the two groups for initial PEI values and during the course of observation, irrespective of the route of administration or the dose of aciclovir and the individual patient's PEI value. The groups were otherwise closely similar with regard to basic demographic and clinical data. 23.3% predominantly aged female patients with more associated diseases than the total patient population had a persistently elevated PEI and stayed in hospital beyond 21 days (mean 35.1 days), representing patients who went on to postherpetic neuralgia.

CONCLUSION

These data further delineate clinical aspects of acute herpes zoster neuralgia, underline the unsolved therapeutic problems associated with this condition despite otherwise effective antiviral treatment, and characterise a subgroup of patients at risk to develop postherpetic neuralgia.

The ascomycin macrolactam pimecrolimus (Elidel, SDZ ASM 981) is a potent inhibitor of mediator release from human dermal mast cells and peripheral blood basophils

BACKGROUND

The ascomycin macrolactam pimecrolimus (Elidel, SDZ ASM 981) has recently been developed as a novel and cell-selective inhibitor of inflammatory cytokine secretion; it has fewer adverse effects than currently available drugs.

OBJECTIVE

In this study, we investigated the capacity of pimecrolimus to directly inhibit in vitro mediator release from human skin mast cells and basophils.

METHODS

Purified cutaneous mast cells or basophil-containing peripheral blood leukocytes were obtained from healthy human donors and preincubated with pimecrolimus (0.1 nmol/L to 1 micromol/L) in the absence or presence of its specific antagonist (rapamycin), cyclosporin A (100 nmol/L to 1 micromol/L), or dexamethasone (1 micromol/L) and then stimulated with anti-IgE or with calcium ionophore A23187 plus phorbol myristate acetate. Cell supernatants were kept for analysis of histamine, tryptase, LTC4, and TNF-alpha.

RESULTS

Pimecrolimus caused a strong and dose-dependent inhibition of anti-IgE--induced release of histamine from mast cells and basophils (maximally 73% and 82%, respectively, at 500 nmol/L pimecrolimus) and of mast cell tryptase (maximally 75%) and a less pronounced inhibition of LTC4 (maximally 32%) and of calcium ionophore plus phorbol myristate acetate--induced mast cell TNF-alpha release (90% maximum at 100 nmol/L pimecrolimus). In contrast, inhibition achieved during mast cell histamine release was maximally 60% with cyclosporin A and only 28% with dexamethasone.

CONCLUSION

These data demonstrate a marked inhibitory capacity of pimecrolimus on mediator release from human mast cells and basophils with a potency exceeding that of cyclosporin A and dexamethasone. Pimecrolimus might thus be expected to be effective in the treatment of mast cell-- and basophil-dependent diseases.

The pharmacologic profile of desloratadine: a review

Desloratadine is a new agent for the treatment of diseases such as seasonal allergic rhinitis and chronic urticaria. The pharmacologic profile of desloratadine offers particular benefits in terms of histamine H1-receptor binding potency and H1 selectivity. Desloratadine has a half-life of 21-24 h, permitting once-daily dosing. No specific cautions are required with respect to administration in renal or hepatic failure, and food or grapefruit juice have no effect on the pharmacologic parameters. No clinically relevant racial or sex variations in the disposition of desloratadine have been noted. In combination with the cytochrome P450 inhibitors, ketoconazole and erythromycin, the AUC and Cmax of desloratadine were increased to a small extent, but no clinically relevant drug accumulation occurred. With high-dose treatment (45 mg/day for 10 days), no significant adverse events were observed, despite the sustained elevation of plasma desloratadine levels. Specifically, desloratadine had no effects on the corrected QT interval (QTc) when administered alone, at high dose, or in combination with ketoconazole or erythromycin. Preclinical studies also show that desloratadine does not interfere with HERG channels or cardiac conduction parameters even at high dose. Desloratadine is nonsedating and free of antimuscarinic/anticholinergic effects in preclinical and clinical studies. Novel antiallergic and anti-inflammatory effects have also been noted with desloratadine, a fact which may be relevant to its clinical efficacy.

GM-CSF downmodulates c-kit, Fc(epsilon)RI(alpha) and GM-CSF receptor expression as well as histamine and tryptase levels in cultured human mast cells

GM-CSF is known primarily as a hematopoietic growth factor, but it has also been shown to inhibit mast cell differentiation in vitro. In order elucidate the mechanisms involved, we investigated the effects of GM-CSF in vitro on the differentiation of human leukemic mast cells (HMC-1 cells) and normal cord blood-derived mast cells (CBMC) under the influence of SCF, NGF, and fibroblast supernatant (FS). Under all culture conditions, GM-CSF induced a dose- and time-dependent reduction in intracellular histamine levels, tryptase activity, and numbers of cells immunoreactive for c-Kit and FcepsilonRIalpha. This effect leveled off between 10-100 ng/ml and after 4 days of culture. There was an associated decrease in mRNA expression for c-kit, FcepsilonRIalpha and tryptase. In contrast, no significant changes in the expression of the NGF receptor TrkA were noted under the same conditions. The GM-CSF receptor was found in HMC-1 cells and CBMC at both the mRNA and protein levels, but its expression decreased during culture with FS, and even more markedly during culture with GM-CSF. GM-CSF thus selectively inhibits in vitro induction and/or upregulation of all major mast cell characteristics in HMC-1 cells and CBMC irrespective of the growth factors present, and a concomitant downregulation of GM-CSF receptors can counteract these effects. GM-CSF may therefore function as a regulatory factor in mast cell growth and differentiation under normal and pathological conditions.

Mastocytosis: recent advances in defining the disease

Mastocytosis is a rare disease characterized by a primary pathological increase in mast cells in different tissues, which may present in a variety of clinical patterns. Major advances have been made in recent years in the understanding of the pathogenesis of mastocytosis. This review is aimed at familiarizing dermatologists with these recent findings, and at exploring their possible implications for the diagnosis and treatment of the condition. The heterogeneous clinical presentation of mastocytosis is detailed with respect to the type of skin lesions, age at onset, family history, organ systems involved, associated haematological disorders and prognosis. Recent genetic findings also indicate different pathogenetic forms of mastocytosis, as adult patients and those with associated haematological diseases usually express activating mutations of the stem cell factor receptor c-kit, whereas most cases of childhood-onset and familial mastocytosis seem to lack these mutations. Despite the presence of c-kit mutations, patients with cutaneous lesions generally have a good prognosis, even when there is involvement of other organs. Some patients, particularly those with childhood-onset disease, experience spontaneous remission, mostly by puberty. c-kit mutations do not explain the initial cause of mastocytosis, and their prognostic significance is as yet unclarified, as is the pathogenesis in patients without the mutations. Furthermore, these novel findings have as yet not resulted in a more effective treatment of the cause of the disease, so that counselling, prevention of exposure to mast cell secretory stimuli, and symptomatic treatment remain the mainstays of current patient management.

Retinoic acid up-regulates myeloid ICAM-3 expression and function in a cell-specific fashion--evidence for retinoid signaling pathways in the mast cell lineage

Investigation of mast cell responsiveness toward retinoic acid (RA) revealed selective promotion of ICAM-3 expression in the human mast cell line HMC-1. This process was dose- and time-dependent and detectable by flow cytometry, Western blot analysis, ELISA, and Northern blot analysis. ICAM-3 modulation was found to be cell-type dependent, detectable also for HL-60 cells and monocytes but not U-937 and only weakly for KU812 cells. Terminally differentiated skin mast cells also failed to up-modulate their ICAM-3, suggesting the requirement for some degree of immaturity for the process. RA-mediated effects on ICAM-1 expression, studied in parallel, were clearly distinct from those on ICAM-3. Investigation of retinoid receptor expression, known to mediate intracellular RA signaling, revealed presence of RAR alpha, RAR gamma, RXR beta, and RXR gamma transcripts in all cell lines studied, and HMC-1 cells were the only line lacking RXR alpha. RAR beta, not expressed at baseline, was induced by RA in a fashion obviously correlating with ICAM-3 up-regulation. Increased ICAM-3 expression was of functional significance, such that processes stimulated or co-stimulated via ICAM-3 (homotypic aggregation, IL-8 secretion) were clearly enhanced upon RA pretreatment, suggesting that RA may contribute via hitherto unrecognized pathways to immune function and host defense.

Expression of mast cell growth modulating and chemotactic factors and their receptors in human cutaneous scars

In order to explore possible mechanisms involved in the previously documented turnover of mast cell subpopulations in human cutaneous scars, we have examined selected factors known to stimulate and/or modulate mast cell hyperplasia (SCF, NGF, TGFbeta1, GM-CSF) and their receptors in human cutaneous scar tissue. On immunohistochemistry, numbers of SCF- and TGFbeta1-positive cells were significantly increased in the epidermis and throughout the dermis in scars (n = 27) of varying ages (4-369 d old), compared with normal skin (n = 12). Furthermore, TRbetaRI, II, and the NGF-p75 receptors were significantly increased in the epidermis, TRbetaRI and NGF-TrkA throughout the dermis, and TRbetaRII, NGF-p75, and GM-CSFR only in the mid- and lower dermis of scars. NGF and GM-CSF expression was in contrast scarce and weak, with no differences between normal skin and scars. In tissue extracts, mRNA levels of SCF, TGFbeta1, TRbetaI and II, and both NGF-receptors, but not GM-CSFR, were significantly increased as well. TRbetaI and II were identified in up to 90% and 83%, respectively, of isolated normal skin mast cells on flow cytometry, and GM-CSFR and NGFR-p75 were identified on 70% and 73%, respectively, of avidin-positive normal mast cells on double immunofluorescence microscopy. As described before for the SCF receptor KIT, GM-CSFR and NGFR-p75 were partly or entirely downregulated on avidin-positive mast cells in scars. The marked upregulation of TGFbeta1, its type I and II receptors, and SCF suggest that these factors play a major role in the orchestration of mast cell increase in human cutaneous scars whereas the role of NGF and GM-CSF is less clear, despite the significant upregulation of their receptors.

Novel unconventional therapeutic approaches to atopic eczema

Atopic eczema is a chronic, recurrent, multifactorial skin disease, and, accordingly, there are numerous therapeutic options for its symptomatic treatment. Conventional medications are however often unsatisfactory for many patients because of adverse effects on long-term use. For this reason, patients often readily welcome unconventional therapeutic approaches. We present here a selected number of such treatment modalities, namely gamma-linolenic acid, Chinese herbal tea, diets eliminating allergens, pseudoallergens, metal salts and sodium, and bioresonance. When stringent scientific criteria are applied in the evaluation of such study results, none of the reviewed alternative treatments provides unequivocal, convincing evidence of its efficacy, even when double-blind, placebo-controlled studies are available. With Chinese herbal tea, potentially serious adverse effects should be considered as well. Any new type of unconventional therapy should thus be thoroughly evaluated and shown to be equal or superior to conventional treatments with regard to both efficacy and tolerability before it is recommended for use in clinical practice.

Mast cells as initiators of immunity and host defense

Until recently, mast cells have been viewed primarily as harmful because of their key role as effector cells of allergic and potentially lethal anaphylactic reactions. Their contribution to human health appeared instead to be limited to the elimination of parasites. There is, however, growing evidence for additional beneficial functions of mast cells, particularly regarding the initiation of acquired immune reactions. Thus, mast cells can phagocytize diverse particles, take up antigens, and express a number of receptors, particularly MHC class I and II antigens, ICAM-1 and -3, CD43, CD80, CD86 and CD40L which allow them to interact with T and B lymphocytes. They can also secrete numerous cytokines that induce and enhance recruitment and functions of lymphocytes. Finally, there is good evidence that mast cells present e.g. pollen and bacterial antigens, respond to bacterial superantigens, but fail to react to endogenously produced antigens or superantigens. Mast cells can also activate B cells directly to produce IgE, but this activity and the ability to produce IL-4 or IL-13 is restricted primarily to basophil leukocytes and mucosal mast cells. Finally, recent evidence attributes a pivotal role to the cells in natural immunity to bacteria. There is also emerging evidence that mast cells can downmodulate the immune response. While these data require further clarification, the basic ability of mast cells to initiate innate and acquired immune reactions can no longer be questioned.

Effects of retinoids on in vitro and in vivo IgE production

BACKGROUND

Retinoids modulate the growth and number of different cell types, including B cells. We could previously show that retinoic acid (RA) strongly inhibits CD40 + IL-4-mediated IgE production in vitro. The aim of the present study was to extend these findings regarding the potential use of retinoids for the treatment of allergic diseases.

METHODS

In vitro IgE production was studied in anti-CD40 + IL-4-stimulated peripheral blood mononuclear cells (PBMC) from allergic donors in the presence of 10(-15)-10(-5) M all-trans and 13-cis RA and in ovalbumin (OVA)-sensitized BALB/c mice treated with RA (20 mg/kg) before and during sensitization. IgE and IgG1 levels were determined in the sera of the mice at day 21 after 2 injections (days 1 and 8) of aluminum hydroxide-absorbed OVA.

RESULTS

All-trans and 13-cis RA inhibited in vitro IgE production from PBMC in a dose-dependent manner, but were more efficient in atopic dermatitis patients with low total serum IgE levels (< 400 kU/ml), maximal inhibition for all-trans RA at 10(-7) M (87%) and for 13-cis RA at 10(-5) M (96%) compared to patients with high serum IgE levels (>2,000 kU/ml), maximal inhibition for both all-trans and 13-cis RA at 10(-5) M (53 and 39%, respectively). In contrast, the in vivo data from OVA-sensitized mice revealed comparable total IgE and IgG1 levels in control versus all-trans RA or CD336-treated groups, specific IgE was even higher in the CD336-treated group (n = 10, 2,814 ng/ml), and was comparable in mice treated with OVA alone or with additional all-trans RA (n = 10, 1,447 and 1,354 ng/ml, respectively).

CONCLUSIONS

These results indicate that the efficacy of retinoids to inhibit IgE production in vitro depends on the frequency of switched cells in the peripheral blood and that in an in vivo model using OVA-sensitized mice, retinoids fail to inhibit IgE production.

alpha-Melanocyte stimulating hormone acts as a selective inducer of secretory functions in human mast cells

In the present study, we have investigated the pro-opiomelanocortin (POMC)-derived neuropeptide alpha-MSH for its ability to modulate activation of human mast cells. The in vitro ability of purified human skin mast cells to secrete various types of mast cell mediators was monitored in response to alpha-MSH at the mRNA and at the protein level. Picomolar concentrations of alpha-MSH induced a dose-dependent release of histamine from isolated human skin mast cells and from skin punch biopsies. However, no effect of alpha-MSH was seen regarding the expression of IL-1, IL-6, IL-8, TGF-beta, and TNF-alpha. Melanocortin receptor MC-1 was identified at the transcriptional level by RT-PCR analysis but not at the protein level, whereas, in leukemic human mast cells (HMC-1), the mRNAs and the proteins for the MC-1 and MC-5 receptor were identified. These results suggest that alpha-MSH may selectively induce acute inflammatory effects via secretion of histamine.

Anti-FcepsilonRIalpha serum autoantibodies in different subtypes of urticaria

BACKGROUND

In recent years, a histamine-releasing anti-FcepsilonRIalpha autoantibody has been demonstrated in about one-third of patients with chronic urticaria. However, its clinical significance is still unclear. The objective was to detect a possible correlation between the occurrence of the anti-FcepsilonRIalpha autoantibody and the clinical type or cause of urticaria.

METHODS

Sera from 66 consecutively seen in- and outpatients with various types of urticaria and five healthy controls were examined for the presence of anti-FcepsilonRIalpha autoantibodies with a sandwich ELISA technique. In addition, basophil histamine release was studied in 13 autoantibody-positive sera.

RESULTS

Anti-FcepsilonRIalpha autoantibodies were found in 17/48 patients with chronic urticaria, in 2/4 with angioedema, in 1/2 with urticarial vasculitis, and in 2/11 with dermographic urticaria. However, no anti-FcepsilonRIalpha autoantibodies were detected in acute, cold, or delayed-pressure urticaria; in urticaria pigmentosa; or in normal controls. Of all chronic urticaria patients, 22 were classified as idiopathic since no underlying cause could be found. Of this group, seven were seropositive for anti-FcepsilonRIalpha. However, anti-FcepsilonRIalpha was also found in patients who went into remission after treatment of identified causes; namely, in one with type I allergy, one with drug intolerance, one with Helicobacter infection, and six with food intolerance. The autoantibody was also detected in 2/4 patients with associated autoimmune diseases. Functional activity was shown in basophil histamine release in 3/4 autoantibody-positive sera of patients with chronic idiopathic urticaria and in 4/6 autoantibody-positive sera of patients who went into remission after the treatment of underlying causes.

CONCLUSIONS

These data confirm that anti-FcepsilonRIalpha autoantibodies in urticaria are mostly found in chronic urticaria. Furthermore, their detection independently of the apparent cause of the urticaria suggests that as yet unidentified mechanisms must be operative, possibly related to the chronic inflammatory process and/or individual predispositions that favor their induction.

Preclinical diagnosis of pseudoxanthoma elasticum - methodological restrictions and ethical problems

Pseudoxanthoma elasticum (PXE) is an inherited connective tissue disease. Only recently, mutations in the MRP6 gene on chromosome 16p13.1 have been identified in PXE families. Up to now, predictive testing has not been available. Since ultrastructural connective tissue alterations in overtly normal skin of predilection sites have supported preclinical diagnosis in children of affected individuals, we have screened the daughters of a PXE patient for these alterations. The patient's biopsy from lesional skin revealed elastin and collagen fibril abnormalities, but biopsies from the clinically inconspicuous daughters showed only ultrastructural alterations of collagen fibrils. These findings are inconclusive regarding the diagnosis of PXE in the daughters. Predictive or preclinical diagnosis of incurable, late-onset disorders creates complex social, ethical, and legal problems which call for special management strategies.

Distribution and potential biologic function of the thrombin receptor PAR-1 on human keratinocytes

Thrombin has recently been shown not only to exert procoagulant activities, but also to induce mitogenic responses of different cell types involved in wound healing via binding to and cleavage of the thrombin receptor. In order to further explore these aspects of thrombin function, human keratinocytes (HaCaT cell line) were examined for their potential mitogenic responsiveness to thrombin and for the dependency of this process on the expression of the high-affinity thrombin receptor. Quiescent keratinocytes were stimulated in the mitogenic assay with alpha-thrombin and the thrombin receptor activating peptides TRAP42-55 (SFLLRNPNDKYEPY) and TRAP42-46 (SFLLR). A strong induction of cell proliferation was noted with alpha-thrombin, TRAP42-55 and TRAP42-46, but not with the "scrambled" peptide (FSLLR). These findings confirm that keratinocytes express the thrombin receptor and that the sequence of the first two amino acids of the generated neo-N-terminus are important for the activation of the receptor. Using cDNA fragments of the 5' coding sequence of the receptor, Northern blot analysis confirmed that HaCaT keratinocytes express the thrombin receptor. Expression of the receptor was also detected on normal human keratinocytes by immunohistochemistry and in situ hybridization. These data demonstrate the expression and biologic function of the human thrombin receptor on human keratinocytes, suggesting that thrombin, among other mediators, plays an important part in the orchestration of epidermal growth and repair processes.

Erythema elevatum diutinum--evidence for disease-dependent leucocyte alterations and response to dapsone

Erythema elevatum diutinum (EED) is a type of leucocytoclastic vasculitis of unknown aetiology. We report a patient with unusually widespread and disabling EED that had been unresponsive to corticosteroids and antibiotics, but resolved on dapsone. Biopsies of fresh lesions showed typical features of leucocytoclastic vasculitis, with prominent neutrophil infiltration, marked expression of the beta(2)-integrins CR3 and LFA-1, and increased mast cell numbers. Older lesions exhibited granulation tissue and fibrosis, macrophages were more dominant, beta(2)-integrins were expressed less markedly, and mast cell numbers were lower. In vitro chemotaxis of the patient's peripheral blood neutrophils prior to treatment showed increased random migration and directed migration towards interleukin-8 (by 424%), but a profoundly decreased responsiveness towards the bacterial peptide analogue N-formyl-methionyl-leucyl-phenylalanine (fMLP) (by 98%). These values returned to normal after dapsone treatment and clinical improvement 5 months later. These findings support the concept that in EED, activation via cytokines such as interleukin-8 allows a selective recruitment of leucocytes to tissue sites, while immune complexes and bacterial peptides sustain the persistent local inflammatory infiltrate and the leucocytoclastic vasculitis.