The inhibition of free radical generation by human neutrophils through the synergistic effects of metronidazole with palmitoleic acid: a possible mechanism of action of metronidazole in rosacea and acne

Summary Metronidazole is clinically effective in treating not only rosacea but also acne inflammation. Yet it is generally considered not to be very effective in inhibiting the growth of anaerobic Propionibacterium acnes. We report here our investigation into the synergistic effects of metronidazole and palmitoleic acid on the anaerobic growth of P. acnes as well as on human neutrophil functions, including the generation of reactive oxygen species (ROS). Both metronidazole and palmitoleic acid, when used alone, only slightly inhibited the growth of P. acnes, and no significant decrease in human neutrophil functions, including the generation of ROS, was observed. But metronidazole used in the presence of palmitoleic acid markedly inhibited the anaerobic growth of P. acnes and decreased ROS generation by neutrophils. However, ROS generated in the xanthine-xanthine oxidase system were not affected. Metronidazole was shown to be clinically effective by decreasing neutrophil-generated ROS at the sites of inflammation with the aid of palmitoleic acid, which is generally present in human skin. By inhibiting oxidative tissue injury under in vivo conditions, treatment with metronidazole results in remarkable improvement of rosacea and acne.     

Impaired neutrophil functions in patients with leukocytoclastic vasculitis

Background Leukocytoclastic vasculitis (LV) is characterized by segmental inflammation of small blood vessels, resulting in ischemic damage to the surrounding tissue. It is considered to be related to a type III hypersensitivity reaction, although the exact etiologic mechanism is not clear. Objective The purpose of this study was to evaluate neutrophil functions in patients with LV in order to understand their role in the pathogenesis of the disease. Methods Neutrophil functions were examined in 25 LV patients. The patients were divided into two groups: Group A consisted of 14 patients with drug-induced LV and Group B consisted of 11 patients where LV was induced by other factors. Results Both groups of patients showed significantly reduced chemotaxis and phagocytosis. Superoxide generation was significantly lower (P < 0.001) only in neutrophils from patients in Group A: 5.8 ± 0.5 nmoles O₂/10⁶ cells/min compared to 9.08 ± 0.8 nmoles O2/106 cells/min in the controls. Preincubation on normal neutrophils with the patients' sera caused an increase in their superoxide generation in accordance with the high IL-8 levels in these sera. Conclusions Neutrophil functions were significantly impaired in patients with LV. It is likely that factors present in LV plasma may chronically activate neutrophils, so that they become refracfory to further stimulation. Our study showed that neutrophil superoxide generation is low only in drug-induced LV; this test may assist in distinguishing such patients from those with LV induced by other causes.     

Enhanced release of inflammatory mediators from lithium-stimulated neutrophils in psoriasis

We have used lithium salts to stimulate degranulation in order to assess neutrophil activity in psoriasis. Evidence is presented for significant enhancement of degranulation of β- glucuronidase (primary granules) and vitamin Bi2-binding protein (secondary granules) from lithium-stimulated neutrophils in psoriatic whole blood. Basal levels of granule markers showed no significant difference between normal and psoriatic neutrophils. On the other hand, enzymes associated with neutrophil function (myeloperoxidase and catalase) were found to be markedly increased in resting psoriatic neutrophils. An important recent development has been the observation that psoriatic neutrophils are ‘activated’ in terms of their neutrophil function. Wahba et al. (1978, 1979) observed enhanced chemotactic and phagocytic properties of isolated psoriatic neutrophils, and Sedgwick, Bergstresser & Hurd (1979, 1980) demonstrated increased adherence of isolated psoriatic neutrophils to glass-wool and nylon fibres. Recently, there have been a number of reports concerning the clearing of psoriasis in patients undergoing haemodialysis and peritoneal dialysis (McEvoy & Kelly, 1976; Buselmeier et al., 1979; Glinski et al., 1979), and it is now believed that improvement was a result of removal of neutrophils rather than some psoriatogenic factor. Lithium salts are commonly used in the treatment of bipolar affective psychosis. Lazarus & Gilgor (1979) drew attention to reports that lithium salts adversely affect the course of psoriasis by direct or indirect mechanisms. They may do so by affecting neutrophil function, thus establishing a relationship between psoriasis and neutrophil activity. Lithium salts can dramatically affect neutrophil activity in terms of granulopoiesis, turnover and migration (Rothstein et al., 1978). We have recently demonstrated that lithium salts have the capacity to induce directly the release of inflammatory mediators from neutrophils in normal whole blood, in the absence of phagocytic stimulation (Bloomfield & Young, 1982). The objective of this investigation was to demonstrate that lithium salts are capable of causing enhanced degranulation from psoriatic neutrophils. In addition, the results would demonstrate in vitro the possible effects which lithium might have in exacerbating psoriasis in vivo, i.e. by causing release of inflammatory mediators from neutrophils which have been shown to be activated.     

Effects of subminimal inhibitory concentrations of minocycline on neutrophil chemotactic factor production in comedonal bacteria,neutrophil phagocytosis and oxygen metabolism

Summary Comedonal bacteria, Propionibacterium acnes, P. granulosum and coagulase-negative staphylococci (CNS) seem to play an important initiating role in the inflammatory process by producing neutrophil chemotactic factors. The attracted neutrophils, after phagocytosis, release inflammatory factors such as reactive oxygen species (ROS). We investigated the effects of minocycline at subminimal inhibitory concentrations (sub-MIC), i.e. one-tenth MIC, on the production of human neutrophil chemotactic factors in comedonal bacteria, and on several inflammatory parameters of neutrophils, including neutrophil phagocytosis and generation of ROS (O ₂ ^– , H₂O₂, O ). ROS generation in a cell-free, xanthinexanthine oxidase system was also assessed. Production of neutrophil chemotactic factors in all strains of P. acnes, P. granulosum and CNS were significantly suppressed by sub-MIC minocycline. Sub-MIC minocycline effectively reduced three kinds of neutrophil-generated ROS (O ₂ ^– , H₂O₂, O ). However, neutrophil phagocytosis and the ROS generated in a cell-free system were not markedly changed in the presence of sub-MIC minocycline. The results suggest that sub-MIC minocycline has an anti-inflammatory effect by inhibiting the production of neutrophil chemotactic factors in comedonal bacteria as well as ROS generated by neutrophils in the inflammatory process of acne.     

Corticosteroid treatment of prolidase deficiency skin lesions by inhibiting iminodipeptide-primed neutrophil superoxide generation

We studied the pathogenetic role of iminodipeptides, and the effects of corticosteroids on the skin lesions of two adult female siblings with prolidase deficiency. The elder sister had had severe skin ulcers and mental retardation since childhood, while the younger sister had shown milder clinical manifestations since late adolescence. The ulcers showed vascular wall thickening and neutrophil infiltration. Oral prednisolone at moderate doses was not effective, but corticosteroid pulse therapy followed by a moderate dose of prednisolone improved the preulcerative indurated lesions and ulcers. A 2-year follow-up of the younger patient indicated that N-formyl methionyl leucyl phenylalanine-induced neutrophil superoxide generation was elevated, in parallel with an increase in the serum iminodipeptide level, when the skin ulcers and preulcerative indurated lesions were most active. Corticosteroid pulse therapy downregulated the superoxide generation by neutrophils. The serum iminodipeptide level, however, did not decrease during 25 days after pulse therapy. These findings suggest that iminodipeptides may play an important part in aggravating the skin lesions by priming neutrophil superoxide generation, and that high-dose corticosteroids improve the skin lesions, probably by inhibiting the infiltration, and superoxide generation by, neutrophils. Neutrophil superoxide generation was more prominent in the elder sister, suggesting that clinical severity may depend on the response of neutrophils to the iminodipeptides. Chronic stimulation by superoxide may cause thickening of cerebral blood vessels and eventual mental retardation.     

Increased advanced oxidation protein products in Behçet's disease: a new activity marker?

Background Behçet's disease (BD) is a chronic inflammatory disease with unknown pathogenesis. As various functions of neutrophils in peripheral blood, such as chemotaxis, phagocytosis and generation of reactive oxygen species (ROS) increase in BD, ROS‐mediated oxidative stress related to neutrophil activation may have an important role in the pathogenesis of BD. Objectives To investigate the importance of neutrophil activation as the main source of oxidative stress through protein oxidation in the pathogenesis of BD, and also to investigate whether one of the products of protein oxidation, advanced oxidation protein products (AOPP), may be used as an activity marker for BD. Methods Patients with BD (n = 49), at active and inactive stages, with or without evidence of uveitis, and healthy volunteers (n = 40) were entered into the study. A full blood count, peripheral blood smears, routine biochemical analyses, C‐reactive protein (CRP) and erythrocyte sedimentation rate (ESR) measurements were performed in all patients preceding the study. Plasma myeloperoxidase (MPO) activity, representing neutrophil activation, and biomarkers of oxidative stress reflecting protein oxidation, such as levels of AOPP and thiol, were measured spectrophotometrically. Statistical comparisons were made using Mann–Whitney U‐tests, Student's t‐tests, anova /post‐anova tests and correlation analyses. Results In all patients, the results of full blood count, peripheral blood smears and routine biochemical analyses were in the normal range, but mean values of CRP and ESR were higher than laboratory reference values. Plasma MPO activity and AOPP levels were found to be higher and thiol values lower in the total patient group and individual subgroups than in controls. Patients with active BD had significantly higher MPO and AOPP levels and lower thiol levels than patients with inactive BD. There was no difference between uveitis‐positive and uveitis‐negative subgroups in MPO and thiol levels, but AOPP levels were lower in the latter group. Patients with active BD ± uveitis were shown to have increased MPO and AOPP but decreased thiol levels in comparison with the inactive BD, uveitis‐negative subgroup. There were strong positive correlations between ESR and CRP, ESR and MPO, ESR and thiol, ESR and AOPP, CRP and MPO, CRP and AOPP, MPO and AOPP, and thiol and AOPP levels in patients with BD. Conclusions Based on this first study, in which MPO‐mediated AOPP formation has been demonstrated, it may be suggested that activated neutrophils may play an important role in the pathogenesis of BD and that chlorinated oxidants of neutrophil origin may lead to oxidative stress, notably protein oxidation. Therefore, AOPP may be a useful marker for monitoring the progress and the severity of the disease activity.     

Recurrent furunculosis: a review of the literature

Background Community‐associated methicillin‐resistant Staphylococcus aureus (CA‐MRSA) is increasing in incidence and manifests as skin and soft tissue infections including furuncles. The majority of studies have focused on the epidemiology of single furuncles and not recurrent disease. There is a lack of data concerning the incidence of furunculosis outside the U.S.A. Objectives This report reviews the literature of recurrent furunculosis and the impact of CA‐MRSA on the disease. Methods Article citations were searched within PubMed. Search terms used were ‘furunculosis’, ‘recurrent furunculosis’, ‘skin abscess’ and ‘recurrent boils’. Articles were discarded if they did not refer to furunculosis secondary to S. aureus. Results A total of 1515 articles were initially retrieved with the term ‘furunculosis’, 77 with the term ‘recurrent furunculosis’, 2778 with the term ‘skin abscess’, and 1526 with the term ‘recurrent boils’. After excluding articles not referring to S. aureus furunculosis, 86 articles were included for this review. Conclusions Furunculosis is increasing within the U.S.A. secondary to the CA‐MRSA epidemic and the resistant organism’s close association with the Panton–Valentine leucocidin (PVL) virulence factor. PVL is associated with follicular infections in general, having its strongest association with furunculosis and its recurrence. The majority of furuncles in the U.S.A. are caused by CA‐MRSA, while elsewhere in the world they are caused by methicillin‐sensitive S. aureus. Nasal carriage of S. aureus is the primary risk factor for recurrent furunculosis and occurs in 60% of individuals.     

Juvenile pityriasis rubra pilaris associated with hypogammaglobulinaemia and furunculosis

We report a case of follicular keratosis with inflammatory changes, consistent with a diagnosis of atypical juvenile pityriasis rubra pilaris. An unusual feature was the occurrence of severe Staphylococcus aureus folliculitis and furunculosis, a phenomenon rarely encountered in pityriasis rubra pilaris and the other follicular keratoses. Standard antibiotic and antiseptic treatment for chronic S. aureus infection was ineffective. The patient was subsequently found to have hypogammaglobulinaemia, and treatment with human polyvalent immunoglobulin infusions was successful in eradicating the sepsis. It is therefore probable that the hypogammaglobulinaemia played a pathogenic role in the development of cutaneous sepsis.     

A recombinant fusion protein derived from dog hookworm inhibits autoantibody‐induced dermal–epidermal separation ex vivo

The proteins secreted by parasitic nematodes are evolutionarily optimized molecules with unique capabilities of suppressing the immune response of the host organism. Neutrophil inhibitory factor (NIF), which is secreted by the dog hookworm Ancylostoma caninum, binds to the β2 integrin CD11b/CD18, which is expressed on human neutrophils, eosinophils, monocytes and macrophages and inhibits neutrophil‐dependent lung injury and neutrophil invasion of ischaemic brain tissue. Neutrophils are key players in the pathogenesis of subepidermal autoimmune blistering diseases (sAIBDs), and their pathogenic activities are crucially dependent on β2 integrin functionality. Based on the template of single‐stranded, dimerizing antibody derivatives, which are already used in cancer treatment, we designed a novel biologic, NIF‐IGHE‐CH4, comprising NIF and the dimerizing but otherwise inert constant heavy subdomain 4 (CH4) of human IgE (IGHE). This molecule was evaluated in a variety of in vitro assays, demonstrating its ability to inhibit pathogenically relevant neutrophil functions such as migration, adhesion and spreading, and release of reactive oxygen species. Finally, we confirmed that NIF‐IGHE‐CH4 inhibits blister formation in an ex vivo assay of sAIBD. These results suggest that NIF‐IGHE‐CH4 is a novel potential anti‐inflammatory drug for the treatment of neutrophil‐mediated diseases such as sAIBDs. This study promotes the drugs from bugs concept and encourages further research and development focused on turning parasite proteins into useful anti‐inflammatory biologics.     

C‐reactive protein and leucocyte activation in psoriasis vulgaris according to severity and therapy

Background Psoriasis vulgaris is a chronic recurrent inflammatory skin disease and psoriatic lesions have shown leucocyte infiltration. Objectives We aimed to study C‐reactive protein (CRP) and leucocyte activation markers/inhibitors as potential monitors of psoriasis vulgaris. Methods A cross‐sectional (n = 73) and a longitudinal study (before, at 3, 6 and 12 weeks of therapy; n = 47) was performed; 10 patients started topical treatment, 17 narrow‐band ultraviolet light B (NBUVB) and 20 psolaren associated to UVA (PUVA); psoriasis severity was defined by Psoriasis Area and Severity Index (PASI). Results Compared with control (n = 38), we found higher CRP levels, total leukocyte/neutrophil count, elastase, lactoferrin and α1‐antitrypsin. Increasing PASI was linked to increasing CRP and a trend to higher elastase and lactoferrin, suggesting that worsening enhances inflammatory response with neutrophil activation. CRP correlated with PASI, total leucocytes, neutrophils, elastase, lactoferrin and α1‐antitrypsin. NBUVB and PUVA presented similar effects. Conclusion We propose CRP as a useful marker of psoriasis severity that could be used to monitor psoriasis and its treatment, and, together with PASI and elastase, could also be used as a global index of severity.     

Human leukocyte elastase and cathepsin G are specific inhibitors of C5a-dependent neutrophil enzyme release and chemotaxis

Circulating human neutrophils from patients with severe inflammatory disorders such as erysipelas and sepsis are specifically desensitized to complement factor C5a stimulation but not to stimulation with other stimuli like N-formyl-methionyl-leucyl-phenylalanine (FMLP), interleukin-8 (IL-8), leukotriene B4 (LTB4), or platelet-activating factor (PAF, 1-O-alkyl-2-acetyl-sn-glycero-3-phosphocholine). In this study, we raised the question whether factors released from polymorphonuclear leukocytes (PMNs) can specifically down-regulate C5a-dependent neutrophil functions. When neutrophils were preincubated with either neutrophil lysates or neutrophil degranulation supernatants, a complete inhibition of C5a-stimulated beta-glucuronidase release and chemotaxis could be observed, whereas FMLP-, IL-8-, LTB4- or PAF-dependent functions were not affected. Serine protease inhibitors like phenylmethylsulfonyl fluoride, antileukoprotease, or elafin abolished this effect. High-performance liquid chromatography of neutrophil degranulation supernatants revealed pronounced inhibition of C5a-dependent neutrophil functions in fractions exerting elastase or cathepsin G activity, but not in fractions exerting proteinase 3 activity. Using purified human leukocyte elastase (HLE), C5a responses like intracellular calcium influx, beta-glucuronidase release, and chemotaxis were also specifically inhibited. Our experiments show that the release of HLE or cathepsin G from neutrophils specifically down-regulates the responsiveness of neutrophils to C5a. Elastase and cathepsin G may therefore play an important role in the down-regulation of acute inflammation.     

Suppressive effects of linoleic acid on neutrophil oxygen metabolism and phagocytosis

On the basis of recent reports that the proportion of linoleic acid (C18:2Cis 9,12), a free fatty acid, is markedly decreased in acne comedones and that tetracycline is effective against acne comedones by acting directly as an antioxidant on infiltrating neutrophils, we investigated the effect of linoleic acid on several inflammatory parameters of neutrophils, including neutrophil chemotaxis, phagocytosis, and generation of reactive oxygen species (ROS). Linoleic acid significantly decreased phagocytosis and the generation of O2-, H2O2, and OH.by neutrophils, whereas it did not significantly inhibit neutrophil chemotaxis or decrease the ROS levels generated in a cell-free, xanthine-xanthine oxidase system. The present study seems to suggest that decreased levels of linoleic acid in acne comedones contribute, in part, to the worsening of acne inflammation by the failure of low levels of linoleic acid to suppress neutrophil phagocytosis and ROS generation.     

Demodex-associated bacterial proteins induce neutrophil activation

Summary Background Patients with rosacea demonstrate a higher density of Demodex mites in their skin than do controls. A bacterium isolated from a Demodex mite from a patient with papulopustular rosacea (PPR) was previously shown to provoke an immune response in patients with PPR or ocular rosacea, thus suggesting a possible role for bacterial proteins in the aetiology of this condition. Objectives To examine the response of neutrophils to proteins derived from a bacterium isolated from a Demodex mite. Methods Bacterial cells were lysed and proteins were partially purified by ÄKTA fast protein liquid chromatography. Isolated neutrophils were exposed to bacterial proteins and monitored for alterations in migration, degranulation and cytokine production. Results Neutrophils exposed to proteins from Bacillus cells demonstrated increased levels of migration and elevated release of matrix metalloprotease 9, an enzyme known to degrade collagen, and cathelicidin, an antimicrobial peptide. In addition, neutrophils exposed to the bacterial proteins demonstrated elevated rates of interleukin 8 and tumour necrosis factor‐α production. Conclusions Proteins produced by a bacterium isolated from a Demodex mite have the ability to increase the migration, degranulation and cytokine production abilities of neutrophils. These results suggest that bacteria may play a role in the inflammatory erythema associated with rosacea.     

Evidence that a neutrophil–keratinocyte crosstalk is an early target of IL‐17A inhibition in psoriasis

The response of psoriasis to antibodies targeting the interleukin (IL)‐23/IL‐17A pathway suggests a prominent role of T‐helper type‐17 (Th17) cells in this disease. We examined the clinical and immunological response patterns of 100 subjects with moderate‐to‐severe psoriasis receiving 3 different intravenous dosing regimens of the anti‐IL‐17A antibody secukinumab (1 × 3 mg/kg or 1 × 10 mg/kg on Day 1, or 3 × 10 mg/kg on Days 1, 15 and 29) or placebo in a phase 2 trial. Baseline biopsies revealed typical features of active psoriasis, including epidermal accumulation of neutrophils and formation of microabscesses in >60% of cases. Neutrophils were the numerically largest fraction of infiltrating cells containing IL‐17 and may store the cytokine preformed, as IL‐17A mRNA was not detectable in neutrophils isolated from active plaques. Significant clinical responses to secukinumab were observed 2 weeks after a single infusion, associated with extensive clearance of cutaneous neutrophils parallel to the normalization of keratinocyte abnormalities and reduction of IL‐17‐inducible neutrophil chemoattractants (e.g. CXCL1, CXCL8); effects on numbers of T cells and CD11c‐positive dendritic cells were more delayed. Histological and immunological improvements were generally dose dependent and not observed in the placebo group. In the lowest‐dose group, a recurrence of neutrophils was seen in some subjects at Week 12; these subjects relapsed faster than those without microabscesses. Our findings are indicative of a neutrophil–keratinocyte axis in psoriasis that may involve neutrophil‐derived IL‐17 and is an early target of IL‐17A‐directed therapies such as secukinumab.     

Antioxidant status in patients with lichen planus

Background. Lichen planus (LP) is an autoimmune inflammatory disease of the mucocutaneous tissue, whose exact pathological course is not yet understood. Many studies have implicated the role of reactive oxygen species (ROS) and the protective role of antioxidants in several autoimmune skin disorders. In this study, serum levels of antioxidants in patients with LP were determined and compared with those of healthy controls. Methods. In total, 30 patients with LP (mean ± SD age 41.63 ± 13.03), who had never received treatment for their disease, were enrolled; 30 healthy people (aged 41.17 ± 13.24) were recruited as the control group. Serum levels of glutathione peroxidase (GPX), vitamin C, selenium, bilirubin and uric acid were determined. Results. The mean plasma level of vitamin C was significantly lower (P < 0.001) in patients compared with controls. A significant positive correlation was found between selenium and GPX in both patients (Spearman ρ = 0.99, P < 0.001) and controls (ρ = 0.10, P < 0.001). Conclusions. Lower serum levels of vitamin C in patients with LP indicates that free radicals and the resulting oxidative damage may be important in the pathogenesis of LP lesions.     

Phagocytosis and oxidative burst by neutrophils in patients with recurrent furunculosis

Neutrophil phagocytosis of fluorescently labelled Staphylococcus aureus and oxidative burst by the neutrophils were assessed by flow cytometry in 22 patients with recurrent furunculosis and in 17 controls. Phagocytosis and oxidative burst were not found to be significantly different between the patients and controls. Low serum iron concentrations were demonstrated in six patients (27%). In these patients with hypoferraemia, oxidative burst was significantly lower than in the patients without hypoferraemia and in the controls. These data suggest that hypoferraemia may be an important predisposing factor in a subgroup of patients with recurrent furunculosis in impairing oxidative killing by neutrophils.     

Distinct compartmentalization of immune cells and mediators characterizes bullous pemphigoid disease

Bullous pemphigoid (BP) is an autoimmune blistering disease characterized by recruitment of leucocytes into skin and release of damaging enzymes, resulting in epidermal detachment and blister formation. To better understand the role of leukotriene B4 (LTB4) and other inflammatory factors in BP pathophysiology, we conducted microscopic and immunohistochemical analyses of preserved skin biopsy sections and conducted flow cytometry and ELISA analyses of matched blood and blister fluid from BP patients. Neutrophils predominated in BP blister fluid, which also contained monocytes/macrophages and T cells, but few to no eosinophils and B cells. In contrast, BP skin histology showed a different pattern, with abundant neutrophils but eosinophils being the predominant immune cell type. LTB4 pathway and neutrophil activation markers were prevalent in BP skin lesions and strongly associated with perivascular neutrophils. Blister fluid neutrophils, monocytes/macrophages and eosinophils all exhibited increased surface expression of leukotriene A4 hydrolase and neutrophil elastase (P = .002 for both). Blister fluid was also enriched in interleukins (IL)-1α, IL-1β, IL-8, IL-10, IL-18, monocyte colony-stimulating factor (M-CSF) and vascular endothelial growth factor (VEGF). Our findings suggest differential leucocyte recruitment from blood into dermis and from dermis into blister, which correlates with disease activity, and presents potential new treatment opportunities for BP.     

Inhibitory effect of sulfonated shale oils (ammonium bituminosulfonate) on the stimulation of neutrophilic granulocytes by the chemotactic tripeptide f-Met-Leu-Phe

Summary Sulfonated shale oils (ammonium bituminosulfonate, ichthammol, Ichthyol), shown previously to induce the directed migration of human neutrophils in Boyden chambers and to inhibit the directed migration towards the chemotactic factors C5a, LTB₄, and f-Met-Leu-Phe, were studied for their effect on other neutrophil functions, which are stimulated by chemotactic factors. Like other chemotactic factors ammonium bituminosulfonate increased the adherence of neutrophils to nylon fibers, but it did not induce the release of the primary granule enzyme glucosaminidase from cytochalasin B-treated cells and it did not stimulate the production of oxygen radicals as measured by lucigenin-dependent chemiluminescence if studied under nontoxic conditions. When added together with the chemotactic tripeptide f-Met-Leu-Phe, ammonium bituminosulfonate inhibited adherence augmentation, enzyme release, and oxygen-radical production induced by the chemotactic factor. The results indicate that ammonium bituminosulfonate not only inhibited chemotactic migration but the whole spectrum of neutrophil functions induced by a chemotactic factor.     

Critical role of neutrophils for the generation of psoriasiform skin lesions in flaky skin mice

Although T cell dysregulation is thought to underlie the pathogenesis of psoriasis, prominent infiltration and microabscess formation by neutrophils is a distinctive hallmark feature of this common disorder. The exact role of neutrophils in the pathogenesis of psoriasiform alterations in vivo, however, is unknown. Similar to human psoriasis, flaky skin mice (fsn/fsn) revealed a prominent infiltrate of neutrophils, and microabscesses within the hyperproliferative epidermis were associated with de novo expression of intercellular adhesion molecule-1. Intraperitoneal injection with the neutrophil-depleting RB6-8C5 monoclonal antibody (anti-Ly-6G) resulted in a dramatic reduction of the epidermal thickness by 58% compared with isotype-treated animals (p < 0.001). In addition, epidermal microabscesses were conspicuously absent (p < 0.001), and cutaneous neutrophils and T cells, but not mast cells or dendritic cells, were markedly reduced in anti-Ly-6G-treated mice. Proinflammatory cytokines, including tumor necrosis factor alpha and interleukin-1, were also downregulated. Therapeutic effects occurred as early as 4 d after beginning of treatment. Wildtype skin was not affected. When the integrin alphaMbeta2 (CD11b/CD18), which mediates neutrophil localization through binding to intercellular adhesion molecule-1, was blocked in vivo with the M1/70 monoclonal antibody, the epidermal thickness was reduced by 31% (p < 0.002), and neutrophil and T cell accumulation was diminished compared with control animals. Likewise, treatment of fsn/fsn mice with the MP1-22E9 monoclonal antibody neutralizing granulocyte macrophage-colony stimulating factor, a cytokine stimulating neutrophils by upregulating alphaMbeta2, resulted in significant reduction of inflammation and acanthosis by 30% (p < 0.003). These results demonstrate a critical pathogenic role of neutrophils for hyperproliferative inflammatory lesions in fsn/fsn mice, suggesting that blocking neutrophil function may have therapeutic benefit in some human skin disorders.     

COMPARISON OF TOPICAL PHENYTOIN WITH NORMAL SALINE IN THE TREATMENT OF CHRONIC TROPHIC ULCERS IN LEPROSY

Background. Trophic ulceration, one of the most common complications of leprosy, is disabling, distressing, and demoralizing for the patient. Methods. The wound healing effects of topical phenytoin powder were compared with those of normal saline in a controlled in-patient study of 100 patients with 110 trophic leprosy ulcers of varying chronicity, over a 4-week study period. Fifty patients were assigned to the topical phenytoin group and 50 to saline therapy group. Ten patients had two ulcers each, and, in these cases, one ulcer was treated with phenytoin and the other with saline. Results. Over the 4-week treatment period healthy granulation tissue appeared earlier, and mean percentage of ulcer volume reduction was greater, in the phenytoin group (72.1 ± 19.9% versus 55.5 ± 21.6%) compared with the control group. Conclusions. This difference was statistically significant at the level of P < 0.001. Phenytoin appears to be a useful agent for the promotion of healing of trophic leprosy ulcers.