Involvement of complement in psoriasis and atopic dermatitis--measurement of C3a and C5a, C3, C4 and C1 inactivator

Clinical features and biomarker differences of severe intrinsic and extrinsic atopic dermatitis

OBJECTIVES

Atopic dermatitis (AD) can be classified into intrinsic AD(IAD) and extrinsic AD(EAD). However, the differences in clinical features and pathogenesis between these two subtypes of AD are currently unclear. This study aimed to analyse the differences in clinical features and peripheral blood biomarkers between Chinese patients with severe IAD and EAD in order to elucidate the physiopathogenesis of AD.

MATERIALS AND METHODS

A total of 316 hospitalised patients definitively diagnosed with severe AD were included in this study. There were 72 cases of severe IAD and 244 cases of severe EAD. The clinical features of the patients were recorded in details. Serum total IgE, IgA, IgG, IgM, complementC3/C4, peripheral blood cell counts, lactate dehydrogenase (LDH), C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), IL-2R, IL-6, IL-8, and TNF-α in AD patients and 60 age-matched healthy controls were analysed. IAD and EAD had similar severity/Scoring Atopic Dermatitis (SCORAD) scores.

RESULTS

Compared with healthy controls, IAD patients had significantly higher total IgE, eosinophils, monocytes, LDH, CRP, IL-2R, IL-6, IL-8 and TNF-α, and lower IgM and C4. EAD patients had significantly higher total IgE, IgA, eosinophils, white blood cell (WBC) counts, neutrophils, monocytes, basophils, LDH, CRP, IL-2R, IL-6, IL-8, TNF-α and lower IgM than healthy controls. IAD patients had a higher percentage of rural/urban living and female/male, a shorter course of disease and lower total IgE, eosinophils, WBC counts, neutrophils, monocytes, basophils, LDH, IgG and C4 than EAD patients. SCORAD scores, eosinophils, LDH expression levels increased with total IgE uniquely in patients with EAD.

CONCLUSIONS

IAD and EAD exhibit specific clinical features and molecular changes. IAD has a more complex physiopathogenesis, and deserves further investigation.

Exploring Psoriasis Inflammatory Microenvironment by NanoString Technologies

Psoriasis is a chronic inflammatory skin disease whose molecular mechanisms and microenvironment are poorly understood. We performed gene expression analysis through the nCounter® PanCancer Immune Profiling Panel (NanoString Technologies, Seattle, WA, USA) on 22 FFPE punch biopsies from 19 psoriasis-affected patients. A subset of five cases was analyzed before (T0) and after 6 months (T6) of treatment with dimethyl fumarate (DMF) to address immune microenvironment changes. Molecular comparisons according to biopsy site and age of onset showed a different distribution of innate immune cells (mast cells, macrophages, NK cells, and DC cells) and pathways (complement regulation and transporter functions). The analysis according to PASI (Psoriasis Area and Severity Index) led to non-significant results, suggesting no link between molecular expression profile and clinical amount of skin disease. In DMF-treated patients, we observed a strong immunomodulatory effect after treatment: A subversion of exhausted CD8 T cells, NK CD56dim cells, Tregs, neutrophils, CD45+ cells, T cells, B cells, and macrophages was reported between the two analyzed time-points, as well as the reduction in pro-inflammatory pathways and molecules, including cytotoxicity, pathogen defense, antigen processing, adhesion, cell cycle, chemokines, cytokines, and interleukins. The inflammatory psoriatic microenvironment can be modulated using DMF with encouraging results, achieving an immune-tolerant and non-inflammatory condition through the regulation of both innate and adaptive immunity.

Age-related macular degeneration and premorbid allergic diseases: a population-based case-control study

Evidence indicates that age-related macular degeneration (AMD) is associated with the prior presence of allergic diseases; however, large-scale studies in the literature are limited. A case-control study was conducted to describe the relationship between premorbid allergic diseases and AMD using Taiwan's National Health Insurance database. Eligibility criteria for inclusion of new adult AMD cases from 2000 to 2013 were set up. We defined the year of diagnosis as the index year. Age-, gender-, index year- matched controls who were drawn from the same database. The case control ratio was 1:4. For all participants, all premorbid conditions staring 1996 to index year were documented. Binary logistic regression was used to describe factors related to AMD occurrence. The AMD group consisted of 10,911 patients, and the comparison group consisted of 43,644 individuals. Patients with AMD showed significant associations with premorbid allergic diseases (aOR 1.54, 95% CI 1.47-1.61), specifically with allergic conjunctivitis (aOR 2.07, 95% CI 1.94-2.20), allergic rhinitis (aOR 1.32, 95% CI 1.25-1.39), asthma (aOR 0.99, 95% CI 0.93-1.06), and atopic dermatitis (aOR 1.04, 95% CI 0.94-1.17). Further analyses indicated that patients with more concurrent allergic diseases have higher associations with AMD than those with fewer concurrent diseases. Patients with more annual medical visits for their allergic diseases also showed higher associations with AMD than those with fewer visits. AMD is significantly associated with premorbid allergic diseases. The underlying mechanisms must be further investigated.

C5a/C5aR1 mediates IMQ-induced psoriasiform skin inflammation by promoting IL-17A production from γδ-T cells

Psoriasis is a chronic relapsing inflammatory skin disease, affecting up to 3% of the global population. Accumulating evidence suggests that the complement system is involved in its pathogenesis. Our previous study revealed that the C5a/C5aR1 pathway is crucial for disease development. However, the underlying mechanisms remain largely unknown. To explore potential mechanisms, psoriatic skin lesions and histological changes were assessed following imiquimod (IMQ) cream treatment. Inflammatory cytokine expression was tested by real-time RT-PCR. Immunohistochemistry and flow cytometry were used to identify inflammatory cell infiltration and interleukin (IL-17A) IL-17A expression. A C5aR1 antagonist (C5aR1a) and PI3K inhibitor (wortmannin) were used for blocking experiments (both in vivo and in vitro) to explore the mechanism. C5a/C5aR1-pathway inhibition significantly attenuated psoriasis-like skin lesions with decreased epidermal hyperplasia, downregulated type 17-related inflammatory gene expression, and reduced IL-17A-producing γδ-T cell responses. Mechanistically, C5a/C5aR1 promoted the latter phenotype via PI3K-Akt signaling. Consistently, C5aR1 deficiency clearly ameliorated IMQ-induced chronic psoriasiform dermatitis, with a significant decrease in IL-17A expression. Finally, blocking C5aR1 signaling further decreased psoriasiform skin inflammation in IL-17-deficient mice. Results suggest that C5a/C5aR1 mediates experimental psoriasis and skin inflammation by upregulating IL-17A expression from γδ-T cells. Blocking C5a/C5aR1/IL-17A axis is expected to be a promising strategy for psoriasis treatment.

C5a/C5aR1 Pathway Is Critical for the Pathogenesis of Psoriasis

Psoriasis is one of the most common chronic inflammatory skin diseases, affecting ~2% of the population. The lack of characterization of the pathogenesis of psoriasis has hindered efficient clinical treatment of the disease. In our study, we observed that expression of complement component 5a receptor 1(C5aR1) was significantly increased in skin lesions of both imiquimod (IMQ) and IL23-induced psoriatic mice and patients with psoriasis. C5aR1 deficiency or treatment with C5a receptor 1 antagonist (C5aR1a) in mice significantly attenuated psoriasis-like skin lesions and expression of inflammatory cytokines and chemokines. Moreover, C5aR1 deficiency significantly decreased IMQ-induced infiltration of plasmacytoid dendritic cells (pDCs), monocytes and neutrophils in psoriatic skin lesions and functions of pDCs, evidenced by the remarkable reduction in the IMQ-induced production of interferon-α (IFN-α) and tumor necrosis factor α (TNF-α), and FMS-like tyrosine kinase 3 ligand (FLT3L)-dependent pDCs differentiation. Accordingly, in vitro treatment with recombinant C5a accelerated pDCs migration and the differentiation of bone marrow cells into pDCs. Furthermore, biopsies of psoriatic patients showed a dramatic increase of C5aR1⁺ pDCs infiltration in psoriatic skin lesions, compared to healthy subjects. Our results provide direct evidence that C5a/C5aR1 signaling plays a critical role in the pathogenesis of psoriasis. Inhibition of C5a/C5aR1 pathway is expected to be beneficial in the treatment of patients with psoriasis.

Bee Venom Alleviates Atopic Dermatitis Symptoms through the Upregulation of Decay-Accelerating Factor (DAF/CD55)

Bee venom (BV)—a complex mixture of peptides and toxic proteins including phospholipase A2 and melittin—promotes blood clotting. In this study, we investigated the anti-atopic properties of BV and the mechanism associated with its regulation of the complement system. BV treatment upregulated the mRNA and protein levels of CD55 in THP-1 cells. Further experiments revealed that the phosphorylation of ERK was associated with upregulation of CD55. A complement-dependent cytotoxicity assay and a bacteria-killing assay showed that BV inactivated the complement system through the induction of CD55. The serum levels of C3 convertase (C3C) and Membrane attack complex (MAC) increased, while CD55 decreased in mice with AD-like lesions from DNCB treatment. However, the levels were inverted when the AD-like mice were treated with BV using subcutaneous injection, and we observed that the AD symptoms were alleviated. BV is often used to treat AD but its mechanism has not been elucidated. Here, we suggest that BV alleviates AD through the inactivation of the complement system, especially by the induction of CD55.

C3a is required for ILC2 function in allergic airway inflammation

Aberrant type 2 responses underlie the pathologies in allergic diseases like asthma, yet, our understanding of the mechanisms that drive them remains limited. Recent evidence suggests that dysregulated innate immune factors can perpetuate asthma pathogenesis. In susceptible individuals, allergen exposure triggers the activation of complement, a major arm of innate immunity, leading to the aberrant generation of the C3a anaphylatoxin. C3 and C3a have been shown to be important for the development of Th2 responses, yet remarkably, the mechanisms by which C3a regulates type 2 immunity are relatively unknown. We demonstrate a central role for C3a in driving type 2 innate lymphoid cells (ILC2)-mediated inflammation in response to allergen and IL-33. Our data suggests that ILC2 recruitment is C3a-dependent. Further, we show that ILC2s directly respond to C3a, promoting type 2 responses by specifically: (1) inducing IL-13 and granulocyte-macrophage colony-stimulating factor, whereas inhibiting IL-10 production from ILC2; and (2) enhancing their antigen-presenting capability during ILC-T-cell cross-talk. In summary, we identify a novel mechanism by which C3a can mediate aberrant type 2 responses to aeroallergen exposure, which involves a yet unrecognized cross-talk between two major innate immune components-complement and group 2 innate lymphoid cells.

Complement Activation in Inflammatory Skin Diseases

The complement system is a fundamental part of the innate immune system, playing a crucial role in host defense against various pathogens, such as bacteria, viruses, and fungi. Activation of complement results in production of several molecules mediating chemotaxis, opsonization, and mast cell degranulation, which can contribute to the elimination of pathogenic organisms and inflammation. Furthermore, the complement system also has regulating properties in inflammatory and immune responses. Complement activity in diseases is rather complex and may involve both aberrant expression of complement and genetic deficiencies of complement components or regulators. The skin represents an active immune organ with complex interactions between cellular components and various mediators. Complement involvement has been associated with several skin diseases, such as psoriasis, lupus erythematosus, cutaneous vasculitis, urticaria, and bullous dermatoses. Several triggers including auto-antibodies and micro-organisms can activate complement, while on the other hand complement deficiencies can contribute to impaired immune complex clearance, leading to disease. This review provides an overview of the role of complement in inflammatory skin diseases and discusses complement factors as potential new targets for therapeutic intervention.

In vitro and in vivo downregulation of C3 by lipoteichoic acid isolated from Lactobacillus plantarum K8 suppressed cytokine-mediated complement system activation

Complement component 3 (C3) is one of the proteins associated with complement cascades. C3 plays an essential role in three different pathways-the alternative, classical and lectin pathways. It is well known that cytokines activate complement system and increase complement component C3 production. In the current study, we found that lipoteichoic acid isolated from Lactobacillus plantarum K8 (pLTA) inhibited tumor necrosis factor-alpha (TNF-α) or interferon-gamma (IFN-γ)-mediated C3 mRNA and protein expression in HaCaT cells. pLTA inhibited C3 expression through the inhibition of the phosphorylation of p65 and p38 in the TNF-α-treated cells, while the inhibition of STAT1/2 and JAK2 phosphorylation by pLTA contributed to the reduction of C3 in IFN-γ-treated cells. When mice were pre-injected with pLTA followed by re-injection of TNF-α, serum C3 level was decreased as compared to TNF-α-injected only. Further studies revealed that membrane attack complex (MAC) increased by TNF-α injection was lessened in pLTA-pre-injected mice. A bactericidal assay using mouse sera showed that MAC activity in pLTA-pre-injected mice was lower than in TNF-α only-injected mice. These results suggest that pLTA can suppress inflammatory cytokine-mediated complement activation through the inhibition of C3 synthesis. pLTA application has the potential to alleviate complement-mediated diseases caused by excessive inflammation.

Therapeutic concentration of lithium stimulates complement C3 production in dendritic cells and microglia via GSK-3 inhibition

Evidence indicates that widely prescribed mood stabilizer, lithium (Li), mediates cellular functions of differentiated monocytic cells, including microglial migration, monocyte-derived dendritic cell (MoDC) differentiation, and amelioration of monocytic malfunctions observed in neuropsychiatric diseases. Here, we surveyed molecules which take major roles in regulating these monocytic cellular functions. MoDCs treated with 1 and 5 mM Li, and microglia separated from Li-treated mice were subjected to microarray-based comprehensive gene expression analyses. Findings were validated using multiple experiments, including quantitative PCR, ELISA and immunostaining studies. Differing effects of Li on the two cell types were observed. Inflammation- and chemotaxis-relevant genes were significantly over-represented among Li-induced genes in MoDCs, whereas no specific category of genes was over-represented in microglia. The third component of complement (C3) was the only gene which was significantly induced by a therapeutic concentration of Li in both MoDCs and microglia. C3 production was increased by Li via GSK-3 inhibition. Li-induced C3 production was seen only in differentiated monocytic cells, but not in circulating monocytes. Our findings highlight a link between Li treatment and C3 production in differentiated monocytic cells, and reveal a regulatory role of GSK-3 in C3 production. Induction of microglial C3 production might be a novel neuroprotective mechanism of Li via regulating interactions between microglia and neurons. GLIA 2015;63:257-270.

Polymorphisms within the C3 gene are associated with specific IgE levels to common allergens and super-antigens among atopic dermatitis patients

Atopic dermatitis (AD) is a chronic inflammatory skin disease. Twin and family studies suggest a strong genetic component of the disease. The keratinocytes secrete high amounts of C3 after stimulation with pro-inflammatory cytokines, which may play a functional role in skin inflammation. In this study, we genotyped four different single nucleotide polymorphisms (SNPs) by melting curve analysis using sequence specific hybridization probes in a well-characterized cohort of AD patients. Among four SNPs within C3 gene, higher frequencies of rs10410674 (23.5% vs 12.2%) and rs366510 (13.8% vs 6.5%) were observed in AD patients as compared with control group. None of the tested polymorphisms showed significant association with the risk of the disease phenotype. Analysis of rs10402876 SNP revealed its association with less severe AD disease expression (low SCORAD). Total serum IgE levels were not different among AD patients having any of the four SNPs. However, we observed significantly less serum-specific IgE levels to common allergens (Dermatophagoides pteronyssinus and birch pollens) and Staphylococcal enterotoxin B in AD patients having rs366510 SNP. Thus, associations of polymorphism within C3 gene with less severe AD disease expression and a weaker sensitization to common allergens suggest the role of these SNPs in the development of AD.

Induction of C3 and CCL2 by C3a in keratinocytes: a novel autocrine amplification loop of inflammatory skin reactions

The complement fragment-3a (C3a) acts via a G protein-coupled C3aR and is of importance in allergic and inflammatory diseases. Recent studies suggest the presence of complement proteins in the epidermal compartment and synthesis of some of these proteins (C3, factor B, and factor H) by human primary keratinocytes (KCs) during inflammation. However, expression of C3aR and its role in human KCs is not elucidated thus far. In this study, we demonstrate the expression of C3aR on KCs as detected by quantitative real-time RT-PCR and flow cytometry. IFN-gamma and IFN-alpha strongly up-regulated the surface expression of C3aR on KCs among all other cytokines tested. After up-regulation of C3aR by IFN-gamma and IFN-alpha, we observed the induction of five genes (CCL2, CCL5, CXCL8, CXCL10, and C3) after stimulation of KCs with C3a in microarray analysis. We confirmed the induction of C3 and CCL2 at RNA and protein levels. Furthermore, incubation of C3 with skin mast cells tryptase resulted in the generation of C3 fragments with C3a activity. In conclusion, our data illustrate that epidermal KCs express functional C3aR. The increases of C3 and CCL2 synthesis by C3a and C3 activation by skin mast cell tryptase delineates a novel amplification loop of complement activation and inflammatory responses that may influence the pathogenesis of allergic/inflammatory skin diseases.

Human monocyte-derived dendritic cells are chemoattracted to C3a after up-regulation of the C3a receptor with interferons

The anaphylatoxin C3a is an important inflammatory mediator in the innate and adaptive immune systems. Recent reports in various animal models have fostered the role of C3a in mediating allergic reactions such as pulmonary allergies. However, data in humans are limited and the cellular targets for C3a are not fully understood. We sought to explore human dendritic cells as a new target for C3a, because C3a receptor (C3aR) expression has been described on myeloid cells, and dendritic cells are likely make contact with C3a at sites of inflammatory reactions. In this study, we demonstrated the expression of the C3aR on human monocyte-derived dendritic cells (MoDC) and its up-regulation by interferon (IFN)-alpha, IFN-gamma and prostaglandin E2 (PGE2). The strongest up-regulation was yielded by the combination of IFN-alpha+ IFN-gamma. Tumour necrosis factor-alpha (TNF-alpha) down-regulated the C3aR. After up-regulation of the C3aR by IFN-alpha+ IFN-gamma, C3a significantly up-regulated the surface expression of CD54, CD83 and CD86, but not of CD40, CD80 or human leucocyte antigen (HLA)-DR. C3a had no effect on the production of interleukin (IL)-10 or IL-12p70, or on the capacity of MoDC to stimulate autologous T-cell proliferation. However, C3a had a direct migratory effect on MoDC, as indicated by the induction of F-actin polymerization and migration in Boyden chamber experiments, which was pronounced after up-regulation of the C3aR with IFN-alpha+ IFN-gamma. Therefore, dendritic cells represent another group of target cells that might be recruited by C3a to areas of inflammation, in particular under conditions where IFNs are increased in the surrounding environment.

The significance of stress hormones (glucocorticoids, catecholamines) for eruptions and spontaneous remission phases in psoriasis

BACKGROUND

In an earlier paper, it was described how acute eruptions of psoriasis may be produced in phases of immune deficiency and in the presence of bacterial antigen-releasing inflammatory foci, whereas clinical spontaneous remissions are produced in phases of immunologic activity. Therefore, it was of interest to investigate whether the stress hormones cortisol/epinephrine are involved in triggering such deficiency and activity phases.

METHODS

During a series of investigations lasting up to 3 years in 95 patients, the following were determined: cortisol/epinephrine levels, polyclonal serum immunoglobulins IgM, IgG, and IgA, total serum IgE, complement C3 and C4 proteins, T cells and subpopulations, as well as streptococcal titers ASO/ADNase B, severity index (PASI) RESULTS: Phases of clinical inactivity are associated with the mechanism, "immunologic regulation," where antibacterial titers are elevated, but all other parameters are unremarkable. Eruption phases (in 32 of 95 patients) showed absolute increases in serum cortisol levels and antibacterial titers, and decreases in serum epinephrine (adrenaline) levels. Phases of spontaneous remission (in 25 of 32 patients) showed, in contrast to the eruption phases, absolute increases in serum epinephrine levels, and significant falls in serum cortisol levels and bacterial titers.

CONCLUSIONS

On the basis of these results, the participation of the immune system is confirmed in the pathogenesis of psoriasis, which is subject to control by higher neurohormonal systems. Cortisol may be involved in the clinical eruption phase, and epinephrine in the remission phase. Both hormones are true antagonists and have important effects on the human immune system if produced in excess via the pituitary-adrenal axis. Infection with Streptococcus pyogenes is an additional trigger for the dermatosis.

Expression cloning of the human C3a anaphylatoxin receptor (C3aR) from differentiated U-937 cells

A cDNA clone encoding the human C3a anaphylatoxin receptor (C3aR) was isolated from a pcDNAI/Amp expression library prepared from U-937 cells which had been differentiated with dibutyryl cAMP to a macrophage-like phenotype. The cDNA clone contained an insert of 4.3 kbp and was able to confer to transfected human HEK-293 cells the capacity to bind specifically iodinated human C3a. Chinese hamster ovary cells co-transfected with this cDNA clone and a G-protein alpha subunit (G alpha-16) became functionally responsive to C3a and a C3a analog synthetic peptide, as measured by increased phosphoinositide hydrolysis. As inferred from the cDNA sequence, the clone encodes a 482-residue polypeptide with seven hydrophobic membrane-spanning helices and a high homology to the human C5a and formyl-Met-Leu-Phe receptors. Uniquely among the family of G-protein coupled receptors, the C3aR contains an exceptionally large second extracellular loop of approximately 175 residues. Northern hybridizations revealed an approximately 2.3-kb transcript as the major and an additional approximately 3.9 kb-transcript as a minor transcription product of the C3aR. The C3aR appears to be widely expressed in different lymphoid tissues, as shown by Northern hybridizations, providing evidence for a central role of the C3a anaphylatoxin in inflammatory processes.

The role of cytokines in the psoriatic inflammation

Psoriasis represents an inflammatory skin disorder which is characterized by a marked hyperproliferation of keratinocytes in association with vascular expansion, fibroblast activation, leukocyte infiltration, alterations of eicosanoid metabolism and of cytokine production. However, it is unclear at present whether these changes may be a cause or a result of the significantly increased keratinocyte turnover. More than one mechanism is involved in triggering active psoriasis, particularly a genetic predisposition and environmental factors affecting the immune system. Most of the therapeutic regimes used for the treatment of psoriasis are immunosuppressive. Therefore, it is tempting to speculate that a specific defect of the immune system represents an important pathogenic principle in psoriasis. There are several lines of evidence that changes in cytokine production by keratinocytes and immunocompetent cells in the skin of the patients (particularly of interleukin-6 and TGF-alpha) may play an important role in the propagation of the inflammatory response in psoriasis. Further studies are required to reveal the role of a local T-cell activation as a basic mechanism for initiation and maintenance of the psoriatic inflammatory response. Accordingly, parameters, such as the evaluation of cytokine production in vitro and in vivo, as well as the measurement of cellular activation products, may be useful tools for diagnosis and monitoring of psoriasis.

Immunomodulating cytokines in atopic dermatitis and psoriasis: production of tumour necrosis factor and lymphotoxin by mononuclear cells in vitro

The immunomodulating cytokines, tumour necrosis factor/cachectin (TNF) and lymphotoxin (LT) are thought to play an essential role as mediators of inflammatory reactions. To evaluate the role of TNF and LT in atopic dermatitis (AD) and psoriasis, we investigated their production by mononuclear cells (MNC) in vitro. The 24-h supernatants of lipopolysaccharide (LPS)- and phytohaemagglutinin (PHA)-stimulated and unstimulated MNC from 26 patients with AD and 20 with psoriasis and from 17 non-atopic healthy controls were tested for the concentrations of TNF and LT using an ELISA technique. In patients with AD, TNF levels were significantly decreased in the supernatant of PHA-stimulated (P less than or equal to 0.005) and LPS-stimulated (P less than or equal to 0.02) MNC in comparison to controls. There was no significant difference in TNF production between psoriatic patients and the control group. Release of LT in the supernatant of PHA-stimulated MNC by patients and controls did not differ significantly. There was no significant spontaneous production of TNF and LT by MNC of patients and controls. These studies indicate that different immunomodulating mechanisms are responsible for triggering the inflammatory response in AD and psoriasis.

Complement C3 proteins in psoriasis

A new polymorphism of the complement factor C3 in human plasma was demonstrated by isotachophoresis in agarose gels followed by immunodetection with rabbit anti-human C3c and C3d immunoglobulins. Four bands were detected in the immunoprint of freshly drawn EDTA-plasma, which were C3s1, C3s2, C3f1 and C3f2. At least four additional C3 components in Mg2+ -zymosan activated plasma were present, which were C3b1 to C3b4. The different forms of C3 in frozen and thawed heparin-plasma from 20 patients with psoriasis and 20 healthy individuals were studied from the immunoprint. The total content of C3 components was 29% greater in the patients with psoriasis than controls. The major difference was in the C3b components which were increased by 46%. In psoriatic patients, the two slow C3 components C3s1 and C3s2 were increased by 24 and 56% respectively, when compared with controls. The two fast C3 components C3f1 and C3f2 were decreased to 29 and 37%. The results suggest a direct involvement of the complement factor C3 in psoriasis.

Elevated levels of interleukin 2 receptor in sera of patients with atopic dermatitis and psoriasis

Elevated levels of serum interleukin 2 receptor (IL2R) represent an early measure of T cell activation. The concentration of IL2R was measured in the sera of patients with atopic dermatitis (n = 58) or psoriasis, without psoriatic arthritis, (n = 26), who had moderate to severe disease activity, and in non-atopic healthy controls (n = 37) by an ELISA technique. Serum IL2R levels were found to be significantly elevated in both disease groups compared with the controls. The increase in serum IL2R may be due to T cell activation in the dermis.

Decreased production of interferon in whole blood cultures derived from patients with psoriasis

Patients suffering from psoriasis show many alterations with respect to their immune system as documented by in vitro test systems. In the present study we investigated the in vitro production of interferons (IFN) of leukocytes from psoriatic patients to stimulation with a variety of IFN inducers. Furthermore, the lymphoproliferative responses were tested. Whole blood cultures of 30 psoriatic patients showing moderate to severe disease activity and 21 cultures from healthy controls were stimulated with the mitogens PHA, ConA, and PWM, with PPD and Tetanus Antigen as IFN gamma inducers and with C. parvum, PolyI-PolyC, and Herpes simplex virus as inducers of IFN alpha. Interferon activity was tested in the supernatant of 48-h cultures by using an antiviral assay. Lymphoproliferation was assayed in 5-d cultures in parallel. Psoriatic patients showed a significantly decreased IFN production to all the stimuli tested. There were no significant differences in the lymphoproliferative responses; only the response to PWM was slightly decreased. The decreased IFN production by leukocytes from psoriatic patients seems to be very remarkable since increased susceptibility to infections is not generally known in these patients.

A simplified assay for the detection of C3a in human plasma employing a monoclonal antibody raised against denatured C3

A monoclonal antibody raised against SDS-denatured C3 was shown to react with both solid-phase C3a and unfragmented C3. However, in the fluid phase the antibody was found to bind only to C3a and not to native C3. These findings indicated that the antibody could be used in an assay to detect C3a in human EDTA-plasma without prior separation of C3a from native C3. A simple and rapid competition ELISA was developed which monitored soluble C3a. 200 microliter of C3a (8 ng) was absorbed to plastic wells over night at 4 degrees C. Thereafter, 50 microliter of sample and 50 microliter of constant amounts of monoclonal antibody conjugated with beta-galactosidase, were incubated for 60 min at 37 degrees C. After washing, the colour reaction was started by adding nitrophenyl-galactopyridine to the wells. The microtitre plate was incubated at 37 degrees C for 30 min and the staining intensity was quantified at 405 nm. The assay detected both C3a and C3ades arg. A strong correlation was obtained between the new technique and an RIA which used an acid precipitation step for the separation of C3a prior to the determination of C3a (r = 0.9). Significantly higher levels of C3a were detected both in plasma from patients with immune complexes (93 +/- 9 ng/ml; P less than 0.1) and in plasma from patients treated in blood oxygenators (140 +/- 19 ng/ml; P less than 0.05) than in plasma from normal subjects (74 +/- 4 ng/ml). The results were not affected by repeated freezing and thawing of the plasma samples.

Neutrophil locomotion and serum chemotactic and chemokinetic activities in pustulosis palmoplantaris compared with psoriasis

Twenty patients with palmoplantar pustulosis (PPP) and 21 patients with psoriasis were compared with respect to the chemotactic response and random migration of their neutrophils (PMNs) and to the chemotactic and chemokinetic activities of their serum. The Boyden chamber technique was used. Compared with the reference group, the PPP neutrophils showed a significant decrease in random migration (p = 0.036) and chemotactic response to casein (p = 0.031), but not to zymosan-activated serum. The psoriasis PMNs had normal chemotactic response, but decreased random migration (p = 0.001). The chemokinetic effects of serum from PPP and psoriatic patients on normal neutrophils were increased (for PPP, p = 0.019 and for psoriasis p = 0.024). The chemokinetic activity of the heated sera was decreased and inversely correlated to the serum level of IgA in both disorders (PPP, p = 0.021; psoriasis, p = 0.013). The chemotactic activity of serum on normal PMNs was decreased in both conditions (PPP, p = 0.001; psoriasis, p = 0.047); this was due to the presence of chemotactic factor inhibitors in 34% of the sera. It seems likely that the high chemokinetic effect of serum both from the PPP and from the psoriasis patients compensates for the slightly low or normal migratory activity of neutrophils from these patients.

Defective monocyte and polymorphonuclear leukocyte chemotaxis and clinical characteristics in atopic dermatitis

Using highly purified cell suspensions, monocyte (MO) and polymorphonuclear leukocyte (PMN) chemotaxis was measured by the 51Cr-labeled cells technique in 30 adult patients with atopic dermatitis (AD). MO chemotaxis was depressed in 60% of the patients; in one-third both MO and PMN chemotaxis was impaired. All patients with normal MO chemotaxis had normal PMN chemotaxis. The defective chemotaxis was related to the presence of cutaneous infection and to the activity of the disease. Cutaneous infection was observed in 70% of the patients with low MO and PMN chemotaxis. We found no relation between the chemotaxis defects and serum IgE levels. Presence of asthma in addition to AD did not influence the results. Preincubation of normal leukocytes with AD plasma did not alter the chemotactic responses. Plasma from atopics had a lower capacity for inducing migration than normal plasma using leukocytes from healthy subjects as test cells.