Impaired NLRP3 inflammasome expression and function in atopic dermatitis due to Th2 milieu.

BACKGROUND: Atopic dermatitis (AD) and psoriasis patients are frequently colonized with Staphylococcus aureus (S. aureus) that produce the staphylococcal exotoxin α-toxin. However, only patients with AD suffer from bacterial superinfections with this pathogen, which implicates immunological differences in AD vs psoriasis in combating these bacteria. S. aureus recognition is partially mediated by intracellular nucleotide-binding oligomerization domain receptors (NLRs), which link α-toxin to caspase-1 activation through the formation of the NLRP3 inflammasome and to IL-1ß secretion. OBJECTIVE: To investigate (i) NLRP3 expression in the context of different T-helper cytokine milieus and (ii) its function in response to sublytic α-toxin stimulation in patients with AD and psoriasis compared with healthy controls. METHODS: NLRP3 expression and function were investigated in lesional AD and psoriasis skin as well as in primary keratinocytes (HPKs) and monocytes upon stimulation with Th1, Th2, Th17 and Th22 cytokines or staphylococcal α-toxin, respectively, at the mRNA and protein (ELISA, immunohistochemistry and immunofluorescence) level. RESULTS: NLRP3 and caspase-1 expressions were reduced in lesional AD skin compared to psoriatic and healthy skin. IL-4, IL-5 and IL-13 downregulated NLRP3 and ASC, whereas interferon-γ upregulated NLRP3 in HPKs. In monocytes, caspase-1 expression was reduced by Th2 cytokines and enhanced by a Th1 milieu. Caspase-1-dependent IL-1ß secretion was impaired in monocytes from patients with AD compared to patients with psoriasis and healthy controls by α-toxin stimulation following priming with lipoteichoic acid. CONCLUSION: Impaired NLRP3 expression and function may partially explain how skin colonization and infection with S. aureus can contribute to chronic skin inflammation in AD.

Functional effects of interleukin 31 in human primary keratinocytes.

BACKGROUND: Interleukin (IL)-31 is a T-cell cytokine acting through a heterodimeric receptor composed of IL-31RA and OSMR which is expressed on epithelial cells including keratinocytes. A major function of IL-31 in atopic dermatitis (AD) is the induction of pruritus in the skin. Inflammatory effects of IL-31 in human primary keratinocytes (HPKs) still remain unclear. We investigated expression, regulation of the IL-31 receptor as well as functions of IL-31 in HPKs. METHODS: Human primary keratinocytes were stimulated with TLR-2 ligands (Pam3Cys, lipoteichoic acid and peptidoglycan), or Th1 and Th2 associated cytokines (IFN-γ and IL-4), respectively. IL-31R expression and regulation as well as functional effects of IL-31 stimulation were then investigated at both the mRNA and protein level and compared with HPKs from patients with AD. The STAT signalling pathway and TLR-2 expression were investigated using Western blot and Immunohistochemical stainings, respectively. RESULTS: Pam3Cys or IFN-γ significantly up-regulated IL-31RA and OSMR expression. IL-31 activated STAT-3 phosphorylation in HPKs which was augmented after preactivation with Pam3Cys or IFN-γ. IL-31 enhanced the secretion of CCL2 after up-regulation of the receptor with Pam3Cys or IFN-γ. However, this was not observed in keratinocytes from AD patients where an impaired TLR-2 expression was found. CONCLUSIONS: Together, our findings show a functional role of IL-31 in HPKs and provide a new link between TLR-2 ligands and IL-31 which might be dysregulated in AD. Altered function of IL-31 may have implications for cutaneous inflammation in eczema where skin colonization with Staphylococcus aureus and dysregulation of TLR-2 have been described.

Psychosis and vulnerability to ECT-induced seizures.

Medical records of patients with major depressive disorders who had received electroconvulsive therapy (ECT) for the first time were studied to test the hypothesis that psychotic patients are more vulnerable to seizures than nonpsychotic patients. This hypothesis was based on studies suggesting a putative purinergic deficiency in psychosis. Results showed that the duration of ECT-induced seizures as a measure of seizure vulnerability was significantly longer in psychotic than in nonpsychotic depressive patients. The association applied for the first ECT as well as for the course of eight ECTs. These findings were still present when covariates such as age, electrical energy applied, dosage of methohexital and succinylcholine, and psychotropic medications such as neuroleptics, benzodiazepines, and tricyclics were included in the statistical analysis. The results are discussed in the context of the role of neurotransmitters such as glutamate, gamma-aminobutyric acid, adenosine, and dopamine on seizure vulnerability and psychosis.

The clinical significance of platelet-associated IgG: a study on 298 patients with various disorders.

Platelet-associated IgG (PAIgG) was studied by a quantitative platelet radioactive anti-IgG test (PRAT) in 298 patients. At the time of investigation, 171 patients were thrombocytopenic (platelet count < 100 X 10(9)/l), 127 had normal platelet counts. Patients fell into the following disease categories: Idiopathic thrombocytopenic purpura (ITP) (N = 81), possible ITP (19), acute ITP (9), systemic lupus erythematosus (22), autoimmune haemolytic anaemia of warm-type (18), systemic blood disease (65), liver diseases (35), other (49). A significant elevation of PAIgG was found in all disease categories. There was a significant correlation between PAIgG and the reciprocal values of platelet counts for most disease groups. No relationship was discernible between PAIgG and hypergammaglobulinaemic states (serum IgG > 1.8 g/l). Platelet survival studies (N = 30) revealed that normal and increased values of PAIgG were associated with normal or shortened platelet mean life span. It is concluded that an elevated PAIgG is only one of several factors involved in the development of immunologically medicated thrombocytopenia.

The problem of platelet autoantibodies. I. Evaluation of the platelet factor 3 availability test for their detection.

To assess two modifications of the platelet factor 3 (PF3) test for platelet antibody detection, an analysis of test conditions was performed with normal test material (serum, plasma, globulin fraction), defined HLA-specific, complement-fixing antisera and a quinidine-induced antiserum. It was shown that, under standardized conditions, the PF3 test revealed known platelet antibodies confirming earlier results. Its reproducibility and, to a lesser degree, its sensitivity were inferior to platelet complement fixation. In contrast, the test did not permit the reliable determination of platelet autoantibodies in sera of 89 thrombocytopenic patients including 36 cases of idiopathic thrombocytopenic purpura. Positive results loosely corresponded to the presence of HLA antibodies in sera.

Evidence of platelet complement-fixing and lymphocytotoxic anti-A-1 antibodies.

3 human antisera exhibiting non HL-A specific antibody were studied in micro-complement fixation with platelets and micro-lymphocytotoxicity. Screening studies as well as absorption and elution studies with platelets, lymphocytes and erythrocytes revealed an antibody activity associated with blood group A-1. Within blood group A-1, a subpopulation of A-1 donor cells- provisionally called "weak A-1" - was defined, which had a minor ability for complement-fixing and lymphocytotoxic A-1-antibody absorption. Contrary to HL-A specific antibodies, acid eluates from platelets of these 3 sera were always negative whereas heat and ether eluates gave positive results. From neutralization studies and studies on the hemolytic activity against A-1 erythrocytes it was concluded, that the A-1-specific antibodies probably are immune antibodies belonging to the IgG class of immunoglobulins.