Infliximab therapy in refractory sarcoidosis: a multicenter real-world analysis.

BACKGROUND: Infliximab is a monoclonal antibody that binds and neutralizes circulating tumor necrosis factor-alpha, a key inflammatory cytokine in the pathophysiology of sarcoidosis. Despite the paucity of randomized clinical trials, infliximab is often considered a therapeutic option for refractory disease. Our study aimed to investigate the effectiveness of infliximab in patients with refractory sarcoidosis. METHODS: Sarcoidosis patients from three tertiary centres were retrospectively identified by pharmacy records based on treatment with infliximab. Treatment with Infliximab was initiated in patients who failed first and second line immunomodulators as determined by a multidisciplinary team of Respirologists, Dermatologists, ENT specialists, Rheumatologists, and Neurologists. Participants were characterized by the primary organ for which infliximab was initiated and the total number of organs involved. Clinical outcomes were categorized as treatment success versus failure. We defined treatment success as (A) improvement of cutaneous, upper airway, lymph node, gastrointestinal, eye, or joint manifestations; or (B) improvement or no change in central nervous system (CNS) or pulmonary manifestations. RESULTS: 33 patients with refractory sarcoidosis were identified. The proportion of treatment success was 100% (95% CI 54.1-100) in CNS, 91.7% (95% CI 61.5-99.8) in cutaneous, 78.6% (95% CI 49.2-95.3) in pulmonary and 71.5% (95% CI 29.0-96.3) in upper airway disease. The use of infliximab was associated with a reduction prednisone dose by 50%. CONCLUSION: Infliximab is possibly an effective therapy for refractory sarcoidosis, with the greatest value in neurologic and cutaneous manifestations. Across all disease presentations, infliximab facilitated a clinically relevant reduction in corticosteroid dose. Relapse is common after discontinuation of infliximab.

A cross-platform analysis of 14,177 expression quantitative trait loci derived from lymphoblastoid cell lines.

Gene expression levels can be an important link DNA between variation and phenotypic manifestations. Our previous map of global gene expression, based on ~400K single nucleotide polymorphisms (SNPs) and 50K transcripts in 400 sib pairs from the MRCA family panel, has been widely used to interpret the results of genome-wide association studies (GWASs). Here, we more than double the size of our initial data set with expression data on 550 additional individuals from the MRCE family panel using the Illumina whole-genome expression array. We have used new statistical methods for dimension reduction to account for nongenetic effects in estimates of expression levels, and we have also included SNPs imputed from the 1000 Genomes Project. Our methods reduced false-discovery rates and increased the number of expression quantitative trait loci (eQTLs) mapped either locally or at a distance (i.e., in cis or trans) from 1534 in the MRCA data set to 4452 (with <5% FDR). Imputation of 1000 Genomes SNPs further increased the number of eQTLs to 7302. Using the same methods and imputed SNPs in the newly acquired MRCE data set, we identified eQTLs for 9000 genes. The combined results identify strong local and distant effects for transcripts from 14,177 genes. Our eQTL database based on these results is freely available to help define the function of disease-associated variants.

A genome-wide association study of atopic dermatitis identifies loci with overlapping effects on asthma and psoriasis.

Atopic dermatitis (AD) is the most common dermatological disease of childhood. Many children with AD have asthma and AD shares regions of genetic linkage with psoriasis, another chronic inflammatory skin disease. We present here a genome-wide association study (GWAS) of childhood-onset AD in 1563 European cases with known asthma status and 4054 European controls. Using Illumina genotyping followed by imputation, we generated 268 034 consensus genotypes and in excess of 2 million single nucleotide polymorphisms (SNPs) for analysis. Association signals were assessed for replication in a second panel of 2286 European cases and 3160 European controls. Four loci achieved genome-wide significance for AD and replicated consistently across all cohorts. These included the epidermal differentiation complex (EDC) on chromosome 1, the genomic region proximal to LRRC32 on chromosome 11, the RAD50/IL13 locus on chromosome 5 and the major histocompatibility complex (MHC) on chromosome 6; reflecting action of classical HLA alleles. We observed variation in the contribution towards co-morbid asthma for these regions of association. We further explored the genetic relationship between AD, asthma and psoriasis by examining previously identified susceptibility SNPs for these diseases. We found considerable overlap between AD and psoriasis together with variable coincidence between allergic rhinitis (AR) and asthma. Our results indicate that the pathogenesis of AD incorporates immune and epidermal barrier defects with combinations of specific and overlapping effects at individual loci.

Integrating pathway analysis and genetics of gene expression for genome-wide association study of basal cell carcinoma.

Genome-wide association studies (GWASs) have primarily focused on marginal effects for individual markers and have incorporated external functional information only after identifying robust statistical associations. We applied a new approach combining the genetics of gene expression and functional classification of genes to the GWAS of basal cell carcinoma (BCC) to identify potential biological pathways associated with BCC. We first identified 322,324 expression-associated single-nucleotide polymorphisms (eSNPs) from two existing GWASs of global gene expression in lymphoblastoid cell lines (n = 955), and evaluated the association of these functionally annotated SNPs with BCC among 2,045 BCC cases and 6,013 controls in Caucasians. We then grouped them into 99 KEGG pathways for pathway analysis and identified two pathways associated with BCC with p value <0.05 and false discovery rate (FDR) <0.5: the autoimmune thyroid disease pathway (mainly HLA class I and II antigens, p < 0.001, FDR = 0.24) and Janus kinase-signal transducer and activator of transcription (JAK-STAT) signaling pathway (p = 0.02, FDR = 0.49). Seventy-nine (25.7%) out of 307 significant eSNPs in the JAK-STAT pathway were associated with BCC risk (p < 0.05) in an independent replication set of 278 BCC cases and 1,262 controls. In addition, the association of JAK-STAT signaling pathway was marginally validated using 16,691 eSNPs identified from 110 normal skin samples (p = 0.08). Based on the evidence of biological functions of the JAK-STAT pathway on oncogenesis, it is plausible that this pathway is involved in BCC pathogenesis.

Vesicular erythema multiforme-like reaction to para-phenylenediamine in a henna tattoo.

Allergic contact dermatitis reaction to topical "black henna" tattoo is usually described secondary to the organic dye para-phenylenediamine, a derivative of analine. Allergic contact dermatitis reactions to para-phenylenediamine are well recognized and most commonly involve an eczematous reaction that may become generalized and an acute angio-edema. Only four previous instances have been reported of an erythema multiforme-like reaction to para-phenylenediamine and its derivatives, including only one mild reaction to a tattoo. A vesicular erythema multiforme-like reaction has not been reported. An erythema multiforme-like reaction to contact allergens is usually caused by potent allergens including plant quinolones in Compositae and sesquiterpene lactones in exotic woods, and it is also reported to topical drugs, epoxy resin, metals (particularly nickel), and various chemicals. A generalized vesicular erythema multiforme-like reaction is unusual, and rarely reported. We describe a 6-year-old boy who developed a localized, eczematous and severe generalized vesicular erythema multiforme-like contact allergy to para-phenylenediamine secondary to a henna tattoo. As henna tattoos are becoming increasingly popular, one should be aware of the possibility of such a reaction. This presentation also highlights the call to ban the use of para-phenylenediamine and its derivatives in dyes.

Atopic dermatitis: insights from linkage overlap and disease co-morbidity.

Atopic dermatitis (AD) is a strongly heritable, chronic relapsing dermatosis that frequently co-occurs with other atopic phenotypes including asthma and allergic rhinitis (the so-called atopic triad disorders). However, despite high levels of co-morbidity, relatively low levels of genomic co-incidence have been observed between atopic triad disorders. Conversely, current mapping data have revealed a striking pattern of co-localisation between AD disease loci and those mapped using another chronic dermatological disease - psoriasis. In this review, we examine the evidence for co-localisation between AD and a range of atopic, infectious, inflammatory and autoimmune diseases, and consider the implications of these data for the AD disease concept and future research in the field.

Investigation of the chromosome 17q25 PSORS2 locus in atopic dermatitis.

Psoriasis and atopic dermatitis (AD) are strongly genetic and inherited as multi-factorial traits. In both diseases, linkage has been reported to chromosome 17q25. For psoriasis, the locus has been labelled PSORS2. Two peaks of association here contain the psoriasis candidate genes SLC9A3R (solute carrier family 9, isoform 3 regulatory factor), NAT9 (N-acetyltransferase superfamily), and RAPTOR (rapamycin (TOR)). We genotyped 14 of the most significantly associated single-nucleotide polymorphisms (SNPs) in these genes in a panel of 148 families (ECZ1) identified through a proband with active AD. The panel contains 350 siblings and 245 sib-pairs. Replication of positive findings was sought in a second panel, MRC-E, comprising of 278 families, 634 siblings, and 470 sib-pairs. SNP genotyping was carried out by Sequenom MassArray technology. Using family-based tests of association (transmission disequilibrium test), rs878906, in intron 3 of NAT9, was significantly associated with AD (P = 0.010) in the ECZ1 panel. In the MRC-E panel, rs895691, between the end of exon 6 of SLC9A3R1 and exon 7 of NAT9, was associated with AD (P = 0.037). These were not significant when multiple comparisons were taken into account. Haplotype analysis revealed no significant associations in either population. These results suggest that the psoriasis candidate genes do not account for previously observed linkage of the 17q25 PSORS2 locus to AD.

HIV-associated psoriasis: pathogenesis, clinical features, and management.

Psoriasis is a chronic papulosquamous skin disease that is thought to be a T-cell-mediated autoimmune disorder of keratinocyte proliferation. The association between psoriasis and HIV infection seems paradoxical, but insights into the role of T-cell subsets, autoimmunity, genetic susceptibility, and infections associated with immune dysregulation might clarify our understanding of the pathogenesis of psoriasis with HIV in general. HIV-associated psoriasis can be clinically confusing because several comorbid skin disorders in patients with HIV can mimic psoriasis. Phenotypic variants such as a Reiter's syndrome or fulminant erythroderma provide diagnostic clues to underlying immunodeficiency. The management of moderate and severe HIV-associated psoriasis is challenging, although patients typically improve with highly active antiretroviral therapy. Conventional systemic treatments might be contraindicated or need dose adjustment to avoid toxicity. New biological treatments in this setting are promising and warrant further study.

The psoriatic transcriptome closely resembles that induced by interleukin-1 in cultured keratinocytes: dominance of innate immune responses in psoriasis.

Psoriasis has been considered an autoimmune, T cell-mediated disorder in which adaptive immune responses predominate over those of non-antigen-specific innate immunity. To test this hypothesis, we profiled the transcriptome of psoriatic tissue and compared the data with that from cultured human keratinocytes exposed to the proinflammatory cytokine interleukin (IL)-1alpha and the Th1 cytokine interferon-gamma. When compared with patient-matched, nonlesional skin biopsies, psoriatic samples exhibited regulation of 90 transcripts including several members of the epidermal differentiation complex, molecules with antimicrobial activity, and hyperproliferation-associated keratins. Stimulation of keratinocytes with interferon-gamma resulted in regulation of 252 transcripts, with particularly strong expression of the CXCR3-binding ligands CXCL9, -10, and -11 and class II major histocompatibility complex genes, primarily those of the HLA-DR and -DP families. In contrast, the transcriptome resulting from exposure of keratinocytes to IL-1alpha elicited differences in just 19 transcripts, particularly genes within the epidermal differentiation complex and antimicrobial molecules, including PI3 and DEFB4. Major differences between the two keratinocyte transcriptomes were exhibited with only five induced IL-1alpha transcripts also regulated in the interferon-gamma set. Unexpectedly, there was a high correlation between psoriatic lesional tissue and the IL-1alpha transcriptome. These findings suggest that the inflammatory milieu in the epidermal microenvironment in psoriasis is more likely dependent on evolutionarily ancient cytokines such as IL-1, rather than those of the adaptive immune response.

Filaggrin mutations in children with severe atopic dermatitis.

Atopic dermatitis (AD) results from strong genetic and environmental interactions. AD shows genetic linkage to Chromosome 1q21. This region contains the epidermal differentiation complex (EDC), which consists of genes that form essential components of epidermal surfaces. Filaggrin (FLG) is one of these. Mutations in FLG/(R501X and 2282del4) are reported to be strongly associated with AD and to influence asthma accompanying AD. We investigated these effects in families recruited through a child with severe AD. We genotyped two panels of families, totalling 426, containing 990 affected and unaffected children. We found significant associations with AD (P=0.0001), asthma (P=0.006), and atopy (P=0.002). The FLG mutations were present in 26.7% of patients with AD, but were also present in 14.4% of children without AD. They were weakly associated with disease severity. The variants were not independently associated with asthma. The overall LOD score for genetic linkage of markers to the region was 3.57. This fell to 2.03 after accounting for the FLG mutations, indicating the presence of other genetic variants influencing AD at this locus. Our results provide further confirmation of the importance of mutations in FLG and the skin barrier in AD pathogenesis. The results indicate that investigations of other genes within the EDC should be undertaken.

The genetics of atopic dermatitis.

Atopic dermatitis (AD) is a chronic itching (pruritic) skin disease. It results from a complex interplay between strong genetic and environmental factors. Genome screens of families with AD have implicated chromosomal regions that overlap with other skin diseases and with inflammatory and autoimmune diseases. These, together with candidate gene studies, provide novel insights into the pathogenesis of AD. The findings suggest a common theme of generalized epidermal dysfunction manifesting as a compromised skin barrier and failure to protect against, or aberrant responses to, microbial insults and antigens. Recent genetic advances with high-throughput methods for gene identification, such as DNA microarrays and whole-genome genotyping, will help further dissect this complex trait. This will aid disease-defining criteria and focused therapies for AD.

Tinea capitis in Kwa-Zulu Natal, South Africa.

Tinea capitis is the most common dermatophyte infection in children. The hair involvement can be classified as endothrix, ectothrix, or favus, and the clinical appearance is variable. The goal of this study was to determine the demography, etiology, and clinical patterns of tinea capitis in South Africa. A prospective, cross-sectional study was conducted over a 1-year period. All cases were classified clinically and subject to Wood light examination, microscopy, and culture. One hundred patients were studied. The male:female ratio was 1.4:1. The mean age was 4.6 years (range 1-11 years). Trichophyton violaceum was isolated in 90% of positive cultures. Wood light was positive in one patient with Microsporum gypseum. The most common clinical variety was the "black dot" type, seen in 50% of patients. Twenty percent of the children presented with more than one clinical type simultaneously. We concluded that the most common cause of tinea capitis in South Africa is T. violaceum. The presentation is variable.