Robert E. Hunger

Expression of the IL-23/Th17 pathway in lesions of hidradenitis suppurativa

BACKGROUND Hidradenitis suppurativa is a debilitating chronic disease primarily affecting intertriginous skin of the axillae, perineum, and inframammary regions. The pathogenesis of this inflammatory disease is still poorly understood. Recently, increased attention has been paid to the role of the immune system. OBJECTIVE Since the interleukin 12 (IL-12)/T helper 1 (Th1) and the IL-23/Th17 pathways are believed to be crucially involved in the pathogenesis of multiple chronic inflammatory diseases, we investigated the expression and cellular source of IL-12, IL-23, and IL-17 in hidradenitis suppurativa. METHODS Ten patients with hidradenitis suppurativa were included in the study. Tissue samples were obtained from lesional skin and compared with healthy skin as a control. Expression of IL-12, IL-23, and IL-17 was analyzed by semiquantitative real-time polymerase chain reaction and immunohistochemistry, and the cellular source of these cytokines was determined by double immunofluorescence. RESULTS IL-12 and IL-23 were found to be abundantly expressed by macrophages infiltrating papillary and reticular dermis of lesional skin. In accordance with the high expression of IL-23 and its important role in the development of T helper 17 (Th17) cells, IL-17-producing T helper cells were found to distinctly infiltrate lesional dermis. LIMITATIONS The sample size was small. CONCLUSIONS Our findings suggest that the IL-23/Th17 pathway is expressed in hidradenitis suppurativa and further support involvement of the immune system. Moreover, targeting the IL-12/IL-23-common subunit p40 with novel monoclonal antibodies may represent a new option for the treatment of this recalcitrant disease.

Cytotoxic Cells Are Activated in Cellular Infiltrates of Alcoholic Chronic Pancreatitis

BACKGROUND & AIMS Perforin messenger RNA (mRNA) expression has been shown to be a specific in vivo activation marker for cytotoxic cells. In this study, the contribution of cell-mediated cytotoxicity in the pathogenesis of alcoholic chronic pancreatitis is assessed. METHODS Tissue sections of patients with alcoholic chronic pancreatitis were analyzed for perforin mRNA expression by in situ hybridization. In a further step, the phenotype and the relative frequency of perforin mRNA-expressing cells were determined. RESULTS In the normal pancreas, perforin mRNA-expressing cells are rarely present (mean, 0.3 cells/mm2). In contrast, the frequency of perforin mRNA-expressing cells is increased severalfold in diseased tissue specimens (mean, 6.6 cells/mm2). The frequency of perforin mRNA-expressing cells is high in the CD56+ (18%) and CD8+ cell population (12%) but low in the CD4+ cell population (1%). CONCLUSIONS The significantly elevated frequencies of perforin mRNA-expressing cells in the pancreas of patients with alcoholic chronic pancreatitis suggest an involvement of cell-mediated cytotoxicity in the pathogenesis of this disease. The preferential localization of these activated cells close to areas with parenchyma provides circumstantial evidence that autoreactive cytotoxic cells may contribute to tissue destruction in alcoholic chronic pancreatitis.

Interactions between Siglec-7/9 receptors and ligands influence NK cell–dependent tumor immunosurveillance

Alteration of the surface glycosylation pattern on malignant cells potentially affects tumor immunity by directly influencing interactions with glycan-binding proteins (lectins) on the surface of immunomodulatory cells. The sialic acid-binding Ig-like lectins Siglec-7 and -9 are MHC class I-independent inhibitory receptors on human NK cells that recognize sialic acid-containing carbohydrates. Here, we found that the presence of Siglec-9 defined a subset of cytotoxic NK cells with a mature phenotype and enhanced chemotactic potential. Interestingly, this Siglec-9+ NK cell population was reduced in the peripheral blood of cancer patients. Broad analysis of primary tumor samples revealed that ligands of Siglec-7 and -9 were expressed on human cancer cells of different histological types. Expression of Siglec-7 and -9 ligands was associated with susceptibility of NK cell-sensitive tumor cells and, unexpectedly, of presumably NK cell-resistant tumor cells to NK cell-mediated cytotoxicity. Together, these observations have direct implications for NK cell-based therapies and highlight the requirement to consider both MHC class I haplotype and tumor-specific glycosylation.

Down-regulation of autophagy-related protein 5 (ATG5) contributes to the pathogenesis of early-stage cutaneous melanoma.

Down-regulation of autophagy-related protein 5 decreases autophagy and contributes to tumorigenesis in human melanoma cells and patients’ tumors. Getting Melanoma to Eat Itself Autophagy, which literally means “self-eating,” is a normal cellular process that allows cells to get rid of unnecessary debris and may help them survive under conditions of stress. Autophagy is thought to be dysregulated in tumor cells, but its exact role is controversial because it appears to be beneficial under some conditions and harmful in others. Now, Liu and colleagues have tried to address this question by examining the role of autophagy in melanoma. The authors specifically focused on one regulator of autophagy, called autophagy-related protein 5 (ATG5). In a group of almost 200 patients with melanoma and 150 with benign melanocytic nevi, the authors saw decreased expression and increased methylation of ATG5 in the tumors compared to benign nevi and normal skin cells. Moreover, the extent of ATG5 expression in patients’ melanoma samples correlated with progression-free survival, such that patients with more ATG5 in their tumors had a better prognosis. Similarly, up-regulating ATG5 in cultured tumor cells inhibited their proliferation and caused them to undergo senescence. The role of ATG5 in melanoma patients’ survival needs to be validated in additional human studies, and similar research should be performed for other types of cancer. Thus far, it can only serve as a prognostic marker, but future research may uncover ways to treat melanoma and other cancers by forcing the tumors to produce more ATG5 and literally eat themselves. The role of autophagy in cancer is controversial: Both tumor-suppressing and tumor-promoting functions have been reported. We show that a key regulator of autophagy, autophagy-related protein 5 (ATG5), is often down-regulated in primary melanomas compared to benign nevi, leading to a reduction of basal autophagy as evidenced by a reduced expression of LC3. A follow-up of 158 primary melanoma patients showed that patients with low levels of ATG5 in their tumors had a reduced progression-free survival. In an in vitro model of melanoma tumorigenesis, where the BRAF oncogene was transduced into normal melanocytes, we observed that lowering ATG5 expression promoted proliferation by precluding oncogene-induced senescence. Hence, it appears that down-regulation of ATG5 contributes to tumorigenesis in early-stage cutaneous melanoma, and the expression of ATG5 and LC3 correlates with melanoma diagnosis and prognosis.

Increased expression of IL-12p70 and IL-23 by multiple dendritic cell and macrophage subsets in plaque psoriasis.

BACKGROUND Psoriasis is a chronic immune-mediated skin disease, in which interleukins 12 and 23 have been postulated to play a critical role. However, the cellular source of these cytokines in psoriatic lesions are still poorly defined and their relative contribution in inducing skin inflammation has been discussed controversially. OBJECTIVES To investigate immunoreactivity of the bioactive forms of IL-12 and IL-23 in plaque psoriasis and to characterize the dendritic cell (DC) and macrophage subsets responsible for the production of these cytokines. METHODS Immunohistochemistry was performed on normal skin (n=11) as well as non-lesional (n=11) and lesional (n=11) skin of patients with plaque psoriasis using monoclonal antibodies targeting the bioactive forms of IL-12 (IL-12p70) and IL-23 (IL-23p19/p40) on serial cryostat sections using the alkaline phosphatase-antialkaline phosphatase. Co-localization of IL-12 and IL-23 with different dendritic cells and macrophage cell markers (CD1a, CD11c, CD14, CD32, CD68, CD163, CD208/DC-LAMP) was performed using double immunofluorescence staining. RESULTS Immunoreactivity for IL-12 and IL-23 was significantly enhanced in lesional psoriatic skin as compared to non-lesional and normal skin. No difference was observed between IL-12 and IL-23 immunoreactivity in any skin types. Both IL-12 and IL-23 immunoreactivity was readily detected mainly in CD11c+, CD14+, CD32+, CD68+ and some CD163+, DC-LAMP+ cells. IL-12 and occasionally IL-23 were also found in some CD1a+ dendritic cells. In addition, an enhanced expression mainly of IL-23 was observed in keratinocytes. CONCLUSIONS Bioactive forms of IL-12 and IL-23 are highly expressed in various DC and macrophage subsets and their marked in situ production suggest that both cytokines have crucial pathogenic role in psoriasis.

Alopecia Areata Universalis Elicited during Treatment with Adalimumab

Adalimumab is a fully humanized recombinant anti-tumour-necrosis-factor (TNF-α) monoclonal antibody which has been approved for rheumatoid arthritis, active ankylosing spondylitis, psoriatic arthritis and Crohn’s disease. We report a case of alopecia areata (AA) universalis occurring 6 months after administration of adalimumab monotherapy in a patient with a long-standing history of psoriatic arthritis and psoriasis. The diagnosis was confirmed by a scalp biopsy which showed a peribulbar infiltrate of both CD4+ and CD8+ T cells, CD1a+ dendritic cells as well as CD68+ and CD163+ macrophages. In addition, immunofluorescence staining for TNF-α was found in the mononuclear cell infiltrate. This case suggests a complex role of TNF-α in the induction of AA.

Diagnostic delay in hidradenitis suppurativa is a global problem.

DEAR EDITOR, Hidradenitis suppurativa (HS) is clinically defined with recognized diagnostic criteria and recognizable physical characteristics. Untreated, the disease causes significant morbidity. The prevalence varies between 0 0003% and 4% depending on the study population. Estimates from insurance databases suggest a prevalence of < 0 1%. This variation strongly suggests a significant selection bias or misclassification, and it may be speculated that not all patients present for care. This is reinforced by clinical experience and published evidence indicating a significant delay in diagnosis. This study explores the delay in diagnosis for patients with HS on an international level. The study (survey) was conducted in 2013. Observational data were collected during routine visits or extracted from case records. Because of the simple and obvious symptomatology of recurrent painful lesions present in restricted welldefined areas of the body, patients’ self-reported history was considered valid regarding onset of symptoms. Consecutive patients with HS and psoriasis were included from each participating centre during a period of 4 months or less. The data were anonymized by removing any names, addresses and social security numbers, and included age, sex, age at disease onset, age at diagnosis, delay in diagnosis, time from onset of symptoms to first physician contact, age at first medical contact, number of physicians seen prior to the diagnosis, family history and disease severity. If the diagnosis was made by a primary care physician or by a specialist other than a dermatologist prior to seeing a dermatologist, this was recorded as the date of the diagnosis. Individual centres were responsible for and obtained any locally required permissions and signed informed consent forms, for example ethics committee approval, in accordance with national registry and data protection rules. Patients diagnosed with HS or psoriasis (and confirmed by the investigator) were included. The primary outcome was quantification of the delay in diagnosis. Additionally, documentation was made of both the delay in visiting a physician (and so gaining access to specialist treatment) and the relative delay in diagnosis of HS compared with psoriasis with/without a family history. The severity of HS was determined by Hurley’s staging criteria: stage I, mild; stage II, moderate and stage III, severe. In patients with psoriasis, severity was evaluated by the Psoriasis Area and Severity Index: score < 7, mild; 7–12, moderate and > 12, severe. The t-test, Wilcoxon rank sum test and v-test were used where appropriate. Univariate and multivariate logistic regression analyses were used to identify factors predictive of significant diagnostic delay. Diagnostic delay > 2 years was defined as significant. Diagnosis, sex, age of onset, family history and disease severity were selected as potentially important

Toll-like receptor 2 is highly expressed in lesions of acne inversa and colocalizes with C-type lectin receptor

Background Acne inversa (hidradenitis suppurativa) is a chronic inflammatory and cicatricial disorder that affects skin areas rich in apocrine glands and terminal hairs, such as perineum and axillae. The exact pathogenesis of the disease is not well understood and the mechanisms by which bacterial superinfection contributes to the disease progression are not clear. Toll‐like receptors (TLRs) expressed by inflammatory cells play a crucial role in the innate immune response to bacteria.

Cutaneous Leukocytoclastic Vasculitis in Dermatomyositis Suggests Malignancy

Background: Dermatomyositis (DM) is a rare connective tissue disease which has been shown to be associated with an underlying malignancy. Objective: Evaluation of the prevalence of malignancy in DM at our clinic and search for characteristics of the paraneoplastic form of disease. Methods: Retrospective review of patient files and histology reports over the period from 1991 to 1998. Results: 23 patients (14 women and 9 men) with DM could be identified in this time period with a median age at diagnosis of 48 years. Malignancies were found in 5 (22%) cases. The skin biopsies of all patients showed features of DM; in 7 cases, a leukocytoclastic vasculitis was detected. Four of the 5 cases with an associated malignancy demonstrated histologically a vasculitis in lesional skin, compared to only 3 out of 18 cases without malignancy (p < 0.05, Fisher’s exact test). Conclusion: Our data suggest that vasculitis in lesional skin biopsies has a predictive value for the presence of underlying malignancy.

Human β-defensin-2 and psoriasin are overexpressed in lesions of acne inversa

BACKGROUND Acne inversa is a chronic inflammatory disorder of apocrine gland-bearing skin. The role of the innate immune system in the pathogenesis of the disease is controversial. OBJECTIVES We investigated the expression of antimicrobial peptide/proteins in acne inversa. METHODS Tissue samples were obtained from patients with acne inversa and compared with normal-appearing skin. The expression of psoriasin and human beta-defensin (hBD)-2 on messenger RNA and protein level was analyzed. RESULTS Both messenger RNA and protein levels of psoriasin and hBD-2 were significantly increased in acne inversa. Macrophages expressing hBD-2 were found in the dermis. LIMITATIONS Small sample size is a limitation. CONCLUSIONS Antimicrobial peptide/proteins are overexpressed in acne inversa lesions as compared with normal-appearing skin. The site of the major expression depends on the particular antimicrobial peptide/protein. Psoriasin is overexpressed in epidermal keratinocytes whereas hBD-2 is produced mainly by dermal macrophages, leaving a relative deficiency of hBD-2 in the epidermis of acne inversa lesions.