Single-cell RNA sequencing profiling in a patient with discordant primary cutaneous B-cell and T-cell lymphoma reveals micromilieu-driven immune skewing.

BACKGROUND: Primary cutaneous lymphomas comprise a heterogeneous group of B-cell and T-cell malignancies which often show an indolent course, but can progress to aggressive disease in a subset of patients. Diagnosis is often delayed owing to clinical and histopathological similarities with benign inflammatory conditions. Especially during early disease, cancer cells are present at relatively low percentages compared with the inflammatory infiltrate, an interplay that is currently only insufficiently understood. OBJECTIVES: To improve diagnostics and perform molecular characterization of a complex type of primary cutaneous lymphoma. METHODS: Single-cell RNA sequencing (scRNA-seq) was performed and combined with T-cell and B-cell receptor sequencing. RESULTS: We were able to diagnose a patient with concurrent mycosis fungoides (MF) and primary cutaneous follicle centre lymphoma (PCFCL), appearing in mutually exclusive skin lesions. Profiling of tumour cells and the tissue microenvironment revealed a type-2 immune skewing in MF, most likely guided by the expanded clone that also harboured upregulation of numerous pro-oncogenic genes. By contrast, PCFCL lesions exhibited a more type-1 immune phenotype, consistent with its indolent behaviour. CONCLUSIONS: These data not only illustrate the diagnostic potential of scRNA-seq, but also allow the characterization of specific clonal populations that shape the unique tissue microenvironment in clinically distinct types of lymphoma skin lesions.

Molecular classification of tumour cells in a patient with intravascular large B-cell lymphoma.

BACKGROUND: Intravascular large B-cell lymphoma (IVLBCL) is a rare type of extranodal LBCL. It is characterized by the proliferation of tumour cells exclusively intraluminally in small blood vessels of different organs. The clinical manifestation depends on the type of organ affected; additionally, a haemophagocytic syndrome can be observed in some patients. OBJECTIVES: The aim was to further understand the nosology of this lymphoma as, due to its rarity and in spite of detailed immunohistochemical investigations, its exact nosology is only incompletely understood. METHODS: We used microarray-based analysis of gene expression of tumour cells isolated from a patient with primary manifestation of the lymphoma in the skin and compared it with various other diffuse LBCLs (DLBCLs) as well as a previously published DLBCL classifier. RESULTS: In unsupervised analyses, the tumour cells clustered together with non-germinal centre B-cell (non-GCB) DLBCL samples but were clearly distinct from GCB-DLBCL. Analogous to non-GCB DLBCL, molecular cell-of-origin classification revealed similarity to bone-marrow derived plasma cells. CONCLUSIONS: The IVLBCL of this patient showed molecular similarity to non-GCB DLBCL. Due to the prognostic and increasingly also therapeutic relevance of molecular subtyping in DLBCL, this method, in addition to immunohistochemistry, should also be considered for the diagnosis of IVLBCL in the future.

Analysis of anti-tumour necrosis factor-induced skin lesions reveals strong T helper 1 activation with some distinct immunological characteristics.

BACKGROUND: Psoriasiform and eczematous eruptions are the most common dermatological adverse reactions linked to anti-tumour necrosis factor (TNF)-α therapy. Yet, a detailed characterization of their immune phenotype is lacking. OBJECTIVES: To characterize anti-TNF-α-induced inflammatory skin lesions at a histopathological, cellular and molecular level, compared with psoriasis, eczema (atopic dermatitis) and healthy control skin. METHODS: Histopathological evaluation, gene expression (quantitative real-time polymerase chain reaction) and computer-assisted immunohistological studies (TissueFAXS) were performed on 19 skin biopsies from patients with inflammatory bowel disease (n = 17) and rheumatoid arthritis (n = 2) with new-onset inflammatory skin lesions during anti-TNF-α-therapy. RESULTS: Although most biopsies showed a psoriasiform and/or spongiotic (eczematous) histopathological architecture, these lesions were inconsistent with either psoriasis or eczema on a molecular level using an established chemokine (C-C motif) ligand 27/inducible nitric oxide synthase classifier. Despite some differences in immune skewing depending on the specific histopathological reaction pattern, all anti-TNF-α-induced lesions showed strong interferon (IFN)-γ activation, at higher levels than in psoriasis or eczema. IFN-γ was most likely produced by CD3/CD4/Tbet-positive T helper 1 lymphocytes. CONCLUSIONS: New-onset anti-TNF-α-induced eruptions previously classified as psoriasis or spongiotic dermatitis (eczema) exhibit a molecular profile that is different from either of these disorders.

Epidermal barrier abnormalities in exfoliative ichthyosis with a novel homozygous loss-of-function mutation in CSTA.

Autosomal recessive exfoliative ichthyosis (AREI) results from mutations in CSTA, encoding cysteine protease inhibitor A (cystatin A). We present a 25-year-old man from Iran with consanguineous parents, who presented with congenital erythroderma, hyperhidrosis and diffuse hyperkeratosis with coarse palmoplantar peeling of the skin, aggravated by exposure to water and by occlusion. Candidate gene analysis revealed a previously unknown homozygous loss-of-function mutation c.172C>T (p.Arg58Ter) in CSTA, and immunostaining showed absence of epidermal cystatin A, confirming the diagnosis of AREI. Ultrastructural analysis by transmission electron microscopy showed normal degradation of corneodesmosomes, mild intercellular oedema in the spinous layer but not in the basal layer, normal-appearing desmosomes, and prominent keratin filaments within basal keratinocytes. Thickness of cornified envelopes was reduced, lamellar lipid bilayers were disturbed, lamellar body secretion occurred prematurely and processing of secreted lamellar body contents was delayed. These barrier abnormalities were reminiscent of (albeit less severe than in) Netherton syndrome, which results from a deficiency of the serine protease inhibitor LEKTI. This work describes ultrastructural findings with evidence of epidermal barrier abnormalities in AREI.

Methotrexate-induced primary cutaneous diffuse large B-cell lymphoma with an 'angiocentric' histological morphology.

A patient with a 25-year history of rheumatoid arthritis and a 3-year history of methotrexate treatment developed a generalized papular rash. The papules rapidly became necrotic and then resolved, leaving a depressed scar. The rapid course of lesion development and regression was reminiscent of pityriasis lichenoides. Histology revealed a nodular infiltrate composed of a mixture of pleomorphic large B cells positive for CD20, CD30 and CD79a, and of small T cells positive for CD3 and CD4. The T cells had a striking angiocentric distribution, with some of the vessels exhibiting fibrinoid necrosis of the vessel wall reminiscent of lymphomatoid granulomatosis. However, B cells were consistently negative for Epstein-Barr virus (EBV) antigen expression. A thorough examination excluded involvement of organs other than the skin. Thus, this patient was classified as having a rare form of an EBV-negative primary cutaneous T-cell-rich B-cell lymphoma in association with methotrexate treatment.

Future perspectives in the treatment of psoriasis.

All available antipsoriatic therapies are of symptomatic character. Treatments established so far are limited in their use due to side effects or lack of efficacy resulting in poor quality of life for affected people. Development of new therapeutic approaches would not only broaden our armamentarium against psoriasis, but could also increase our understanding of the pathogenesis of this disease. In brief, 2 main targets represent attractive candidates, either the keratinocyte itself or the immune system. Promising therapeutic strategies include: (1) the search for new psoriasis susceptibility genes and their resulting phenotypes; (2) the interference with certain parts of cell signaling pathways that are involved in inflammatory processes; (3) the inhibition or elimination of activated T lymphocytes, e.g. by blocking of costimulatory signals or by deviation of a pathogenic immune response into a nonpathogenic one; (4) the blockade of proinflammatory cytokines; (5) the inhibition of leukocyte extravasation or trafficking; (6) the inhibition of angiogenesis. Some of these strategies are in phase 2 trials, others have already reached phase 3 status and are close to being approved by medicine agencies, and some are still visions of the future. This book chapter will give an overview of these new treatment strategies.

Rapid progression of an anal Buschke-Lowenstein tumour into a metastasising squamous cell carcinoma in an HIV-infected patient.

BACKGROUND: Buschke-Löwenstein tumour (BLT) of the anogenitalia is a locally invasive, destructively growing verrucous carcinoma that does not metastasise. Histologically BLT resembles benign condylomata acuminata. Nevertheless, the tumour grows relentlessly and may rarely progress into squamous cell cancer (SCC). RESULTS: A human immunodeficiency virus (HIV)-infected immunosuppressed patient developed (peri)anal warts accompanied by recurrent abscesses and fistulae. Histology revealed condylomata acuminata, and low-risk genital human papillomavirus (HPV) type 11b was detected. Six months later, the tumour had progressed into an ulcerated SCC that destroyed the rectum and perineum, with metastases to the inguinal lymph nodes. Whereas highly active antiretroviral therapy (HAART) effectively suppressed HIV replication, radiochemotherapy plus anti-EGFR antibody did not halt tumour progression, and the patient died from tumour-cachexia. DISCUSSION: As far as is known, this is the first report demonstrating rapid progression of a BLT into a metastasising SCC in an HIV-infected patient.

Analysis of the prodynorphin promoter polymorphism in atopic dermatitis and disease-related pruritus.

Pruritus is one of the key symptoms in atopic dermatitis (AD). The prodynorphin polypeptide is a precursor protein of pruritus-modulating opioid peptides. It is encoded by the prodynorphin gene (PDYN). To investigate a possible correlation of PDYN promoter polymorphisms with intensity of pruritus in patients with AD, we genotyped 211 Austrian patients with AD and 197 nonatopic controls. No significant association of the PDYN promoter polymorphism with AD in general was found when patients with AD were compared with controls. The analysis of possible associations with pruritus intensity also showed no relevant difference in the allelic distribution between patients with different pruritus-score values. These data argue against an important role of the PDYN promoter polymorphism in AD in general and in the development of disease-related pruritus, although owing to our small sample size, a weak effect cannot be excluded. Additional studies are needed to further evaluate the influence of PDYN polymorphism in pruritus.

Efficacy and safety results from the randomized controlled comparative study of adalimumab vs. methotrexate vs. placebo in patients with psoriasis (CHAMPION).

BACKGROUND: Biologic therapies such as adalimumab, a tumour necrosis factor antagonist, are safe and effective in the treatment of moderate to severe chronic plaque psoriasis. OBJECTIVES: To compare a biologic agent with methotrexate, a traditional systemic agent, to define clearly the role of biologics in psoriasis. METHODS: Patients with moderate to severe plaque psoriasis were randomized to adalimumab (80 mg subcutaneously at week 0, then 40 mg every other week, n=108), methotrexate (7.5 mg orally, increased as needed and as tolerated to 25 mg weekly; n=110) or placebo (n=53) for 16 weeks. The primary efficacy endpoint was the proportion of patients achieving at least a 75% improvement in the Psoriasis Area and Severity Index (PASI 75) after 16 weeks. Safety was assessed at all visits through week 16. RESULTS: After 16 weeks, 79.6% of adalimumab-treated patients achieved PASI 75, compared with 35.5% for methotrexate (P<0.001 vs. adalimumab) and 18.9% for placebo (P<0.001 vs. adalimumab). Statistically significantly more adalimumab-treated patients (16.7%) than methotrexate-treated patients (7.3%) or placebo-treated patients (1.9%) achieved complete clearance of disease. The response to adalimumab was rapid, with a 57% improvement in mean PASI observed at week 4. Adverse events were similar across treatment groups. Adverse events leading to study discontinuation were greatest in the methotrexate group, primarily because of hepatic-related adverse events. CONCLUSIONS: After 16 weeks, adalimumab demonstrated significantly superior efficacy and more rapid improvements in psoriasis compared with either methotrexate or placebo.

Human papillomavirus type 26 infection causing multiple invasive squamous cell carcinomas of the fingernails in an AIDS patient under highly active antiretroviral therapy.

Squamous cell carcinoma (SCC) of the nail unit is a rare disorder. An association with high-risk genital human papillomavirus (HPV) infection has been reported. We report a 28-year-old human immunodeficiency virus (HIV)-infected bisexual man who had multiple invasive SCC of the fingers, infected with the rare type HPV 26. Classification of HPV 26 as high- or intermediate-risk type has been uncertain, due to its rare presence in cervical cancer. Despite successful treatment with highly active antiretroviral therapy (HAART), the patient developed extensive hyperkeratotic nailbed proliferations of all fingers. Tumours were refractory to treatment and invaded into adjacent tissues. X-rays of the hands demonstrated bone invasion, necessitating amputation of distal phalanges of several fingers. Histologically, highly differentiated preinvasive and invasive verrucous SCCs were identified. Molecular DNA typing identified HPV 26 in the SCCs and in some premalignant lesions. By in situ hybridization HPV 26 DNA was detected in numerous tumour cells, indicating productive infection with high-level amplification of the viral genome. In the remaining proliferations, high-risk HPV type 58, cutaneous HPVs and a putative new HPV type were identified. HPV 26 infection appears to be causally involved in the development of SCC of the nail unit in this immunosuppressed patient. Timely evaluation of chronic verrucous nailbed tumours is recommended, especially in immunocompromised patients. Identification of HPV 26, besides known high-risk HPV types, may identify patients at risk for developing SCC of the nailbed and possibly at other locations.

Successful use of acitretin in conjunction with narrowband ultraviolet B phototherapy in a child with severe pustular psoriasis, von Zumbusch type.

Severe pustular psoriasis von Zumbusch type is a therapeutic challenge not only in adults, but even more in children. We report a 3(1/2)-year-old boy who developed a generalized flare of diffusely scattered pustules on erythematous skin which rapidly progressed to large exuding areas. The clinical presentation and investigations including histopathological examination of a biopsy and negative bacterial cultures were consistent with the diagnosis of pustular psoriasis von Zumbusch type. Upon initial treatment with methylprednisolone, acitretin and antibiotics the extent of the disease declined. However, several attempts to reduce the dose of the oral corticosteroid were followed by immediate severe flares. Additional treatment with narrowband ultraviolet B (NB-UVB, 311-313 nm UVB) resulted in a rapid arrest of disease activity and allowed the corticosteroid to be tapered off. After 10 irradiations the patient was both off steroid and disease free. NB-UVB therapy was subsequently reduced to twice-weekly exposures and acitretin gradually diminished to a maintenance dose of 0.3 mg kg(-1) daily. We conclude that NB-UVB in conjunction with acitretin is a potent therapeutic regimen for the treatment of severe pustular psoriasis von Zumbusch type in childhood.

Successful treatment of an aciclovir-resistant herpes simplex type 2 infection with cidofovir in an AIDS patient.

Management of the increasing frequency of aciclovir-resistant herpes simplex virus (HSV) infections among immunocompromised human immunodeficiency virus-infected people demands additional treatment options. We report the case of a 38-year-old patient with acquired immune deficiency syndrome who suffered from a perianal butterfly ulcer, which was HSV-2 positive by polymerase chain reaction (PCR) analysis. The ulcer appeared during treatment of a cytomegalovirus (CMV) pneumonitis with ganciclovir. Despite additional valaciclovir therapy the lesion gradually progressed in size. Investigations including histology, PCR analysis and in situ hybridization of a biopsy from the growing ulcer margin confirmed the presence of HSV-2 infection. Importantly, HSV isolates from this specimen were resistant to aciclovir. Based on a report about the successful treatment of aciclovir-resistant HSV infection with cidofovir, our patient received this drug intravenously at a dose of 5 mg kg-1 body weight once weekly for a total of 3 weeks. Concomitant oral probenecid and prehydration were administered to minimize nephrotoxicity. Within 30 days of treatment the ulcer had almost (> 95%) completely healed. We conclude that cidofovir is a potent antiviral drug with a potential usefulness in the treatment of aciclovir-resistant HSV-2 infection. It deserves further investigation in clinical trials.

MART-1/Melan-A and tyrosinase transcripts in peripheral blood of melanoma patients: PCR analyses and follow-up testing in relation to clinical stage and disease progression.

The use of tyrosinase-based polymerase chain reaction (PCR) tests for the detection of circulating tumour cells in the blood of melanoma patients has led to highly controversial results. We here report on the analysis of 120 blood samples from 76 stage I to IV melanoma patients using a new MART-1/Melan-A PCR system in conjunction with the tyrosinase-specific assay reported in the literature. While there were no positive results in localized disease (stages I and II), identification of specific PCR products in stage III melanoma patients was restricted to the MART-1/Melan-A tests, with positive results in 11% (two out of 19) of the blood specimens analysed. Stage IV melanoma patients presented with the highest incidence of detectable mRNA levels, with positive results for tyrosinase in 38% (12 out of 32) and for MART-1/Melan-A in 22% (seven out of 32). By delineating 64 follow-up specimens covering sampling periods of up to 33 weeks, stable mRNA expression profiles were identified in nearly 95%. Four patients, however, showed PCR changes towards positive MART-1/Melan-A expression that were linked to metastatic melanoma progression. Taken together, PCR tests for tyrosinase and MART-1/Melan-A seem to lack sufficient detection frequencies for the routine monitoring of melanoma disease. Regarding the link between MART-1/Melan-A seroconversion and the development of metastatic disease, further studies are needed to clarify the clinical value of this observation.

Isolation and characterization of dermal lymphatic and blood endothelial cells reveal stable and functionally specialized cell lineages.

A plexus of lymphatic vessels guides interstitial fluid, passenger leukocytes, and tumor cells toward regional lymph nodes. Microvascular endothelial cells (ECs) of lymph channels (LECs) are difficult to distinguish from those of blood vessels (BECs) because both express a similar set of markers, such as CD31, CD34, podocalyxin, von Willebrand factor (vWF), etc. Analysis of the specific properties of LECs was hampered so far by lack of tools to isolate LECs. Recently, the 38-kD mucoprotein podoplanin was found to be expressed by microvascular LECs but not BECs in vivo. Here we isolated for the first time podoplanin(+) LECs and podoplanin(-) BECs from dermal cell suspensions by multicolor flow cytometry. Both EC types were propagated and stably expressed VE-cadherin, CD31, and vWF. Molecules selectively displayed by LECs in vivo, i.e., podoplanin, the hyaluronate receptor LYVE-1, and the vascular endothelial cell growth factor (VEGF)-C receptor, fms-like tyrosine kinase 4 (Flt-4)/VEGFR-3, were strongly expressed by expanded LECs, but not BECs. Conversely, BECs but not LECs expressed VEGF-C. LECs as well as BECs formed junctional contacts with similar molecular composition and ultrastructural features. Nevertheless, the two EC types assembled in vitro in vascular tubes in a strictly homotypic fashion. This EC specialization extends to the secretion of biologically relevant chemotactic factors: LECs, but not BECs, constitutively secrete the CC chemokine receptor (CCR)7 ligand secondary lymphoid tissue chemokine (SLC)/CCL21 at their basal side, while both subsets, upon activation, release macrophage inflammatory protein (MIP)-3alpha/CCL20 apically. These results demonstrate that LECs and BECs constitute stable and specialized EC lineages equipped with the potential to navigate leukocytes and, perhaps also, tumor cells into and out of the tissues.

Inflammatory skin disease in K14/p40 transgenic mice: evidence for interleukin-12-like activities of p40.

The proinflammatory cytokine interleukin-12, a p35/p40 heterodimer, is produced by resident cells in skin and has been implicated as a pathogenetic factor in T-cell-mediated skin diseases. Secretion of heterodimeric interleukin-12 is always accompanied by production of p40 monomer and p40/p40 homodimer. To investigate the possible in vivo role of p40 per se, we generated mice that constitutively express monomeric and homodimeric p40 in basal keratinocytes. These mice spontaneously developed an eczematous skin disease that was characterized by hyperkeratosis, focal epidermal spongiosis, and a mixed inflammatory infiltrate composed of T cells (CD4+), macrophages, eosinophils, mast cells, and few neutrophils. Fluorescence-activated cell sorter analysis of transgenic epidermal cell suspensions revealed induction of major histocompatibility complex class II molecules on keratinocytes and a 2-3-fold increase in the content of Langerhans cells. Cytokines produced by these activated epidermal cells include interleukin-1alpha and tumor necrosis factor alpha. The skin disease in K14/p40 mice was similar to that of littermate mice that received injections of interleukin-12, suggesting overlapping in vivo functional properties. As induction of interferon-gamma is a major function of interleukin-12, we tested the in vitro ability of transgenic p40 to induce interferon-gamma. In contrast to interleukin-12, transgenic p40 did not stimulate interferon-gamma secretion by cultured splenocytes. We conclude that transgenic p40 and interleukin-12 are equally capable of initiating cutaneous inflammation. Despite these in vivo similarities, there is a clear functional difference between interleukin-12 and transgenic p40 in vitro, suggesting that interferon-gamma is not a major factor contributing to interleukin-12-like activities of transgenic p40.

Cytokines regulate proteolysis in major histocompatibility complex class II-dependent antigen presentation by dendritic cells.

Endo/lysosomal proteases control two key events in antigen (Ag) presentation: the degradation of protein Ag and the generation of peptide-receptive major histocompatibility complex (MHC) class II molecules. Here we show that the proinflammatory cytokines tumor necrosis factor alpha and interleukin (IL)-1beta rapidly increase the activity of cathepsin (cat) S and catB in human dendritic cells (DCs). As a consequence, a wave of MHC class II sodium dodecyl sulfate stable dimer formation ensues in a catS-dependent fashion. In contrast, the antiinflammatory cytokine IL-10 renders DCs incapable of upregulating catS and catB activity and in fact, attenuates the level of both enzymes. Suppressed catS and catB activity delays MHC class II sodium dodecyl sulfate stable dimer formation and impairs Ag degradation. In DCs exposed to tetanus toxoid, IL-10 accordingly reduces the number of MHC class II-peptide complexes accessible to tetanus toxoid-specific T cell receptors, as analyzed by measuring T cell receptor downregulation in Ag-specific T cell clones. Thus, the control of protease activity by pro- and antiinflammatory cytokines is an essential feature of the Ag presentation properties of DCs.

Cutaneous elimination of 2,3,7,8-tetrachlorodibenzo-p-dioxin.

BACKGROUND: After exposure, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) is excreted via the faeces, breast milk and epidermal lipids. OBJECTIVES: To determine to what extent TCDD is eliminated via the skin and to evaluate whethe cutaneous elimination can be accelerated by the application of petrolatum. METHODS: In two patients severely intoxicated with TCDD, material obtained from the skin surface and, in one patient, cerumen and the content of epithelial cysts, was analysed for TCDD. RESULTS: The TCDD concentration in the initial blood sample taken was 144 000 pg g(-1) blood fa in patient 1, and 26 000 pg g(-1) blood fat in patient 2. Six months later, when the skin tests were performed, the blood TCDD levels had decreased to 80 900 and 16 100 pg g(-1) blood fat, respectively. In the two samples of pooled cyst contents from patient 1, TCDD levels of 34 400 an 18 600 pg g(-1) fat were found. A cerumen sample contained TCDD at 20 500 pg g(-1) fat. In the material collected from the skin surface we observed a linear increase of the amount of TCD measured per test field with time, indicating a continuous elimination of TCDD via the skin. Th daily amount of TCDD eliminated via the skin was 1.51 pg cm(-2) in patient 1 and 0.57 pg cm(-2) in patient 2. Application of petrolatum led to a twofold increase in the amount of TCDD measured in patient 1, but had no significant effect in patient 2. CONCLUSIONS: In our patients, elimination of TCDD via the skin, most probably through desquamating scales, represented 1-2% of the overall daily TCDD elimination rate, with regard to the body surface and when calculated on the basis of the half-life of TCDD at the time of the skin test. If a more typical overall elimination half-life of 7 years is used as the basis for the calculatio the skin would account for 9% (patient 1) and 15% (patient 2) of the overall elimination. Although we observed an increase in TCDD in material derived from the skin surface of up to 100% after application of petrolatum in patient 1, such an approach appears not to be a feasible means to increase elimination. Owing to the small amount of TCDD measured in skin-surface material, as well as in the cyst contents and cerumen obtained from one patient, contamination of the environment and other persons appears highly unlikely.

Definition, classification, and routine diagnosis of urticaria: a consensus report.

Urticaria is a well-known disease entity; however, with an increasing understanding of the molecular mechanisms involved in its pathogenesis, there is also growing evidence for a heterogeneity of urticaria. Currently it is sometimes difficult to compare divergent data reported by different centers researching urticaria due to a lack of precisely described patient populations. A consensus definition and classification of the disease and its subtypes, taking into account new developments, are therefore needed. In addition, this consensus report provides a guideline for diagnostic procedures in different subtypes of urticaria.