Ole Clemmensen

Ulcerative colitis following B lymphocyte depletion with rituximab in a patient with Graves’ disease

The possible adverse consequences of biological therapies in inflammatory bowel diseases (IBDs) were recently highlighted in this journal by D’Haens ( Gut 2007; 56 :725–32). We here describe a hitherto unappreciated adverse effect to treatment with the B lymphocyte (B cell) depleting agent rituximab (RTX),1 namely the occurrence of ulcerative colitis and arthritis shortly after treatment with RTX. Our patient, a 45-year-old Caucasian female, had had mild irritable bowel symptoms since 1992 at which time rigid sigmoidoscopy and bowel x ray were normal. She had never received any therapy, had never previously had joint pain, and was not predisposed to IBD. In April 2005 she was diagnosed with Graves’ disease, and after uncomplicated standard methimazole therapy she received four weekly doses of 375 mg/m2 RTX from day 1 to 22 as part of a clinical trial.2 The trial was approved by the local ethics committee …

Incidence of congenital melanocytic nevi in newborn babies in Denmark

Three hundred fourteen unselected babies were examined within 96 hours of delivery. Three (1%) of the infants had clinically recognizable pigmented lesions. Two of the lesiohs (mean, 0.6%; range, 0.1%–2.3%; 95% confidence limits) proved histologically to be compound melanocytic nevi. The histology displayed almost identical patterns, with large nests of melanocytes at the dermoepidermal junction and only few nevus cells in the papillary dermis. A 0.6% incidence rate corresponds to 330 congenital melanocytic nevi in Denmark each year (range, 55–1265; 95% confidence limits). Because histology does not seem to be an accurate diagnostic tooi to sort out the malignant potential of the small congenital melanocytic nevi, prospective studies are needed to characterize the premalignant melanocytic nevi, whether congenital or acquired.

Adenocarcinoma arising in a foregut cyst of the mediastinum

A case of malignant transformation in a mediastinal cyst of the esophageal reduplication type is presented. The cyst had been recognized 39 years previously, but remained asymptomatic until sudden growth occurred. It was resected totally from the esophagus and the patient recovered well. A review of the literature showed that malignancy in mediastinal foregut cysts is extremely rare.

Histological distinction between early allergic and irritant patch test reactions: follicular spongiosis may be characteristic of early allergic contact dermatitis

Comparative light microscopic studies have revealed subtle differences between allergic and irritant reactions in the skin. In the search for specic differences, we focussed on the early inammatory response. This pilot study was conducted to test the hypothesis that follicular spongiosis can differentiate between early allergic and irritant patch test reactions. 8 patients with known contact allergy to either colophony or quarternium‐15 participated in the study. In each patient, allergic and irritant patch tests reactions were elicited, and 4‐mm punch biopsies were taken after 6–8 h from clinically equipotent reactions. Paired sets of slides were assessed blindly by 2 pathologists. 1 patient showing a pityrosporum folliculitis was excluded from the study. All biopsies from allergic patch tests were characterized by follicular spongiosis, while biopsies from irritant patch tests showed no recognizable changes except a slight follicular spongiosis in 1 patient. The 2 pathologists agreed independently on the correct classication in 6 out of 7 cases (p= 0.0156). We tested an optimized model, selecting non‐irritant allergens and a well‐known irritant. Further investigations are needed to elucidate the diagnostic signicance of the histological classication of allergic and irritant cutaneous reactions in punch biopsies.

Signet ring cell carcinoma of the eyelid – the monocle tumour†

We report the clinical and histopathological characteristics of two cases of signet ring cell carcinoma of the eye lids, and discuss the histogenesis of this neoplasm. Two 72‐year‐old Caucasian males both presented with slowly growing tumours of the eyelids. The tumours were excised and specimens were examined using light‐ and transmission electron microscopic techniques. Clinically, the tumours infiltrated both eyelids on one side of the face with swelling and periocular inflammation, creating a monocle‐like appearance. Extensive clinical work‐up excluded periocular metastases. Histopathologically, the tumours were composed of rather bland cells with mainly histiocytoid morphology. A minor proportion had a signet ring cell appearance. The cytoplasmic inclusions giving the signet ring morphology were PAS‐ and colloidal iron positive. The tumour cells reacted with antibodies against cytokeratins, carcinoembryonic antigen, epithelial membrane antigen, gross cystic disease fluid protein‐15 and lysozyme. Transmission electron microscopy demonstrated tumour cells containing intracytoplasmic vacuoles lined by microvilli. The tumour cells aggregated in duct‐like clusters. A diagnosis of primary signet ring cell carcinoma was made in both cases. Histopathological, immunohistological and ultrastructural findings indicated that the tumours were of sweat gland origin.

A new amyloidosis caused by fibrillar aggregates of mutated corneodesmosin.

Heterozygous nonsense mutations in the CDSN gene encoding corneodesmosin (CDSN), an adhesive protein expressed in cornified epithelia and hair follicles, cause hypotrichosis simplex of the scalp (HSS), a nonsyndromic form of alopecia. Truncated mutants of CDSN (mutCDSN), which bear the N‐terminal adhesive Gly/Ser‐rich domain (GS domain) of the protein, abnormally accumulate as amorphous deposits at the periphery of hair follicles and in the papillary dermis of the patient skin. Here, we present evidence that the mutCDSN deposits display an affinity for amyloidophilic dyes, namely Congo red and thioflavin T. We also detected the serum amyloid protein component in the dermis of HSS patients. We demonstrated that recombinant forms of mutCDSN and of the GS domain assemble in vitro into ring‐shaped oligomeric structures and fibrils. The amyloid‐like nature of the fibrils was demonstrated by dye binding and Fourier transform infrared spectrometry measurements. We showed that the ring‐shaped oligomers of mutCDSN, but not the fibrillar forms, are toxic to cultured keratinocytes. Finally, online algorithms predicted the GS domain to be a particularly disordered region of CDSN in agreement with circular dichroism measurements. This identifies HSS as a human amyloidosis related to the aggregation of natively unfolded mutCDSN polypeptides into amyloid fibrils.—Caubet, C., Bousset, L., Clemmensen, O., Sourigues, Y., Bygum, A., Chavanas, S., Coudane, F., Hsu, C.‐Y., Betz, R. C., Melki, R., Simon, M., Serre, G. A new amyloidosis caused by fibrillar aggregates of mutated corneodesmosin. FASEB J. 24, 3416–3426 (2010). www.fasebj.org

Genome-wide expression analysis of human in vivo irritated epidermis: differential profiles induced by sodium lauryl sulfate and nonanoic acid.

The pathogenesis of irritant contact dermatitis (ICD) is poorly understood, and genes participating in the epidermal response to chemical irritants are only partly known. It is commonly accepted that different irritants have different mechanisms of action in the development of ICD. To define the differential molecular events induced in the epidermis by different irritants, we collected sequential biopsies ((1/2), 4, and 24 hours after a single exposure and at day 11 after repeated exposure) from human volunteers exposed to either sodium lauryl sulfate (SLS) or nonanoic acid (NON). Gene expression analysis using high-density oligonucleotide microarrays (representing 47,000 transcripts) revealed essentially different pathway responses (1/2)hours after exposure: NON transiently induced the IL-6 pathway as well as a number of mitogen-activated signaling cascades including extracellular signal-regulated kinase and growth factor receptor signaling, whereas SLS transiently downregulated cellular energy metabolism pathways. Differential expression of the cyclooxygenase-2 and matrix metalloproteinase 3 transcripts was confirmed immunohistochemically. After cumulative exposure, 883 genes were differentially expressed, whereas we identified 23 suggested common biomarkers for ICD. In conclusion, we bring new insights into two hitherto less well-elucidated phases of skin irritancy: the very initial as well as the late phase after single and cumulative mild exposures, respectively.

Extraction of high‐quality epidermal RNA after ammonium thiocyanate‐induced dermo‐epidermal separation of 4 mm human skin biopsies

Abstract:  To obtain a separation of the epidermal and dermal compartments to examine compartment specific biological mechanisms in the skin, we incubated 4 mm human skin punch biopsies in ammonium thiocyanate. We wanted to test (i) the histological quality of the dermo‐epidermal separation obtained by different incubation times; (ii) the amount and quality of extractable epidermal RNA and (iii) its impact on sample RNA expression profiles assessed by large‐scale gene expression microarray analysis in both normal and inflamed skin. At 30‐min incubation, the split between dermis and epidermis was not always histologically well‐defined (i.e. occurred partly intra‐epidermally), but also varied between subjects. Consequently, curettage along the dermal surface of the biopsy was added to the procedure. This modified method resulted in an almost perfect separation of the epidermal and dermal compartments, and satisfactory amounts of high‐quality RNA were obtained. Hybridization to Affymetrix HG_U133A 2.0 GeneChips showed that ammonium thiocyanate incubation had a minute effect on gene expression resulting in only one significantly downregulated gene (cystatin E/M). We conclude that epidermis can be reproducibly and almost completely separated from the dermis of 4 mm skin biopsies by 30 min incubation in 3.8% ammonium thiocyanate combined with curettage of the dermal surface, producing high‐quality RNA suitable for transcriptional analysis. Our refined method of dermo‐epidermal separation will undoubtedly prove valuable in the many different settings, where the epidermal and dermal compartments need to be evaluated separately.

Antigen‐Presenting Activity of Non‐Langerhans Epidermal Cells in Contact Hypersensitivity Reactions

Despite the critical role of the Langerhans cells in the induction of contact hypersensitivity reactions, non‐Langerhans antigen‐presenting cells in already sensitized individuals may play a role in the elicitation phase of a contact hypersensitivity reaction, following epicutaneous challenge with antigens, the number of CD1+ DR+ epidermal Langerhans cells increased in a time‐dependent way and. concomitantly. CD1−OKM5+ DR+ epidermal non‐Langerhans cells appeared. In parallel with this, the capacity of epidermal cells to present both alloantigens and auto, nominal antigens increased, and 4 days after initiation of the contact hypersensitivity reactions 33–53% of the epidermal antigen‐presenting capacity was due to CD1− non‐Langerhans antigen‐presenting cells. Thus, contact hypersensitivity skin reactions are accompanied by the appearance of non‐Langerhans antigen‐presenting cells capable of presenting both alloantigens and auto/nominal antigens.

Treatment influencing down-staging in EORTC Melanoma Group sentinel node histological protocol compared with complete step-sectioning: A national multicentre study

AIM Metastasis size in melanoma sentinel lymph nodes (SLNs) is an emerging prognostic factor. Two European melanoma treatment trials include SLN metastasis diameters as inclusion criteria. Whilst diameter estimates are sensitive to the number of sections examined, the level of this bias is largely unknown. We performed a prospective multicentre study to compare the European Organisation for Research and Treatment of Cancer (EORTC) recommended protocol with a protocol of complete step-sectioning. METHODS One hundred and thirty-three consecutive SLNs from seven SLN centres were analysed by five central sections 50μm apart (EORTC Protocol) followed by complete 250μm step-sectioning. RESULTS Overall, 29 patients (21.8%) were SLN-positive. The EORTC Protocol missed eight of these metastases (28%), one metastasis measuring less than 0.1mm in diameter, seven measuring between 0.1 and 1mm. Complete step-sectioning at 250μm intervals (Extensive Protocol) missed one metastasis (3%) that measured less than 0.1mm. Thirteen treatment courses (34%) performed if inclusion was based on the Combined Protocol would not be performed if assessed by the EORTC Protocol. Thus, 10 patients would be without completion lymph node dissection (EORTC MINITUB study), whilst three patients would not be eligible for anti-CTLA4 trial (EORTC protocol 18071). The corresponding number with the Extensive Protocol would be three; one patient for the MINITUB registration study and two patients for the anti-CTLA4 study. CONCLUSIONS Examining SLNs by close central sectioning alone (EORTC Protocol) misses a substantial number of metastases and underestimates the maximum metastasis diameter, leading to important changes in patient eligibility for various treatment protocols.