Luigia Venegoni

Twenty-one cases of blastic plasmacytoid dendritic cell neoplasm: focus on biallelic locus 9p21.3 deletion

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare and aggressive malignancy derived from precursors of plasmacytoid dendritic cells. We analyzed 21 cases with array-based comparative genomic hybridization (aCGH). Complete or partial chromosomal losses largely outnumbered the gains, with common deleted regions involving 9p21.3 (CDKN2A/CDKN2B), 13q13.1-q14.3 (RB1), 12p13.2-p13.1 (CDKN1B), 13q11-q12 (LATS2), and 7p12.2 (IKZF1) regions. CDKN2A/CDKN2B deletion was confirmed by FISH. This scenario argues for disruption of cell cycle at G(1)/S transition, representing a genetic landmark of BPDCN, and possibly contributing to its pathogenesis. Statistical analysis of overall survival in our series highlighted an association of poor outcome with biallelic loss of locus 9p21.3. We suggest that, in the absence of reliable parameters for predicting prognosis in BPDCN other than age, tumor stage, and/or clinical presentation, simple methods, such as FISH for CDKN2A/CDKN2B, could help to identify the most aggressive cases.

Expression of tissue factor by eosinophils in patients with chronic urticaria.

Background: Although several cases of chronic urticaria (CU) are currently regarded as autoimmune in origin, associated with histamine-releasing autoantibodies, an activation of blood coagulation via tissue factor (TF) and a strong expression of TF in lesional skin have been described. Eosinophils, which are involved in CU skin lesions, have recently been demonstrated as the major source of TF in human blood. We assessed whether eosinophils are the cellular source of TF in CU skin lesions. Methods: Twenty patients with severe CU were studied. Skin biopsy specimens were taken from wheals. The control group consisted of specimens of perilesional normal skin from different types of skin tumours (10) and various skin disorders with non-eosinophilic infiltrates, including leukocytoclastic vasculitis (7), lichen planus (8) and mastocytosis (3). TF expression was evaluated by immunohistochemical methods using an anti-TF monoclonal antibody. Co-localization of TF and eosinophil cationic protein, a classic cell marker of eosinophils, was investigated by double-staining studies using 2 specific monoclonal antibodies in the 4 specimens showing the highest TF reactivity scores. Results: All specimens from patients with CU clearly showed TF expression that was absent in all normal control specimens (p = 0.0001) and in the skin disorders with non-eosinophilic infiltrates (p = 0.001–0.0001). The double-staining experiments for TF and eosinophil cationic protein clearly showed that the TF-positive cells were eosinophils. Conclusions: Eosinophils are the main source of TF in CU lesional skin. This finding highlights the role of these cells in the pathophysiology of CU and might pave the way for new therapeutic strategies.

Activation of blood coagulation in bullous pemphigoid: role of eosinophils, and local and systemic implications.

Background  Bullous pemphigoid (BP) is a blistering skin disease caused by autoantibodies to hemidesmosomal proteins, with eosinophils participating in blister formation. Eosinophils are a source of tissue factor (TF), an initiator of blood coagulation.

Treatment of Refractory Pemphigus with the Anti-CD20 Monoclonal Antibody (Rituximab)

Background: Pemphigus is a severe blistering disorder caused by autoantibodies to desmogleins 1 and 3. Because some patients with pemphigus never enter into remission, new immunosuppressants are warranted. Rituximab is a chimeric monoclonal antibody binding to the CD20 antigen on B cells, which proved to be effective in recalcitrant pemphigus. Objectives: To evaluate the efficacy and safety of rituximab in refractory pemphigus and to investigate its effects on the autoantibody profile. Patients and Methods: Six patients with recalcitrant pemphigus were treated. Rituximab was administered intravenously at a dosage of 375 mg/m2 body surface once weekly for 4 weeks. Results: Three pemphigus foliaceus patients and 1 with mucocutaneous pemphigus vulgaris (PV) showed complete response over a follow-up period of up to 18 months. In one oral PV, control of the disease was achieved using pulse therapy with cyclophosphamide following rituximab withdrawal. In one PV with vegetating features, good improvement was obtained after 6 rituximab infusions. All patients tolerated the treatment well. Anti-desmoglein autoantibodies significantly decreased only in pemphigus foliaceus. Conclusions: This study highlights that rituximab is a valuable drug for refractory pemphigus, although the response of mucous membranes and cutaneous folds may be delayed.

Cutaneous extranodal NK/T-cell lymphoma: a clinicopathologic study of 5 patients with array-based comparative genomic hybridization

Extranodal natural killer/T-cell (ENK/T) lymphoma is a rare neoplasm, subcategorized into ENK/T-nasal (ENK/T-N) and ENK/T-nasal type (ENK/T-NT) lymphomas. ENK/T-NT lymphoma with initial presentation in the skin is known as primary cutaneous ENK/T-NT (PC-ENK/T-NT) lymphoma. The aim of this study was to investigate pathogenesis, genomic alterations, and prognosis of cutaneous ENK/T lymphomas to provide further insights into clinicopathologic features and genetic mechanism of lymphomagenesis. A retrospective case study of 5 white patients affected by ENK/T lymphoma (4 PC-ENK/T-NT and 1 ENK/T-N with cutaneous involvement) was performed. Most of the cases presented with multiple nodules and ulcerations localized on the extremities. A considerable percentage had disease in advanced stage with a 12-month survival rate of 40%. Genomic alterations were detected by array-based comparative genomic hybridization that showed gains of 1q, 7q and loss of 17p in the cases of PC-ENK/T-NT lymphomas and gain of 7q and loss of 9p, 12p, 12q in the case of ENK/T-N lymphoma. In conclusion, ENK/T lymphoma is a very aggressive entity, and, in our cases, the exclusively cutaneous presentation was not associated with a better prognosis. The results of our array comparative genomic hybridization analysis could be useful to better define the different ENK/T lymphoma subgroups with cutaneous involvement.

Cytokeratin profile in basal cell carcinoma.

Origin of basal cell carcinoma (BCC) is still unclear. We studied the cytokeratin (CK) profile in BCC using monoclonal antibodies against 12 CKs to further investigate the suggested origin of the tumor from follicular matrix cells or from follicular outer root sheath cells and to determine if BCC subtypes can be identified on the basis of their CK profiles. Cases of pilomatricoma and samples of fetal skin served as controls to establish the CK profile in matrical cells and developing follicles during intrauterine life, that of the epidermis and cutaneous adnexa in adult life having been determined in a previous study. The most significant findings were as follows: (a) CK 5 and CK 17 positivity in all the BCCs studied; (b) CK 7, CK 8, CK 18, and CK 19 positivity in 30/52, 33/52, 42/52, and 14/52 BCCs, respectively; (c) CK 14 negativity in almost all the BCCs studied; and (d) lack of CK 1 expression only in 2/2 morpheiform BCCs and 4/10 nodular BCCs. The study suggests a tumorous differentiation toward follicular outer root sheath cells and, in most cases, also toward the glandular components of the pilosebaceous-apocrine unit. No significant difference in the CK profile among the BCC subtypes studied was found.

The usefulness of clonality for the detection of cases clinically and/or histopathologically not recognized as cutaneous T‐cell lymphoma

Background  The determination of clonality has proven to be a useful adjunct to the diagnosis of cutaneous lymphocytic infiltrates. It is considered particularly helpful for the distinction of mycosis fungoides (MF) and inflammatory dermatoses.

Primary cutaneous T-cell lymphoma expressing FOXP3: A case report supporting the existence of malignancies of regulatory T cells

Regulatory T (Treg) cells, which represent 5% to 10% of peripheral T cells, regulate the activities of T-cell subsets by performing immunosuppressive functions and thus preventing the development of autoimmune responses. The majority of Treg cells are CD4+, CD25+, and FOXP3+. Recently, it has been demonstrated that the tumor cells in adult T-cell leukemia lymphomas can function as Treg, raising the question of whether any variant of primary cutaneous T-cell lymphoma may also express a regulatory phenotype. We describe an extraordinary case of primary cutaneous T-cell lymphoma clinically characterized by protean cutaneous manifestations and histologically showing a pattern consistent with epidermotropic pleomorphic medium-/large-cell primary cutaneous T-cell lymphoma. The majority of neoplastic cells were CD4+ CD25+ T cells and strongly expressed FOXP3. With this background, the current case, characterized by an aggressive course requiring polychemotherapy, may support the existence of lymphoproliferative malignancies of Treg cells.

Clinicopathological and molecular study of primary cutaneous CD4+ small/medium-sized pleomorphic T-cell lymphoma

Primary cutaneous CD4+ small‐/medium‐sized pleomorphic T‐cell lymphoma (CD4+ PCSM‐TCL) is a rare lymphoproliferative disorder with a favorable prognosis. Distinguishing it from other cutaneous lymphomas is often a challenge.

Extracellular microRNA signature of human helper T cell subsets in health and autoimmunity

Upon T cell receptor stimulation, CD4+ T helper (Th) lymphocytes release extracellular vesicles (EVs) containing microRNAs. However, no data are available on whether human CD4+ T cell subsets release EVs containing different pattern of microRNAs. The present work aimed at filling this gap by assessing the microRNA content in EVs released upon in vitro T cell receptor stimulation of Th1, Th17, and T regulatory (Treg) cells. Our results indicate that EVs released by Treg cells are significantly different compared with those released by the other subsets. In particular, miR-146a-5p, miR-150-5p, and miR-21-5p are enriched, whereas miR-106a-5p, miR-155-5p, and miR-19a-3p are depleted in Treg-derived EVs. The in vitro identified EV-associated microRNA signature was increased in serum of autoimmune patients with psoriasis and returned to healthy levels upon effective treatment with etanercept, a biological drug targeting the TNF pathway and suppressing inflammation. Moreover, Gene Set Enrichment Analysis showed an over-representation of genes relevant for T cell activation, such as CD40L, IRAK1, IRAK2, STAT1, and c-Myb in the list of validated targets of Treg-derived EV miRNAs. At functional level, Treg-derived (but not Th1/Th17-derived) EVs inhibited CD4+ T cell proliferation and suppressed two relevant targets of miR-146a-5p: STAT1 and IRAK2. In conclusion, our work identified the miRNAs specifically released by different human CD4+ T cell subsets and started to unveil the potential use of their quantity in human serum to mark the pathological elicitation of these cells in vivo and their biological effect in cell to cell communication during the adaptive immune response.