Pemphigus refers to a group of autoimmune blistering skin diseases, mainly identified as pemphigus vulgaris and pemphigus foliaceus, both characterized by the presence of autoantibodies against keratinocyte adhesion molecules, leading to loss of cell-cell adhesion with consequent blister formation. Pemphigus vulgaris is reported to be associated with human leukocyte antigen DR4 and/or DR6 whereas no data are available on pemphigus foliaceus, except for the endemic Brazilian form (fogo selvagem), which is reported to be associated with DR1 and DR4. We here report human leukocyte antigen molecular typing on a total of 87 patients, 61 with pemphigus vulgaris and 26 with pemphigus foliaceus, versus 128 healthy matched controls. Generic typing showed an increase of DRB1*04 and DRB1*14 and a decrease of DRB1*07 in both pemphigus vulgaris and pemphigus foliaceus patients. Molecular subtyping of DR4+ and DR14+ subjects showed a highly significant association between the DRB1*1401 and both pemphigus vulgaris (p < 0.0001) and pemphigus foliaceus patients (p < 0.0001) together with a significant increase of the linked DQB1*0503 (pemphigus vulgaris p < 0.0001; pemphigus foliaceus p < 0.0001). Moreover, whereas the association between DRB1*0402 and pemphigus vulgaris (p < 0.0001) has been confirmed, no significant association between a specific allele of the DR4 group and pemphigus foliaceus, has been found. Therefore, at least in Italian patients, pemphigus vulgaris and pemphigus foliaceus share DRB1*1401 and DQB1*0503, as susceptible human leukocyte antigen alleles, whereas DRB1*0402 is only found associated with pemphigus vulgaris. The observation that both diseases, pemphigus vulgaris and pemphigus foliaceus, carry the same susceptible human leukocyte antigen alleles has been interpreted as a common genetic background predisposing to pemphigus as, like in other autoimmune disorders, it is not sufficient to explain the onset of the disease on the basis of the sole aforementioned alleles. Other linked genes and/or environmental factors should play a facilitating role in the outbreak of pemphigus, either pemphigus vulgaris or pemphigus foliaceus.

Kaposi's sarcoma appeared on a chronically lymphedematous leg of a 75-year-old man. Immunologic investigations revealed a lack of cellular immune response confined to the involved lower limb. Regional disorders of immune surveillance are thought to play an important role in the early stages of Kaposi's sarcoma.

A case is reported of trimethylaminuria that first developed in adulthood without any apparent cause. The patient developed a characteristic fish odour of his sweat, urine and to his breath after the consumption of choline-rich foods. Elevated levels of trimethylamine were present in the urine after dietary tests and identified by means of gas chromatography.

We report a case of tinea capitis mimicking tufted hair folliculitis in a 56-year-old European man, who presented with a 4-year history of pain and erythema in an area of scarring alopecia of the occipital scalp, with scales and tufts of hair emerging from individual follicles. Histological examination showed hair plugging, and a dense perifollicular infiltrate of plasma cells, lymphocytes, and neutrophils. There was widespread scarring and fibrosis. Bacterial cultures were negative for Staphylococcus aureus, but fungal cultures and periodic-acid-Schiff stain were positive for Trichophyton tonsurans. Videodermatoscopy of the lesion showed a pattern consistent with folliculitis decalvans. Diagnosis was made on the basis of the clinical, histological, microbiological and videodermatoscopy data. After 30 days of systemic antifungal treatment, there were a substantial clinical improvement and disappearance of pain. After 5 months, a residual cicatricial area was seen with some hair tufts emerging from a single orifice.