Increased Mast Cell Numbers in the Sclerotic Skin of Porphyria cutanea tarda

Abstract

We quantitated numbers of mast cells in the sclerotic skin noted on the dorsa of the hands of 10 patients with porphyria cutanea tarda (PCT) and compared them with those of diffuse scleroderma and healthy controls. Mast cell counts in sclerodermoid skin of PCT patients were significantly greater than those in involved skin of 9 patients with diffuse scleroderma in its late stage and also greater than those in normal skin of 8 controls. When mast cell density was analyzed according to the depth of the dermis, an 84% increase was noted in the uppermost layer (0–0.2 mm in depth) and a 150% increase in the second uppermost layer (0.2–0.4 mm in depth) in the patients with PCT when compared with those in the corresponding sites of the controls. These results suggest a possible role of mast cells in the pathogenesis of sclerodermoid skin of PCT.

Porfiria cutânea tardia

“…42 C' activation causes generation of anaphylotoxin (C5a), 33 releasing histamine form mast cells, which stimulate collagen production. 43 Fibrosis may also be secondary to vascular injury. 36 Eicosanoid metabolism -In vitro incubation of peritoneal macrophages of rats or of fibrosarcoma cells with hematoporphyrin derivatives, followed by radiation of 630nm, results in the generation of prostaglandin E 2 (PGE 2 ).…”

“…84,85 Plaques are white-yellowish, hardened and they occur in photoexposed or protected areas. 43 The association with scleroderma is rare 86 Other cutaneous changes are cicatritial alopecia, 69 precocious aging with solar elastosis and comedones, 81,82 and onycholysis. 81 Non-cutaneous manifestations are peripheral neuropathy, 87 Van der Hoeve scleromalacia perforans, 88 palmar fibromatosis, 82 deafness, insomnia, personality changes, conjunctivitis and epiphora.…”

“…104 In sclerodermiform lesions, dermis sclerosis is caused by increased collagen I, similar to systemic scleroderma, 36,84 and there is a significant number of mast cells in the inflammatory infiltrate. 43 Exposed skin often displays considerable solar elastosis. 36 With PAS (periodic acid Schiff) staining, hyaline material, PAS-positive and diastase-resistant is found in the upper dermis vessel walls and in the DEJ (Figure 6).…”

"Porfiria cutânea tardia. Estudo evolutivo das características clínicas e laboratoriais: bioquímica, imunofluorescência e microscopia óptica"

“…A histamina liberada pelos mastócitos, sob a influência da anafilotoxina (C5a), pode estimular a produção de colágeno pelos fibroblastos e produzir alterações esclerodermóides. 73 Esta hipótese baseia-se nos seguintes fatos: (1 Estudos adicionais dos efeitos porfirinogênicos do HCB, TCDD e PCB sugerem que a ativação metabólica do citocromo P450 e os FRO mediados pelo ferro estão associados ao ataque à UROD no sítio catalítico. 24,101 Além da inativação da UROD no sítio catalítico, eles também têm a capacidade de induzir a ALA sintetase através da depleção do heme, secundária à indução das isoenzimas do citocromo P450, e isto leva à geração de substrato em excesso para uma enzima que se encontra inibida.…”

“…62 A esclerose da derme é causada pelo aumento do colágeno I, semelhante à esclerodermia sistêmica 140 e no infiltrado inflamatório há um número significativo de mastócitos. 73 A imunofluorescência direta (IFD) permite a diferenciação entre a PCT esclerodermiforme e a esclerodermia, pois na última a imunofluorescência geralmente é negativa. 140 A pele exposta freqüentemente exibe uma quantidade considerável de elastose solar.…”