Porphyria cutanea tarda. Evolution study of the clinical and laboratory features: biochemistry, immunofluorescence and light microscopy / "Porfiria cutânea tardia. Estudo evolutivo das características clínicas e laboratoriais: bioquímica, imunofluorescência e microscopia óptica"

AUTOR(ES)
DATA DE PUBLICAÇÃO

2006

RESUMO

Porphyria cutanea tarda is caused by the inherited or acquired partial deficiency of the uroporphyrinogen decarboxylase enzyme activity, resulting in the accumulation of uroporphyrin and hepta-carboxyl porphyrinogen in the liver. The purpose of this study was to investigate the clinical and laboratory features: biochemistry and the alterations on skin morphology, on light microscopy and immunofluorescence of 28 patients with the diagnosis of porphyria cutanea tarda, before and after treatment with chloroquine. We report the results of light microscopy and direct immunofluorescence on 23 patients with active porphyria cutanea tarda before treatment, seven patients with clinical remission, and eight patients with clinical and biochemical remission, i.e. inactive porphyria. Seven patients were females (25%) and 21 were males (75%). Alcohol intake was the predominant etiological factor in male patients and estrogen therapy in female patients (contraceptive agents or postmenopausal hormone replacement therapy). Hepatitis C was present in 57,1% of the patients (71,4% of the males and 14,3% of the females). In light microscopy of 23 patients, 86,9% had subepidermal bullae and 95,6% had deposits of PAS-positive diastase-resistant material thickening the vessel wall of the superficial dermis. This thickening of the vessel persisted after biochemical remission in four of five patients but it was less intense. Of the 23 patients with active porphyria, the direct immunofluorescence of four patients was negative and 19 patients revealed IgG and complement (C3) bound in a rather characteristic pattern in and around vessel walls and on the dermal-epidermal junction. IgG was present on the vessels of 65,2% and on the dermal-epidermal junction of 47,8%. C3 was present on the vessels of 52,2% and on the dermal-epidermal junction of 39,1%. The fluorescence on the vessel walls was homogeneous, moderate or very intense and its presence and intensity was as noticeable as on the dermal-epidermal junction in 57,9% of the patients. Patients with clinical remission or biochemical remission had deposit of IgG on the vessel wall in 85,7% and 87,5%, respectively, and deposit of C3 on the vessel wall in 14,3% and 37,5%, respectively. Comparing the patients before treatment to those with clinical remission or with biochemical remission, the number of cases with deposit of C3 on the vessel lessoned (from 52,2% before treatment to 14,3% and 37,5%, respectively). Patients with biochemical remission had the fluorescence predominating on the vessel walls rather than on the dermal-epidermal junction (71,4%). Immunofluorescence mapping of the dermal-epidermal junction, in order to determine the level of the subepidermal split, was possible in seven patients with active porphyria without previous treatment. In three cases all the antigens, i.e. BP180 (bullous pemphigoid antigen), laminin, type IV collagen and type VII collagen, were found on both sides of the bulla (no split level); in two cases all the antigens were found on the floor of the bulla (intra-epidermal split); in one case type IV collagen was found on the roof and type VII collagen on both sides of the bulla (split occurred on the sublamina densa); and in one additional case all the antigens were found on the roof of the bulla (split occurred below sublamina densa). Therefore no standard split level occurs on the dermal-epidermal junction. Probably what defines the split level is the photodynamically induced lysosomal damage affecting keratinocytes of the basal layer and/or dermal cells.

ASSUNTO(S)

chloroquine precipitating factors porfiria cutânea tardia/terapia porfiria cutânea tardia/complicações porphyria cutanea tarda/complications porphyria cutanea tarda/physiopathology fatores desencadeantes cloroquina review [publication type] imunofluorescência revisão [tipo de publicação] porphyria cutanea tarda/therapy porphyria cutanea tarda/pathology porfiria cutânea tardia/patologia fluorescent antibody technique porfiria cutânea tardia/fisiopatologia

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