SKIN CHANGES IN FILARIAL AND NON-FILARIAL LYMPHEDEMA OF THE LOWER-EXTREMITIES

The pathogenesis of lymphoedema in patients infected with Wuchereria b ancrofti or Brugia malayi remains unclear. Lymph stasis and local immu nological reactions seem to play the main role. In order to discrimina te between the obstructive and immunological effects of the parasite, a comparative histological study of skin specimens obtained from two g roups of patients, one with filarial and the other with postsurgical l ymphedema of lower extremities, was performed. In both groups patients suffered lymph stasis, in the first due to filariasis, in the other d ue to removal or irradiation of pelvic lymph nodes. The patients with filarial infection showed hyperproliferation of keratinocytes, focal a cantholysis, accumulation of lymphocytes at the epidermo-dermal juncti on, profuse pericapillary and perivenular mononuclear infiltrations in the dermis marginated granulocytes in capillaries and, in some cases, subepidermal granulocytic infiltrates. There were many dilated initia l lymphatics and lymphatic ''lakes'' between thick collagen. fibre bun dles. Monoclonal antibody analysis revealed that the most common cells in the infiltrates were macrophages (CD 68+). All mononuclear and end othelial cells were HLA-DR+. In contrast, the skin specimens of non-fi larial patients revealed only moderate proliferation of keratinocytes, increased numbers of CD1+ epidermal Langerhans cells, moderate perica pillary infiltrates of CD68+, CD4+ and CD8+ cells, and evidently less intensive marking of cells with anti-HLA-DR antibody. There were few i nitial lymphatics visible. These findings indicate that filarial lymph oedema is complicated by a severe inflammatory component, which is muc h less expressed in postsurgical lymph stasis.