[Hypocomplementaemic leucocytoclasic vasculitis. (Mac Duffie's syndrome). One case with bacterial lymphadenitis...

Mac Duffie's syndrome includes a hypocomplementaemic allergic vasculitis with essentially cutaneous and articular manifestations. Its pathogenesis, still incompletely elucidated, involves the precipitation of immune complexes in the walls of the all vessels. The problem remains as to whether the alteration in the complement system is merely a reflection of this formation of immune complexes, or if it is primary, favourising the chronic infections which produce such complexes. The significance of the presence of low molecular weight precipitins reacting with C1g in the serum of a number of patients remains uncertain. The case reported, with its new clinical features, does not provide an answer to these questions but emphasises the possible role of chronic infections in the origin of this syndrome.