An immunohistological study of IgA nephropathy and a report of its incidence in Ireland.

We report an incidence of IgA neph ropathy of 14.9% encountered in a total of 562 renal biopsies examined over a period of three years. Reference is made to the incidence reported in other countries. Details of light and fluorescence microscopical findings are correlated with clinical presentation and renal function in an effort to establish prognostic parameters. The results suggest that the presence of IgM deposits with extensions into capillary loops are associated with the more severe histological patterns. In contrast, the finding of classical IgA-IgG nephropathy and the occurrence of the lesion in younger patients is associated with less extensive structural damage.