Long-standing spontaneous clinical remission and glomerular improvement in primary IgA nephropathy (Berger's disease).

Of the 244 cases of IgA nephropathy diagnosed at Necker Hospital before 1981, 9 patients (3.7%) developed spontaneous clinical remission of long duration. Three of these 9 patients presented with gross hematuria, while in the others the disease was discovered by the finding of proteinuria at routine urinalysis. During the disease course 5 patients had recurrent episodes of gross hematuria, lasting several years in 4. At the time of the first biopsy all patients had hematuria and permanent proteinuria. In 1 patient, renal biopsy showed only an increase in mesangial matrix while in the others segmentary lesions were observed, affecting less than 30% of the glomeruli in 6. Diffuse mesangial deposits of IgA were present in all. During the follow-up, proteinuria and microscopic hematuria gradually decreased and completely disappeared within 4-14 years after the onset of the disease. A repeat biopsy performed during remission in 4 patients showed, in 3, an improvement of glomerular lesions and a significant decrease in IgA mesangial deposits in parallel with clinical recovery. As in other types of 'primary' glomerulonephritis, these data indicate that the initial disorder in IgA nephropathy may be spontaneously reversible even after a long course of the disease.