Apoptotic cells in six patients with IgA nephropathy in repeat biopsies

Abstract

SUMMARY: Programmed cell death is a selective process of physiological cell deletion and is known as apoptosis. The purpose of the present study was to determine the relationship between the existence of apoptotic cells in glomeruli and the clinical or histopathological findings obtained in repeat renal biopsies of patients with IgA nephropathy. Repeat renal biopsy specimens were obtained from six patients with IgA nephropathy. The nick end labelling method (TUNEL) was used for the detection of apoptotic cells. Clinical laboratory data, i.e. urinary protein excretion, creatinine clearance (Ccr), blood urea nitrogen (BUN) and serum creatinine, (s‐Cr) were obtained from these patients. At the first renal biopsy, apoptotic cells in the glomeruli were observed in three out of six patients using TUNEL. These patients were classified as the severe glomerular damage group. The other three patients without apoptotic cells were in the mild glomerular damage group. Mean levels of urinary protein excretion at the first renal biopsy in the patients with apoptotic cells were slightly higher than those in patients without apoptotic cells. Levels of Ccr in patients with apoptotic cells were lower than those in patients without apoptotic cells. There were no significant differences in the levels of BUN and s‐Cr in patients with or without apoptotic cells. Two patients with apoptotic cells in glomeruli at the first renal biopsy did not show apoptotic cells at the second renal biopsy. These two patients showed improvement not only in clinical laboratory findings but also in histological findings at the second biopsy. Only one patient with apoptotic cells at the first and second biopsies exhibited deterioration at the second biopsy. All three patients without apoptotic cells at the first renal biopsy also showed deterioration of the clinical laboratory and histopathological findings. It is postulated that various factors other than apoptosis might induce progression of renal injuries in such patients. It appears that the clinical laboratory data, i.e. proteinuria, renal function and histopathological findings, might be influenced by apoptosis in patients with IgA nephropathy. It is postulated that apoptosis may induce reduction of excess proliferative glomerular mesangial cells and/or infiltrating cells and tissue repair.