Table 1

Definition of kidney outcome, of indications to second biopsy and of histological score

Definition of kidney events
KFIDecrease in eGFR ≥30% confirmed by at least three determinations for at least 3 months
Proteinuric flare21Increase in proteinuria without modification of serum creatinine of at least 2 g/24 hours if the previous proteinuria was <3.5 g/24 hours or doubling if previous proteinuria was ≥3.5 g/24 hours
Nephritic flare21Increase in serum creatinine of at least 30% over the last value, associated with nephritic urinary sediment, with or without increased proteinuria
Arterial hypertensionSystolic blood pressure >140 mm Hg and/or diastolic blood pressure >90 mm Hg in sitting position (mean of three consecutive measurements)
Complete kidney responseProteinuria<0.5 g/24 hours, normal or near normal eGFR (within 10% of normal eGFR of previously abnormal)
No complete kidney responseAll the other cases
Histological assessment
Light microscopySpecimen fixed in 5% formalin
Stains used: H&E, periodic acid-Schiff, silver methenamine and Masson’s trichrome/AFOG
Neutrophil infiltration/karyorrhexis
Endocapillary hypercellularity
Hyaline deposits
Cellular/fibrocellular crescents
Fibrous crescents
Fibrinoid necrosis
Glomerular sclerosis
(<25% of glomeruli)
(25%–50% of glomeruli)
(>50% of glomeruli)
Interstitial inflammation
Interstitial fibrosis
Tubular atrophy
(<25% of the cortex)
(25%–50% of the cortex)
(>50% of the cortex)
  • AFOG, Acid Fuchsin Orange G; eGFR, estimated glomerular filtration rate; KFI, kidney function impairment.