Introduction:
The kidney biopsy (KB) remains the gold standard for diagnosing and evaluating lupus nephritis (LN) inflammatory activity and chronic damage. The usefulness of repeat KB is still a matter of debate for assessing response to therapy; differentiating proteinuria from inflammation or chronic damage; and monitoring drug tapering and suspension. The aim of this study was to evaluate LN patients who underwent a second KB, examining the reasons for performing repeat biopsies, the changes in histopathology, and the shifts in activity and chronicity indices, to determine the clinical significance of this procedure.
Methods:
We retrospectively reviewed KB of 55 patients from several hospitals. Light microscopy and immunofluorescence were analysed by nephrologists specialized in kidney pathology. The sample included patients who had their first KB and repeated it between 2000 and 2021. If more than two biopsies were performed, only the first and second ones were considered. The results were categorized according to the International Society of Nephrology/Renal Pathology Society classification of LN and reclassified if necessary. Statistical analysis was conducted using SPSS® and statistical significance was defined as p ≤ 0.05.
Results:
Of 55 patients, 46 were female (83.64%) and the mean age at the time of the first biopsy was 29.64±10.96 years. The average interval between the KB was 46±35 months. We’ve considered 110 KB, but patients were submitted to a total of 121 procedures: 6 had 3 KB, 1 had 4, and another one had 5. Most patients underwent a second biopsy due to disease recurrence (81.82%), while did so due to lack of treatment response (12.73%), decision to suspend treatment (3.64%) or unknown reasons (1.82%). There was no statistical difference between groups, except that, in the first biopsy, patients were more likely to present higher activity (5.31±3.76 vs. 3.09±3.42, p=.002) and lower chronicity scores (1.80±2.50 vs. 3,11±3.17, p =.019). The distribution of ISN/RPS classes according to biopsy is shown in table 1.
A switch of classes occurred in 36 patients, mainly those who had a proliferative first KB (77.78%). On non-proliferative first KB, most class II patients (3/4) displayed proliferative transformation (p = .005). On proliferative cases (44 patients with class III, IV, III/IV+V), 63.64% showed a change in classification (28/44): 60.71% to a non-proliferative status (17/28), mainly to class V (8/17), and 10.71% to a more proliferative class (3/28).
Among patients who had recurrence of the disease, 66.67% showed a change in classification (30/45), with 23.33% aggravating the proliferative status (7/30). Of the patients who had a failure of response to treatment, 3 out of 7 changed classes to a more proliferative status. The 2 patients who were proposed for treatment suspension both had class IV initially and in the second KB had 3/9 glomeruli with global sclerosis with no other changes, and a class II with 0 activity and chronicity scores, respectively.
Conclusions:
The data highlights the value of repeating KB to gain crucial insights into disease progression, therapy response, and treatment decision-making. This is particularly important given the evolving and complex nature of LN and allows optimal patient management.
I have no potential conflict of interest to disclose.
I did not use generative AI and AI-assisted technologies in the writing process.