POS1018 THE PREDICTIVE ROLE OF HISTOLOGICAL FINDINGS IN REPEATED KIDNEY BIOPSIES IN LUPUS NEPHRITIS PATIENTS WITH LONG-TERM FOLLOW-UP (2024)

Results: The main characteristics of the cohort are the following: females = 13/20 (65%); age at LN diagnosis = 32.15 ± 11.74; years of follow-up = 14.7 ± 9; patients who underwent two biopsies = 11/20 (55%); patients who underwent three biopsies = 9/20 (45%)(Table 1).

We observed that patients showing contraction of the renal function as measured by CKD class ≥3 at the time of the first biopsy showed significantly lower levels of complement, both C3 and C4 (100% CKD ≥3 versus 50% CKD < 3, p<0.05), and higher CI at the subsequent biopsies (5.2 ± 0.9 CKD ≥3 versus 3.6 ± 1 CKD < 3 at 2^nd biopsy, p <0.05; 6.3 ± 2 CKD ≥3 versus 3.6 ± 0.9 CKD < 3 at 3^rd biopsy).

The same was observed with respect to patients that developed ESRD at follow-up, again showing significantly lower levels of complement, both C3 and C4 (100% ESRD versus 50% no ESRD, p<0.05), and higher CI at the subsequent biopsies (5.5 ± 1 ESRD versus 3.7 ± 1 no ESRD at 2^nd biopsy, p<0.05; 7 ± 1.7 ESRD versus 3.7 ± 0.8 no ESRD at 3^rd biopsy, p<0.05),

In addition, when specifically focusing on AI and CI, we observed that a CI ≥4 at first biopsy and a CI ≥5 at second biopsy were associated to a decline of the renal function during the follow-up, assessed by eGFR and CKD class ≥3 (eGFR and CI 1^st biopsy ≥4, Log Rank test p<0.05, eGFR and CI 2^nd biopsy ≥5, Log Rank test p<0.05, CKD class ≥3 and CI 1^st biopsy ≥4, Log Rank test p<0.05, CKD class ≥3 and CI 2^nd biopsy ≥5, Log Rank test p<0.05), but also to a higher risk of developing ESRD (ESRD and CI 1^st biopsy ≥4, Log Rank test p<0.001, ESRD and CI 2^nd biopsy ≥5, Log Rank test p<0.001)(Figure 1).

When focusing on patients’ management, we observed a statistically significant difference in patients who were treated with the intensified B-lymphocyte depletion protocol between the first and the second biopsy, with respect to a CI ≥3 (100% no intensified protocol versus 24% intensified protocol, p<0.001), ≥4 (80% no intensified protocol versus 14% intensified protocol, p<0.05) and ≥5 (43% no intensified protocol versus 0% intensified protocol, p<0.05) at the second biopsy, with patients not undertaking the therapy showing higher CI.

Conclusion: A chronicity index ≥4 at first biopsy and a ≥5 at second biopsy seems to be associated to a decline of the renal function in LN patients (assessed by eGFR and CKD class ≥3) and to a higher risk of developing ESRD. Moreover, complement consumption (C3 and C4) at diagnosis seems to be associated to a more enhanced sclerotic process and a more pronounced deterioration of the renal function as well. Histological findings in repeated kidney biopsies might predict patients with worse renal outcomes.

Table 1. Summary of the main characteristics of the cohort.