Antineutrophil cytoplasmic antibodies (ANCA) in lupus nephritis patients and its relation to disease activity and histopathological features

Aim of the work

To describe the frequency of antineutrophil cytoplasmic antibodies (ANCA) in lupus nephritis (LN) patients at the time of renal biopsy and to study the relation to the disease activity and histopathological features in renal biopsy.

Patients and methods

Eighty adult LN patients with activity defined by the renal domains of the assessed SLE disease activity index (SLEDAI) and indicated for renal biopsies were enrolled. Clinical manifestations and systemic lupus international collaborating clinics damage index (SLICC-DI) were assessed. Serum level of cytoplasmic (c-ANCA) and perinuclear (p-ANCA) was measured using enzyme linked immunosorbent assay. Histopathological features of renal biopsy including activity (AI) and chronicity (CI) indices were assessed according to the modified national institute of health (NIH).

Results

The mean age of patients was 30.9 ± 8.8 years, disease duration 4.2 ± 4.1 years and 73 were females. The mean SLEDAI was 10.6 ± 4.8 and SLICC-DI was 1.2 ± 1.2. Twelve (15 %) patients had positive ANCA; 41.7 % anti-MPO, 33.3 % anti-PR3 and 25 % having double positivity. Class IV was significantly higher in ANCA negative (p = 0.04), while class V was significantly higher in ANCA positive (p = 0.019). The AI and CI were comparable between ANCA positive and negative patients (p > 0.05). A significant correlation was found between SLEDAI and AI (r = 0.35,p = 0.005) and between SLICC-DI and CI (r = 0.29,p = 0.019). Hyaline deposits (r = 0.83,p = 0.04) and interstitial inflammation (r = -0.85,p = 0.03) significantly correlated with the anti-myeloperoxidase level in positive cases.

Conclusion

Presence of ANCA affects the histopathological class of LN. Clinical activity and damage in LN correlate with activity and chronicity respectively in renal biopsy.