Background/Purpose: Lupus nephritis (LN) class III or IV is associated with a poor prognosis for both patient and renal survival. Since antiphospholipid syndrome (APS) is reported to worsen the prognosis of LN, LN patients with APS should be treated with conventional immunosuppressive treatment plus antiplatelet or anticoagulation therapy according to the recommendations for LN management. However it has been unclear whether these therapies would benefit antiphospholipid antibodies (aPL)-positive LN patients not meeting the diagnostic criteria. Here, we evaluated the effect of antiplatelet therapy in addition to conventional immunosuppressive therapy for LN patients positive for aPL without definite APS.

Methods: Patients with biopsy-proven LN class III or IV who did not take hydroxychloriquine were retrospectively evaluated. We selected patients positive for anticardiolipin antibody (aCL) or lupus anticoagulant (LA) who did not meet the criteria for a diagnosis of APS. The patients were divided into two subgroups according to whether antiplatelet therapy was received. The cumulative complete renal response (CR) rate, relapse-free rate, and change in estimated glomerular filtration rate (eGFR) over 3 years after induction therapy were calculated.

Results: We identified 17 patients who received antiplatelet therapy and 21 who did not. Baseline clinicopathological characteristics and immunosuppressive therapy did not show a statistically significant difference between the two groups except for a significantly higher incidence of LN class IV in the treatment group (p = 0.03). There was no significant difference in cumulative CR rate, relapse-free rate, or eGFR change between these subgroups. However, when data on LA-positive patients were assessed, a significant improvement in eGFR was found (p = 0.04) in patients receiving antiplatelet therapy (Figure 1).

Conclusion: Addition of anti-platelet therapy was associated with an improvement of eGFR in LA-positive patients with LN class III or IV. There may be a wider indication for antiplatelet therapy in LN, in addition to its use in patients with a definite APS diagnosis.