Lack of association between antiphospholipid antibody and WHO classification in lupus nephritis

To study the prevalence of antiphospholipid antibody (aPL) in patients with biopsy proven lupus nephritis (LN) and to investigate if there is any association between the presence of serum aPL and WHO classes.

Seventy-one patients (68 female and 3 male, mean age 31 years, range 10-67) meeting ACR criteria for the classification of SLE and with biopsy proven LN were included. For every patient, we evaluated anticardiolipin antibodies, lupus anticoagulant and renal biopsy classified according to the WHO classification criteria (activity and chronicity scores were included). Twenty-four hour urinary protein at the time of biopsy was considered.

Twenty-nine patients had class V LN, 27 had class IV, 11 had class III, 3 had class II and 1 had class I. Twenty-seven (40.2%) patients were aPL positive. The prevalence of aPL positive patients was 45% in class V, 33.3% in class IV and 45.6% in class III. We did not find any significant association between the presence of aPL and the WHO class (p = 0.61 with class V, p = 0.31 with class IV and p = 0.73 with class III). There was no association between the presence of aPL and activity (p = 0.52) or chronicity scores (p = 0.42). We also did not find any association between proteinuria and the presence of aPL (p = 0.3).

Our results suggest that there is no association between the presence of aPL and the different WHO classes. The presence of these antibodies does not seem to be related to histological activity or the chronicity of lupus nephritis nor proteinuria.