Abstract:

 Abstract Objective: To investigate the clinical characteristics, renal histological features and the prognosis in patients of Class II LN with nephrotic syndrome. Methodology: One hundred twenty four cases（112 females，12 males，mean age 29.22±11.4 years） of LN class II were divided into nephritic syndrome group (NS, n=27) and non-NS group (n=97). The degree of mesangial proliferation was graded into normal (M0)、mild (M1)、moderate (M2) and severe (M3). Diffuse foot process effacement was defined as more than 50% of the glomerular capillary loops showing foot process effacement by EM. Clinical, immunological, pathological features and prognosis were compared between the two groups. Results: No significant differences in gender, onset age, LN duration, and SLE duration were found between the two groups. Compared with non-NS group, the patients with NS group had a much higher incidence of renal manifestations as the first onset symptom (77.8% vs 15.5%, P<0.01) and acute kidney injury (29.6% vs 0, P<0.01), but much lower incidence of malar rash (40.7% vs 69.1%, P<0.01), fever (14.8%vs62.9%，P<0.01), arthritis (29.6% vs 75.3%, P<0.01), hematuria (0 vs 34%,p<0.01) and serum anti-dsDNA positivity (29.6% vs 52.6%, P<0.05). In renal histology, the NS group had less severe mesangial proliferation (M2+M3: 7.4% vs 59.8%，P<0.01), but significantly higher incidence of diffuse foot process effacement (88.9% vs 0，P<0.01) than that in non-NS group. Remission rate showed no differences between the two groups (100% vs 98.4%, P>0.05), but the recurrence rate was much higher in NS group than that in non-NS group (69.9% vs 33.3%, P<0.01), and no patient progressed to end stage renal failure after the follow-up for 8-125 months (median 55 months) and 6-274 months(median 57 months) respectively. Repeated renal biopsy in 7 patients (2 in NS group and 5 in non-NS group) after relapsing showed no histological transformation in the NS group, while all five patients in the non-NS group showed histological transformation (2 to class III, one to class IV,V and V+IV respectively). Conclusion: Our data demonstrate that the nephrotic “class II” LN is a podocyte disease which should be differentiated from the class II LN with mesangial proliferation. Further studies are needed to explore the pathogenesis of podocyte injury in SLE.