The impact of antiphospholipid antibodies in children with lupus nephritis

BACKGROUND AND OBJECTIVES: To evaluate the frequency of antiphospholipid antibodies (APLa) among patients with childhood lupus nephritis (cLN) and to assess their impact on long-term renal outcomes. DESIGN AND SETTING: This is an observational hospital based study. PATIENTS AND METHODS: Patients with cLN diagnosed by renal biopsy seen between January 2002 and June 2014 were included. APLa positivity was defined if detection was positive on 2 occasions 6–12 weeks apart during their follow up. Demographic features, age at disease onset, disease duration, follow-up duration and clinical and laboratory variables at the time of renal biopsy were collected. The renal biopsy was reviewed for the nephritis class, microthrombi, activity and chronicity indices. Renal outcome measures included the serum creatinine levels, protein/creatinine ratio and end stage renal disease (ESRD). RESULTS: Fifty-nine, (49 female) patients with a mean age of 19.8 years and mean disease duration of 6.8 years were involved. APLa were detected in 46 (78%) patients. Twenty-two patients had class IV nephritis, which was more prevalent in APLa positive patients. The frequencies of class III and V nephritis was similar in 10 patients in each class (7 patients in each class with APLa). The presence of APLa did not correlate with nephritis activity or the chronicity indices. Microthrombosis was found in 10 patients, and 8 of them had APLa. Patients with APLa had a higher frequency of elevated serum creatinine and hypertension, 9 developed ESRD, and 7 had APLa. There was no statistically significant association between the presence of APLa and the accrual damage index and clinical manifestations. Furthermore, there was no association between APLa and other autoantibodies. CONCLUSION: The frequency of APLa in cLN was high. While the association is not statistically significant, APLa positive patients tend to develop renal microthrombi and are probably at higher risk of ESRD.