Fractional excretion ratio of activated leukocyte cell adhesion molecule (ALCAM) as a potential biomarker in lupus nephritis patients

Aim of the work

To investigate the use of fractional excretion ratio (FE) of activated leukocyte cell adhesion molecule (ALCAM) in patients with lupus nephritis (LN) and whether, in comparison to the absolute urine levels, they demonstrate improved diagnostic performance.

Patients and methods

42 systemic lupus erythematosus (SLE) patients; Group 1: 14 inactive SLE patients, Group 2: 14 active non-renal SLE, Group 3: 14 active lupus nephritis. All participants were evaluated as regards the following: Thorough medical history and clinical evaluation, disease activity and renal activity assessment using the SLE disease activity index 2000 (SLEDAI-2 K), LN histological class, activity and chronicity index were evaluated using International Society of Nephrology/Renal Pathology Society Criteria (ISN/RPS). Serum and urine ALCAM levels were assayed using ELISA. FE ratio was calculated as follows: (urinary biomarker/urinary creatinine)/ (serum biomarker/serum creatinine).

Results

The mean age of the patients was 26.6 ± 10.4 years and were 36 females and 6 males (F:M 6:1). Groups were comparable for age (p = 0.65) and gender (p = 1). Active LN patients had a greater FE of ALCAM (0.08 ± 0.04) compared to inactive (0.01 ± 0.01) and active non-renal (0.02 ± 0.02) (p < 0.001). FE significantly correlated with 24-hour urinary proteins (r = 0.67, p < 0.001), erythrocyte sedimentation rate (r = 0.51, p < 0.001) and SLEDAI-2 K (r = 0.71, p < 0.001), negatively with both C3 and C4 (r = -0.52 and r = -0.56, p < 0.001) and with hemoglobin (p = 0.008). They had 100 % sensitivity and 92.2 % specificity for detection of active LN.

Conclusion

The FE ratio provides a potentially diagnostic value in LN assessment, since the FE of ALCAM performed better in active LN and is significantly related to the disease activity.