Clinical significance of platelet-lymphocyte ratio in systemic lupus erythematosus patients: Relation to disease activity and damage

Aim of the workTo assess platelet–lymphocyte ratio (PLR) in systemic lupus erythematosus (SLE) patients and study its clinical significance, its relation to disease activity and damage.Patients and methodsThis study included 52 adult SLE patients and 50 matched control. All patients were subjected to full clinical examination, disease activity was measured by SLE disease activity index (SLEDAI), and damage was assessed by using Systemic Lupus International Collaborating Clinics Damage Index (SLICC-DI). Laboratory and immunology profiles included the complete blood count (CBC) with differential white blood cell (WBC) counts and estimation of PLR, erythrocyte sedimentation rate (ESR), liver and kidney function, alkaline phosphatase (ALP), serum calcium (Ca) and phosphorous (P), lipid profile, 24hr urinary protein, renal biopsy, anti-nuclear antibody (ANA), anti-double stranded deoxyribonucleic acid (anti-dsDNA), serum complements (C3,C4).ResultsThe mean age of SLE patients was 33.1 ± 9.2 years (20–58 years), with mean disease duration of 5.4 ± 5.02 years (0.25–20 years). The PLR was significantly higher in patients (189.9 ± 136.4; 23.9–782.9) than control (95 ± 29.9; p < 0.0001). The WBC and platelets count was comparable between patients and control (7.1 ± 1.7 x10³/mm³ and 243.4 ± 51.3 x10³/mm³; p = 0.3 and p = 0.51 respectively). The lymphocytic count was significantly lower in patient compared to control (1.9 ± 1.1 x10³/mm³ vs 2.7 ± 0.8 x10³/mm³)(p < 0.0001). PLR would significantly predict activity (p = 0.02) with a sensitivity of 94.3% and specificity of 100% at a cut-off value of 33.6. There was no association of PLR with the damage index.ConclusionPLR might be considered a valuable and un-expensive tool in assessment and prediction of SLE disease activity.