Neutrophil-to-lymphocyte ratios and platelet-to-lymphocyte ratios in juvenile systemic lupus erythematosus: correlation with disease manifestations.

Background: This retrospective study aimed to investigate the usefulness of neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) for organ involvement and disease activity in newly diagnosed juvenile systemic lupus erythematosus (jSLE).

Methods: A total of 186 jSLE inpatients were included for analysis. All participants' clinical characteristics and laboratory data were obtained from medical records. The Systemic Lupus Erythematosus Disease Activity Index 2000 (SLEDAI-2K) score scale was used to assess disease activity. Mann-Whitney U test and Kruskal-Wallis test were performed for non-parametric variables between the groups. Spearman rank correlation coefficient was used to analyze correlations between variables.

Results: The NLR was significantly higher in participants with serositis as compared those without serositis [2.72 (1.71-5.0) vs. 2.08 (1.42-3.15), P=0.038]. The PLR was significantly higher in participants manifesting symptoms of cutaneous rash [130.0 (92.6-235.0) vs. 112.0 (49.3-169.0), P=0.002], and arthritis [167.0 (106.0-243.0) vs. 106.0 (53.6-176.0), P<0.001], as compared to participants without such involvement. The PLR in participants with hematological involvement was significantly lower than in those without such involvement [111.0 (53.6-191.0) vs. 138.0 (107.0-185.0), P=0.016]. The PLR in participants with positive anti-Smith (anti-Sm) antibody was significantly higher than that in those with negative anti-Sm antibody [140.0 (91.6-228.0) vs. 114.0 (60.9-176.0), P=0.006]. The NLR showed positive correlations with serositis (r=0.153, P=0.037), complement C3 and C4 (r=0.152, P=0.038 and r=0.177, P=0.016, respectively). The PLR showed positive correlations with cutaneous rash (r=0.227, P=0.002), arthritis (r=0.290, P<0.001), anti-Sm antibodies (r=0.20, P=0.006) and erythrocyte sedimentation rate (ESR, r=0.159, P=0.03). Negative correlations were found between PLR and hematological involvement (r=-0.177, P=0.015).

Conclusions: Both the NLR and PLR had correlations with serological indicators, and may predict organ involvement in jSLE, particularly cutaneous, arthritis, serositis, and haematological involvement.