Are there any novel markers in acute rheumatic fever: neutrophil-to-lymphocyte ratio, platelet-to-lymphocyte ratio, and monocyte-to-lymphocyte ratio

Objective: The aim of this study was to investigate the relationship between C-reactive protein and erythrocyte sedimentation rate and neutrophil-to-lymphocyte, platelet-to-lymphocyte, and monocyte-to-lymphocyte ratios in acute rheumatic fever in children.

Method: In this retrospective study, 182 patients with acute rheumatic fever and 173 controls were included. Complete blood count parameters, and neutrophil-to-lymphocyte, monocyte-to-lymphocyte, and platelet-to-lymphocyte ratios were recorded for all the patients underwent transthoracic echocardiography.

Results: Neutrophil-to-lymphocyte, monocyte-to-lymphocyte, and platelet-to-lymphocyte ratios were significantly higher in patients with rheumatic heart disease than patients without cardiac involvement (p < 0.05). C-reactive protein and erythrocyte sedimentation rate levels were found to have a positive correlation with neutrophil-to-lymphocyte (r = 0.228, p = 0.001; r = 0.355, p = 0.001), platelet-to-lymphocyte (r = 0.227, p = 0.01; r = 0.149, p = 0.005), and monocyte-to-lymphocyte ratios (r = 0.117, p = 0.005; r = 0.107, p = 0.044). Cardiac involvement was present in 152 (83.5%) of the patients. Neutrophil-to-lymphocyte, monocyte-to-lymphocyte, and platelet-to-lymphocyte ratios were significantly higher in patients with rheumatic heart disease than patients without cardiac involvement (p < 0.05). Patients with carditis were grouped according to mitral, aortic, or both valve involvement but there was no significant difference between the groups with respect to neutrophil-to-lymphocyte, monocyte-to-lymphocyte, and platelet-to-lymphocyte ratios. In addition, neutrophil-to-lymphocyte and monocyte-to-lymphocyte ratios were significantly higher in patients with Sydenham's chorea than without chorea (p < 0.05).

Conclusion: Neutrophil-to-lymphocyte, platelet-to-lymphocyte, and monocyte-to-lymphocyte ratios may help make the diagnosis of acute rheumatic fever and its prognosis by serial measurements in follow-up but none of them tell us the severity of carditis. Also, this is the first study showing the positive correlation between Sydenham's chorea and neutrophil-to-lymphocyte and monocyte-to-lymphocyte ratios. Further studies are needed to confirm this hypothesis, as this is the first study in the literature on this topic.