High neutrophil : lymphocyte ratio is associated with refractory Kawasaki disease

Background The clinical significance of the neutrophil : lymphocyte ratio ( NLR ) has not yet been fully elucidated in Kawasaki disease ( KD ). The purpose of this study was to investigate the relationship between NLR and response to i.v. immunoglobulin ( IVIG ), and its effect on coronary abnormalities in KD . Methods A total of 196 KD patients treated with IVIG were analyzed. Baseline NLR was evaluated immediately before IVIG therapy and the patients classified into two groups according to NLR . The clinical data, other inflammatory biomarkers, and coronary complications were also assessed. Results Kawasaki disease patients with NLR  ≥ 5 had a greater incidence of IVIG refractoriness than the NLR  < 5 group (31.7% vs 4.3%, P  <   0.001), but this was not related to the development of coronary abnormalities. The change in NLR after IVIG (i.e. Δ NLR ) was significantly decreased in the coronary abnormality group (2.65 ± 1.88 vs 3.81 ± 2.55, P  =   0.042). On multivariate analysis, high NLR and CRP were independent predictors of IVIG refractoriness during the acute phase of KD ( P  =   0.032 in NLR ; P  =   0.029 in CRP , respectively). Conclusions High NLR was closely associated with resistance to IVIG , but it was not related to the occurrence of coronary abnormalities in KD . Low Δ NLR after IVIG , however, was significantly associated with coronary artery abnormalities.