Correlations between inflammatory response and the increased lymphocyte percentage or CD19+ cell count in Kawasaki disease children undergoing intravenous immunoglobulin in different age intervals

Background: Intravenous immunoglobulin (IVIg) is used commonly in Kawasaki Disease (KD) but the inflammatory condition during this course remains unclear. We evaluated the inflammatory response before and after the performance of IVIg in KD children in different age intervals to explore precise markers of inflammation and to help individualized treatment of IVIg Methods: A retrospective survey involving 60 KD children was performed. According to different age intervals, all patients were divided into 5 groups. Linear regression and correlation analysis were performed between the percentage of decreased neutrophil and that of increased lymphocyte in all groups and so did between the absolute cell count of CD19 + cells and the level of interleukin-10 (IL-10) in patients aged 4 and over. Results: During the acute phase of KD, after the treatment of IVIg all patients’ reduced percentage of neutrophil correlated positively well with the increased percentage of lymphocyte. With age increased, the correlation coefficients valued higher which were 0.91 (group of less than 1 year), 0.87 (1 year), 0.91 (2 years), 0.97 (3 years), 0.99 (4 years and over) respectively with p value less than 0.01 in all groups. Growing age obviously correlated positively with the value of correlation coefficient (r = 0.88, P < 0.05). In the patients aged 4 and over, abnormal higher CD19 + cell absolute count before the administration of IVIg correlated positively with the scope of reduced IL-10 after the performance of IVIg (r = 0.71, P < 0.05). Conclusions: During the acute phase of KD children with older age, the regulatory effect of IVIg on the immune response was better and the following recovery of immune function was more rapidly. In KD children aged 4 years and over the abnormal proliferating CD19 + B cell played dominant role in active humoral immune and may have the function of the IL-10 secretion as a compensatory response to balance the overactive humoral immune. Combined assessment of CD19 + B cell absolute count and the extent of IL-10 reduction after IVIg may be a marker of therapeutic effect of IVIg on inflammatory immune response in older KD children.