The pathophysiologic significance of lymphocyte subset determination in children with infectious mononucleosis, mycoplasma pneumonia and Henoch–Schönlein purpura

OBJECTIVE: This study aimed to explore lymphocyte subset determinations as an aid to understanding the pathophysiology of infectious mononucleosis (IM), pneumonia due to mycoplasma infection (P-MI) and Henoch–Schönlein purpura in children. METHODS: The peripheral blood lymphocyte subsets of 45 children with IM, 20 children with P-MI, and 31 children with Henoch–Schönlein purpura (HSP), who were treated in the pediatrics department of our hospital from April 2019 to February 2020, were determined by flow cytometry, and the number and percentage of lymphocyte subsets with CD3+, CD3 + CD4+, CD3 + CD8+, CD3 + CD4+/CD3 + CD8+, CD3–CD16 + CD56+, and CD3–CD19 + cells were observed, and the results were compared and analyzed. RESULTS: (1) The percentages of CD3+, CD3 + CD8 + lymphocyte subsets in children in IM group were significantly higher than those in children with P-MI and HSP, and the percentages of CD3-CD19 + lymphocyte subsets in children in IM group were significantly lower than those in children with P-MI and HSP. The percentages of CD3 + CD4 + lymphocyte subsets in children in the three groups were the lowest in children with IM, and the highest in children with P-MI.The differences in the percentages of CD3+, CD3 + CD4+, CD + CD8+, and CD3-CD19 + lymphocyte subsets among the IM, P-MI, and HSP groups were statistically significant (P < 0.01). (2) The results of CD3 + CD4+/CD3 + CD8 + in the three groups were the lowest in children with IM and the highest in children with P-MI. There was a significant difference among the three groups (P < 0.01); The ages of the children with IM and P-MI were lower than that of the children with HSP (p < 0.01), while there was no difference in the ages of the children with IM and P-MI (p > 0.05). (3) The difference in the percentage of CD3–CD16 + CD56 + lymphocyte subsets among the three groups was not statistically significant (P > 0.05). CONCLUSION: The determination of peripheral blood lymphocyte subsets is of significance for understanding the pathophysiology of IM, mycoplasma pneumonia, and HSP in children. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12887-022-03770-9.