Significance of relative and absolute content of blood lymphocyte subopopulations for differential diagnosis of viral and bacterial meningitis in children

The search for markers of early etiological verification of meningitis is an urgent task for clinical laboratory diagnostics. Objective of the study is to determine the significance of relative and absolute content of blood lymphocyte subpopulations for early differential diagnosis of viral and bacterial meningitis in children. Materials and methods. There was performed a clinical and laboratory examination of 61 children, 37 of them were diagnosed with viral meningitis, and 24 ones – with bacterial purulent meningitis. The control group included 15 healthy children. The relative and absolute content of the main subpopulations (T-lymphocytes: T-helpers (Th), cytotoxic T-lymphocytes (CTL), NK, B-cells) and small subpopulations (NKT, DNT- and DPT-lymphocytes, CD3+CD8br, CD3+CD8dim, CD3-CD8+NK) of lymphocytes was assessed by flow cytometry. Statistical analysis of the data was carried out. Results . The decrease of relative and absolute content of all studied subpopulations was identified during an acute period of bacterial purulent meningitis, in comparison with the control group, with the exception of B-lymphocytes, the number of them was increased. Absolute content of all subpopulations was reduced in case of viral meningitis compared with the control group, the relative content did not have any significant differences, with the exception of an increase in the relative content of B-lymphocytes. Calculation of diagnostic sensitivity and specificity revealed the effectiveness of identification of both relative and absolute content of lymphocyte subpopulations for differential diagnosis of viral or bacterial meningitis. Identification of B-lymphocytes, NKT, CD3+CD8dim in the blood had the highest diagnostic efficiency (area under the ROC curve (AUC) ranging from 0,9 to 1). Conclusion. Assessment of relative and absolute content of blood lymphocyte subpopulations is an effective tool for laboratory differential diagnosis of viral and bacterial meningitis and can be used as an early differential diagnostic criterion, especially in case of impossibility to analyze the composition of cerebrospinal fluid.