ABSTRACT
Introduction: Covid-19 patients may have unusual arrangements of their blood count, compared to most viral infections. Neutrophilia can be associated with lymphopenia within the first few days. Therefore, an increasing neutrophil to lymphocyte ratio on admission has been considered an indicator of the disease severity Among the qualitative anomalies associated with the quantitative ones, reactive lymphocytes and nucleocytoplasmic morphological changes of the neutrophil granulocytes have been reported.Our study aimed to evaluate whether these leukocyte abnormalities modify the morphology of the instrumental cytograms of the Mindray BC6800plus haematological analyser resulting in diagnostic utility. Method(s): We evaluated the instrumental scattergrams provided by the Mindray BC6800plus analyser in 61patients admitted to the Monaldi and SS Trinita Hospitals (Naples and Borgomanero, Italy) with clinical evidence of SARSCoV- 2 infection confirmed with PCR research of viral RNA, comparing them with 61 healthy subjects. We used the 3D-Cube function - which allows a three-dimensional observation - to evaluate the lymphocyte and neutrophil cluster morphology in the DIFF scattergram. Blood cell morphology was assessed by microscopy. A prolonged microscopic review was performed in case of relevant lymphopenia. Result(s): Covid-19 samples showed evocative anomalies of the lymphocyte clusters in 47 out 61 samples (77%) related to the peripheral blood's morphological findings. Cytographic abnormalities concern the presence of an additional high fluorescence lymphocyte cluster - always well separated from the main one - with numerical consistency ranging between a few units to a few dozen (range 7.0 - 126) (Figure 1). Interestingly, the rotation of the 3D-Cube shows a widening of the high fluorescence cells along the FS axis attributable to the heterogeneity of cellular size (Figure 2). The microscopic review showed activated lymphocytes ranging between plasmacytoid and type III Downey morphologies. Positional indices of the neutrophil clusters showed significant differences from normal. Conclusion(s): Further studies need to associate positional indices with cytographic and microscopic anomalies of the neutrophils. The morphology of the lymphocyte clusters resulting from the 3D projections makes possible an accurate activated lymphocytes quantification, especially in severe lymphopenia thus evocative for Covid-19 infection and helpful for diagnostic and prognostic purposes.