Changes in morphology of white blood cells on peripheral smear in COVID-19 infection

Background: COVID-19 is an infectious disease caused by a newly discovered coronavirus, and has spread around the world in a deadly pandemic. The first case of COVID-19 was reported from Wuhan, China in December 2019. This is also called as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) because of its homology with SARS virus. The most common hematological manifestation of coronavirus is lymphopenia which is due to depletion of lymphocytes by coronavirus infection. Other manifestations are neutrophilia and mild thrombocytopenia. Literature is full of quantitative hematological parameters but the researches on morphology of white blood cells is still ongoing. We at our institute done study on 60 confirmed positive cases of COVID-19, and analyzed those peripheral smears in terms of morphology of white blood cells.Methods: The study was done using peripheral smear staining with methylene blue stain and was screened for various changes in white blood cells in peripheral smear.Results: Changes in the white blood cells were examined in the peripheral smear and findings were made in the tabular form.Conclusions: To conclude that all these changes are due to the virus infecting them or are secondary to pathogenesis of COVID disease, needs to be evaluated by larger studies

Polarized helper T cells in tubercular pleural effusion: phenotypic identity and selective recruitment

Containment of Mycobacterium tuberculosis critically depends on orchestrated generation of Th1 cells and their selective recruitment at the pathologic sites. Understanding the mechanism involved in this process is important for defining better intervention strategies. We investigated the surface phenotype of Th1 cells and the role of chemotactic factors in their selective recruitment in tuberculosis pleural effusion and tuberculin site. Memory T cells obtained from the pleural fluid expressed a battery of homing receptors such as CD11a, CCR5 and CXCR3. Similar expression profile was noted on T cells infiltrating the tuberculin site. Expression of their respective ligands such as ICAM-1, RANTES, MIP1-α, Mig and IP-10 were detected at pathologic sites. In vitro assay of T cell adherence to activated human umbilical vein endothelial cells (HUVEC) expressing chemotactic ligands suggests an important role of these homing molecules in their selective trafficking. Here, we demonstrate a hierarchy of CXCR3 in effector cell adhesion to HUVEC in vitro, although CD11a and CCR5 were also observed to mediate cell adhesion in an additive fashion. Findings of the present study provide mechanistic insights into the critical events of T cell trafficking in tuberculosis and may help designing better therapeutic modalities