Hematological Changes in the Second Wave of SARS-CoV-2 in North India

Abstract

Background COVID-19 is a rapidly spreading pandemic caused by SARS-CoV-2. India experienced a second wave peak in mid of April 2021, and it emerged as a medical crisis. This study was taken up to show if the hematological and peripheral blood changes can be used as a readily available tool to demarcate the patients needing ICU care so that the ICU can be utilized more prudently. Material and method One hundred reverse transcription-polymerase chain reaction (RT-PCR) confirmed cases of COVID-19, 50 each from ICU and non-ICU wards, were included in this observational study. At the time of admission blood sample was collected for evaluation of hematological parameters. Results We noted that 74% of patients admitted in ICU were males and 28% were more than 60 years of age. In ICU patients, the absolute neutrophil count (ANC) was significantly raised when compared to non-ICU cases (p=0.023). The nadir absolute lymphocyte count (ALC) was 0.11x10⁹/L in ICU patients and 0.95x10⁹/L in non-ICU patients. There was a significant increase in neutrophil-lymphocyte ratio (NLR; p<0.001) in ICU patients with a proposed cut-off value of 7.73. Platelet-lymphocyte ratio (PLR) was also raised in ICU patients; however, this increase was not significant (p= 0.623). The proposed cut-off value of PLR is 126.73. A significant reduction in a lymphocyte-monocyte ratio (LMR) was observed in ICU patients when compared to non-ICU cases (p<0.001). Thrombocytopenia was more commonly seen in ICU patients; however, this was not statistically significant. Viral-induced cytopathic effects like plasmacytoid lymphocytes with cytoplasmic granules, the presence of toxic changes in neutrophils, and large-sized platelets were commonly observed in ICU patients. Conclusion Our results suggest that hematological parameters like ANC, absolute lymphocyte count (ALC), platelet count, NLR, PLR, and peripheral smear changes are simple assessment factors that can serve as indicators for the severity of COVID-19 and will demarcate the patients who need ICU-care. This will help in the judicious use of ICU facilities for patients who are actually in need.

Keywords: covid-19 hematological changes; covid-19 india; covid-19 induced cytopathic changes; neutrophil-to-lymphocyte ratio (nlr); platelet-to-lymphocyte ratio (plr); sars-cov-2 infection; second wave of covid-19.

Figure 1. Receiver operating characteristic (ROC) curve

The receiver operating characteristic (ROC) curve shows the relative diagnostic performance of neutrophil-lymphocyte ratio (NLR), lymphocyte-monocyte ratio (LMR), and platelet-lymphocyte ratio (PLR). The area under the curve (AUC) of LMR is less than 0.50; hence it can not be used as a potential diagnostic marker. The cut-off values detected are 7.73 for NLR and 126.73 for PLR.

Figure 2. Peripheral blood smear showing various changes in lymphocyte

a: atypical lymphocytes showing round to irregular nucleus, opened chromatin, prominent nucleoli, abundant cytoplasm with distinct variable azurophilic granules (virocyte/covicyte); b: large granular lymphocyte (red arrowhead); c and d: Downey cells showing irregular nucleus, hyperbasophilic cytoplasm with pod formation; e: apoptotic lymphocyte (green arrowhead); f: macrophage in circulation (broad black arrowhead) adjacent to atypical lymphocyte (short black arrowhead). Leishman 400-1000x

Figure 3. Peripheral blood smear showing various changes in neutrophils/granulocytes

a and b: dysplastic neutrophils; c: toxic changes like coarse cytoplasmic granules, vacuoles, and irregular nuclear lobulations; d: C-shaped, fetus-like COVID-19 nuclei; e: granulocytes showing cell rupture/lysis; f: dysplastic cell showing nuclear clumping and rounding of the nucleus; g: eosinophil undergoing pyknosis; h: karyolysis, melting of nuclear chromatin with enzymes released by the lysosomes of the dead cells, hypergranular cytoplasm with perinuclear hypogranular areas; i: dysplastic cell showing pseudo-Pelger like nuclei; j: dysplastic change in the form of ring nucleus; k: apoptotic cells; l: circulating myelocyte. Leishman 200-400x

Figure 4. Peripheral blood smear

a: activated monocyte with multiple cytoplasmic vacuoles and fine granules; b: circulating giant platelet with irregular cytoplasm; c: activated lymphocyte with adherent platelets. Leishman 400-1000x