Lymphopenia predicts disease severity of COVID-19: a descriptive and predictive study

Abstract

BackgroundCoronavirus disease-2019 (COVID-19) is a rapidly escalating epidemic caused by SARS-CoV-2. Identification of a simple and effective indicator to assess disease severity and prognosis is urgently needed. MethodsDynamic changes of blood lymphocyte percentage (LYM%) in 15 death cases, 15 severe cases as well as 40 moderate cases of COVID-19 patients were retrospectively analyzed. A Time-LYM% model (TLM) was established according to the descriptive studies and was validated in 92 hospitalized cases. ResultsResults from death and severe cases showed that LYM% in blood tests were inversely associated with the severity and prognosis of COVID-19. LYM% in moderate type of patients with COVID-19 remained higher than 20% 10-12 days after symptom onset. In contrast, LYM% was lower than 20% in severe cases. However, LYM% in severe cases was higher than 5% 17-19 days after the onset of the disease, while it fell below 5% in death cases. Accordingly, we established a Time-LYM% model (TLM), which was validated as an independent criterion of disease classification in another 92 hospitalized patients with COVID-19. ConclusionLymphopenia can be used as an indicator of disease severity and prognosis of COVID-19 patients. TLM is worth of application in the clinical practice.

Preliminary study to identify severe from moderate cases of COVID-19 using NLR&RDW-SD combination parameter

“…In addition, this study found that the red blood cell parameters (RBC, HGB, HCT) were significantly reduced in the severe group, while the morphological parameters (RDW-CV, RDW-SD) were significantly higher in the severe group than moderate patients, which may result from the immune damage that leads to the suppression of the bone marrow, leading to the gradual increase of anemia that causes the compensatory hyperplasia of erythroid cell line, a large number of immature red blood cells released to the peripheral blood, the activation of red blood cell apoptosis and peripheral phagocytosis, therefore result in the increase of the red blood cell distribution width [31]. In the comparison of the biochemical and coagulation indexes tested, it was found that as the disease progressed, DBil, GLO, BUN, Cr, Cys C, CK, Mb, LDH and FBG in the severe group were significantly higher than that in the moderate group (P <0.05); meanwhile, ALB, Na + and Ca 2+ in the severe group were significantly lower than that in the moderate group (P <0.05), which is also consistent with recent reports by most scholars [11,16,[26][27][28].…”

“…The significant lymphopenia in the severe group may be caused by the SARS-CoV-2 continuing to invade more lymphocytes, proliferate and cause the lymphocytes to die even to become depleted when they reach the spleen and other immune organs. The lymphopenia has been reported by many scholars [9,11,14,16,[25][26][27][28]. The same phenomenon was also seen in SARS-CoV and MERS-CoV infections [29][30].…”

Hematological findings and complications of COVID‐19

“…Therefore, serial assessment of lymphocyte count dynamics may be predictive of patient outcome. Tan et al have proposed a model based on lymphocyte counts at two time points; patients with less than 20% lymphocytes at days 10‐12 from the onset of symptoms, and less than 5% at days 17‐19 have the worst prognosis 32 …”

A special case of COVID-19 with long duration of viral shedding for 49 days

“…S1. Noteworthily, the levels of blood lymphocytes, interleukin-6 and procalcitonin have been recognized as indicators for disease severity and prognosis of COVID-19 patients by us and others 5,9 . These three indexes were all normal and stable in this patient ( Fig.…”