Table 1.
Clinical and laboratory characteristics of patients with SARS-CoV2 infection.
Fig 1.
Lymphocyte and eosinophil counts in different groups of illness severity of COVID-19.
(A) The median lymphocyte counts were significantly different among the four groups (P<0.0001). The median lymphocyte count of mild cases was 2.45 (0.98–3.81) × 10⁹/L, which was significantly higher than in general cases (1.12 [0.43–9.54] × 10⁹/L, P<0.01), severe cases (0.77 [0.37–2.26] × 10⁹/L, P<0.001) and critical cases (0.74 [0.17–1.56] × 10⁹/L, P<0.001). The median lymphocyte count of general cases was significantly higher than that of severe cases (Fig 1A, P<0.01). We further compared the association of eosinophil counts and disease severity. (B) The median eosinophil counts were significantly different among the four groups (P = 0.0009). The median eosinophil count of mild cases was 0.09 (0.03–0.3) × 10⁹/L, which was significantly higher than that in the general cases (0.01 [0.00–0.35] × 10⁹/L, P<0.01) and severe cases (0.01 [0.00–0.42] × 10⁹/L, P<0.001), but there was no difference between mild cases and critical cases (0.00 [0.00–0.09] × 10⁹/L). ***, P<0.001; **, P<0.01; *, P<0.05.
Fig 2.
Correlation of lymphocyte count and laboratory tests.
Lymphopenia was highly correlated with CRP levels (A), serum albumin levels (B) and neutrophil counts (D). No significant correlation was found between lymphocyte count and Ct value (C). Spearman rank correlation analysis (r) and P values are provided in each graph. CRP, C-reactive protein; Ct value, cycle threshold value.
Fig 3.
ROC plots express the prognostic value of illness severity of lymphopenia compared with CRP and LDH levels.
ROC curves to predict patients with (A) pneumonia of severe grade or critical grade, (B) bilateral lung involvement in lung CT scan, and (C) abnormal lung image on discharge. The diagonal line indicates an AUC of 0.5 (no discrimination between the two states). The blue line indicates CRP level; The green dashed line indicates lymphocyte count; The pink dotted line indicates LDH level. LYM, lymphopenia; CRP, C-reactive protein; LDH, lactate dehydrogenase; AUC, area under the curve; ROC, receiver-operator curve.
Fig 4.
Kaplan-Meier curves for the duration of hospitalization according to lymphocyte count.
Fig 5.
Recovery time (from admission to the date of normalization) of lymphopenia, eosinopenia, CRP level, chest radiograph and clearance time of SARS-CoV2 RNA (from admission to the date of second negative detection result of SARS-CoV2 RNA) was compared using a two-way ANOVA.
The recovery time of those indicators above were significantly different (P = 0.0001). In mild and general cases, the median recovery time of lymphocyte was 9.0 (3.0–14.0) days, which was significantly shorter than that of SARS-CoV2-RNA (median 11.0 [3.0–32.0] days, P<0.05); the median recovery time of CRP was 7.5 (1.0–14.0) days, which was significantly shorter than that of SARS-CoV2-RNA (P<0.001); the median recovery time of CT scan was 7.0 (2.0–16.0) days, which was significantly shorter than that of eosinophils (median 9.0 [2.0–26.0] days, P<0.05) and SARS-CoV2-RNA (P<0.001). In severe and critical cases, the median recovery time of lymphocyte was 9.0 (3.0–23.0) days, which was significantly shorter than recovery as evidenced by CT scan (median 12.5 [4.0–32.0] days, P<0.05) and SARS-CoV2-RNA (median 15.0 [8.0–31.0] days, P<0.001). The median recovery time of eosinophils was 12.0 (3.0–23.0) days, which was significantly shorter than that of SARS-CoV2-RNA (P<0.05). The comparisons between other indicators were not significant. LYM, lymphopenia; Eo, eosinopenia; CRP, C-reactive protein. ***, P<0.001; **, P<0.01; *, P<0.05.
Fig 6.
Kaplan-Meier curves for TTR in patients receiving IVIG treatment.
(A) Kaplan-Meier curves for TTR according to treatment of IVIG in patients with lymphopenia; (B) Kaplan-Meier curves for TTR according to lymphocyte count in patients treated with IVIG.