Profile of study participants
Samples were collected in the first wave of COVID-19 from September 2020 to November 11, 2020, and subsequently in the 2nd wave from March 10 to March 20, 2021.Total 70 COVID-19 samples and 15 symptomatic but non-COVID-19 but corona virus positive (common cold)samples in total 6 categories (groups 1–6) were recruited as described in Table 1. Age, sex and comorbidity distribution of the samples are given in the Table 1 and Figure S1. Interestingly, comorbid patients with moderate and severe outcome (groups 3b and 5, respectively) showed female dominance and higher mean age than the corresponding groups without co-morbidity (group 3a and 4 respectively).
Table 1
Study subject groups and distribution of age and sex
Category Covid-19 +/- by RT-PCR | Group ( # ) | Asymptomatic (A) or symptomatic (S) | Required Oxygen support (Yes /No) | ICU / Death outside ICU (Yes /No) | comorbidity (Yes/No) | No of samples used | Age (M ± SD) | Sex ratio %M, %F |
Case | RdRP + ve E gene + ve | 1 * asymptomatic | A | No | No | No | 16 | 37.25 ± 19.25 | 37%, 63% |
2 * mild | S | No | No | No | 20 (total) | 18 | 47.57 ± 16.32 | 52%, 48% |
Yes | 2 |
3 Moderate | 3a | S | Yes | No | No | 9 (total) | 4 | 58.8 ± 14.7 | 51 ± 18.6 | 33.3, 66.6% | 75%, 25% |
3b | S | Yes | No | Yes | 5 | 65.2 ± 7.1 | 0%, 100% |
4 Severe | S | Yes | Yes | No | 12 | 42.5 ± 17.9 | 83%, 17% |
5 Severe | S | Yes | Yes | Yes | 13 | 51 ± 15.7 | 38%, 62% |
| RdRP -ve E gene + ve | 6 Non COVID-19 Como cold | S | No | No | No | 15 | 37.3 ± 11.7 | 46%, 53.8% |
*As the groups recover without complication at home quarantine or in general facility we assumed this patient groups should have effective immune response correlated with the good clinical outcome irrespective of present or absent of any comorbidity. |
Table 2
Deriving best fitted model of ‘Severity Score’ using the combinations of Ct values of different T cell markers in naso/oro swab RNA
Principle of Ct value combinations | Non-severe Group (n = 10) Mean ∆Ct/∆Ctcombinations | Severe Group (n = 9) Mean ∆Ct/∆Ctcombinations | Significance of difference: Severe vs non-severe COVID-19 cases by T-TEST Pvalue |
A. ΔCt values normalized with ACTB | T1- ACTB | 12.61 | 13 | 0.7 |
T2- ACTB | 3.67 | 3.07 | 0.20 |
T3- ACTB | 13.87 | 13.2 | 0.56 |
T4- ACTB | 6.47 | 9.49 | 0.01* |
T5- ACTB | 12.38 | 12.64 | 0.82 |
T6- ACTB | 6.83 | 6.34 | 0.51 |
T7- ACTB | 9.44 | 9.95 | 0.67 |
T8- ACTB | 7.89 | 9.86 | 0.18 |
B. Composite ΔCt values by Combination of ACTB normalized ΔCt values | T4 + T2-2ACTB | 10.14 | 12.56 | 0.07 |
T4 + T8-2ACTB | 10.70 | 19.35 | 0.0027 |
T2 + T8-2ACTB | 11.56 | 12.93 | 0.38 |
C. Composite ΔCt values by combinations of T cell phase specific markers | T4-T2 | 2.81` | 6.42 | 0.0022 |
T8-T2 | 4.22 | 6.79 | 0.093 |
T4-T8 | -1.42 | -0.37 | 0.60 |
T4 + T8-2.T2 | 7.03 | 13.21 | 0.0006 |
ACTB: β-actin, Ct: cycle threshold of the individual target genes in RT-PCR,ΔCt:Difference of two Ct values as indicated, n: Number of samples, * P statistically significance at P < 0.05. |
Average interval from the onset of symptoms to time of sample collection was 4.1 ± 3.2 (0–12) days. No statistical difference was observed in sampling time between mild (group2) and moderate to severe patients (groups 3, 4 and 5). Duration from the date of sample collection to the date of hospital admission for moderate to severe patients (groups 3, 4 and 5) was 0.26 ± 1.34 (1–4) days. For those patients who died due to COVID-19, the mean interval from sample collection to the time of death was 5.1 ± 5.7 (0–18) days (Table S2).Average hospital stay of COVID-19 patients who were treated in ICU and survived was 18.6 ± 9.5 (7–39) days compared to 13.5 ± 4.7(6–20) days for those treated in general facility (Table S3).
Evaluation of T cell response markers for their ability to predict COVID-19 outcome.
One of the important adaptive defence mechanisms to control virus infection is T cell activation. We hypothesized that low expression of T cell resting state markers and high expression of activation state markers will represent early virus clearance, indicating a good prognosis.We choseT cell marker genes that represent a resting, naive or suppression state of T cells (T1:FOXP3; T2, ZFP36; T6, CD62L;T7, CCR7)and those indicative of an active state (T3, CD25;T4, CD69;T5, IL17; T8, GZMB). Individual function of the genes is given in Table S3 (16, 17, 30–42).
Initial screening of T cell markers and development of severity score.
Initially, we screened the T cell response markers in 10 samples from non severe group (asymptomatic/mild/moderate groups i.e., groups 1 + 2 + 3) vs. 9 samples from poor outcome groups in which patients either died or survived following ventilator support (i.e., groups 4 + 5). Mean absolute Ct values of all the potential T cell markers (T1 - T8) are shown in Table S4. Evaluation of conventional expression of markers (as indicated by β-actin-normalized Δ Ct values) demonstrated that only T2 (ZFP36), T4(CD69) and T8(GZMB) had the highest differential expression (P ≤ 0.2, t-test) between severe and non-severe COVID-19 cases and also had detectable expression in most of the samples (Table 2A, Table S4). While ZFP36 showed lower mean Δ Ct (high expression), CD69 and GZMB showed higher mean Δ Ct (low expression) in severe cases relative to non-severe cases, indicating relatively lower T cell activation in severe COVID-19 cases. Although increased expression of both the genes CD69 and GZMB in non-severe cases relative to the severe cases were detected, only CD69 showed statistically significant increase in expression (0.01). However, differences of individual expression (normalized by β-actin) of the three short-listed transcripts in the two clinical groups were not high enough to be utilized for making a clinical decision. Therefore, a single composite score by rational combination of the individual Δ Ct values was derived to amplify the small difference between the two clinical outcome groups. Thus T2 (ZFP36), T4 (CD69) and T8 (GZMB) were taken for Δ Ct combination analysis for deriving a single composite score as described in Tables 2B and 2C. Interestingly, when Δ Ct values of CD69 and GZMB were derived by subtracting Ct value of ZFP36 (subtraction of Ct of the opposite phase specific markers)instead of β-actin and both the Δ Ct values were combined [ΔT4(T4-T2) + ΔT8(T8-T2)] the resulting score was able to differentiate two clinical groups with the highest level of significance (P = 0.0006). On the other hand when the Δ Ct was derived by subtracting two activation phase (same phase) T cell markers (T4-T8), no statistical significance (0.6) was observed between the severe and non severe groups indicating the robustness of the rational combination method (Table 2C). So the Ct value combination score T4 + T8-2T2 was used as ‘severity score’ for the subsequent sample analysis for its evaluation to predict the disease outcome.
Comparing severity score in the spectrum of COVID-19 outcome.
The ‘severity score’ was distributed normally in COVID-19 and non-COVID-19 control groups as verified by Kolmogorov-Smirnov Test of Normality (Table S5). Mean “severity scores” in different COVID-19 outcome groups have been described in Table 3. Intraday (4–17%) and inter-day coefficient of variation (CV) values were determined (12–21%) and shown in Table S6. We observed a graded increase in severity score along the spectrum of COVID-19 outcome from asymptomatic/mild to death (Table 3). As groups 1 and 2 showed no significant difference in severity score and clinically recovered without any complications, they were combined (7.44 ± 3.26) and used as reference to compare with relatively more severe outcomes. Though group 3 had slightly higher severity score, it was not statistically significant. However, groups 4 and 5 showed significantly higher severity scores (13.86 ± 3.38, P = 2.2x10− 5 and 12.56 ± 5.71, P = 7.9x10− 3, respectively). Expectedly, group 5 which consist of severe/critical co-morbid patients, showed slightly lower mean value than group 4 which consists of severe/critical COVID-19 patients without comorbidity. Mean severity scores in both the subgroups of samples of group 4 subjects who either succumbed to death or survived following treatment in ICU were higher than in group 5. We also compared these scores with those from symptomatic non COVID-19 corona virus infection (group 6). Interestingly, we observed slightly higher score for symptomatic non COVID-19 corona virus infection but the difference compared to combined groups 1 and 2 was not significant (8.86 ± 3.36, P = 0.119 ).
Table 3
Association of clinical outcome of COVID-19 with T cell based ‘Severity Score’ detected in leftover RNA samples of oro-/ nasopharyngealswab following COVID-19 diagnosis
Group | Description | N | Severity score (M ± SD) (range) | One sided Significance P | %Severity score > 12 %(n/N) | Odd ratio OD (95%CI) P |
1 | Asymptomatic | 13 | 7.43 ± 3.15 | P = 0.49 | 7.6 (1/13) | 1.09 (0.06–19.6) P = 0.9 |
2 | Mild symptomatic | 12 | 7.46 ± 3.51 | 8.3 (1/12) |
1 + 2 | Asymptomatic/mild symptomatic | 25 | 7.44 ± 3.26 | Reference | 8 (2/25) | Reference |
3 (moderate) | 3a | O2 required (HQ/G) | No co morbidity | 8 | 3 | 8.09 ± 2.44 | 8.2 ± 1.5 | 0.28 | (0/8) | 1.64 (0.13-20) P = 0.702 |
3b | co morbidity | 5 | 7.98 ± 3 |
4 (Severe/critical, No co morbidity) | Death/ICU(Include death outside ICU) | 11 | 13.86 ± 3.38 | 0.000022 | 91 (10/11) | 115 (9.3–1419) P = 0.0002 |
Death | 7 | 15.14 ± 2.77 | 0.00000011 | 100 (7/7) | 141 (6. 1- 3276) 0.002 |
ICU (Survived) | 4 | 11.62 ± 4.57 | 0.08 | 75 (3/4) | 34 (2.4-505.7) P = 0.0097 |
5 (Severe/critical, with co-morbidity) | Death/ICU(Include death outside ICU) | 11 | 12.56 ± 5.71 | 0.0079 | 64 (7/11) | 20 (3.0-134.) P = 0.009 |
Death | 7 | 14.54 ± 5.73 | 0.0093 | 71 (5/7) | 28 (3.2–256) P = 0.0026 |
ICU | 4 | 9.49 ± 4.87 | 0.23 | 50 (2/4) | 1.5 (1.0-131) P = 0.05 |
4 + 5 (Combined ) | Death/ICU(Include death outside ICU) | 22 | 13.21 ± 4.63 | 0.000010 | 77 (17/22) | 39 (6.7–226) P < 0.0001 |
Death/ventilator required | 16 | 14.54 ± 3.88 | 0.00000076 | 88 (14/16) | 80.5 (10–638) p < 0.0001 |
Death (all) | 14 | 14.72 ± 4.10 | 0.0000047 | 86 (12/14) | 69 (8.6–552) P = 0.0001 |
ICU (survived) | 8 | 10.56 ± 4.52 | 0.051 | 62.5 (5/8) | 19 (2.5–146) P = 0.0044 |
6 | non covid19 corona infection | 11 | 8.86 ± 3.36 | 0.119 | | 1.15 (/0.09-14) P = 0.91 |
HQ:Recovered in home quarantine,G: Patientsrecovered in general hospital facility, N: Number of a particular category, n: number of subjects having severity score > 12 (high risk category) among N, * P statistically significance at P < 0.05. |
To understand the diagnostic efficiency of ‘severity score’, area under ROC curve (AUC) was determined (Fig. 1B). AUC indicated well separation of ‘severity score’ to identify severe groups from the corresponding non severe groups. Expectedly, the highest separation was with non co-morbid severe group (group 4) (AUC = 0.88, 95%CI: 0.73-1) while inclusion of comorbid groups (4 + 5) resulted in slightly less (AUC = 0.82, 95%CI: 0.69–0.96) separation from the corresponding non severe group (1 + 2 + 3) (Figs. 1B, IV and III, respectively). However, combined non severe groups did not show any separation with group 6 (AUC: 0.61 (95%CI: 0.39–0.83) (Fig. 1B, II).Optimum cut off point was determined by the ‘cut point to maximize Youden's J and test efficiency’(29). Interestingly, when we used noncomorbid samples or all the subjects (including comorbid), in both cases the optimum cut-off was 12.06 (Fig. 1 BV–VI).This suggests that comorbidity does not affect the baseline value of the score. For practical purpose, we chose a cut-off of 12 for the severity score. Therefore, a score more than 12 was considered to be high. Agreement of repeated independent tests in reference to severity score cut-off (high/low) has been given in Table S7. Distribution of the severity scores of all the groups (1–6) along the cut-off point has been shown in the dot plot (29) in the Fig. 1C.
We observed that out of 25 combined asymptomatic and mild groups (1 + 2), only two samples showed high severity score (8%). On the other hand, 91% (P = 0.0002) and 64% (P = 0.009) of patients in groups 4 and 5 showed high severity score, respectively. When group 4 (no co-morbidity) was divided into dead and ICU(survived) groups, we observed that all 7 patients who died had high severity score (100%, P = 0.002) whereas 3 out of 4 patients who survived had high severity score (75%; P = 0.0097). The same in group 5 were71% (P = 0.0026) and 50% (P = 0.05), respectively. Interestingly, the two out of seven subjects who died due to COVID-19 in group 5 showed severity score below the cut-off value and both the patients had pre-existing chronic kidney disease (CKD). When we combined patients who died and those who survived but required ventilation support, irrespective of the presence or absence of comorbidity, the ‘severity score’ was 88% (14/16; P = 0.0001). None of the 8 samples in group 3 showed high severity score.
For the COVID-19subjects without comorbidity, sensitivity of detecting severe/critical cases without comorbidity (group 4) was 91% (10/11), (95% CI: 58.7–99.8), whereas the specificity of ‘severity score’ for detecting favourable outcome (i.e., with asymptomatic/mild/moderate symptoms) was 92.6% (25/27; 95% CI: 75.7–99). However, combining comorbid and non-comorbid subjects, the sensitivity dropped to 77.3% (95% CI: 54.6–92.2) while specificity slightly increased to 93.9% (95% CI: 79.8–99.3) (Table 4).
Table 4
Performance of ‘severity score’ and ‘Impaired IL-10 response’ as diagnostic test identifying outcome of COVID-19
| Performance of “Severity Score“ | Performance of “impaired IL-10 response” |
Statistics | Covid19 outcome: Requiring ICU support /death (No co-morbidity) | Covid19 outcome: Requiring ICU support /death (with or without co-morbidity) | Covid19 outcome: Requiring O2/ICU support /Death, No co-morbidity | Covid19 outcome: Requiring O2/ICU support /death (with or without co-morbidity) |
Yes (N) | No (N) | Yes (N) | No (N) | Yes (N) | No (N) | Yes (N) | No (N) |
Confusion Matrix | Risk Detected | 10 | 2 | 17 | 2 | 9 | 6 | 16 | 7 |
Risk not detected | 1 | 25 | 5 | 31 | 5 | 28 | 15 | 29 |
Total | 11 | 27 | 22 | 33 | 14 | 34 | 31 | 36 |
Test performance | % (95% CI) | % (95% CI) | % (95% CI) | % (95% CI) |
Sensitivity Specificity | 91 (58.7–99.8) 92.6 ( 75.7–99) | 77.3 (54.6–92.2) 93.9 (79.8–99.3) | 64.2 (35.1–87.2) 82 (65.5–93.2) | 51.6 (33.1–69.8) 80.5 (64.0-91.8) |
Risk detected: Severity score > 12 or ‘Impaired IL-10 response’ detected; Risk not detected: Severity score < 12 or ‘Impaired IL-10 response’ not detected; N: Number of cases, CI: Confidence Interval |
We did not find any significant correlation between severity score and duration of illness before the swab sampling among the spectrum of COVID-19 outcome groups (Table S7a). However in milder outcome group (group 2) a weak non-significant negative correlation (R = 0.25) while in severe group (group 4 + 5) a weak non-significant positive correlation (R = 0.31) with duration of illness before the swab sampling for the test were observed (Table S7a). Severity score was moderately correlated with duration of hospital stay (R = 0.55, P = 0.04, Table S7b). We also did not find any association of the “severity score” with age and sex (Table S8) suggesting that these variables have little effect on the observed difference in severity scores among different COVID-19 outcome groups.
Profile of co-morbidities found in this study is described in Table 5. Diabetes mellitus (DM) was the most frequent comorbidity which was 50% (9/18) of the total comorbid patients including mild, moderate to severe COVID-19 outcome groups (group 2, 3, 5). Out of 9 DM patients, cases having DM alone, combination of DM with hypertension (HTN) and combination of DM with chronic kidney disease (CKD) were 5, 3 and 1cases respectively. Next frequent co morbidity was HTN (7/18) which was either alone (4 cases) or in combination with DM (3 cases). Interestingly, when DM was the only comorbidity, all the 5 DM patients had low severity score (< 12) and were survived even though one of the patients had insulin dependent DM. However, out of 4 HTN patients (alone), 2 had higher severity score while 1 succumbed to death. In combined DM + HTN, out of 3 cases 2 had higher severity score while 1 succumbed to death. Rest of the comorbidity including cancer, anaemia, TB and all the affected subjects had high severity score and succumbed to death.
Table 5
Comorbidity profile along with severity score and COVID-19 outcome
Comorbidity | No of cases | High severity score (> 12) | Covid19 Outcome |
Death | Survived |
DM | 5 | 0 | 0 | 5 |
DM + HTN | 3 | 2 | 1 | 2 |
DM + CKD | 1 | 0 | 1 | 0 |
CKD | 1 | 0 | 1 | 0 |
HTN | 4 | 2 | 1 | 3 |
Cancer | 1 | 1 | 1 | 0 |
Anaemia | 1 | 1 | 1 | 0 |
TB | 1 | 1 | 1 | 0 |
Thyroid | 1 | 0 | 0 | 1 |
Total | 18 | 7 | 7 | 11 |
DM: Diabetes mellitus, HTN: Hypertension, CKD: Chronic kidney disease, TB |
Evaluation of innate immune response gene expression in oral-/nasopharyngeal swabs
We first screened the left over RNA samples for expression of a representative interferon response gene (OAS3), an inflammation marker (IL-6) and an anti-inflammatory response marker (IL-10). The target gene expression was normalized by housekeeping gene β-actin. When we compared overall normalized mean ∆Ct values of all three genes in asymptomatic/mild groups (groups 1 + 2) and moderate/severe groups (groups 3 + 4 + 5), only IL-10 showed slightly higher ∆Ct (1 cycle difference) value in moderate/severe groups (groups 3 + 4 + 5) whereas no deference was observed in ∆Ct values of OAS3 and IL-6 (Table 6)mean Ct value of β-actin was comparable in both the asymptomatic/mild and moderate/severe groups. Percentage of samples with nodetectableIL-10expression (as per our criteria ΔCt > 12.5) was also slightly higher in severe infection group compared to milder group (64% vs. 44.4%, p = 0.1) without statistical significance. OAS3 showed 100% detectable expression in all the samples (Table 6). The percentage of patients with no detectable IL-6expression was also not significantly different in asymptomatic/mild groups and moderate/severe groups (Table 6). Interestingly impaired IL-10response, as defined by nodetectableIL-10expression (ΔCt > 12.5) but high OAS3 expression (ΔCt < 9), showed significantly higher proportion in moderate/severe relative to asymptomatic/mild groups (P = 0.006) (Table 6).
Table 6
Comparison of normalized Ct values of IL10, OAS3 and IL6, in assymptomatic/mild and moderate/severe groups and modelling for detecting severe group.
Mode of analysis | Potential biomarkers of innate immunity response | Group 1 + 2(36) Mean ± SD | Group 4 + 5 + 3(31) Mean ± SD | T-TEST (P) | Cocktail of 15 sample of group 6S |
ΔCt values normalized with ACTB | IL-10-ACTB | 11.77 ± 2.8 | 12.75 ± 1.9 | 0.1 | 12.3 ± 0.4 |
OAS3-ACTB | 7.35 ± 2.35 | 7.57 ± 1.9 | 0.7 | 9 ± 0.6 |
IL6-ACTB | 11 ± 3.2 | 11 ± 2.8 | 1.0 | 12.2 ± 0.75 |
| % no expression/ ΔCt > 12.5 | % no expression/ ΔCt > 12.5 | | |
% no expression or ΔCt > 12.5 | IL10-ACTIN | 44.4% (16/36) | 64.5% (20/31) | 0.1 | |
OAS3-ACTIN | 0%(0/36) | 0%(0/31) | 1.0 | |
IL6-ACTIN | 42%(15/36) | 45% (14/31) | 0.80 | |
Composite model: low IL10 in the background of high OAS3 expression | ΔCt Il10 > 12.5, ΔCt OAS3 < 9 | 19.4% (7/36) | 51.6% (16/31) | 0.006* | |
ACTB: β-actin ,ΔCt : Ct difference between target gene – β-actin,* P statistically significance at P < 0.05 |
The proportion of ‘impaired IL-10 response’ in different COVID-19 outcome subgroups is described in Table 7. Since the percentage of patients with impaired IL-10 response in asymptomatic group (group 1) was not different from that in mild group (group2), the two groups were combined and used as reference for comparison with more severe outcome groups. Among group 4 and 5 patients who died, 66.6% and 62.5%, respectively (P≤0.03)had impaired IL-10 response. This data indicate a significant association of impaired IL-10 response with poor clinical outcome. The association of impaired IL-10 response with poor clinical outcome was statistically stronger in combined critical groups (death or survived with support of ventilator, irrespective of comorbidity) (64.7%, P = 0.0038) compared to combined asymptomatic/mild groups. Interestingly, among the co-morbid subjects, percentage of patients with impaired IL-10response in groups with moderate outcome(subgroup 3b,Table 1) and ICU admission (but survived) were 40% and 0%, respectively, whereas in non-comorbid groups, the same were 66.6% and 60% respectively (Table 7). In Fig. 1, the distribution of IL-10 response among COVID-19 subjects without and with comorbidity is shown as indicated. It seems that among noncomorbidity subjects, detection of impaired IL-10 response was more consistent across the spectrum of COVID-19 outcome from moderate to critical patients. No statistically significant association of ‘impaired IL-10 response’ with age and sex was observed in asymptomatic/mild (1 + 2) or moderate/severe (3 + 4 + 5) groups (Table S9)
Table 7
Association of clinical outcome of COVID-19 with ‘impaired IL-10 response’ detected in leftover RNA samples of oro-/ nasopharyngeal swab following COVID-19 diagnosis
Group | Description | N | Impaired IL-10 expression: % (n/N) | Fisher exact probability P | Odd ratio OD (95%CI) p |
1 | asymptomatic/ | 16 | 18.7 (3/16) | 1.0 (group 1 vs 2) | 1 (0.2–5.7) p = 0.92 (group 1 vs 2) |
2 | Mild | 20 | 20 (4/20) |
1 + 2 | asymptomatic/mild | 36 | 19 (7/36) | Reference | Reference |
3 (moderate) | 3a | O2 required (HQ/G) | No Co- morbidity | 8 | 3 | 50 (4/8) | 66.6 (2/3) | 0.09 | 0.13 | 4 (0.8–20.7) P = 0.084 | - |
3b | Co morbidity | 5 | 40.0 (2/5) | 0.3 | - |
4 (Severe/critical, No co morbidity) | Death/ICU(Include death outside ICU) | 11 | 64 (7/11) | 0.009* | 7.25 (0.72-12) P = 0.0087* |
Death | 6 | 66.6 (4/6) | 0.03* | 8.2 (1.25-54) P = 0.028* |
ICU (survived) | 5 | 60 (3/5) | 0.08 | 6.2 (0.87-44) P = 0.069 |
5 (Severe/critical, with co-morbidity) | Death/ICU(Include death outside ICU) | 12 | 41.7 (5/12) | 0.14 | 2.9 (0.71-12) P = 0.13 |
Death | 8 | 62.5 (5/8) | 0.023* | 6.9 (1.3–36) P = 0.02* |
ICU(survived) | 4 | 0 (0/4) | 1 | 0.437 (0.02-9) P = 0.59 |
4 + 5 | Death/ICU(Include death outside ICU) | 23 | 52 (12/23) | 0.01* | 4.4 (1.3–13) P < 0.0177* |
Death/ventilator required | 17 | 64.7 (11/17) | 0.0038* | 6.9 (1.87-25) P = 0.0037* |
Death (all) | 14 | 64 (9/14) | 0.005* | 6.6 (1.65–26.6) P = 0.0076* |
ICU (survived) | 9 | 33 ( 3/9 ) | 0.39 | 2 (0.4–10) P = 0.37 |
Impaired IL-10expression: defined as ΔCt IL-10 > 12.5, ΔCt OAS3 < 9 in RT PCR (low/undetectable IL-10 expression on the background of high pro inflammatory OAS3 expression), HQ: Recobered in home quarantine, G:Patients recovered in general hospital facility, N: Number of particular category, n: number of subjects having impaired IL-10 expression (high risk category) among N, * Pstatistically significance at P < 0.05 |
Among non-comorbidCOVID-19 subjects, impaired IL-10 response was able to detect moderate to severe COVID-19 outcome (groups 3a and 4) as a combined group with an sensitivity 64.2% (95% CI:35.1–87.2) and specificity 82% (95% CI:65.5–93.2). However, combining co-morbidity reduced the sensitivity to 52% (95% CI: 33.1–69.8), whereas specificity was still 82.8% (95% CI: 64.0-91.8) (Table 4).
Undercurrent principle of Severity Score and impaired IL-10 response in determining COVID-19 outcome have been shown in the schematic diagram in Fig. 2.