1. The clinical characteristics of the enrolled neonates
Fifty-nine full-term neonates were enrolled in this study, including 40 neonates with sepsis (30 EOS and 10 LOS) and 19 uninfected neonates as controls. Temperature was 38.1℃ (IQR 37.13℃-38.65℃) and 36.8℃ (IQR 36.5℃-37.2℃) in neonates with sepsis and control, respectively (p < 0.0001). In 13 neonates with positive blood culture, the following pathogens were isolated: Escherichia coli (7 cases), Streptococcus lactis (4 cases), Klebsiella (1 case) and Enterococcus faecium (1 case). The levels of serum C reactive protein(CRP) and Serum amyloid protein A (SAA) in neonates with sepsis reached 9.11 mg/ml (IQR 6.54 mg/ml-10.13 mg/ml) and 29.38 mg/ml (IQR 4.83 mg/ml-36.24 mg/ml), respectively, which were significantly higher compared to the control group (both p < 0.0001). The neutrophil counts of sepsis and control neonates were 9.06 × 109/L (IQR 5.34 × 109/L-14.84 × 109/L) and 6.14 × 109/L (IQR 4.29 × 109/L-7.76 × 109/L) (p = 0.018), respectively. There was no significant difference in the counts of monocytes, lymphocytes, and platelets between the two groups (all p > 0.05). The detailed information of the clinical characteristics was shown in Table 1.
Table 1
The clinical characteristics of the enrolled neonates
Variable | Neonate sepsis (n = 40) | Control (n = 19) | p value |
Age | 12(3.25–19.75) | 10(7-16.25) | 0.672 |
(Median, IQR), days |
Male gender, n (%) | 25(62.5) | 13(68.4) | 0.775 |
Temperature (℃) | 38.1(37.13–38.65) | 36.8(36.5–37.2) | < 0.0001 |
Blood culture, n (%) | 13(32.5) | nd | nd |
Early of sepsis, n (%) | 30(75) | 0 | nd |
WBC(x109/L) | 17(11.68–21.13) | 12.1(9.9–14.7) | 0.005 |
Neutrophils(x109/L) | 9.06(5.34–14.84) | 6.14(4.29–7.76) | 0.018 |
Monocytes(x109/L) | 1.49(0.90–2.05) | 1.26(0.96–51.46) | 0.189 |
lymphocytes(x109/L) | 4.07(3.14–5.53) | 4.22(3.43–5.02) | 0.942 |
Platelets(x109/L) | 316.5(249–436) | 262(227–345) | 0.076 |
CRP (mg/ml) | 9.11(6.54–10.13) | 0.35(0.18–0.69) | < 0.0001 |
SAA (mg/ml) | 29.38(4.83–36.24) | 0.38(0.04–3.86) | < 0.0001 |
Note: nd, not done; WBC, White Blood Cell; CRP, C reactive protein; SAA, serum amyloid protein A. Values are given as median (interquartile range). |
2. The levels of serum cytokines and chemokines in neonatal sepsis
We compared serum cytokines and chemokines levels between neonates with sepsis and controls. Since the level of CCL15 was not in the quantitative range of the assay and exceeded the highest calculated concentration, we did not analyze it further. As shown in Table 2, pro-inflammatory cytokines IL-6, IL-8, TNF-α, and IL-1β were significantly higher in neonates with sepsis than those in controls (all p < 0.05). There was no difference in the levels of IL-4, IFN-γ, IL-17, IL-2, IL-10, GM-CSF, and IL-16 between the two groups (all p > 0.05). Serum MIF was remarkably increased in neonates with sepsis, which was 6270 pg/ml (IQR 4615 pg/ml-11820 pg/ml) and 4947 pg/ml (IQR 3204 pg/ml-6767 pg/ml) in sepsis and controls, respectively (p = 0.0223). As shown in Table 3, serum CXCL13, CXCL1, CXCL2, CXCL5, CXCL6, CXCL16, CCL27, CCL2, CCL8, CCL3, CCL20, CCL23, CCL27, CX3CL1 were significantly increased in neonates with sepsis compared to controls (all p < 0.05).
Table 2
The serum levels of cytokines in control group and neonatal sepsis group.
Cytokine | Control group | Sepsis group | p value |
GM-CSF (pg/ml) | 125.2(87.8-234.3) | 149.4(96.62–228.9) | 0.4533 |
IFN-γ(pg/ml) | 105.5(78.75–167.2) | 107.8(76.35–160.6) | 0.6977 |
IL-1β (pg/ml) | 10.93(5.955–11.22) | 12.02(10.68–18.19) | 0.0071 |
IL-2 (pg/ml) | 30.52(14.01–46.2) | 36.81(24.28–45.02) | 0.2794 |
IL-4 (pg/ml) | 38.02(25.45–42.63) | 36.1(30.99–43.43) | 0.418 |
IL-6 (pg/ml) | 24.25(12.9-39.01) | 58.57(37.03–236.6) | < 0.0001 |
IL-8 (pg/ml) | 38.5(17.45–64.08) | 262.1(130.1–630) | < 0.0001 |
IL-10 (pg/ml) | 89.27(42.78–134.7) | 95.2(67.34–137.3) | 0.2871 |
IL-16 (pg/ml) | 1176(617.8–1832) | 1005(727.2–1331) | 0.3417 |
MIF (pg/ml) | 4947(3204–6767) | 6270(4615–11820) | 0.0223 |
TNF-α (pg/ml) | 45.72(26.27–55.92) | 53.14(44.26–79.38) | 0.0213 |
IL-17 (pg/ml) | 1.13(0-2.525) | 1.792(0.3479–5.423) | 0.1723 |
Table 3
The chemokine levels of serum in control group and neonatal sepsis group.
Chemokine | Control group (n = 19) | Sepsis group (n = 40) | p value |
CCL21(pg/ml) | 7380(4948–15970) | 6356(3958–9688) | 0.1434 |
CXCL13(pg/ml) | 53.38(41.35–72.76) | 86.9(51.3-142.8) | 0.003 |
CCL27(pg/ml) | 1565(945–2621) | 2041(1385–2895) | 0.0361 |
CXCL5(pg/ml) | 969.7(550.4–1366) | 1187(929.4–1947) | 0.0321 |
CCL11(pg/ml) | 63.4(50.19–89.31) | 77(58.22–89.35) | 0.4947 |
CCL24(pg/ml) | 263(122.4-485.8) | 231.1(124.8-356.8) | 0.4493 |
CCL26(pg/ml) | 70.31(46.26–102.6) | 77.38(58.56–98.76) | 0.3283 |
CX3CL1(pg/ml) | 365.9(223.1-584.3) | 609.7(529.9-857.1) | < 0.0001 |
CXCL6(pg/ml) | 48.4(30.76–95.48) | 88.18(54.28–108.4) | 0.005 |
CXCL1(pg/ml) | 277.9(244.3-332.5) | 436.8(359.2–763) | < 0.0001 |
CXCL2(pg/ml) | 143.3(54.57–315.1) | 331.3(186.3-700.9) | 0.0027 |
CCL1(pg/ml) | 112.6(96.16–145.3) | 116.7(88.1-153.7) | 0.7378 |
CXCL10(pg/ml) | 171.4(87.76–262.7) | 210(97.66–593.5) | 0.185 |
CXCL11(pg/ml) | 23.95(7.658–36.5) | 20.28(13.38–53.64) | 0.8251 |
CCL2(pg/ml) | 77.22(28.18–166.8) | 168(89.07–363.4) | 0.0011 |
CCL8(pg/ml) | 32.67(21.28–39.7) | 61.6(40.28–101.8) | < 0.0001 |
CCL7(pg/ml) | 204(145.8-377.9) | 238.5(151.5-370.6) | 0.5557 |
CCL13(pg/ml) | 53.52(12.8-87.72) | 47.06(22.71–91.9) | 0.7478 |
CCL22(pg/ml) | 1694(1061–3421) | 1234(774.3–1615) | 0.0829 |
CXCL9(pg/ml) | 658.3(251.5-960.4) | 604.7(394.3–1069) | 0.4413 |
CCL3(pg/ml) | 16.28(9.845–30.3) | 58.16(32.58–136.5) | < 0.0001 |
CCL20(pg/ml) | 25.24(13.16–42.4) | 50.93(20.63–97.86) | 0.0074 |
CCL19(pg/ml) | 902.2(274.9–1714) | 772.5(466.5–1381) | 0.8356 |
CCL23(pg/ml) | 273.6(107.9-609.3) | 1092(554.5–2366) | < 0.0001 |
CXCL16(pg/ml) | 965.4(774.3–1152) | 1218(1105–1364) | 0.0004 |
CXCL12(pg/ml) | 1559(423–1790) | 1215(410.4–1607) | 0.279 |
CCL17(pg/ml) | 269.7(100.5-999.8) | 417.5(122.4–1024) | 0.705 |
CCL25(pg/ml) | 1156(698.6–1498) | 1285(895.3–1792) | 0.3123 |
Subsequently, we further analyzed the differences of these cytokines and chemokines between EOS and LOS. As shown in Table 4, the levels of serum CXCL6, CXCL1, IL-6, CXCL10, CXCL11, CCL20, and IL-17 were higher in LOS than those in EOS (all p < 0.05). Conversely, the levels of serum IL-16, CXCL16, CCL22 were lower in LOS than those in EOS (all p < 0.05).
Table 4
The levels of serum cytokines and chemokines between EOS and LOS.
Cytokine/ Chemokine | EOS (n = 10) | LOS (n = 30) | p value |
CXCL6(pg/ml) | 66.55(37.7-97.69) | 93.27(61.68–121.5) | 0.0299 |
CXCL1(pg/ml) | 370.1(266-449.8) | 528.6(393.9-957.2) | 0.0408 |
IL-6(pg/ml) | 44.18(32.08–57.81) | 87.68(44.9-354.5) | 0.0479 |
IL-16(pg/ml) | 1449(1099–1948) | 885(607.4–1211) | 0.0015 |
CXCL10(pg/ml) | 110.9(62.27–268.6) | 253.3(136.2-705.1) | 0.0415 |
CXCL11(pg/ml) | 11.81(5.853–20.38) | 22.48(16.25–62.85) | 0.0152 |
CCL22(pg/ml) | 1485(1179–3912) | 1164(619.3–1440) | 0.0276 |
CCL20(pg/ml) | 22.86(14.3-40.77) | 62.76(32.03–124.9) | 0.0093 |
CXCL16(pg/ml) | 1403(1169–1532) | 1207(1007–1334) | 0.0351 |
IL-17(pg/ml) | 0.43(0-0.97) | 2.89(1.16–6.47) | 0.003 |
There were 13 neonates with positive blood culture and 27 neonates with negative blood culture among 40 neonates with sepsis. We compared the levels of serum cytokines and chemokines between positive blood culture and negative blood culture. The levels of CXCL6, TNF-α, CCL8, CCL23 in neonates with positive blood culture were significantly higher than those with negative blood culture (all p < 0.05) (Table 5). There was no difference in the levels of other cytokines and chemokines between the two groups (date not shown).
Table 5
The chemokine and cytokine levels of serum in blood culture positive group and blood culture negative group.
Cytokine/ Chemokine | Positive (n = 13) | Negative (n = 27) | p value |
CXCL6(pg/ml) | 99.88(65.67–157.9) | 82.05(51.1-102.2) | 0.0444 |
CCL8 (pg/ml) | 92.06(49.62–375.7) | 43.81(38.66–76.02) | 0.0373 |
CCL23(pg/ml) | 1954(528–3292) | 746.2(366.1–1223) | 0.0311 |
3. The levels of cytokines and chemokines were decreased after treatment
The serum of 15 neonates with sepsis before and after treatment were collected. 41 cytokines and chemokines were measured. As shown in Supplemental Digital Content – Fig. 1, IL-6, IL-8, TNF-α, IL-1β, CXCL13, CXCL16, CCL27, CCL3, CCL23, CX3CL1 were significantly decreased after treatment (all p < 0.005).
4. The association between the levels of cytokines and chemokines and the severity of organ function.
We further analyzed the associated between the levels of cytokines and chemokines and the SOFA score. As shown in the Supplemental Digital Content – Fig. 2, the levels of CX3CL1, CXCL2, CCL8, and TNF-α were all positively correlated with SOFA scores (all p < 0.05).