Cytokine response over the course of COVID-19 infection in pregnant women

Abstract

Objective: To study how severity and progression of coronavirus disease (COVID-19) affect cytokine profiles in pregnant women.

Materials and methods: 69 third-trimester, pregnant women were tested for COVID-19 infection and SARS-CoV-2 specific IgM and IgG antibodies. Patients were stratified according to SARS-CoV-2 Reverse Transcriptase-PCR (RT-PCR) status and serology (IgM and IgG) status. Cytokines G-CSF, HGF, IL-18, IL-1Ra, IL-2Ra, IL-8, and IP-10 were measured via ELISA. Retrospective chart review for COVID-19 symptoms and patient vitals was conducted, and cytokine levels were compared between SARS-CoV-2 positive and negative cohorts, by seronegative and seropositive infection, by time course since onset of infection, and according to NIH defined clinical severity.

Results: IL-18, IL-1Ra, and IP-10 increased in the 44 RT-PCR positive pregnant women compared to the 25 RT-PCR negative pregnant controls. Elevated cytokine levels were found in early infections, defined by positive RT-PCR and seronegative status, and higher cytokine levels were also associated with more severe disease. By IgM seroconversion, IL-8 and IP-10 returned to levels seen in uninfected patients, while IL-18 levels remained significantly elevated.

Conclusion: Cytokine profiles of third-trimester pregnant women vary with the time course of infection and are correlated with clinical severity.

Keywords: Cytokine profile; Interferon; Interleukin; Pregnancy; SARS-CoV-2.

Fig. 1

Cytokine levels in SARS-CoV-2 infected pregnant women. Cytokine values between RT-PCR positive (Positive) and RT-PCR negative (Negative) patients. Each point represents an average of two technical repeats per patient. All positive cytokine cutoffs were 0 (dashed line). Statistical significance was calculated using Mann-Whitney Wilcox rank sum test.

Fig. 2

Cytokine differences between NIH clinical severity groups in COVID-19 patients. Cytokines values between RT-PCR negative (uninfected) patients and RT-PCR positive patients grouped as asymptomatic, mild/moderately symptomatic, and severely symptomatic according to NIH Guidelines. Each point represents an average of two technical repeats per patient. All positive cytokine cutoffs were 0 (dashed line). Statistical significance was calculated using Mann-Whitney Wilcox rank sum test.

Fig. 3

Cytokine differences and serology status. Cytokines values between uninfected controls (PCR-SER−) vs SARS-CoV-2 RT-PCR+ patients that are seronegative (PCR + SER−) or seropositive for IgM and or IgG (PCR + SER+). Each point represents an average of two technical repeats per patient. All positive cytokine cutoffs were 0 (dashed line). Statistical significance was calculated using Mann-Whitney Wilcox rank sum test.

Supplementary figure 1

Cytokine levels throughout the time course of infection. RT negative patients (none) were compared to the RT-PCR positive patients separated into Early (IgM-IgG-), Middle (IgM+IgG-/+), and Late (IgM-IgG+) infection. All positive cytokine cutoffs were 0 (dashed line). Statistical significance was calculated using Mann-Whitney Wilcox rank sum test.

Supplementary figure 2

Relationship between individual cytokine levels. Paired cytokine values were plotted for IP-10 vs. IL-1Ra (A), IL-18 vs. IL-1Ra (B), and IL-18 vs. IP-10 (C). Comparisons were stratified by Negative infection (LEFT), Positive infection but seronegative (MIDDLE), and Positive infection and seropositive (RIGHT) status. Pearson correlation analysis and linear regression were performed on log2-scaled cytokine values. CIs are represented by shaded region (95% CI 0.80-0.97).