Dynamic shifts in lung cytokine patterns in post-COVID-19 interstitial lung disease patients: a pilot study

Abstract

Introduction:

The pathogenesis of post-COVID interstitial lung disease, marked by lung tissue scarring and functional decline, remains largely unknown.

Objectives:

We aimed to elucidate the temporal cytokine/chemokine changes in bronchoalveolar lavage (BAL) from patients with post-COVID interstitial lung disease to uncover potential immune drivers of pulmonary complications.

Design:

We evaluated 16 females diagnosed with post-COVID interstitial lung disease, originating from moderate to severe cases during the second epidemic wave in the Autumn of 2020, treated at the Pneumology Department of the Arad County Clinical Hospital, Romania. Their inflammatory response over time was compared to a control group.

Methods:

A total of 48 BAL samples were collected over three intervals (1, 3, and 6 months) and underwent cytology, gene, and protein expression analyses for pro/anti-inflammatory lung cytokines and chemokines using reverse transcription polymerase chain reaction and enzyme-linked immunosorbent assay.

Results:

One month after infection, there were significant increases in the levels of IL-6 and IL-8. These levels decreased gradually over the course of 6 months but were still higher than those seen in control. Interferon-gamma and tumor necrosis factor alpha exhibited similar patterns. Persistent elevations were found in IL-10, IL-13, and pro-fibrotic M2 macrophages’ chemokines (CCL13 and CCL18) for 6 months. Furthermore, pronounced neutrophilia was observed at 1 month post-COVID, highlighting persistent inflammation and lung damage. Neutrophil efferocytosis, aiding inflammation resolution and tissue repair, was evident at the 1-month time interval. A notable time-dependent reduction in CD28 was also noticed.

Conclusion:

Our research provides insight into the immunological processes that may lead to the fibrotic changes noted in the lungs following COVID-19.

Plain language summary

Dynamic shifts in lung cytokine patterns in post-COVID-19 interstitial lung disease patients: a pilot study

The objective of this pilot study was to investigate changes in lung cytokine pro- and anti-inflammatory profiles among patients with interstitial lung disease after COVID-19 infection. Background: Post-COVID lung disease represents a significant health concern that demands comprehensive research. The pathogenesis of post-COVID interstitial lung disease, marked by lung tissue scarring and functional decline, remains largely unknown. Methods: We evaluated 16 females diagnosed with post-COVID interstitial lung disease, originating from moderate to severe cases during the second epidemic wave in the Autumn 2020, treated at the Pneumology Department of the Arad County Clinical Hospital, Romania. Their inflammatory response over time was compared to a control group. A total of 48 BAL samples were collected over three intervals (1, 3, and 6 months) and underwent cytology, gene, and protein expression analyses for pro/anti-inflammatory lung cytokines and chemokines using RT-PCR and ELISA The interrelationships between the expression levels of various pro-inflammatory and anti-inflammatory cytokines and chemokines by Pearson’s correlations was investigated. Results: One month after infection, there were significant increases in the levels of IL-6 and IL-8. These levels decreased gradually over the course of six months but were still higher than those seen in control. IFN-γ and TNF-α exhibited similar patterns. Persistent elevations were found in IL-10, IL-13, and pro-fibrotic M2 macrophages’ chemokines (CCL13 and CCL18) for six months. Pronounced neutrophilia was observed at 1 month post-COVID, highlighting persistent inflammation and lung damage. Neutrophils efferocytosis, aiding inflammation resolution and tissue repair, was evident at the 1-month time-interval. A notable time-dependent reduction in CD28 was also noticed. Conclusions: Our research provides insight into the immunological processes that may lead to the fibrotic changes noted in the lungs following COVID-19.