From the paper:

>Also referred to as the neutrophil chemotactic factor, IL-8 recruit’s neutrophils and NK-cells to sites of inflammation where they can clear infected cells and promote wound healing.

>It is possible that the apparent lack of IL-8 in long-COVID patients may be responsible for at least some of the debilitating symptoms including post-exertional malaise, fatigue, and persistent cough, shortness of breath and chest pain.

>In this scenario, the acute SARS-CoV-2 infection damages the lungs, the cytokine milieu unfolds as described above, recruiting cells to the site of damage where the cells can either (a) help control the infection and induce a wound healing environment and the individual recovers normally; or (b) the infection causes abundant cellular infiltration leading to a high concentration of immune cells in a relatively small physical space, ultimately causing more tissue damage, which is not efficiently repaired in the absence of IL-8.

>Predictably, under scenario ‘b’ the individual remains having difficulty with oxygen transfer from the lungs into the blood stream. Therefore, if the macrophages and other cells that secrete IL-8 become exhausted or are otherwise incapable of secreting IL-8, neutrophils will not be recruited to assist in the wound healing process in the lung once the infection has been cleared [63]. Scenario ‘b’ therefore emerges as a potential model to explain certain long-COVID complications based on lack of IL-8.

>IFNγ is secreted by the innate immune Natural Killer cells (NK) and Natural Killer T cells (NKT) as well as the adaptive immune CD4+ Th1 and CD8+ Cytotoxic T Lymphocytes (CTL) after the development of antigen-specific immunity [64]. Together with IL-12, IFNγhelps drive the differentiation of Th1 cells, which in turn can secrete IL-2, TNFα, and IFNγ [65]. The observed lack of circulating IFNγ (Figure 1 and Table 2) in the plasma of patients suggests either severe immune dysfunction or exhaustion.

The war in the lungs is over, but there are too many soldiers still there, hanging out, causing drama. What's not happening: they need to be transported away and the engineering+construction crews need to come in to start rebuilding.