Table 2.
Major cell types found in the lamina propria, their major function(s), and impacts seen in the cells during ALD
| Cell type | Layer | Major function(s) | ALD impacts | References |
|---|---|---|---|---|
| Dendritic cells | Lamina propria | Microbe sampling, seize harmful pathogens in the lumen; | Fewer pools of dendritic cells | 89-93, 96, 97, 101, 102, 109, 110 |
| Instigate intestinal adaptive immune response through TLR5; | ||||
| Induce IgA, stimulate Treg cell and Th17 cell differentiation; | ||||
| Specific subsets of DC associate with GAPs; | ||||
| Present luminal antigens to T cells within mesenteric lymph nodes inducing tolerance or immunity. | ||||
| ILC3s | Lamina propria | Interleukin production (IL-17, IL-22) in the intestine spurring an innate immune response | Interleukin production is hindered Amplifies bacteria translocation. |
90, 112, 114, 116, 117 |
| Macrophages | Lamina propria | Produce fewer cytokines in response to LPS compared to other tissue macrophages; | Increase in number | 119-122 |
| Secrete anti-inflammatory cytokines (IL-10) that can assist with differentiation of Tregs. | ||||
| Th1 and Th2 cells | Lamina propria | In balance, assist with immune response through inflammation and regulate T and B cell proliferation. | Balance is compromised, favoring Th2 cells and promoting tissue damage. | 129, 130, 133-135 |
| Th17 cells | Lamina propria | Key player in inflammation; | Increase in number; | 47, 90, 136, 137, 139, 140 |
| Activated by lamina propria dendritic cells. | Pro-inflammatory. | |||
| IgA | Lamina propria | Prevents invading microbes from gaining access through barrier; | Conflicting findings, some have reported overall decrease and other findings have shown no change; | 142-149 |
| Destroys pathogenic microbes | Further research needed. | |||
| MAIT cells | Lamina propria | Release cytokines (IFN-γ, TNFα, IL-17) Destroy cells infected with bacteria |
Fewer presense and less efficient in function. | 150 |
Impacts seen during ALD include evidence from human patients and/or evidence from mouse models fed various ethanol diets. Abbreviations: ALD: alcohol-associated liver disease; GAPs: goblet cell associated-antigen passages; IFN-γ: interferon-gamma; IgA: immunoglobulin A; IL: interleukin; ILCs: innate lymphoid cells; LPS: lipopolysaccharide; MAIT: mucosa-associated invariant T cells; Th: T helper cells; TLRs: toll-like receptors; TNF: tumor necrosis factor; Treg: regulatory T cells.