Core Framework & Diagram Treg Cells: The Immune Brake

It's not just a strength issue — more precisely, a 'precision' and 'braking' problem. Autoimmune disease is the immune system incorrectly targeting its own tissue for attack, with Treg cells unable to effectively suppress this wrong attack. Some autoimmune disease patients don't have universally strong immunity (they may be equally susceptible to infections), but attacks on self-tissue can't be suppressed — this is a regulatory mechanism problem, not just a strength problem.

Glucocorticoids (like prednisone) work through multiple mechanisms: directly suppressing multiple immune cell types (T cells, B cells, macrophages, neutrophils) in terms of activation and proliferation; suppressing pro-inflammatory cytokine gene expression; increasing anti-inflammatory cytokine production; and promoting Treg cell expansion. But long-term side effects are significant: elevated infection risk, osteoporosis, diabetes, adrenocortical suppression.

Some evidence exists but effects are modest and highly strain-dependent. Certain specific Lactobacillus strains (like Lactobacillus rhamnosus GG) have shown in animal experiments and some human studies that they can promote intestinal Treg cell expansion, improving immune tolerance. This is a mechanism by which gut microbiota influences Treg development through 'training' the immune system. But most commercial probiotic products have insufficient clinical evidence for definitive recommendations.

Treg cell therapy is currently in clinical trial stage, with the most active areas in organ transplantation (type 1 diabetes, kidney transplant) and autoimmune diseases. Main technical approaches: ex vivo expansion of patient's own Treg cells for reinfusion (autologous Treg therapy), and genetically engineered CAR-Treg cells (giving Treg cells CAR for specific target antigen recognition to improve targeting). Early results show good safety, but efficacy and durability require larger-scale clinical data validation.