The immune system is not a single organ or a single process. It is a network of cells, signalling proteins, and biological mechanisms that must remain in a precise state of balance to function effectively. When that balance shifts, in either direction, the consequences can be wide-ranging.
Two broad patterns of immune dysfunction are clinically relevant:
Immune underactivity, a reduced capacity to mount effective responses against pathogens, leading to:
- Frequent or recurrent infections that take longer than normal to resolve
- Prolonged recovery from illness
- Persistent fatigue and low energy, often linked to subclinical immune activation
- Poor response to vaccination
- Susceptibility to opportunistic infections
Immune overactivity/dysregulation, a misdirected or chronically elevated immune response, contributing to:
- Chronic low-grade systemic inflammation
- Elevated inflammatory markers without a clear diagnosis
- Autoimmune tendencies or confirmed autoimmune conditions
- Inflammatory skin, joint, or gastrointestinal symptoms
- Increased oxidative stress and mitochondrial impairment
In many patients, both patterns are present simultaneously, an immune system that is simultaneously exhausted and dysregulated, unable to respond effectively where needed, whilst generating unnecessary inflammation elsewhere.