Science Behind the Flares

Flares are periods when symptoms of chronic inflammatory or autoimmune conditions suddenly worsen due to increased immune system activity. During a flare, the immune system releases inflammatory mediators such as cytokines, interleukins, and tumor necrosis factor (TNF). These substances increase inflammation in tissues and lead to symptoms such as pain, swelling, fatigue, and redness. Medical research shows that flares occur when internal biological factors and external triggers disturb the normal regulation of the immune system.

Stress is one of the most studied triggers associated with disease flares. When a person experiences psychological or physical stress, the body activates the hypothalamic–pituitary–adrenal (HPA) axis. This process leads to the release of stress hormones such as cortisol and adrenaline. While cortisol normally helps control inflammation, chronic stress can dysregulate the immune system and increase inflammatory responses. As a result, people with autoimmune or inflammatory disorders may experience worsening symptoms or flare episodes during prolonged stress.

Sleep also plays a crucial role in immune system regulation and inflammation control. Adequate sleep helps maintain hormonal balance and supports immune defense mechanisms. Poor sleep quality or sleep deprivation can increase levels of inflammatory markers such as C-reactive protein and pro-inflammatory cytokines. Research indicates that individuals who do not get sufficient sleep may have increased susceptibility to disease flares, fatigue, and decreased ability to recover from inflammatory episodes.

Environmental and lifestyle factors can also contribute to the development of flares. These include infections, changes in weather, poor diet, and excessive physical or emotional strain. Infections can stimulate immune activity, while environmental triggers may activate inflammatory pathways in the body. Additionally, unhealthy lifestyle patterns such as poor nutrition or lack of physical balance may weaken the body’s ability to regulate immune responses, increasing the likelihood of symptom exacerbation.

Understanding the biological mechanisms behind flares is important for managing chronic conditions. Medical professionals often recommend strategies such as stress management, regular sleep patterns, balanced nutrition, and appropriate medical treatment to reduce flare frequency. By identifying individual triggers and maintaining healthy lifestyle habits, patients can improve symptom control and overall quality of life while reducing the impact of inflammatory flare episodes.

This picture explains how changes in the immune system happen before a disease flare in patients with Systemic Lupus Erythematosus (SLE). It shows how different parts of the immune system (innate immunity, adaptive immunity, and effector molecules) interact and produce inflammatory signals before symptoms become severe.

First, the diagram shows the innate immune system, which is the body’s first line of defense. Cells such as macrophages (MΦ) and plasmacytoid dendritic cells (pDC) release immune mediators like APRIL, BLyS, IFN-α/β, and IL-10. These molecules stimulate B cells, which produce antibodies. Before a flare occurs, the levels of certain immune mediators increase or decrease, indicating that the immune system is becoming dysregulated.

Second, these signals influence the adaptive immune system, particularly T helper cells (Th1, Th2, Th17) and regulatory T cells (Treg). Cytokines such as IL-12, IL-6, IL-23, IL-1, and IL-13 guide the differentiation of these T cells. Each T cell type produces different cytokines. For example, Th1 cells produce IFN-γ and IL-2, Th2 cells produce IL-5 and IL-13, and Th17 cells produce IL-17A and IL-21. These cytokines increase inflammation and contribute to autoimmune activity.

Third, the effector molecules on the right side of the diagram include chemokines and soluble receptors. Chemokines such as CCR5, CCR3, and CXCR3 help recruit immune cells to tissues. Soluble receptors like TNFRI, TNFRII, TRAIL, Fas, and CD40L regulate immune signaling. Changes in these molecules can increase immune cell activity and inflammation before a clinical flare appears.

Finally, the figure highlights that immune mediator levels change before visible disease symptoms occur. The red labels represent molecules that increase before a flare, while blue labels represent those that decrease. This suggests that monitoring these immune markers may help doctors predict or detect disease flares earlier in patients with SLE.

In summary, the diagram illustrates how interactions between innate immunity, adaptive immunity, cytokines, and chemokines lead to immune system activation prior to an SLE flare, helping researchers understand and potentially predict disease progression.

References

Irwin, M. R. (2015). Why sleep is important for health: A psychoneuroimmunology perspective. Annual Review of Psychology, 66, 143–172. https://doi.org/10.1146/annurev-psych-010213-115205

National Institute of Arthritis and Musculoskeletal and Skin Diseases. (2023). 

Autoimmune diseases and inflammation. U.S. Department of Health and Human Services. https://www.niams.nih.gov

McEwen, B. S. (2007). Physiology and neurobiology of stress and adaptation: Central role of the brain. Physiological Reviews, 87(3), 873–904. https://doi.org/10.1152/physrev.00041.2006

Besedovsky, L., Lange, T., & Born, J. (2019). Sleep and immune function. Pflügers Archiv – European Journal of Physiology, 463, 121–137. https://doi.org/10.1007/s00424-011-1044-0

July 12 • Written by Ifza Zia • Edited by Nathan Lee and Erin Tran