Immunity is often spoken of in vague unknowable terms.  But the immune system is a fascinating and complex system that shares many points of overlap between modern biomedicine and traditional Chinese medicine (TCM) as well as many points of departure. Both systems recognize that the human body is constantly exposed to potential threats. Both systems also acknowledge that health depends on a delicate balance between vigilance and regulation: the immune system must be strong enough to repel invaders, but not so reactive that it turns against the self or non-threatening stimuli in the environment.

In this piece, I want to give a quick review of modern immunology and Chinese medicine’s concept of immunity. We’ll walk through how Western medicine describes the layers of immune response, from first detection to coordinated attack. Then we’ll turn to the Chinese medicine, with a focus on Lung and Spleen physiology, and the critical role of wei qi. My goal is not to force the two systems into a false equivalence, but to show how clinicians can utilize both, and apply them in patient care.

Part I. Modern Immunology

Immunity refers to the body’s network of cells, tissues, and signaling molecules that work together to identify and neutralize threats. These threats may be pathogens (viruses, bacteria, fungi, parasites), or non-living foreign substances (pollen, splinters, transplanted tissue). Sometimes, the “threat” is endogenous such as cancer.

The Two Arms: Innate and Adaptive Immunity

Innate Immunity

Innate immunity is the body’s first line of defense, acting within minutes to hours by recognizing broad patterns of pathogens rather than unique details. It relies on physical barriers such as skin, mucosal membranes, and secretions. Defenders such as neutrophils, macrophages, and natural killer (NK) cells, and cytokines provide a stage two response for things that engage the physical barriers. These mechanisms engulf invaders, release inflammatory mediators, and set the stage for the more targeted responses of adaptive immunity.

Adaptive Immunity

Adaptive immunity is the body’s targeted defense system.  It is geared to recognize and eliminate very specific antigens with precision. It can take several days to develop, but provides highly specific protection by activating T cells to coordinate the immune response, B cells to produce antibodies that mark pathogens for destruction, and finally memory cells that ensure a rapid and effective reaction upon re-exposure to the same threat. Together, innate and adaptive immunity form a layered defense: front line protection detection and precision attack.

What Happens When the Body Detects an Infection?

Recognition

Recognition begins when a virus enters the respiratory tract and airway epithelial cells detect its characteristic patterns, triggering the release of interferons and cytokines that signal danger and initiate the immune response.

Recruitment

During recruitment, neutrophils and monocytes migrate to the site of infection while dendritic cells engulf viral particles and transport their antigens to the nearest lymph nodes, linking the innate response to the activation of adaptive immunity.

Activation of Adaptive Immunity

Activation of adaptive immunity occurs in the lymph nodes, where dendritic cells present viral antigens to T cells. The T cells then activate, proliferate, and coordinate the immune response, stimulating B cells to differentiate and release antibodies precisely tailored to the invading virus.

Effector Phase

In the effector phase, T cells identify and destroy infected host cells while antibodies neutralize viruses, block their entry into new cells, and mark them for clearance; at the same time, the cytokine network amplifies the immune response while also guiding its resolution.

Resolution and Memory

During resolution and memory, regulatory T cells suppress immune activity once the infection is cleared, while memory T and B cells persist in the body, providing long-term immunity and enabling a faster, more effective response upon re-exposure.

Foreign Bodies vs. Pathogens

Interestingly, the body does not respond identically to all challenges. Infection with living pathogens triggers both innate and adaptive arms, often with inflammation, fever, and antigen-specific memory. Non-living foreign matter such as a splinter, pollen, or a prosthetic joint often provokes foreign body reactions mediated predominantly by macrophages, in which the immune system recognizes “not self” but lacks antigen-specificity. Transplanted tissue represents a middle case: the immune system recognizes foreign antigens on donor cells, activating adaptive immunity and leading to graft rejection unless appropriately suppressed. Thus, context shapes the nature of immune response.

Part II. Immunity in Chinese Medicine

Chinese medicine does not frame immunity in terms of cells, cytokines, or antibodies. Instead, it describes the body’s ability to resist external pathogenic influences and maintain balance through the coordinated action of the organ systems and qi dynamics.

The Role of the Lung

In classical texts, the Lung is described as the first organ to encounter external influences through breathing, and its functions are central to immunity. It governs qi and respiration, distributing qi throughout the body; regulates the exterior by controlling the skin, body hair, and dispersing protective qi; and opens to the nose and throat, making it a common entry point for pathogens. When Lung qi is strong, the body is resilient against colds, flus, and respiratory infections, but when weakened, patients become more susceptible to recurrent illness, allergies, and lingering coughs.

The Defensive Layer

Wei qi, often considered the closest analogue to innate immunity in Chinese medicine, is generated by the Spleen and distributed by the Lung. It circulates outside the channels in the skin and muscles, guarding against pathogenic influences while also warming the body and regulating sweating and pores. When wei qi is strong, sweating is appropriate and external pathogens are effectively repelled; when deficient, the pores remain open and patients become vulnerable to chills, spontaneous sweating, and recurrent viral infections.

The Spleen and Long-Term Immunity

The Spleen’s role is less dramatic but equally vital. By transforming food and drink into qi and blood, it provides the raw material for wei qi. Spleen deficiency undermines Lung function. Thus, building immunity in TCM often involves strengthening both Lung and Spleen, not just dispersing exterior pathogens.

Pathogenic Factors and Immunity

Chinese medicine describes pathogens not as microbes but as climatic influences: wind, cold, heat, damp, dryness. Each can invade when wei qi is weak or when the environment overwhelms the body. Wind-cold resembles viral upper respiratory infections; wind-heat parallels bacterial sore throat or influenza; damp-heat evokes sinusitis, intestinal infections, or skin eruptions. Rather than focusing on directly destroying pathogens, treatment focuses on supporting the body’s ability to repel by balancing and clearing excessive natural influences. For example, if a patient is experiencing symptoms consistent with wind-cold, treatment warms and releases the exterior and may dry damp if necessary—supporting the body’s capacity to restore harmony and resist pathogens.

Part III. Points of Overlap and Divergence

First Line of Defense

Western medicine emphasizes skin, mucosa, and innate immune cells; TCM highlights wei qi circulating at the surface.

Coordination and Communication

Western frameworks focus on cytokines and cell signaling; TCM emphasizes the Lung’s dispersing and descending of qi and the Spleen’s nourishing role.

Memory

Western medicine describes adaptive immunity via T and B memory cells; TCM discusses constitutional strength (jing) and enduring wei qi robustness that shape responses to recurrent challenges.

Pathogens

Western categories include viruses, bacteria, and fungi; TCM speaks of wind, cold, damp, and heat.

Clinical Relevance for Practitioners

• Patients with frequent colds and fatigue may fit TCM’s wei qi deficiency or a Western frame of impaired innate immunity.
• Chronic allergic rhinitis or asthma reflects both Lung qi imbalance and dysregulated immune responses.
• Long-standing digestive issues with susceptibility to infections align with Spleen deficiency in TCM and highlight the importance of gut health and the microbiome in Western immunology.

Ultimately, both systems remind us that immunity is not only about attacking pathogens. It is about balance, resilience, and recovery.

Conclusion

Modern immunology and Chinese medicine describe the same phenomenon through different languages. Western medicine dissects cells and signaling molecules; Chinese medicine describes qi dynamics, pathogenic influences, and interaction with our environment. For clinicians, the opportunity lies in seeing patients through both lenses, appreciating how lifestyle, constitution, and environment shape immunity, and applying Chinese medicine alongside modern diagnoses and understanding. When educating patients, it is useful to blend the languages—we can speak of T cells and wei qi together—to enrich our capacity to guide patients toward health in a complex world.