Your Immune System Isn't Weak. Your Genes Are Just Different.

HLA-DQ2 is one of your immune system’s main translators. Its job is to grab pieces of proteins (antigens) from pathogens or food and display them on the surface of immune cells like a wanted poster. T-cells read these posters and decide whether to attack. If HLA-DQ2 is present, your immune system is equipped to recognize a very specific set of threats. If it’s absent, you never recognize those same threats. Simple as that.

Approximately 25-30% of people with European ancestry carry HLA-DQ2. People with this variant have a dramatically elevated risk of celiac disease, because their HLA-DQ2 displays gluten peptides in a way that triggers autoimmune attack. But HLA-DQ2 also increases risk for type 1 diabetes, thyroid autoimmunity, and other conditions where the immune system attacks the body’s own cells. The variant itself isn’t the problem; the problem is that your immune system now sees gluten or self-antigens as a threat when most people don’t.

If you carry HLA-DQ2, you don’t just have a higher risk of celiac disease. You likely have broader autoimmune vulnerability. You might react to foods that shouldn’t trigger immune responses. You might have non-celiac gluten sensitivity. You might develop thyroid antibodies for no obvious reason. Your immune system is primed to recognize a very specific set of molecules as dangerous, and when it does, it attacks aggressively.

CTLA4 is your immune system’s brake pedal. T-cells are warrior cells that attack infections and cancer, but they need to know when to stop. CTLA4 is a checkpoint protein that sits on T-cells and tells them to power down after they’ve done their job. Without a functioning CTLA4 brake, T-cells keep firing even after the threat is gone. They attack the body’s own cells, harmless antigens, and sometimes nothing at all.

Approximately 45% of people carry the +49A>G variant in CTLA4. People with this variant have reduced CTLA4 function, meaning their T-cells remain more active and less responsive to the off-signal. This variant is directly linked to increased risk of autoimmune diseases like Graves’ disease, Hashimoto’s thyroiditis, type 1 diabetes, and rheumatoid arthritis. But the effect is more subtle than that. Even without a full autoimmune diagnosis, people with this variant tend to have more reactive immune systems, more food sensitivities, more frequent allergic responses, and longer recovery times after infections.

If you carry the CTLA4 variant, your immune system is essentially running hot. You might overreact to minor infections. Food sensitivities might feel intense and last longer than they should. You might have multiple autoimmune conditions or family history of autoimmunity. Your immune system isn’t broken; it’s just biased toward staying activated rather than resting.

TLR4 is your immune system’s smoke detector for bacteria. It sits on the surface of immune cells and detects lipopolysaccharide (LPS), the outer membrane of gram-negative bacteria. When TLR4 detects LPS, it triggers the innate immune response: fever, inflammation, neutrophil recruitment, and antibody production. Without functional TLR4, your body is essentially flying blind in the presence of certain bacterial infections.

Approximately 10% of people with European ancestry carry the D299G variant in TLR4. People with this variant have significantly reduced ability to recognize LPS from common gram-negative bacteria, meaning they mount a delayed or weakened early immune response. This doesn’t mean they can’t fight infections; it means they’re slower to detect them. The consequence is often that by the time symptoms appear and the adaptive immune response kicks in, the infection has already established itself more deeply.

If you carry the TLR4 variant, you might notice that you don’t get the early warning signs of infection that most people get. You might go from feeling fine to suddenly very sick with little gradual decline. Respiratory infections might progress more quickly. Gut infections might cause more severe symptoms because the initial detection was too slow. Food poisoning or stomach bugs might hit harder.

TNF stands for tumor necrosis factor-alpha. It’s one of your body’s primary alarm bells. When TNF is released, it signals that something is wrong: infection, injury, or danger. TNF triggers fever, increased vascular permeability (letting immune cells reach infected tissue), and amplified inflammatory signaling. A little TNF is essential for fighting infection. Too much TNF causes collateral damage: tissue inflammation, systemic sickness, and chronic disease.

Approximately 30% of the population carries the -308A allele in TNF. People with this variant produce significantly higher levels of TNF-alpha in response to immune challenges, amplifying their inflammatory response at the systemic level. This means that when they get infected, fight an allergy, or experience any immune trigger, their TNF levels spike higher and stay elevated longer than in people with the common genotype. Over time, this creates a baseline of elevated systemic inflammation.

If you carry the TNF variant, you likely experience more severe symptoms during infections: higher fevers, more body aches, more fatigue, longer recovery times. You might have chronic inflammatory conditions like rheumatoid arthritis or psoriasis. You might experience brain fog and fatigue that correlates with infection exposure. You might have elevated baseline inflammation markers even when you’re not acutely sick.

IL6 is inflammation’s amplifier. When TNF and other initial signals go out, IL6 keeps the inflammatory response going, recruits more immune cells, and drives the shift from acute to chronic inflammation. Small amounts of IL6 are necessary for healing. But when IL6 is overproduced, inflammation becomes self-perpetuating. Acute inflammation turns into chronic inflammation. Brain fog, fatigue, joint pain, and autoimmune flares all correlate with elevated IL6.

Approximately 40% of people carry the -174C allele in IL6. People with this variant produce higher IL6 in response to immune triggers, meaning their inflammatory response is more sustained and harder to shut off. The C allele is associated with higher baseline IL6, higher IL6 responses to stress and infection, and increased risk of depression, cognitive decline, and chronic inflammatory diseases. Importantly, IL6 drives neuroinflammation, which translates directly to brain fog, mood disturbance, and anxiety.

If you carry the IL6 variant, you likely notice that inflammation lingers. After an infection, you might feel tired and foggy for weeks. Emotional stress might trigger physical inflammation (joint pain, headaches) that persists. You might have depression or anxiety that correlates with inflammation. You might experience worse brain fog on high-inflammation days.

FUT2 is a glycosyltransferase. Its job is to add fucose sugars to ABO blood type antigens and then secrete those sugars into your saliva, tears, and digestive tract. These sugars feed specific bacteria. People with a functional FUT2 gene are “secretors.” People with non-functional variants are “non-secretors.” This single gene difference creates entirely different microbiome compositions.

Approximately 45-50% of people are non-secretors (carry non-functional FUT2 variants). Non-secretors have reduced bacterial diversity, less beneficial Bifidobacterium and Faecalibacterium species, and enrichment of potentially pathogenic bacteria. This creates a microbiome that is inherently less stable and less capable of training the immune system properly. The result is that non-secretors are more vulnerable to infection, have higher rates of food sensitivities, and often experience more severe IBS and gut inflammation.

If you’re a non-secretor (FUT2 variant), your microbiome is naturally less diverse and more prone to dysbiosis. You might get infections more easily, especially respiratory infections. You might have persistent gut issues, food sensitivities, or IBS that doesn’t fully resolve with standard interventions. Your immune system isn’t getting the training it needs from a healthy microbiome, which means it’s more reactive and less regulated.