IFN-gamma is an essential immune protein for immune response against infectious bacteria, viruses, and fungi. Learn more about the normal ranges & how to increase or decrease it.
What Is Interferon-gamma (INF-g, IFN-g)?
IFN-gamma (IFN-γ or type II interferon) is an immune protein. It is essential for the body’s immune response against fungal, bacterial, and viral infections. It controls genes that are responsible for immune and inflammatory responses and activates macrophages, natural killer cells, and neutrophils [1].
IFN-gamma levels generally increase during infections or immune disorders. This cytokine is a part of the Th1 immune response [2].
Normal Range of Interferon-Gamma Levels
Lab results are commonly shown as a set of values known as a “reference range”, which is sometimes referred to as a “normal range”. A reference range includes the upper and lower limits of a lab test based on a group of otherwise healthy people.
Your healthcare provider will compare your lab test results with reference values to see if any of your results fall outside the range of expected values. By doing so, you and your healthcare provider can gain clues to help identify possible conditions or diseases.
Some lab-to-lab variability occurs due to differences in equipment, techniques, and chemicals used. Don’t panic if your result is slightly out of range in the app – as long as it’s in the normal range based on the laboratory that did the testing, your value is normal.
However, it’s important to remember that a normal test doesn’t mean a particular medical condition is absent. Your doctor will interpret your results in conjunction with your medical history and other test results.
Have in mind that a single test isn’t enough to make a diagnosis. Your doctor will interpret this test, taking into account your medical history and other tests. A result that is slightly low/high may not be of medical significance, as this test often varies from day to day and from person to person.
The normal range may vary by test.
- <2.0 pg/mL
- 5 pg/mL or less
- ≤3.0 pg/mL
High Interferon-Gamma
IFN-gamma levels normally increase as you age [3].
Lipopolysaccharides (LPS) are one of the most significant simulators of interferon-gamma. LPS can be elevated by bacterial infections, a “leaky gut”, or other health conditions. Nitric oxide also increases interferon-gamma levels [4].
Conditions Associated with High Interferon-Gamma Levels
The conditions we discuss here are commonly associated with high interferon-gamma levels, but this single symptom is not enough for a diagnosis. Work with your doctor to discover what underlying condition might be causing you abnormally elevated interferon-gamma levels and to develop an appropriate plan to improve your health.
High IFN-gamma levels can be caused by:
- Canker sores (recurrent aphthous stomatitis), as seen in a study on 21 people [5]
- Patchy hair loss (alopecia areata), as seen in a study on 60 people [6]
- Alcoholism, as seen in a study on 47 stable chronic alcoholics [7]
- Alcoholic liver scarring (cirrhosis), as seen in a study on 26 alcoholics [8]
- Measles (acute phase, <7 days of illness), as seen in a study on 54 people [9]
- Hepatitis B, as seen in a study on 60 people [10]
- Tuberculosis, as seen in 2 studies on 10 people with active tuberculosis and 430 with latent tuberculosis infection [11, 12]
- Multiple sclerosis, as seen in 2 studies on 50 people [13, 14]
- Systemic sclerosis, as seen in a study on 49 people [15]
- Isoniazid treatment for tuberculosis, as seen in a study on 26 people [16]
- Melioidosis (an infectious bacterial disease), as seen in a study on 62 people with severe melioidosis [17]
Elevated IFN-gamma levels are commonly associated with:
- Severe airway inflammation in asthmatic patients, as seen in a study on 17 people [18]
- Psoriasis severity, as seen in 2 studies on 51 people [19, 20]
- Kidney damage in type 2 diabetic patients, as seen in a study on 100 diabetics [21]
- Increased severity of heart disease, as seen in a study on 104 people with coronary heart disease and type 2 diabetes [22]
- Amyotrophic lateral sclerosis (ALS) disease progression, as seen in a study on 52 people [23]
- Lupus, as seen in a study on 64 people [24]
- Mixed connective tissue disease, as seen in a study on 15 people [24]
- Tumor stage, tumor size, and recurrence of liver cancer, as seen in a study on 63 patients [25]
How to Lower Interferon-Gamma Levels
The most important step is to get medical attention to identify and treat any underlying health conditions that may be causing high interferon-gamma levels. You may also try the following complementary approaches if your doctor determines that they may be helpful in your case.
A lifestyle change that will help you not only lower your IFN-gamma levels but also improve your overall health is to exercise more. Endurance training (but not moderate exercise) helped decrease IFN-gamma levels in a clinical trial on 30 healthy but sedentary men [26].
As previously mentioned, IFN-gamma levels are increased in alcoholics. Reducing your intake of alcohol may not only lower your IFN-gamma levels but also protect you from the well-known harmful effects of this substance [27].
Eat a diet high in omega-3 fatty acids may also help you lower your IFN-gamma levels, based on preliminary evidence in mice. Some foods with high omega-3 levels include fatty fish, shellfish, and fortified dairy products [28, 29].
The following dietary supplements lowered IFN-gamma levels (mostly in animal studies):
- Fish oil [30]
- Curcumin [31]
- Olive leaf extract [32, 33]
- Andrographis [34, 35]
- Boswellia [36]
- Lithium [37]
- Theanine [38]
- Glucosamine [39]
- Ginkgo [40]
- American ginseng [41]
- Theaflavins [42]
- Nettle leaf [43]
- EGCG [44]
- Aloe [45]
- Resveratrol [46]
This IFNG gene page has more substances that can reduce interferon-gamma.
However, remember that none of these substances is approved for medical use by the FDA. Supplements generally lack solid clinical research. Regulations set manufacturing standards for them but don’t guarantee that they’re safe or effective. Speak with your doctor before supplementing and never use them as a replacement for proven therapies.
Low Interferon-Gamma
The conditions we list here are commonly associated with low interferon-gamma levels, but this single symptom is not enough for a diagnosis. Work with your doctor to discover what underlying condition might be causing you abnormally low interferon-gamma levels and to develop an appropriate plan to improve your health.
Conditions Associated with Low Interferon-Gamma Levels
- Endurance exercising training, as seen in a clinical trial on 30 healthy men [26]
- Second-hand smoke exposure, as seen in a study on 40 children exposed to cigarette smoke [47]
- Candida albicans oral infection, as seen in a study on 26 people chronically infected [48]
- Trauma, as seen in a study on 38 trauma patients [49]
- Heart surgery, as seen in a study on 20 people who underwent this procedure [50]
- Epstein Barr virus infection, as seen in a case study and a study in cells [51, 52]
- Hepatitis C, as seen in a study on 63 people [53]
- Corticosteroid treatment, as seen in a study on 131 people receiving these drugs for leprosy [54]
How to Raise Interferon-Gamma Levels
Again, the most important step is to get medical attention to identify and treat any underlying health conditions that may be causing high interferon-gamma levels. You may also try the following complementary approaches if your doctor determines that they may be helpful in your case.
As opposed to endurance training, moderate exercise can enhance IFN-gamma production. This was the case in a clinical trial on 16 healthy men [55].
Sun exposure promotes nitric oxide release, which in turn can increase interferon-gamma levels, as seen in a clinical trial on 24 healthy volunteers [56].
Supplements that increased interferon-gamma levels in clinical trials include:
- Glutamine [49]
- Probiotics (Lactobacillus rhamnosus GG) [57]
- Vitamin E [58]
- Glycine [59]
This IFNG gene page has more substances that can increase interferon-gamma levels.
However, remember that none of these substances is approved for medical use by the FDA. Supplements generally lack solid clinical research. Regulations set manufacturing standards for them but don’t guarantee that they’re safe or effective. Speak with your doctor before supplementing and never use them as a replacement for proven therapies.
Interferon Gamma Genes and SNPs
Interferon-gamma levels are also determined by variations in the IFNG gene, such as the variants:
