Essential Facts About NK Cells: Natural Immunity and the Consequences of Incomplete Viral Clearance

Did You Know... What is the Common Cold?

The common cold is an upper respiratory tract infection primarily caused by mild viruses. Most cases resolve within 1-2 weeks. Common symptoms include a sore throat, runny nose, nasal congestion, coughing, sneezing, hoarseness, and fatigue. In some cases, additional symptoms may occur, such as a high fever (38-39°C), headache, earache, muscle pain, and loss of taste or smell.

Symptoms are usually most severe during the first 2-3 days and gradually improve thereafter. The common cold typically lasts 7-10 days in adults and 10-14 days in children under five. Even after recovery, a cough may persist for up to two weeks.

There is no direct cure for the common cold. Treatment focuses on relieving symptoms through rest, adequate hydration, nutritious food, and Vitamin C intake to boost the immune system—specifically Natural Killer (NK) cells, which help speed up recovery. Medications such as pain relievers, fever reducers, decongestants, and cough suppressants can also help alleviate symptoms.

Since the common cold is caused by a virus, antibiotics are ineffective and unnecessary. Medical guidelines advise against using antibiotics without specific indications, as improper use increases the risk of future antibiotic resistance.

Although the common cold is usually self-limiting, it can sometimes lead to secondary bacterial infections or spread to nearby organs, causing complications such as middle ear infections, sinusitis, pharyngitis, bronchitis, or pneumonia. These conditions require prompt treatment to prevent serious health risks.

A simple sign of a secondary bacterial infection following a viral cold is a change in mucus or phlegm color from clear to green, often accompanied by a prolonged fever.

What Protects Us from Viral Infections?

Normally, our immune system protects us from infections. However, if immunity is compromised or NK cell activity is low, the body becomes more susceptible to secondary bacterial infections after a viral illness, leading to the complications mentioned above.

The human body contains approximately 2-5 billion NK cells, accounting for about 5% of lymphocytes in the blood. However, NK cell levels can decline due to weakness or aging. Studies show that NK cell activity peaks around age 20 and gradually decreases with age, which correlates with an increased risk of cancer. Lifestyle factors such as high stress, nutrient deficiencies, low protein intake, lack of sleep, alcohol consumption, and smoking also contribute to this decline. Frequent infections like herpes, shingles, hepatitis, or recurring colds may indicate weakened immunity or low NK cell activity.

Advanced technology now allows for blood testing to assess NK cell activity, a key indicator of immune status. A blood sample is sent to a laboratory to evaluate how effectively NK cells respond to foreign pathogens. This test requires approximately 72 hours to complete, and the results help doctors assess your risk of disease and cancer immediately.

The latest research on the Osaki Method, developed by Dr. Junichi Masuyama, M.D., Ph.D., an expert in immunotherapy, in collaboration with the New City Osaki Clinic in Tokyo (published in Cytotherapy Journal, 2016), has introduced a highly effective technique from Japan. This method has been proven to significantly increase both the number and potency of NK cells. Cultured NK cells from this process are highly active and can be safely used for cancer treatment.

The Osaki Method is a safe, globally standardized technique used in Japan for cancer treatment. It allows for the expansion of NK cells from just 50 cc of blood into tens of billions of highly activated NK cells.

In Thailand, MEDEZE NK laboratory, under MEDEZE GROUP, is the exclusive provider authorized to use this technique for NK cell expansion. MEDEZE has also partnered with Dr. Junichi Masuyama, the inventor of "Highly Active NK Cell Therapy," bringing direct expertise in cancer treatment to patients.