Natural Killer Cells -
Immunotherapy for Cancer Treatment

As cancer cells grow and spread, they adapt and learn new ways to avoid being eliminated by the immune system. Certain cells in the immune system, known as cytotoxic T cells, fight infection and disease in the body by locating and identifying antigen markers on invading cells and then injecting those cells with a poison to kill them. As cancer cells grow and spread to other parts of the body, they actually shed their antigens, which are their identifying information or "fingerprints." As a result, cytotoxic T cells chase the antigens, only to find that there are no invading cancer cells attached to them. That is why natural killer cells (NK cells or NKT cells) are so important to boosting the body's ability to fight cancer- they are capable of independently recognizing and killing cancer cells without relying on the cancer cells' identifying information or fingerprints.

Why Natural Killer Cells are the Most Important Cancer Cells in the Body

NK cells are therefore one of the most important components of the immune system, especially the innate immune response. While these cells are critical to immune response, they are also relatively scarce, comprising roughly only 10% of circulating peripheral blood lymphocytes in the body.

NK cells regulate the immune system primarily through cytokine secretion, and they are the body's primary defense against metastatic disease. NK cells also are responsible for producing interferon-gamma, which is a key cytokine that drives antitumor cellular immune responses. Even more importantly for cancer patients, NK cells exert cytotoxic effects with great specificity and without harming host tissue.

The Importance Of Natural Killer Cells in Cancer Progression and Prognosis

Research has shown that decreased numbers or function of NK or NKT cells tend to predispose cancer patients to more aggressive tumor growth, with a continuing decrease in the number of these cells and antitumor function as the disease progresses. In contrast, restoration of NK and NKT function by means of chemotherapy, immunomodulatory agents or adoptive immunotherapy typically leads to enhanced cellular immune tumor-response and higher survival rates, as demonstrated in animal studies and human clinical trials.

Significantly depressed NK activity has been reported in breast, colon, head and neck cancers, liver cancer, leukemia, lung cancer, melanoma, ovarian cancer, pancreatic cancer, prostate cancer, and renal cell carcinoma. Likewise, significant depression of NKT cell number and/or function has been noted in patients with breast cancer, colon cancer, head and neck cancer, lung cancer, melanoma, multiple myeloma, prostate cancer, and renal cell carcinoma.

NK cells can be an independent prognostic factor in many forms of cancer. Research has shown that for just about every type of cancer, if the patient has increased numbers of and better functioning NK cells, he or she will have a better prognosis compared to someone who has decreased and poorly functioning NK cells. Also, NK cell number and function is generally higher in people who respond to chemotherapy or radiation, as compared to those who don't respond to such treatments. NK cells are also prognostic of cancer metastasis and recurrence.

Using Natural Killer Cells' Cluster Designation Markers As Benchmarks In Cancer Patients

As with cancer cells, all cells have protein "fingerprints" on their surfaces. For white blood cells, these fingerprints are called cluster designation makers, or CD markers. The CD markers are assigned numbers for identification purposes, and cells are either positive or negative for these markers. These markers allow cells to be distinguished and identified.

CD56 is the primary fingerprint for natural killer cells and natural killer T cells, which distinguishes them from other cells. In addition to CD56, natural killer T cells also carry a CD3 marker. CD56 is a good marker to look for in patients with cancer. Numbers of CD56 cells in these patients are typically lower than in healthy individuals, and they trend downwards as disease progresses. Usually these diseases are able to gain a foothold in the first place because the immune system is already compromised or "distracted" by another infection. Patients who have lower than normal immune system function are referred to as "immunocompromised."

How Can We Help You With This Information?

Once we have identified a patient as being a candidate for AAIT, we use a machine called an apheresis unit to obtain billions of white blood cells from the patient. In healthy adults, less than 8% of white blood cells are NK cells. This number, of course, is even lower in patients with late-stage, metastatic cancer. About 20% of the cells we obtain from the apheresis procedure cannot be expanded or re-infused back into the patient, because they are the wrong type of cell to do the necessary job of fighting cancer. However, these cells do help the right cells grow, so they are not disposed of during the process. They play a very important role in helping the right cells grow and mature.

Once the white blood cells are obtained, we "wash" the cells in saline to sterilize them, and then we "feed" them to keep them alive. However, our goal is not just to keep the cells alive; we also want to train them how to fight and be productive again. Once that is accomplished, we want to make as many of them as we can to build an army of competent, motivated cells. To accomplish this goal, we use some FDA-approved agents called cytokines. Cytokines are proteins that occur naturally in the body. They are used by the cells of the immune system to talk to one another. Each cytokine sends its own particular signal to a particular type of cell. The cytokines we use send signals to three major types of cells: natural killer cells, natural killer T cells, and cytotoxic T lymphocytes. Once cytokines are added, the 20% of cells that are the "wrong" type of cell produce more cytokines themselves, helping to feed the right cells and speeding up the process of expansion. This process is conducted over a span of three to four weeks.

The goal is to end up with billions of properly trained cells that are capable of recognizing and killing tumor cells. Just to be sure these cells are the "right" cells and can do their job, we test the cells in three areas:

• Quantity - The number of cells makes all the difference when it comes to fighting cancer. Whereas other natural killer cell vaccines exist in low numbers, our AAIT treatment multiplies natural killer cells into the multi-billions.
• Quality - We perform cytotoxicity assays to make sure the natural killer cells are activated to kill tumors. We test the NK cells against tumor cell lines to establish their killing ability.
• Sterility - We make sure our natural killer cell vaccine is clean and has no contaminants.

This treatment not available in US and it is not FDA approved for the treatment of cancer. Patients should consult with their doctors before considering any therapy or treatment. Envita Mexico is governed under Mexican law and medical legal jurisdiction, and in no way do we make any guarantees or claims of any outcomes for this or any other treatment. The information above is for educational purposes only.

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