The immune system is the system of specialized cells and organs that protect an organism from outside biological influences.

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(Though in a broad sense, almost every organ has a protective function - for example, the tight seal of the skin or the acidic environment of the stomach.) When the immune system is functioning properly, it protects the body against bacteria and viral infections, destroying cancer cells and foreign substances.

If the immune system weakens, its ability to defend the body also weakens, allowing pathogens, including viruses that cause common colds and flu, to grow and flourish in the body.

The immune system also performs surveillance of tumor cells, and immune suppression has been reported to increase the risk of certain types of cancer..

For more information about the topic Immune system, read the full article at Wikipedia.org, or see the following related articles:

Natural killer cell — Natural killer cells (also known as NK cells, K cells, and killer cells) are a type of lymphocyte (a white blood cell) and a component of innate …  > read more

White blood cell — White blood cells (also called leukocytes or immune cells) are cells which form a component of the blood. They help to defend the body against …  > read more

T cell — T cells are a subset of lymphocytes that play a large role in the immune response. The abbreviation “T” stands for thymus, the organ in which their …  > read more

Antiviral drug — Antiviral drugs are a class of medication used specifically for treating viral infections. Like antibiotics, specific antivirals are used for …  > read more

Note: This page refers to an article that is licensed under the GNU Free Documentation License. It uses material from the article Immune system at Wikipedia.org. See the Wikipedia copyright page for more details.

Source: M. D. Anderson News Release 03/03/08
For most Americans, meals tend to center around meat. To significantly decrease a person’s risks of developing colorectal cancer,

experts at The University of Texas M. D. Anderson Cancer Center suggest a new approach to meal planning that focuses more on fruit and vegetable dishes.

According to recent findings issued by the American Institute for Cancer Research (AICR), consuming more than 18 ounces, or a little over a pound, of

red meat (pork, beef, lamb and goat) each week can significantly increase a person’s risks for developing colorectal cancer. In addition, every ounce and

a half of red meat a person eats over 18 ounces increases their risks by 15 percent.

March is Colorectal Cancer Awareness Month and National Nutrition Month, and nutritionists at M. D. Anderson Cancer Center are encouraging

people to increase portion sizes of the vegetable, fruit, whole grain and/or bean dishes being served and decrease the portion size of meat.

Focus on Fruit and Vegetable Dishes

Instead of asking what goes well with pork chops, ask what goes well with broccoli and sweet potatoes,said Sally Scroggs, senior health education specialist

in M. D. Anderson’s Cancer Prevention Center. That way, your serving of meat becomes more of a side dish and not the center of the meal.
Red meat contains substances linked to colon cancer,Scroggs said.For example, some studies suggest that the heme iron (the compound that gives red meat its color)

may increase the risk of developing colon cancer.

AICR recommends that two-thirds of a meal consist of plant-based foods. Consuming less red meat and more plant-based foods can significantly decrease

a person’s risks of developing colorectal cancer.

Don’t Eliminate Red Meat

Scroggs emphasizes that these recommendations are not meant to encourage people to completely eliminate red meat from their diet. Consuming red meat in modest amounts is a valuable source of nutrients, including protein, iron, zinc and vitamin B12. Moderation is the key,Scroggs said.

According to the United States Department of Agriculture, Americans were eating an average of 36 ounces of red meat every week in 2006, Scroggs said.

Scroggs recommends serving about three ounces (about the size of a deck of cards) of cooked red meat at meals. If you follow this recommended serving size,

you can include red meat in as many as six meals of your weekly diet.

Avoid Processed Meats

AICR also recommends eating very little processed meat (meat preserved by smoking, curing, salting or adding chemical preservatives), such as ham, bacon,

hot dogs, sausages, pastrami and salami. Every ounce and a half of processed meat eaten a day is thought to increase a person’s risks of developing colorectal cancer by 21 percent.

“A good idea to avoid eating processed meats as much as possible,Scroggs said.”Save that hot dog for special occasions, such as a family cookout or the ballpark.”

Colorectal cancer is the third most common cancer found in men and women in this country. The American Cancer Society estimates almost 150,000 new cases of colorectal cancer in the United States for 2008. Colorectal cancer is the second leading cause of cancer death among Americans but is considered a highly preventable disease.

Source: M. D. Anderson News Release 03/03/08
For most Americans, meals tend to center around meat. To significantly decrease a person’s risks of developing colorectal cancer,

experts at The University of Texas M. D. Anderson Cancer Center suggest a new approach to meal planning that focuses more on fruit and vegetable dishes.

According to recent findings issued by the American Institute for Cancer Research (AICR), consuming more than 18 ounces, or a little over a pound, of

red meat (pork, beef, lamb and goat) each week can significantly increase a person’s risks for developing colorectal cancer. In addition, every ounce and

a half of red meat a person eats over 18 ounces increases their risks by 15 percent.

March is Colorectal Cancer Awareness Month and National Nutrition Month, and nutritionists at M. D. Anderson Cancer Center are encouraging

people to increase portion sizes of the vegetable, fruit, whole grain and/or bean dishes being served and decrease the portion size of meat.

Focus on Fruit and Vegetable Dishes

Instead of asking what goes well with pork chops, ask what goes well with broccoli and sweet potatoes,said Sally Scroggs, senior health education specialist

in M. D. Anderson’s Cancer Prevention Center. That way, your serving of meat becomes more of a side dish and not the center of the meal.
Red meat contains substances linked to colon cancer,Scroggs said.For example, some studies suggest that the heme iron (the compound that gives red meat its color)

may increase the risk of developing colon cancer.

AICR recommends that two-thirds of a meal consist of plant-based foods. Consuming less red meat and more plant-based foods can significantly decrease

a person’s risks of developing colorectal cancer.

Don’t Eliminate Red Meat

Scroggs emphasizes that these recommendations are not meant to encourage people to completely eliminate red meat from their diet. Consuming red meat in modest amounts is a valuable source of nutrients, including protein, iron, zinc and vitamin B12. Moderation is the key,Scroggs said.

According to the United States Department of Agriculture, Americans were eating an average of 36 ounces of red meat every week in 2006, Scroggs said.

Scroggs recommends serving about three ounces (about the size of a deck of cards) of cooked red meat at meals. If you follow this recommended serving size,

you can include red meat in as many as six meals of your weekly diet.

Avoid Processed Meats

AICR also recommends eating very little processed meat (meat preserved by smoking, curing, salting or adding chemical preservatives), such as ham, bacon,

hot dogs, sausages, pastrami and salami. Every ounce and a half of processed meat eaten a day is thought to increase a person’s risks of developing colorectal cancer by 21 percent.

“A good idea to avoid eating processed meats as much as possible,Scroggs said.”Save that hot dog for special occasions, such as a family cookout or the ballpark.”

Colorectal cancer is the third most common cancer found in men and women in this country. The American Cancer Society estimates almost 150,000 new cases of colorectal cancer in the United States for 2008. Colorectal cancer is the second leading cause of cancer death among Americans but is considered a highly preventable disease.

Last Updated: 2008-04-01 11:17:07 -0400 (Reuters Health)

Developing anemia during chemotherapy to treat early-stage breast cancer seems to affect the risk of the cancer coming back. The small study reviewed here found that women who became anemic while getting chemotherapy after early-stage breast cancer surgery were more than twice as likely to have the cancer come back 5 years after surgery compared to women who didn’t develop anemia. Almost 20% of the women with chemotherapy-related anemia had the cancer come back 5 years after surgery compared to only 8.9% of the women who didn’t develop anemia.

Many women in the study were followed for more than 5 years. The researchers found that the women in the study who developed anemia had a risk of the cancer coming back at any time (including longer than 5 years after surgery) that was almost 3 times greater than the women who didn’t develop anemia.

Although the risk of the cancer coming back in the breast was different, the researchers found that the risk of the cancer coming back in another place in the body (metastatic cancer) was the same for women who did and didn’t develop anemia. Also, the risk of dying from breast cancer was the same for women who did and didn’t develop anemia.

Chemotherapy is commonly used after early-stage breast cancer surgery to lower the risk of the cancer coming back. Anemia is a common side effect of chemotherapy, but not all women who get chemotherapy develop anemia. Radiation therapy is also used to lower the risk of the cancer coming back when a woman has lumpectomy instead of mastectomy. In addition to chemotherapy, the women in this study got radiation therapy if they had lumpectomy.

The researchers aren’t sure why the women who developed chemotherapy-related anemia were more likely to have the cancer come back.

Doctors sometimes use medicines to prevent or treat chemotherapy-related anemia. This research didn’t look at whether these medications could lower the risk of the cancer coming back. Even with these medicines, many women will still develop some level of anemia, which could affect their risk of the cancer coming back.

If you’re getting chemotherapy after surgery as part of your treatment plan for early-stage breast cancer, talk to your doctor about anemia and steps you can take to lower both the risk of anemia and the cancer coming back. Visit the breastcancer.org Chemotherapy section to learn more about chemotherapy and its side effects.

ScienceDaily (June 26, 2008) - Complementary medicines can help mild depression and premenstrual syndrome. Not all dietary supplements and “alternative” products are harmless though. German Institute urges consumers to be more critical of health claims.

Many people use “alternative” or complementary products because they see them as a more gentle form of medicine. The German Institute for Quality and Efficiency in Health Care has now analysed the latest research on several products and released the results along with a guide for consumers.

St John’s wort (hypericum), for example, could help ease mild depression, but it does not help with severe depression. It also probably cannot help with the symptoms of premenstrual syndrome (PMS). However, calcium and vitamin B6 (pyridoxine) might help relieve PMS. On the other hand, evening primrose oil has not been proven to help.

Herbal medicines and dietary supplements can also have risks

According to the Institute, conflicting research results in recent years have caused confusion and controversy about St. John’s wort. It concluded this is partly because the effects vary from product to product, and the effect depends too on how severe depression is. The controversy highlights the importance of looking at all clinical trial results to gain a better picture of health care treatments.

“Consumers need to be more critical of all health claims,” according to the Institute’s Director, Professor Peter Sawicki. “This is as true of dietary supplements and complementary medicines as it is of prescription medicine. Just because a product is made from a plant or vitamins, it does not mean it is necessarily safe in very high doses or for frequent use. And not all medicinal products can provide as much relief as patients expect.” The growing evidence that high doses of some vitamins and antioxidants can cause cancer or earlier death is an important reminder that dietary supplements are not necessarily harmless.

All treatments and products should face the same scientific standards for effectiveness and safety

Patients need to consider several questions before choosing any treatment, including a dietary supplement. Professor Sawicki: “Doctors and patients need to know whether treatments have been proven to work in enough good clinical trials that measured benefits large enough to matter to the patient. Whether a medicine is made from a plant or manufactured in a laboratory, the same scientific standards apply if you want to know which treatment might be the best for you.”

To help consumers, the Institute also published a new guide for consumers considering using dietary supplements or complementary medicine products. The fact sheet lists key questions that could help people make decisions for or against a particular treatment.

The fact sheet, along with research results on a range of treatments, is available at  www.informedhealthonline.org.

Adapted from materials provided by Institute for Quality and Efficiency in Health Care

ScienceDaily (June 30, 2008) — Scientists at Wake Forest University Baptist Medical Center are about to embark on a human trial to test whether a new cancer treatment will be as effective at eradicating cancer in humans as it has proven to be in mice.

The treatment will involve transfusing specific white blood cells, called granulocytes, from select donors, into patients with advanced forms of cancer. A similar treatment using white blood cells from cancer-resistant mice has previously been highly successful, curing 100 percent of lab mice afflicted with advanced malignancies.

Zheng Cui, Ph.D., lead researcher and associate professor of pathology, will be announcing the study June 28 at the Understanding Aging conference in Los Angeles.

The study, given the go-ahead by the U.S. Food and Drug Administration, will involve treating human cancer patients with white blood cells from healthy young people whose immune systems produce cells with high levels of cancer-fighting activity.

The basis of the study is the scientists’ discovery, published five years ago, of a cancer-resistant mouse and their subsequent finding that white blood cells from that mouse and its offspring cured advanced cancers in ordinary laboratory mice. They have since identified similar cancer-killing activity in the white blood cells of some healthy humans.

“In mice, we’ve been able to eradicate even highly aggressive forms of malignancy with extremely large tumors,” Cui said. “Hopefully, we will see the same results in humans. Our laboratory studies indicate that this cancer-fighting ability is even stronger in healthy humans.”

The team has tested human cancer-fighting cells from healthy donors against human cervical, prostate and breast cancer cells in the laboratory — with surprisingly good results. The scientists say the anti-tumor response primarily involves granulocytes of the innate immune system, a system known for fighting off infections.

Granulocytes are the most abundant type of white blood cells and can account for as much as 60 percent of total circulating white blood cells in healthy humans. Donors can give granulocytes specifically without losing other components of blood through a process called apheresis that separates granulocytes and returns other blood components back to donors.

In a small study of human volunteers, the scientists found that cancer-killing activity in the granulocytes was highest in people under age 50. They also found that this activity can be lowered by factors such as winter or emotional stress. They said the key to the success for the new therapy is to transfuse sufficient granulocytes from healthy donors while their cancer-killing activities are at their peak level.

For the upcoming study, the researchers are currently recruiting 500 local potential donors who are 50 years old or younger and in good health to have their blood tested. Of those, 100 volunteers with high cancer-killing activity will be asked to donate white blood cells for the study. Cell recipients will include 22 cancer patients who have solid tumors that either didn’t respond originally, or no longer respond, to conventional therapies. The study will cost $100,000 per patient receiving therapy, and for many patients (those living in 22 states, including North Carolina) the costs may be covered by their insurance company. There is no cost to donate blood.

For more information about qualifications for donors and participants, go to http://www.wfubmc.edu/LIFT (Web site will be available the evening of 6/27.) Cancer-killing ability in these cells is highest during the summer, so researchers are hoping to find volunteers who can afford the therapy quickly.

“If the study is effective, it would be another arrow in the quiver of treatments aimed at cancer,” said Mark Willingham, M.D., a co-researcher and professor of pathology. “It is based on 10 years of work since the cancer-resistant mouse was first discovered.”

Volunteers who are selected as donors — based on the observed potential cancer-fighting activity of their white cells — will complete the apheresis, a two- to three-hour process similar to platelet donation, to collect their granulocytes. The cancer patients will then receive the granulocytes through a transfusion — a safe process that has been used for more than 30 years. Normally, the treatment is used for patients who have antibiotic-resistant infectious diseases. The treatment will be given for three to four consecutive days on an outpatient basis. Up to three donors may be necessary to collect enough blood product for one study participant.

“The difference between our study and the traditional white cell therapy is that we’re selecting the healthy donors based on the cancer-killing ability of their white blood cells,” said Cui. The scientists are calling the therapy Leukocyte InFusion Therapy (LIFT).

The goal of the phase II study is to determine whether patients can tolerate a sufficient amount of transfused granulocytes for the treatment. Participants will be monitored on a regular basis, and after three months scientists will evaluate whether the treatment results in clear clinical benefits for the patients. If this phase of the study is successful, scientists will expand the study to determine if the treatment is best suited to certain types of cancer.

Yikong Keung, M.D., a medical oncologist, is the chief clinical investigator of the study. Gregory Pomper, M.D., assistant professor of pathology and the director of the Wake Forest Baptist blood bank, will oversee the blood banking portion of the study.

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ScienceDaily (July 11, 2008) — Medical science may be a significant step closer to climbing into the driver’s seat of an important class of immune cells, researchers at Washington University School of Medicine in St. Louis report in Nature Immunology.

The researchers showed that a single protein, HS1, enables key functions of natural killer (NK) cells, which kill early cancers and fight off viral infections. The protein allows the NK cells to pursue their targets, latch on to them and configure the cellular machinery it uses to kill them.

“Further study of how HS1 controls these processes may open up new possibilities for revving up the NK cells to fight infection and cancer,” says senior author John Cooper, M.D., Ph.D., professor of cell biology and physiology. “We also may be able to use this same protein to inhibit the activities of other immune cells and prevent them from contributing to autoimmune conditions such as diabetes.”

Cooper, who is a member of the Siteman Cancer Center at Washington University and Barnes-Jewish Hospital, studies how different types of cells use a primary component of their skeletal system known as an actin network. Earlier, his laboratory had probed the role of a protein called cortactin in specialized cells that break down bones. They showed that cortactin’s effects on the actin network made it possible for the cells to form a tightly sealed bond with bones.

“This bond is analogous to a plunger,” says first author Boyd Butler, Ph.D., a postdoctoral fellow in Cooper’s laboratory. “The cell sits down on the bone, seals tightly, and then starts secreting the acid and other compounds that break down the bone.”

NK cells have to form a similar plunger-like bond, known as a lytic synapse, with the targets they attack. They do not make cortactin but produce HS1, which is a very similar protein. Butler decided to see what would happen to NK cells in human blood samples if he turned down their ability to make HS1. The resulting cells were severely disabled: They couldn’t effectively pursue target cells, bind to them or prepare to kill them.

Prior research by other scientists had revealed that when NK cells are in motion or attacking a target, HS1 has chemical modifications attached to it at specific points. Giving the NK cells normal HS1 restored their lost functions, but when researchers gave the NK cells HS1 where these attachment points had been altered, the cells were selectively disabled. Changing one attachment point prevented them from pursuing target cells, while changing the other impaired their ability to bind to targets and kill them.

“Tight regulation is very important to prevent NK cells from harming the body’s own tissues,” Boyd says. “This ability to switch where the control signal goes makes HS1 a powerful regulator of NK cell activity–it allows the cells to provide just the right services at the right time.”

Cooper and Boyd plan follow-up studies that will start at the attachment points on HS1 and trace connections with and influences on other proteins.

“NK cells are very good at nipping early cancers in the bud,” says Cooper. “If we can better understand how they’re activated, this could lead us to ways to make them better killers of cancers and cells infected by viruses and other invaders.”

Funding from the National Institutes of Health, the National Institute of Allergy and Infectious Diseases and the Siteman Cancer Center supported this research.

Journal reference:

1. Butler B, Katendieck DH, Cooper JA. Differentially phosphorylated forms of HS1 mediate distinct functions in natural killer cells. Nature Immunology, Online June 29, 2008

Adapted from materials provided by Washington University in St. Louis, via EurekAlert!, a service of AAAS.