Tag Archives: Immune system

it’s all about the immune system

Researchers in Western Australia are investigating new ways of bolstering the immune system in an effort to fight cancers like mesothelioma.

Like most types of cancer, malignant mesothelioma occurs primarily in people over 65. That is also the time in life when the immune system typically weakens. Researchers from Curtin University and the University of Western Australia say it is no coincidence that people become more susceptible to mesothelioma as their immunity wanes. In addition to age-related immune dysfunction, mesothelioma patients experience a further decline in immunity caused by the growing tumor itself.

To better understand the connection between declining immunity and the onset of mesothelioma, the researchers are focusing on a particular type of immune system cell called a macrophage. Macrophages are white blood cells that help to remove debris and pathogens from the body while stimulating an immunity response in other immune system cells.

“Macrophages make up to 50 percent of the mesothelioma and lung cancer tumor burden,” observed Curtin University’s Dr. Connie Jackaman in a recent online article at Science Network. Jackaman says this could make macrophages “a viable therapeutic target if we can understand how they function with age and tumor suppression.”

When the research teams exposed both young and old mice to fluid produced by mesothelioma and lung cancer tumors, the old mice showed a “more immunosuppressive tumor microenvironment.”  When older mice were treated with a type of immunotherapy (IL-2 anti-CD40 antibody), macrophages in the old mice were reactivated, restoring the production of tumor-fighting T-cells. This result suggests that, if macrophages could be appropriately activated in human mesothelioma patients, it could theoretically “rescue both age-related and tumor-induced immune dysfunction.”

The researchers say their next step will be to see if they can cause tumors such as mesothelioma to shrink in live patients by targeting their macrophages.

new mesothelioma immunotherapy drug entering phase 2 trials in USA

The makers of a new cancer vaccine say they have enrolled the first mesothelioma patients in a study that will combine their drug with chemotherapy against this virulent cancer.

The drug, currently known as CRS-207, CRS-207 is based on an attenuated (made less potent) version of Listeria monocytogenes,  modified  in order to produce a powerful immune response against cells that produce mesothelin. Mesothelin is a tumor-associated antigen produced by several types of cancer cells, including mesothelioma cells. Because it works in conjunction with the body’s natural immune responses, the CRS-207 vaccine is classified as a type of immunotherapy.

CRS-207 has already been evaluated in a Phase 1 trial of 17 patients with mesothelioma and several other end-stage cancers. Although most ‘end stage’ cancer patients have just a few months to live, six of the 17 patients treated with CRS-207 lived 15 months or longer. Based on those promising results, two new Phase 2 clinical trials of CRS-207 have been launched – one for patients with metastatic pancreatic cancer and one for patients with malignant pleural mesothelioma.

The CRS-207 trial of mesothelioma is being conducted at the National Cancer Institute in Bethesda, Maryland under the direction of noted mesothelioma researcher Dr. Raffit Hassan and at the H. Lee Moffitt Cancer Center in Tampa, Florida where Dr. Scott Antonia is the lead researcher.

In the new Phase 2 mesothelioma trial, newly-diagnosed mesothelioma patients will start their therapy by receiving two prime vaccinations with CRS-207. They will then receive the standard mesothelioma chemotherapy regimen of cisplatin with pemetrexed.  When their chemotherapy round concludes, these mesothelioma patients will receive at least 2 additional ‘booster’ shots of CRS-207. The aim of Phase 2 drug trials is to study a drug’s safety and efficacy profile and to determine the best dosing strategy. The CRS-207 trial is currently recruiting newly-diagnosed mesothelioma patients and is set to conclude in December 2013.

Immunotherapy for Mesothelioma Shows Promise

A growing number of studies have pointed to the value of unconventional treatments like immunotherapy for mesothelioma.Immunotherapy refers to any treatment protocol which aims to harness the body’s own immune system to fight cancer cells.  In a recent article in The Lancet Oncology, two National Cancer Institute researchers summarized some of the most promising immunotherapy approaches now being investigated for mesothelioma:

In dendritic cell-based immunotherapy, dendritic cells are harvested from the patient. Outside the body, these cells are stimulated to activate a cytotoxic response against cancer cells.  When they are returned to the body – usually by attaching them to an inactivated virus – the dendritic cells stimulate an immune response against tumor cells (such as mesothelioma) that produce a particular kind of antigen.  The cancer vaccine Provenge is an example of dendritic cell-based immunotherapy.

Listera-based cancer vaccines use a live bacterium (Listeria) to carry tumor-specific antigens into cells. The Listeria virus produces certain chemicals that allow it to escape detection in the body until it is inside the target cells, making in a good vector for delivering anti-cancer antigens.

Other vaccines being tested against mesothelioma include allogeneic tumor cell vaccines, which use specially treated cells removed from the mesothelioma tumor itself and returned to the patient and WT1 analogue peptide vaccines. WT1 analogue peptide vaccines seek out certain chemicals that are overexpressed in cancer cells and have been shown to induce T cell immune responses in patients with mesothelioma and non-small cell lung cancer.

As always it is promising to see this research is underway- just need to hang on in there long enough.

ongoing immunotherapy research for mesothelioma

Immunotherapy involves manipulating the immune system to fight disease. Some types of cancer, including mesothelioma, take hold in the body in part by ‘shutting down’ the natural immunotoxins, or cell killers, that would normally attack them. Now, scientists are working with a number of molecules designed to jump start the immune system and help it recognize, target, and even ‘remember’ invading mesothelioma cancer cells.

Using a mouse model of mesothelioma, Harvard researchers investigated the roles of three factors effecting immunity: regulatory T-cells, intratumoural transforming growth factor (TGF)-â and cytotoxic T lymphocyte-associated antigen-4 (CTLA4). The researchers then treated the mesothelioma with a combination of monoclonal antibodies and a TGF-â soluble receptor, specifically designed to target these three immune system factors.

With this ‘triple treatment’, the team reports, not only did the tumors clear up long term, but the cancer-killing immune cells appeared to retain a memory of the mesothelioma tumor cells that would prepare them to ward off future invasion. The report goes on to suggest that clinical application of immunotherapies against mesothelioma “may be improved by simultaneously targeting multiple mechanisms of immune suppression”.

Another recent study of the regulatory T-cells, for example, suggests that their manipulation may be a way to improve the effectiveness of chemotherapy for mesothelioma.

I think there are already TGF trials underway in this country, so progress is being made. It does look as though this line of treatment is where there is currently greatest focus so lets hope results come through sooner rather than later.

astragalus and the immune system

Astragalus membranaceus

Image via Wikipedia

There’s lot of info on the web about different therapies that can help in cancer treatment, not too sure about a lot of them , some claims have a whiff of snake oil about them, with very little evidence.

Did come across astragalus the other day,not too sure about some of the wider claims but did think there might be something in the evidence on supporting the immune system, albeit the evidence seems to be based on animal rather than human subjects.

Given the blood count didn’t recover too well last time, have decided to give this as go for the next two weeks and we’ll see how we get on.

Astragalus

Keywords: bei qi, huang qi, ogi, hwanggi, milk vetch, heart function, immune system

© Steven Foster

Introduction
This fact sheet provides basic information about the herb astragalus—common names, uses, potential side effects, and resources for more information. Native to China, astragalus has been used for centuries in traditional Chinese medicine. In the United States, the herb gained popularity in the 1980s. There are actually over 2,000 species of astragalus; however, the two related species Astragalus membranaceus and Astragalus mongholicus are the ones primarily used for health purposes.

Common Name—astragalus, bei qi, huang qi, ogi, hwanggi, milk vetch

Latin Names—Astragalus membranaceus, Astragalus mongholicus

What Astragalus Is Used For
Historically, astragalus has been used in traditional Chinese medicine, usually in combination with other herbs, to support and enhance the immune system. It is still widely used in China for chronic hepatitis and as an adjunctive therapy in cancer.
It is also used to prevent and treat common colds and upper respiratory infections.
Astragalus has also been used for heart disease.
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How Astragalus Is Used
The root of the astragalus plant is typically used in soups, teas, extracts, or capsules. Astragalus is generally used with other herbs, such as ginseng, angelica, and licorice.

What the Science Says
The evidence for using astragalus for any health condition is limited. High-quality clinical trials (studies in people) are generally lacking. There is some preliminary evidence to suggest that astragalus, either alone or in combination with other herbs, may have potential benefits for the immune system, heart, and liver, and as an adjunctive therapy for cancer.
NCCAM-funded investigators are studying the effects of astragalus on the body, particularly on the immune system.

Side Effects and Cautions
Astragalus is considered safe for most adults. Its possible side effects are not well known because astragalus is generally used in combination with other herbs.
Astragalus may interact with medications that suppress the immune system, such as the drug cyclophosphamide taken by cancer patients and similar drugs taken by organ transplant recipients. It may also affect blood sugar levels and blood pressure.
People should be aware that some astragalus species, usually not found in dietary supplements used by humans, can be toxic. For example, several species that grow in the United States contain the neurotoxin swainsonine and have caused “locoweed” poisoning in animals. Other species contain potentially toxic levels of selenium.

Tell all your health care providers about any complementary and alternative practices you use. Give them a full picture of what you do to manage your health. This will help ensure coordinated and safe care. For tips about talking with your health care providers about CAM, see NCCAM’s Time to Talk campaign.