Research

Mammoth Effort: Scientists Turn to Ice Age Species to Develop Artificial Blood for Humans

By Lia Steakley, Social Media Producer, Stanford University School of Medicine

Woolly mammoths, which initially evolved in warm climates where African and Asian elephants now live, migrated to the cold regions of Eurasia in the Pleistocene glacial period. To survive living in the harsh permafrost, the Ice Age icons underwent distinct evolutionary changes such as growing long fur.

In examining the woolly mammoth’s genetic make-up, scientists discovered a blood protein that carries oxygen from the lungs to the rest of the body in the woolly mammoth has mutations in its DNA that make it different from that of its Asian elephant cousins. Scientists believe the mutation helped woolly mammoths survive freezing temperatures and could serve as a blueprint for creating artificial blood products for modern medical procedures that involve reducing patients’ body temperature. According to a Biochemistry release:

[Scientists] didn’t have a woolly mammoth blood sample, so they made the hemoglobin protein in the laboratory by using fragmented DNA sequences from three mammoths that died in Siberia between 25,000 and 43,000 years ago. Compared to hemoglobin from Asian elephants and humans, the woolly mammoth protein was much less sensitive to temperature changes, which means it can still easily unload oxygen to tissues that need it in the cold, whereas the other hemoglobins can’t. This is likely due to at least two of the mutations in the woolly mammoth hemoglobin gene. These insights could lead to the design of new artificial blood products for use in hypothermia induced during heart and brain surgeries.

Click here to be taken to the original post on Scope.

AIDS Screening: Stanford Blood Center’s Pioneering Role

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By Ed Engleman, MD, Founder and Medical Director, Stanford Blood Center

During the early 1980s we decided to apply new research technology to a clinical problem: the prevention of the transmission by transfusion of Acquired Immune Deficiency Syndrome (AIDS). The problem was highly charged with social, political, legal, ethical, and economic overtones complicating the technical and medical issues at hand. In a decision that engendered intense controversy, in 1983 Stanford Blood Center instituted the first blood testing program specifically intended to reduce the risk of transfusion transmission of the then uncharacterized, but presumed infectious cause of AIDS.

AIDS epidemic: The initial response of the government and blood banking organizations
In 1981 the first cases of AIDS were reported in a cluster of homosexual men. In the two years following this report, the disease was diagnosed in many more homosexual men as well as in intravenous (IV) drug users, hemophiliacs, and transfusion recipients. The pattern of cases led the U.S. Public Health Service (PHS) to conclude in March 1983 that AIDS was caused by an infectious agent that was transmissible both sexually and parenterally. Recognizing that some asymptomatic individuals likely harbored the etiologic agent for AIDS, and that this agent was transmissible by blood, the PHS recommended in March 1983 that blood centers request that members of groups at increased risk for AIDS voluntarily refrain from donating blood. AIDS risk groups were defined, at that time, as sexually active homosexual or bisexual men with multiple partners, Haitian entrants to the United States, present or past abusers of IV drugs, patients with hemophilia, and sexual partners of individuals in the above groups. Blood centers around the country implemented the PHS recommendation by providing prospective donors with an information sheet that described AIDS risk groups and requested that donors exclude themselves if they met the definition of risk.

It was predictable, however, that this approach wouldn’t work very well. First, it relied entirely on donor self-deferral. Second, the PHS definition of homosexual AIDS risk behavior was vague, making it possible for a prospective donor with a history of homosexual activity to feel that he personally was not at risk for AIDS and to proceed with blood donation. Nonetheless, in the spring of 1983, a joint statement issued by the American Red Cross (ARC), American Association of Blood Banks (AABB), and the Council of Community Blood Centers estimated the risk of getting AIDS from transfusion as "one in a million". This proclamation, intended to reassure the public, was based on the small number of reported AIDS cases as of that date; it did not take into account the epidemic pattern of spread and the lag between infection and development of clinical illness.

AIDS epidemic: The initial response of Stanford Blood Center
In the years that followed, the number of reported transfusion-transmitted AIDS cases increased geometrically, and it became apparent that the above statement, which was never retracted, underestimated the risk of transfusion by several orders of magnitude. In the spring of 1983 two patients with AIDS were treated at Stanford Hospital. Neither patient belonged to any of the identified AIDS risk groups, but both patients had received transfusions at other institutions in the San Francisco area and likely represented cases of transfusion-transmitted AIDS.

At this point, my colleagues and I at Stanford Blood Center felt that the presence of the presumed etiologic agent for AIDS in the local blood supply could not be ignored. Because of the potential lethality of this infection, we felt that self-deferral should not be relied upon as the sole means of protecting the blood supply.

An unusual aspect of AIDS was that every patient, as well as many high-risk persons without symptoms who went on to develop the disease months to years later, had a selective loss of white blood cells called CD4 T cells. In the year prior to the appearance of AIDS, my research group at Stanford Blood Center had identified these cells as playing a critical role in initiating immune responses. The loss of CD4 T cells in AIDS is what renders patients susceptible to a wide range of infectious diseases. Another population of white blood cells, called CD8 T cells, is generally spared in patients with AIDS until very late in the disease. Thus, the ratio of CD4 to CD8 cells (CD4/CD8) in the blood of AIDS patients and many high risk individuals was reduced from the normal level (approximately 2:1) to less than 1.

Research team develops a surrogate test
Since T cell abnormalities appeared to be a direct consequence of infection with the AIDS agent, we believed that testing for a reduced CD4/CD8 ratio would prove effective as a “surrogate” screening test for blood donors, even though we knew that transient inversions of this ratio could occur under benign conditions not related to AIDS. Because of my long-standing research interest in T cells and their subsets, we had access to a specialized instrument called a flow cytometer on which we could perform CD4/CD8 ratio analyses. Our particular instrument, which was commercially available, could be used for rapid testing of large numbers of samples. The cost of each test, including reagents and technician salary, was approximately $10. To assess the potential utility of this test, we carried out a pilot study on AIDS patients, individuals at high risk for AIDS, and healthy individuals who had no known risk. In this study a CD4/CD8 ratio of less than or equal to 0.85 identified all AIDS cases and the majority of likely AIDS carriers. Based on these results, in July 1983 Stanford Blood Center began screening all blood donations for reduced CD4/CD8 ratio, and blood from donors with a CD4/CD8 ratio less than or equal to 0.85 was destroyed.

In some donors, the abnormality resolved spontaneously, and future donations with normal ratios were transfused. However, the abnormality persisted in donors with a severely reduced ratio. Eight months after initiation of the T cell testing program, we were informed that a blood donor had been diagnosed with AIDS. His only donation to our center had occurred during the first month of the T cell testing program. This donation had been discarded because of a CD4/CD8 ratio of 0.29. This result represented early confirmation that our T cell screening program was successfully removing at least some AIDS-contaminated units. However, multiple units of blood donated by this individual at other blood centers during the preceding 3 years had been transfused.

All blood donations at Stanford were tested for reduced CD4/CD8 ratio between July 1983 and June 1985. A total of 33,831 blood donations were screened and 586 donations, or 1.7%, had CD4/CD8 ratios less than or equal to 0.85 and were discarded.

Serum samples retained from these donors with low CD4/CD8 ratio were tested for HIV antibody when this test became available in 1985, and 1.9% were positive for antibody to HIV.

Thus we estimate that the T cell screening program removed from the blood supply approximately 1.9% of 586, or 11 HIV-infected blood donations. Our blood center typically divides blood donations into three components (red cells, plasma, and platelets), each of which is potentially transfused into a different patient. Therefore, our removal of 11 HIV-infected units protected up to 33 patients from acquiring this disease.

Criticism of our test
Despite the fact that by 1984 cases of transfusion-transmitted AIDS were increasing rapidly, neither the government nor national blood banking organizations recommended testing donor blood for AIDS. Indeed, despite evidence that high-risk individuals were showing up as blood donors, and that our blood test was effective at identifying such individuals, the blood banking organizations actively opposed the use of our test. They thought it was too expensive, that positive tests would reduce the number of eligible donors and cause blood shortages, and that high-risk individuals would present as blood donors simply to obtain a free AIDS test. With regard to our own program, we experienced no blood shortages as a consequence of discarding units from donors with abnormal T cell ratios, nor was there any evidence to suggest that individuals at high risk for AIDS donated blood as a result of our T cell testing program. In fact, the percentage of donors with abnormal CD4/CD8 ratio decreased over the two years of donor T cell testing, presumably due to self-deferral.

Retrospect
After HIV was discovered and a screening test to detect antibody to the virus was developed and mandated for purposes of screening all blood donors in the U.S., the extent of HIV contamination of the blood supply was finally revealed. Contrary to the estimates of "one in a million" risk from the national blood banking organizations, nearly 1 in 700 units of blood donations in metropolitan areas in the U.S. were found to be infected with HIV at the time of licensure of the HIV antibody test in 1985. In San Francisco frequency was closer to 1 in 100. We estimate that the total number of transfusion-related HIV transmissions that occurred from 1983 to1985 was at least 10,000-20,000. It seems evident that most of these cases could have been avoided had our test been used.

Once information about the extent of AIDS in the blood supply became known, the public reacted angrily to what was perceived as a conspiracy to deceive. This anger was heightened when the public also learned about the refusal of other blood banks to use the test we had developed. Thereafter, under considerable pressure from congress, the FDA adopted an aggressive policy requiring all blood banks to rigorously test donated blood for a variety of potentially dangerous infectious agents. As a result, today more than 10 such tests are routinely used and the blood supply is safer than it has ever been. Are we proud of the test we developed and the decision we made to use it at Stanford, despite intense criticism from our blood banking colleagues? You bet!

1. More detailed information on our AIDS testing program can be found in: Galel, SA., Lifson, JD and Engleman, EG. Prevention of AIDS Transmission through screening of the blood supply. Annual Reviews of Immunology 13:201-27, 1995.

2. Although I led the effort to develop and apply our AIDS test, the program would not have been successful without the participation of Jeffrey Lifson, Dennis Sasaki, Claudia Benike and Susan Galel, who were members of my research group at the time, as well as the unwavering support of my faculty colleague, Carl Grumet, and the former Chairman of the Department of Pathology, David Korn.

Some Reflections on the 30th Anniversary of AIDS

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The following piece is by Ruthann Richter, Director of Media Relations at the Stanford School of Medicine. Ruthann is the author of an award-winning book, Face to Face: Children of the AIDS Crisis in Africa which recently won an Eric Hoffer Award.

The June 1981 report could have ended up as just a footnote in history – five gay men in Los Angeles with a rare case of pneumonia. But that CDC report would mark the beginning of an unprecedented epidemic, as these men were suffering from a lethal virus, later characterized and called HIV, which would go on to infect 60 million people worldwide.

As a medical writer, I remember those early days, when this strange disease had no name, and the medical and political world were turned upside down.

One of the many controversies I covered was the decision by the Stanford Blood Center to be the first in the country to test for the virus in donated blood. The move was reviled in the blood banking industry, for it called into question the safety and reliability of the nation’s blood supply. The blood center later would be vindicated, as every other bank would ultimately follow suit and routinely test for HIV. Center Director Ed Engleman, MD, says Stanford’s early initiative saved some 30,000 lives.

In the early 1990s, I went to work at San Francisco General Hospital, the epicenter of the epidemic in this country. SFGH was the site of the first AIDS clinic, known as Ward 86, and I remember spending many hours there, often accompanied by national news crews, visiting patients with rail-thin bodies being drained by the disease. The only anti-AIDS drug available then was AZT, toxic and not very effective. Patients received palliative care, as well as medications to treat their various complications: cancer, eye disease, major skin rashes, fungal infections, diarrheas and so on. It was a grim time.

Then in 1996, at the International AIDS Conference in Vancouver, researchers announced the advent of a three-drug cocktail that could knock down the virus. The landscape in this country would change dramatically, as antiretrovirals would become the mainstay of care, ultimately evolving into a single-pill-a-day treatment for what has become a chronic disease, like heart disease or diabetes. AIDS wasn’t cured, but it could be controlled.

But it would be years before those medications would make it across the ocean to Africa, where two-thirds of the world’s HIV patients – about 22 million people – now live. I would have my first experience in Africa in 2004, and I came away from it feeling absolutely devastated. I have never forgotten the vision of a 34-year-old woman, Susan Andukais, lying on a makeshift wooden bed in her tin shack in Kenya, being nursed by her oldest child, 13-year-old Esther. Esther also had her three brothers to look after; they were all starved for food, comfort and the essentials of life. Susan died for lack of antiretroviral medication – an outrage to me at a time when these drugs were universally available in the West. By my third visit to Africa in 2007, more and more people were receiving medication, as programs sponsored by the U.S. government, private organizations and world bodies like the Global Fund to Fight AIDS, Tuberculosis and Malaria were scaling up. But now, with the world economic crisis, these drug programs are in jeopardy.

So I am both wary and hopeful. I am wary as I know there will be even greater suffering and loss in Africa if there is not continued – and even increased – access to medication and care. At the same time, the science of AIDS has advanced tremendously on so many fronts – from a basic understanding of the immune system to new treatments and new methods of prevention. It was telling indeed that at the last International AIDS Conference in Vienna, researchers even ventured to talk (albeit with many caveats) about the possibility of a cure.

So we can only hope that in the next 30 years, AIDS indeed will be just a footnote in history.

Click here to be taken to the original piece on Scope, the School of Medicine's blog.

Type-2 Diabetes an Autoimmune Disease?

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Guest post by Krista Conger, Science Writer for Communications & Public Affairs at Stanford School of Medicine. Click here to be taken to the original post on Scope, Stanford School of Medicine's blog.

Stanford researchers, led by pathologist Edgar Engleman, MD, reported today in Nature Medicine that type-2 diabetes is looking more and more like an autoimmune disease, rather than a strictly metabolic disorder. According to co-first author Daniel Winer, MD:

This work will change the way people think about obesity, and will likely impact medicine for years to come as physicians begin to switch their focus to immune-modulating treatments for type-2 diabetes.

Winer shares co-first authorship with his twin brother, Shawn Winer, MD, PhD, and research associate Lei Shen, MD, PhD, (pictured above, right, with Engleman, left). Daniel Winer was a post-doctoral fellow in Engleman's lab when the research was conducted; both Winer brothers are now at the University of Toronto.

Type-2 diabetes is characterized by the gradual development of insulin resistance, which affects the ability of the body to properly metabolize glucose. It's associated with being overweight, but it can also have a genetic component. Despite the fact that millions of people have type-2 diabetes, the root cause of the insulin resistance is not known. In 2009, Daniel and Shawn Winer showed (also in Nature Medicine; subscription required) that T cells of the immune system were involved. Now they found that another immune cell, called a B cell, also plays an important role.

From our release:

The researchers found that mice genetically engineered to lack B cells were protected from developing insulin resistance even when they grew obese on the high-fat diet. However, injecting these mice with B cells or purified antibodies from obese, insulin-resistant mice significantly impaired their ability to metabolize glucose and caused their fasting insulin levels to increase.

Interestingly, treating the mice with a compound called anti-CD20, which targets mature B cells for destruction, kept the animals from developing insulin resistance. The human version of anti-CD20, called rituximab, is already FDA-approved to treat some blood cancers and autoimmune disorders.

The topic of diabetes has been covered a few times by experts at our Cafe Scientifique series. Click here to read an article from one such expert, Thea Cooper, co-author of Breakthrough: Elizabeth Hughes, the Discovery of Insulin, and the Making of a Medical Miracle.

Photo by Lorna Tolentino

Lifesaving Research at Stanford Blood Center

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By Erin Crager, Marketing Intern, Stanford Blood Center

The collateral damage associated with chemotherapy and radiation treatment may soon be a thing of the past. Medical students have traditionally been taught that the body’s immune system generally doesn’t turn on itself, even in the presence of a tumor. But Ed Engleman, MD and his research team at Stanford Blood Center have developed a method for training the body’s immune system to do just that for prostate cancer. Their research over the past eighteen years has opened new doors for potentially curing other forms of cancer, as well.

At the moment, the process works by removing white blood cells from the body and training them to fight specific cancerous cells that make up the tumor. Engleman compares it to the way a vaccine works. “What we’re trying to do is to use these cells to educate the immune system to fight the cancer and essentially that’s what you do with a preventative vaccine.” The major difference is this “vaccine” is used for advanced prostate cancer. The difficulty with fighting tumors often has to do with the fact that cancerous cells look identical to cells that make up the tissue from which they derived. Without immunotherapy, as the process is called, the immune system cannot distinguish between these two.

Engleman and his team chose to study prostate cancer for many reasons, but a major deciding factor was that the prostate gland is not essential to live. Before clinical trials were under way, a major concern was the potential for collateral damage in the tissue from which the cancer originated. In the case of prostate cancer this wouldn’t prove to be as detrimental as lung or colon cancer, for example.

The process has proved to be quite accurate, which raises the question of whether other forms of cancer can be cured using the same method. There is still one more hurdle for prostate immunotherapy. Cost. Currently the three-day process of removing cells from the body is laborious and thus quite expensive. Engleman believes that some day it will be possible to train the body’s immune system without isolating the white blood cells. For the time being, the process relies on removal.

Engleman suggested the likelihood that immunotherapy will eventually oust chemo and radiation therapy as the dominant forms of cancer treatment, noting that combining all three could be a much more effective way of treating cancer.

He was quick to point out the importance of the source of research material—the blood donors. “This would not have been possible without the Blood Center. We have the buffy coats from the donors, without which we wouldn’t have been able to figure out how to isolate these cells. And without the cooperation of the nursing staff and the research staff, none of this would have been possible.”

Click here to watch Engleman's talk on this subject at a recent Cafe Scientifique event.