Organs ‘too risky’ to donate may be safer than we think. We crunched the numbers and here’s what we found

Accepting a donor kidney with a small risk of carrying HIV or hepatitis B or C might be worth thinking about.

Karen Waller, University of Sydney and Angela Webster, University of Sydney

Organs from potential donors once rejected as being unsafe to transplant may not be as risky as once thought, new Australian research shows.

Our study, published in the Medical Journal of Australia, suggests organs from injecting drug users or men who have sex with men, for instance, could safely open up the pool of available organs. That’s so long as donors test negative for blood-borne infections, such as HIV, and hepatitis B and C.

Currently, organs from this and other groups considered high risk are often rejected outright, for fear of transmitting hidden infections to the recipient.

If transplant criteria were based on viral status rather than belonging to a particular group, we estimate this could mean up to 30 more people could receive a transplant a year in NSW alone.

Read more:
Why are only some viruses transmissible by blood and how are they actually spread?

Which high-risk groups are usually rejected as donors?

Many infections can potentially be transmitted as a result of an organ transplant. But this happens very rarely due to strict governance, involving careful screening and selection of donors.

Blood-borne viruses, such as hepatitis B, hepatitis C or HIV, are a particular concern, because historically these had the most potential to have devastating consequences for the organ recipient.

Some potential organ donors have behaviours that put them at increased risk of infection. National and international guidelines perceive high-risk groups for these viruses to include:

  • people who inject illicit drugs

  • men who have sex with men

  • sex workers

  • people who have recently been in jail

  • sexual partners of any of these groups, or of people with a blood-borne virus.

People from these groups are often declined as organ donors, even when tests for blood-borne viruses are negative, and sometimes without even being tested.

That’s because of the worry about the risk of the donor being recently infected but that infection not yet showing up in blood tests. This is know as the “window period”. If a window-period infection occurred, people could unwittingly transmit the virus.

When we used Australian data, here’s what we found

So how big a risk are we talking about?

Until recently, Australian guidelines have relied on US estimates of risk, although there are important differences in the prevalence of blood borne viruses in the US and elsewhere compared with Australia.

We believed the risk of window-period infection in Australia was likely to be lower, possibly much lower, than was appreciated. So, we were concerned some potential donors might be turned away who could actually have donated safely.

So, we identified data from sources including journal articles, government reports and conference abstracts between Jan 1, 2000 and Feb 14, 2019 to see how common blood-borne viruses were in people with high-risk behaviours in Australia.

Read more:
Charlie Sheen and ten million dollars worth of HIV stigma

We found, as expected, men who have sex with men have the highest risk of HIV in Australia. But for each person who tests negative for HIV, the risk of transmitting the virus was around one in 6,500. This is lower than the US estimate, which sits at one in 2,500. The difference was more pronounced for injecting drug users in Australia, where one in 50,000 would have a window period infection, compared to one in 2,000 in the US.

The window period risk was higher for hepatitis C. Among the riskiest groups, this was around one in 500, similar to overseas studies. There were no studies overseas to compare to for hepatitis B. We found the risk of a window period infection was at most one in 200 from the riskiest group (although we may being cautious and over-estimating this risk).

Read more:
Explainer: the A, B, C, D and E of hepatitis

What does this mean?

First, we suggest all potential organ donors with high-risk behaviours be assessed with the test that gives the shortest window period, to minimise the chance of missing a recent infection.

All potential donors with an increased risk of infection should have blood tests, then their risk of transmission assessed.

This means testing for the presence of the virus itself (via DNA or RNA testing) rather than relying on tests that look for markers of infection (serological testing).

For potential donors who test negative, our data can be used to help clinicians put the small risks of infection transmission in context for organ recipients.

What’s the alternative?

For most people, an organ transplant is the best treatment for organ failure and can be life-saving.

For people with kidney failure, the alternative is dialysis. But this gives shorter survival, poorer quality of life, and incurs higher costs to the health system than treatment with a kidney transplant. For the heart, liver and lungs, there are no other long-term options; without a transplant, people whose organs fail will eventually die.

But there are not enough organ donors to go round. Around 1,500 Australians are waiting for a transplant.

Even so, the option of receiving a donor organ with even a very small risk of transmitting infection may not seem immediately appealing. But this needs to be balanced against the considerable health consequences of foregoing a transplant and remaining on the waiting list.

For most people, an organ transplant is the best treatment for organ failure and can be life-saving.

In 2018 in Australia there were 554 deceased donors who donated organs to 1,543 transplant recipients. Over the same period, 39 people died while waiting for a transplant, and a further 236 were removed from the waiting list due to ill health.

Even with our newly calculated low risk of transmission, there are ways of minimising the risks further, or with new treatments, curing the viral infections if they are transmitted.

For instance, with HIV, medications could be provided to recipients, to further reduce the risk of transmission. If the recipient develops hepatitis C, there are now drugs that can cure it completely. And, for hepatitis B, many people are now vaccinated, which prevents transmission.

Read more:
Three ethical ways to increase organ donation in Australia

What’s happening internationally?

Donors at increased risk of blood-borne viruses are used internationally.

In the US, over 25% of organ donors now fit these criteria, mainly due to the opioid epidemic and associated increased deaths from overdose.

This strategy has led to an increase in hepatitis C transmissions from donors to recipients. But hepatitis C can be cured with an eight-week course of treatment, even among transplant recipients.

Researchers have also shown an increase in survival for patients who accepted kidneys from people at increased risk of viral infection compared to those who opted to remain on the waiting list.

Does this mean more people could have transplants?

So could our work make a tangible impact on the number of Australians receiving transplants?

Our preliminary work suggests there could have been up to a 5% increase in donors in NSW alone between 2010-2015, if we had accepted donors with risk behaviours but negative test results. There could have been five more donors a year, who can each donate to up to six recipients (so up to 30 additional recipients a year).

Our early results on the risk of infection were recently incorporated into national guidelines produced by the Transplantation Society of Australia and New Zealand for organ transplantation.

In Victoria, people waiting for a kidney transplant can now consent to receiving organs with these risks when they are put on the waiting list.

We hope our research sparks discussion among patients and doctors to consider what risks are important to patients, and where their values and preferences lie. Better evidence for decision-making should certainly help.The Conversation

Karen Waller, PhD candidate, University of Sydney and Angela Webster, Professor of Clinical Epidemiology, University of Sydney

This article is republished from The Conversation under a Creative Commons license. Read the original article.

The skin is a very important (and our largest) organ: what does it do?

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It doesn’t just hold everything in.
Unsplash/Lucaxx Freire

Cara McDonald, St Vincent’s Hospital Melbourne

This article is part of our series about skin: why we have it, what it does, and what can go wrong.

Our skin is a big deal – literally. It’s the largest organ in the body and one of the most complicated. It has many roles in the maintenance of life and health, but also has many potential problems, with more than 3,000 possible skin disorders.

Not only does the skin hold everything in, it also plays a crucial role in providing an airtight, watertight and flexible barrier between the outside world and the highly regulated systems within the body. It also helps with temperature regulation, immune defence, vitamin production, and sensation.

The skin is unique in many ways, but no other organ demands so much attention and concern in both states of disease and health. There is a huge focus on skin health, with fierce competition to have glowing, clearer, healthier, younger and fresher skin. And this focus can cause secondary problems with self-esteem and mental health.

So, what exactly is our skin meant to do and how does it impact our life?

The structure of the skin

The skin is divided into three layers known as the epidermis, dermis and subcutis. These layers are well defined but together they allow the skin to function effectively.

The epidermis is the outermost, cellular layer of the skin which varies in thickness depending on the body site. On average it’s less than half a millimetre thick. The epidermis resembles a “brick wall” of cells known as keratinocytes, which are bound tightly together and act to prevent free movement of moisture, pathogens and chemicals into or out of the body.

Keratinocytes replicate from the basal layer and work their way up to the outer surface (known as the stratum corneum) over a period of about 28 days. Once they reach the surface the tight bonds between them break apart and they are shed.

Other than keratinocytes, pigment-producing cells known as melanocytes and immune cells known as Langerhans cells also exist within the epidermis. Melanocytes inhabit the basement membrane, at the base of the epidermis and produce a pigment known as melanin both innately (giving the skin its natural colour), and in response to ultraviolet light (UV) exposure (giving the skin a sun tan).

The melanin is a brown pigment that is taken up into the overlying keratinocytes. This pigment will then absorb UV light (from the sun) when it hits the skin, thereby protecting the basal calls underneath from UV damage.

The epidermal cells also develop hair follicles, sweat glands and sebaceous (oil) glands which extend down into the layer below known as the dermis. The small ducts from each of these glands open onto the skin surface. Sweat and sebum (oil) provide an antibacterial and protective barrier on the skin.

The dermis lies beneath the epidermis and is 20-30 times thicker. It’s made up of a dense layer of fibrous (collagen) and elastic (elastin) tissue. The dermis gives the skin its integrity, strength and elasticity; and houses blood vessels, glands and hair follicles, as well as nerves and their receptors.

Beneath the dermis lies the subcutis (also known as the hypodermis), a specialised layer of adipose (fat) and fibrous tissue. The thickness of this layer varies dramatically depending on the site and a person’s body shape and weight. It cushions the body from external trauma, insulates from the cold and stores energy (fat).

We pay more attention to the health of our skin than perhaps any other organ.
Unsplash/Isabelle Winter

The function of the skin

The extraordinary array of functions performed by healthy skin is still coming to light. The basic day-to-day functions include:

  • Working as a barrier – protecting against water loss as well as physical and chemical injury, and bugs

  • Helping us fight off bugs, allergens, toxins and carcinogens via the parts of our immune system that exist in our skin

  • Regulating our temperature by dilating and constricting our blood vessels near the skin surface, controlling the transfer of heat out of the body. Temperature is also regulated by evaporative cooling due to sweat production and by the insulating effect of erect hairs on the skin surface. Heat loss is also affected by the insulating layer of subcutaneous fat

  • Protecting us from UV radiation by producing melanin

  • Giving us the sense of touch _ providing interaction with physical surroundings, allowing all fine and gross motor activities and allowing pleasurable and sexual stimulation

  • The production of Vitamin D, which helps prevent many diseases including osteoporosis, cancer, heart disease, obesity and neurological diseases

  • Wound healing

  • Beauty and physical attraction – the quality and condition of the skin greatly contributes to the perception of health, wellness, youth and beauty.

What is normal skin and how can you optimise it?

Normal healthy skin has many important roles and thus should be treated with care and respect. Many people only start focusing on the skin once there is an abnormality or at least a perceived problem.

Common concerns include dryness, sensitivity, oiliness, congestion, wrinkles, sun damage and signs of ageing. Although these states are all within the spectrum of normal functional skin, they may be considered problematic if severe or undesirable.

You only get one skin. Don’t do this to it.
Unsplash/Maciej Serafinowicz

Normal, healthy skin that is not exposed to excessive physical or environmental insults may not require any specific care or protection, but for those who want to optimise or improve their skin, some basic steps can make a big difference.

The key to skin care is consistency and routine, and it can take time to appreciate the changes. A basic regime of daily protection from excessive UV radiation, protection from excessive irritation and drying (by avoiding drying soaps, excess water or irritating chemicals) and aiding of the skin’s barrier properties (using a moisturising protective layer) will result in noticeable improvement in almost all skin.

The ConversationSwitching and changing products and routines is usually counterproductive and will prevent you from seeing expected improvement in time. It’s worth looking after your skin, as you’ll wear it every day for the rest of your life.

Cara McDonald, Consultant Dermatologist, St Vincent’s Hospital Melbourne

This article was originally published on The Conversation. Read the original article.