I love picking mushrooms, especially funnel chanterelles. They are small, brown and easy to recognize on their yellow, slightly angular stem, which is hollow from the hat down to the root. In addition the gills under the cap extends down the stem. Yet, in recent years I have become more careful when I pick and clean the funnel chanterelles. I do not want include a piece of deadly webcap by pure carelessness.

When I worked on my PhD project on HLA molecules, I also examined my own HLA genes. HLA molecules are essential for the immune system’s T cells to detect viruses and bacteria.

That’s a 25% chance that a sister or brother has inherited the same HLA haplotypes from parents as yourself.

There are a large number of different HLA gene variants and thus many different HLA molecules. But each of us has inherited only a limited number of HLA gene variants, a mere total of 6 -16 different HLA molecules each. The HLA genes are so closely located on chromosome number 6, that they are usually inherited together as a “package”. Thus we inherit one package of about 6-8 HLA genes from our father and the same from our mother. These packages (or haplotypes) are quite stable, so many people have actually inherited the same combination of HLA genes although they are not otherwise related.

It turned out that I had inherited an unprecedented combination of HLA genes. Simply a new haplotype! The entire family was investigated and we discovered that the new haplotype originated from the Norwegian west coast. As a byproduct of this effort, I learned that I have inherited exactly the same HLA genes as my sister.

It is here that the deadly webcap enters the scene. This fungus, which resembles the funnel chanterelle and grows in the same locations, is extremely toxic. Kidney failure is certain 7-10 days after having eaten even a tiny piece. There have been several tragic incidents over the last decade, where families have mistaken funnel chanterelle for deadly webcap and where everyone in the family has got kidney failure after ingestion of the fungus. It is not so many years ago that deadly webcap was first found in Norway. Mushrooms experts believe that this fungus has become increasingly common, and puts this in the context of environmental pollution.

Treatment of kidney failure is kidney transplantation. It is possible to get a new kidney from “anyone”, but it is a great advantage if the donor and the recipient have as many HLA molecules in common as possible. We want to avoid that the immune system consider the new kidney to be a huge collection of bacteria or viruses and sets off to get rid of it as quickly as possible.

If the HLA molecules of the kidney are similar to those of the patient, the T cells will in principle experience the new kidney as similar to the original kidney. In practice, however, kidney transplant patients are always given medication that suppress T cells to avoid that they attack the transplanted kidney.

We all have two kidneys, while one is adequate for good health. Norway is a world leader in the use of kidney transplants from living donors. These donors are usually relatives of the patient, and shares half or all of the HLA molecules with the patient. A sister or brother who have inherited exactly the same HLA genes as the patient, is of course the most ideal organ donor of all.

So every fall, when I wander in the darkest corners of the pine forest around Oslo looking for funnel chanterelles, I think of my HLA-identical sister and that I MUST NOT inadvertly get the deadly webcap in the basket together with the chanterelles. And for safety’s sake, I eat the chanterelles myself, my sister will be served something different when she comes for dinner.

Blogpost by Anne Spurkland, originally posted in Norwegian October 1, 2012
English version posted August 23, 2016