Immunoglobulin-related amyloidosis (AL amyloidosis)

Plasma cells are antibody-making white blood cells that live in the bone marrow. In this condition a group of identical plasma cells — a clone — makes one piece of an antibody, called a light chain, in a shape that will not fold properly.

The misfolded light chains clump together into insoluble fibres called amyloid, and those deposits build up in organs and stop them working. "AL" stands for amyloid light chain, and "amyloid" is the name of the deposit rather than of a single disease.

The damage is done by what the protein does around the body, not by a tumour crowding out the marrow. The clone itself is usually small — published reviews put it at around 7% to 10% of the plasma cells in the marrow, below the level that defines myeloma.

That is worth being clear about, because the two get confused constantly. This is a distinct diagnosis from multiple myeloma, though the two can occur together. Bone lesions, high tumour burden and "cancer that has spread" all belong to myeloma and not here.

Amyloid deposits can land in the heart, the kidneys, the liver, the gut, the nerves and soft tissue. The Amyloidosis Research Consortium states it can affect any organ except the brain.

A clone of plasma cells produces a light chain whose structure is unstable, so it misfolds and aggregates. The instability comes from changes acquired in the gene for that light chain during a person’s life.

It is not inherited, and it is not caused by anything anyone did. The inherited form of amyloidosis is a different disease with a different cause, as is the form that follows long-running inflammation.

In US claims data covering 2007 to 2015, the number of new diagnoses each year stayed flat while the number of people living with the diagnosis roughly doubled. That reflects people living longer with it and being found more often — not a rise in the disease.

The deposits stiffen and disrupt whatever tissue they land in, and which organs are affected decides almost everything about how the illness goes.

The heart is the most commonly affected organ, and heart involvement dominates how the disease is staged and how it behaves. There is a second mechanism in the heart worth knowing about: the circulating light chains are themselves toxic to heart muscle cells, separately from the physical deposits. That is part of why bringing light chain production down can help the heart before any deposit has cleared.

The symptoms that finally get investigated are ordinary-sounding ones. The NCI lists severe fatigue, purple skin spots, an enlarged tongue, diarrhoea, swelling from fluid build-up, and tingling or numbness in the legs and feet. Breathlessness and swollen ankles are common too.

Most people have more than one organ involved by the time it is diagnosed.

Staging here is built from blood markers of heart strain rather than from how much disease there is. Several staging systems exist side by side and they use different markers, different thresholds and different numbering — a stage in one is not the same group of people as the same-numbered stage in another.

Treatment aims at the plasma cell clone, to stop it making the light chain. It does not clear the amyloid that is already there — organ recovery, where it happens, comes slowly and partially from the damage stopping rather than from the deposits being removed.

First-line treatment is now built around daratumumab, an antibody drug given by injection, combined with three other drugs. The FDA granted it full approval for newly diagnosed AL amyloidosis in November 2025, converting an earlier accelerated approval.

That approval carries limits which belong on this page as much as the approval does. The FDA states the combination is not indicated and not recommended for people with the most severe grades of heart involvement outside of clinical trials, and the prescribing information carries a warning that serious or fatal heart events occurred with it.

For a minority of people, an autologous stem cell transplant is part of treatment — the person’s own stem cells, collected in advance and returned after high-dose chemotherapy.

Who can have one is decided by organ function rather than by how much disease there is. Heart function, blood pressure, kidney function, lung function and how many organs are involved are what the criteria measure. Someone can be turned down for a transplant while having a very small clone, and that is not the same thing as being too unwell in general.

Published reviews estimate that only around 20%, or no more than 20% to 25%, of people with this condition are eligible — mostly because of heart involvement and late diagnosis. Neither review gives a denominator behind that, so we are passing it on as their estimate rather than as a measured figure. Some people who are not eligible at diagnosis become eligible later, once drug treatment has improved their organ function.

Where the transplant sits is genuinely contested and has moved. An early randomised trial that included people with advanced heart involvement did not show a benefit over drug treatment alone. Later groups, selected far more carefully, did much better, and transplant-related death rates at specialist centres have fallen sharply. EBMT’s 2025 recommendations say people without severe heart failure may benefit, and add that newer antibody drugs are likely to reduce how often it is used.

The most common experience before diagnosis is being told it is something else. A median of 2.7 years from first recorded symptom to diagnosis, and in one patient survey nearly a third of people had seen five or more doctors first. If that is your story, it is the documented norm rather than bad luck or a failure to explain yourself.

Diagnosis is invasive and takes more than one step: a tissue biopsy to show the amyloid, then specialist testing to identify which protein it is made of, plus blood and urine tests, heart scans and often a cardiac MRI. Identifying the protein is not a formality — a monoclonal protein in the blood is common in older people and does not on its own prove the amyloid is the AL kind.

Much of what follows is organ support rather than cancer treatment: diuretics and heart failure care, kidney management up to and including dialysis, nutritional support where the gut is involved. Living with this is often about the heart and kidneys week to week.

In the 2015 patient survey, more than half of respondents described treatment as difficult to tolerate. That survey reached people through US patient organisations, so it over-represents people well enough to join one — but it is the largest first-person account available.

For the minority who go to transplant: stem cells are collected from the bloodstream through a machine that separates them out and returns the rest, stored, then given back after high-dose chemotherapy. It is the person’s own cells throughout. It still means weeks of very low blood counts, infection risk, transfusion support and a long recovery.

Because this is a rare disease, clinical trials are a normal part of care rather than a last resort.

A person newly diagnosed with AL amyloidosis does not need a matched bone marrow donor. Nobody is starting a search, and there is no match to find.

The transplant used here, where it is used at all, is autologous — the person’s own cells, collected beforehand and given back. None of the sources we read describes a donor transplant as a treatment for this condition.

We are saying this first and plainly because it is the most common misunderstanding about this diagnosis, and because a charity that recruits donors has an obvious incentive to blur it.

There is a donation these patients genuinely do depend on, and it is not ours. People going through high-dose chemotherapy with an autologous rescue spend weeks with very low blood counts and are commonly transfused. Blood and platelet donors are who that comes from.

One honest connection is worth drawing. The machine that collects a patient’s own stem cells here is the same technology used to collect blood stem cells from an unrelated donor for someone with leukemia. That is a bridge in understanding, not a claim that anyone on this page needs a registry donor.