AL Amyloidosis
AL (or primary) amyloidosis is the most commonly diag-
nosed form of the disease, accounting for 85% of all cases
in developed countries. The disorder begins in the bone
marrow, the soft tissue that fills the cavities of our bones,
where red and white blood cells are formed. One kind of
white blood cell, called plasma cells, produces antibodies
that protect us from infections. These antibody proteins (im-
munoglobulins) are made up of light and heavy chain mol-ecules. Normally, our plasma cells produce whole antibod-
ies, and our body breaks down these proteins and recycles
them after a short time. In AL, though, too many unas-
sembled, misfolded light chains are being made. These “free
light chains” (and, in rare cases, free heavy chains) cannot
be broken down efficiently. They bind together to form amy-
loid fibrils that build up in the extracellular space of organs
and tissues. In this way, the body’s normal functioning is
impaired. Problems typically arise in the kidney, heart, liver,
spleen, nerves, intestines, skin, tongue, and blood vessels.