This document discusses abnormal antibodies. It begins by defining antibodies and how they function by binding to antigens to signal immune cells to remove invading microbes. It then discusses several types of abnormal antibodies seen in pathological processes, including Bence Jones proteins found in the urine of multiple myeloma patients, heavy chain disease involving overproduction of immunoglobulin heavy chains, and cryoglobulinemia involving abnormal proteins that precipitate from blood serum when chilled.

1. Abnormal Antibodies
Shrishti Mund
II MBBS

2. What is an Antibody?
• Antibody, also called immunoglobulin, a protective protein produced by
the immune system in response to the presence of a foreign substance, called
an antigen.
• Antibodies recognise and latch onto antigens in order to remove them from the body.

4. How do they function?
• The antibody binds to specific antigens. This signals the other cells of the immune
system to get rid of the invading microbes.
• The strength of binding between the antibody and an antigen at a single binding
site is known as the antibody’s affinity for the antigen. The affinity between the
antibody and the antigen binding site is determined by the type of bond formed.
• Since an antigen can have multiple different epitopes, a number of antibodies can
bind to the protein. When two or more antigen binding sites are identical, an
antibody can form a stronger bond with the antigen.

6. • Immunoglobulins are basically proteins that function as
antibodies.
• The terms antibody and immunoglobulin are often used
interchangeably.

7. Abnormal Antibodies
• Apart from antibodies, other structurally similar proteins
(abnormal antibodies) are seen in many pathological
processes.
• The earliest description of an abnormal immunoglobulin
was the discovery by Bence Jones (1847) of protein
named after him.

8. • The Bence Jones protein, when found in urine, is
suggestive of multiple myeloma.
• It can be identified in the urine by its characteristic
property of coagulation when heated to 50 C but
resolving at 70 C.
• These proteins are light chains of immunoglobulins and
so may occur as the kappa or lambda form (either one,
not both).

9. • Multiple myeloma is a plasma cell dyscrasia in which
there is unchecked proliferation of monoclonal plasma
cells.
• This results in excessive production of the particular
immunoglobulin produced by the clone.

10. • Heavy chain disease is a form of paraproteinemia and plasma cell
dyscrasia that involves the proliferation of cells producing immunoglobulin
heavy chains.
• It is characterised by overproduction of the Fc parts of immunoglobulin heavy
chain.
• Three types of heavy chain disease (HCD) have been identified based on the
class of immunoglobulin heavy chain produced (alpha, gamma, mu) by the
malignant cells.

11. • Cryoglobulinemia: The presence in blood of abnormal proteins called
cryoglobulins that have the unusual property of precipitating from the blood serum
when it is chilled and redissolving upon rewarming. Cryoglobulins can increase the
risk of blood clots forming in the brain (stroke), eyes, and heart.
• Cryoglobulins can also cause inflammation of blood vessels (vasculitis), which
increases the risk of artery blockage. Cryoglobulinemia can also accompany
another disease, such as multiple myeloma, dermatomyositis, or lymphoma.
Sometimes, small amounts of cryoglobulins are detected in blood samples from
people who have no apparent symptoms.

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