myeloma and paraproteins Flashcards
what are antibodies
where are they produced
immunoglobulins
produced by B cells (mostly plasma cells)
can be either soluble or membrane bound
1y role of antibodies and how they do this
recognise and bind pathogens
this may directly impede the biological process of direct other components of the immune system by ‘tagging’ the antigen
immunoglobulin structure
Y shaped structure
2 heavy chains
2 light chains
variable domain - fragment antigen binding (FAB)
everything else is constant - Fc portion (defined by the heavy chains)
what does the Fc portion of the antibody define
defines the role/subclass of the antibody
what are the 5 types of heavy chains
gamma - IgG alpha - IgA Mu - IgM delta - IgD epsilon - IgE
IgM - role
initial phase of antibody production
exists as a pentamer (5 molecules circulate together) - highest molecular weight
how prevalent is IgG
most prevalent antibody subclass - 75% of total
followed by IgA then IgM
what is IgA for
mucous membrane immunity - tends to be in the gut
what is IgE for
parasite immune responses
hypersensitivity
what are the 2 types of light chains
kappa of lambda
- random selection for each cell
- each cell will only make 1 type of light chain w/ 1 specificity
free light chains are also found in the blood at low levels - difficult to measure
what is a paraprotein
monoclonal immunoglobulin present in blood or urine
what do paraproteins indicate
if present, it tells us that there is monoclonal proliferation of a B lymphocyte/plasma cell somewhere in the body
how do we detect paraproteins
separates protein based on size and charge
forms a characteristic pattern of bands of different widths and intensities base on proteins present
tells us whether there are any abnormal levels
what does total immunoglobulin levels tell us
measures Ig subclasses by heavy chain/Fc section
what does electrophoresis tell us
assesses antibody diversity, identifies paraprotein
what does immunofixation tell us
identifies what class of paraprotein is present e.g. IgG, IgM
what does levels of light chains tell us
assesses imbalance/XS of light chains in urine/serum
you should have approximately equal levels of light chains
when does immunoglobulin gene rearrangement occur
process of antibody production
initial IgM production
cells mature
IgA and IgG production
what do IgM paraproteins indicate
lymphoma
maturing B lymphocytes make IgM antibody at the start of the immune response
what do IgG and IgA paraproteins indicate
myeloma
mature plasma cells generate these types of immunoglobulin after isotype switching
what is myeloma
neoplastic disorder of plasma cells, resulting in XS production of a single type of immunoglobulin (paraprotein)
who gets myeloma
peaks in 7th decade
ethnicity - commoner in Black population than White
why do clinical manifestations occur in myeloma
may result from direct effect of plasma cells, or effect of paraprotein
