Clinical Biochemistry of Domestic Animals (Sixth Edition) - UMK ...

VII. Interpretation of Serum Protein Profiles
147
(a)
(c)
Albumin
(b)
β γ
α 2
α 2
Albumin
β 2
γ 1
α 1 β 1
γ 2
α 1
Albumin
(d)
γ
γ
FIGURE 5-9 Densitometer trace of
serum protein electrophoresis on agarose
gel from (a) a dog with malignant
lymphoma showing increases
in α-, β -, and γ-globulins, A:G ratio
0.67; (b) a dog with B cell tumor
showing hypoalbuminemia, a spike in
α 2 -globulins, increased β-globulins,
and a polyclonal immunoglobulinemia,
A:G ratio 0.15; (c) a cat with
feline infectious peritonitis showing
increased α 2 -globulins and a polyclonal
gammopathy, A:G ratio 0.36;
(d) a cat with hypoalbuminemia and
an IgG monoclonal gammopathy A:
G ratio 0.20.
α 2
β
Albumin
α 1
α 1
α 2 β
and only occasionally the sharp monoclonal spikes of
multiple myeloma, Waldenstrom’s macroglobulinemia, or
lymphoma are seen ( Macewen et al. , 1977 ). Waldenström’stype
macroglobulinemia with hyperviscosity and IgM
monoclonal spikes have been reported in dogs ( Hurvitz
et al. , 1971 ; Macewen et al. , 1977 ).
In the horse, increased levels of β -globulins have been
observed on SPE of serum from animals infected with the
intestinal parasites Strongylus vulgaris and Strongyloides
westeri . The peak can appear as a monoclonal gammopathy
in which an equine-specific immunoglobulin, IgG(T),
is produced ( Mair et al. , 1993 ). This immunoglobulin may
also migrate in SPE with an α 2 mobility ( Kent and Roberts,
1990 ).
iii . β - γ Bridging The phenomenon of β-γ bridging
suggests chronic active hepatitis. In this case, there is no
clear separation between the β 2 and γ 1 -fraction, which
results from an increase of IgA, IgM, or both. Rarely a lowgrade
gammopathy of lymphoma may result in a β-γ bridge.
iv . Increased γ -Globulin (Broad Increase): Polyclonal
Gammopathy The diffuse or broad increases in the γ -
globulins that characterize polyclonal gammopathies are a
result of the heterogeneity of the clones of B lymphocytes
and plasma cells, which produce a heterogeneous mix of
immunoglobulins. Any one or all of the immunoglobulins
IgM, IgG, or IgA can be present, but a preponderance of
one is usually observed.
The chronic inflammatory disease profile may be manifested
by a variety of disease states such as malignancies in
general ( Fig. 5-9b ), chronic infections ( Fig. 5-9c ), and collagen
diseases. There is a concomitant decrease in albumin
as a result of decreased synthesis ( Fig. 5-9b ).
Chronic hepatitis, hepatic abscesses, and suppurative disease
processes also exhibit changes characteristic of chronic
disease ( Rumbaugh et al. , 1978 ). In these cases, the polyclonal
increase is more marked and the hypoalbuminemia
more severe than in other chronic inflammatory diseases.
This phenomenon may reflect the severity of the disease
process and the more intense antigenic response generated.
Immunologically mediated disease processes are also
characterized by polyclonal increases. These may be
immune processes directed against “ self, ” that is, autoimmune
disease, or against external antigenic stimuli. In
either case, a multiple immunological response is elicited,
one or more organs may be affected, and polyclonal
increases are observed on the electrophoretogram. Immune
complexes trapped in the glomeruli and reacting with antigens
are thought to be involved in the glomerulonephritis
often seen with heartworms, pyometra, and systemic lupus
erythematosus (SLE). SLE is a multifaceted disease in the
dog often found in association with autoimmune hemolytic
anemia, thrombocytopenia, glomerulonephritis, and polyarthritis.
The basic abnormality in SLE is the LE factor, an
antinuclear antibody , and the widespread dissemination of
nuclear–antinuclear complexes throughout highly vascular
structures.