rev:February 3, 1997
Return (Index/Home Page)
Return (IgG Subclass Kits)
Return ( IgG
Subclass Book Table of Contents)
The following book on the IgG Subclass is made available by the permisssion
of CLB Reagents (Netherlands). It is for your personal use and may not be
reproduced without the permission of CLB Reagents. This material is for
information use only and should not be construed as medical advice. We are
not responsible for any misprints or error or ommissions. Certain charts
,graphs and table have been ommitted or changed in style (not content)
to fit this web site. Please use this information as part of your discussion
with your medical professional.
4.3 IgG subclasses and allergy (85,86,87)
Among allergen-specific IgG antibodies in allergic individuals, there is
a preponderance of IgG1 and IgG4, while IgG2 and IgG3 responses are small.
Other findings in allergic patients include the following:
-Elevated IgG4 concentrations often occur in sera of patients with atopic eczema and dermatitis, probably as the result of prolonged antigenic stimulation (88).
-In allergy to many different allergens, allergen-specific IgG antibodies are predominantly of the IgG4 subclass and their levels increase during desensitization therapy. In the antibody response to desensitization/immunotherapy, initially mainly IgG1 is formed, whereas IgG4 becomes more prominent after 1-2 years.
Allergen-specific IgG4 has often been regarded as a two-headed phenomenom:
potentially harmful as well as potentially protective However, when more
is found out about IgG4 antibodies, the harmful effects are hard to substantiate.
The protective effects are still debated, but particularly from the field
of parasitology the evidence is accumulating that IgG4 does, under certain
conditions, effectively interfere with allergen-induced, IgE-medical effector
cell triggering, i.e. IgG4 acts as a blocking antibody. Recent data indicate
a striking similarity with respect to the type of antigen that triggers the
IgG4 and IgE immune responses. Since a marked difference in epitope specificity
exists between the IgG4 and IgE antibodies, only a fraction of the
allergen-specific IgG4 can interfere effectively with IgE binding. The use
of IgG4 antibody assays to monitor immunotherapy is justifiable, but its
value should not be overrated. However, if no IgG4 antibody is induced by
conventional immunotherapy, the therapy is likely to have been ineffective.
An immunotherapy may be considered to be immunologically effective if a
substantial increase (10 to 100 fold) in allergen-specific IgG4 is induced
(89).
Return ( IgG
Subclass Book Table of Contents)
Return (IgG Subclass
Kits)
HOME (index Page)
RDI Divison of Fitzgerald Industries Intl
34 Junction Square Drive
Concord MA 01742-3049
USA
phone (978) 371-6446 or (800) 370-2222
fax (978) 371-2266
EMAIL:antibodies@fitzgerald-fii.com