Læknablaðið - 15.05.1984, Page 4

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LÆKNABLADID
Nýr doktor í Læknisfræði — Ingvar Teitsson
Ingvar Teitsson varði í nóvember sl. doktors-
ritgerð sína við Lundúnaháskóla, St. Mary’s
Hospital Medical School. Ritgerð hans nefnist
Antiglobulins in relation to rheumatic dis-
eases: Development of ELISA assays and
their application in prospective and family sur-
veys. Hér fer á eftir útdráttur úr ritgerðinni:
Enzyme-linked immunosorbent assays (ELI-
SA) were developed for the measurement of
rheumatoid factors (RF) of the IgM, IgA and
IgG isotypes. The assays are based on the
adsorption of rabbit IgG to a solid phase,
followed by incubations of sample dilutions
and enzyme-labelled isotype-specific anti-hu-
man immunoglobulins. Due to interference by
IgM RF it was found essential to pepsin digest
the rabbit anti-human IgA used for the IgA
RF assay. By using a monoclonal mouse anti-
human IgG and an enzyme-linked goat F(ab’)2
anti-mouse IgG, pepsin digestion of samples
to be tested for IgG RF was only marginally
beneficial. The results were expressed as units
with reference to dilutions of an internal
standard. The IgG RF and IgA RF assays are
sensitive and specific but their reproducibility
needs to be improved.
A low percentage of normals was found to
have raised serum IgG antiglobulins which
reacted preferentially with ruminant IgG. This
probibits the use of ruminant IgG as substrate
in tests for autoreactive IgG antiglobulins.
These antiglobulins may represent a deviation
from the normal, acquired immunological
unresponsiveness to bovine milk proteins. The
IgM but not the IgG responses of 29 individu-
als to 14 pneumococcal polysaccharides corre-
lated positively with their anti-ruminant IgG
levels.
In a study of 181 members of an inbred
Icelandic family, a significant aggregation of
rheumatoid arthritis (RA) was found in those
members whose parents both belonged to the
family. These members also had significantly
higher serum IgG and IgM levels than their
relatives. Joint symptoms and IgM RF levels
correlated positively with the age of the
family members while IgA RF levels showed
no such association, perhaps indicating that
different mechanisms may be involved in the
production of these two RF isotypes.
Thirty-three patients with early inflamma-
tory joint disease, 28 of whom developed RA,
were followed prospectively for 2-4 years.
Changes in serum IgA RF levels correlated
significantly with concurrent changes in clini-
cal activity, and those seven who presented
with raised serum IgA RF developed signifi-
cantly more bone erosions than the remaining
cases. By contrast, none of the five patients
who presented with raised IgM RF only,
developed an erosive disease.
These observations are consistent with de-
fective immunoregulation and excessive T
helper effect in RA.