Læknablaðið : fylgirit - 01.05.1978, Page 130

IgG-RF after DTT treatment. Among the seropos.
were 19 women and 17 men, mean age 51 years
(20 - 72) and mean duration of disease 8.7 years
(1 - 40). Among the seroneg. were 21 women
2 men, mean age 47.7 years (24 - 70) and mean
duration of disease 7.6 years (1 - 25). IgG-RF
was seen in sera from 44% of the seropos. and
44.57o of the seroneg. patients, and only 3.7% of
the controls. The titer of IgG-RF varied between'
1:9 to 1:72. As well as the titer - 1:9 as >1:9
a statistically significant difference between the
arthritis group and the controlgroup was seen
(p < 0.01, 3C2 test). No difference between the
seropos. and seronegative arthritis group was
seen. 55 of the total 59 RA patients had clinical
activity in their disease. No correllation between
presence of IgG-RF and the sedimentation reaction
(SR), ANA (organspecific as well as organ non-
specific) or elevated gammaglobulin in the serum
was found. Mean duration of the disease was 10
and 9.1 years in the seropos. resp. the seroneg.
which had IgG-RF. In the patients without presence
of IgG-RF the mean duration of disease was 8.5
and 5.8 years in the seropos. and the seroneg.
groups respectively.
Acknowledgements:
This work has been supported by the Danish
Association Against Rheumatism, Copenhagen.
Sum m ary:
An indirect immunofluorescence method was
used for the detection of IgM- and IgG- Rheuma-
toid Factors, (IgMRF and IgGRF) in heat inacti-
vated sera. Regarding IgMRF, positive reactions
were found in sera from 29/30 seropositive and
3/24 seronegative rheumatoid patients and from
1/20 blood donors. Correlation was found between
positive staining and the Waaler-Rose reaction
and the RA-Latex reaction. Now again sera from
seropositive and seronegative rheumatoid patients
and healthy blood donors were inactivated and
before immunofluorescent testing treated with a
solution of dithiothreitol (DTT) in phosphate buffered
saline (0,154 g/100 ml), which reduce disulfid
bindings, and inactivate the polymeric IgM (and
IgA-) antibodies. This makes it possible to
differentiate between IgM and IgG antibodies and
to avoid false positive reactions for IgG-RF
caused by a possible binding of normal IgG to
IgMRE. After DTT treatment RA-Latex positive
sera became negative. The method was shown to
be specific for the Fc-fragment of the antigen-
IgG used in the testsystem.
By testing sera pretreated with DTT, occur-
rence of IgGRF was found in 16/36 (44%) of
seropositive- and 10/23 (44,9%) of seronegative
patients with definite rheumatoid arthritis, and
in 2/54 (3,7%) controls in a titer 1:9. IgGRF
titer varied between 1:9 and 1:72. The differ-
ence between sera from rheumatoid patients and
controls was significant (p< 0,01,3C?-test) for
IgG-RF-titerKl:9 as well as > 1:9, whereas no
difference between seropositive and seronegative
rheumatoid arthritics was found, regarding IgG-RF.
No correllation between occurrence of IgG-RF and
other laboratory parameters was found.
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