Læknablaðið : fylgirit - 01.10.1980, Blaðsíða 17

fever, involvement of several organ sys-
tems, viz. heart, lungs, kidney, skin, eyes
and joints, were of infectious nature and
that such clinical and obviously systemic
reactions were associated with infectious
immunity. The close resemblance between
manifestations of chronic infectious dis-
eases and several ICTDs naturally made it
probable to the clinician that ICTDs were
infectious diseases of unknown ethiology.
As a matter of fact, the pattern of clinical
symptoms and signs in the ISTDs still re-
mind the clinician in many ways of chronic
infectious. And probably, this is still a
highly relevant ethiological possibility for
some ICTDs. New evidence in support of
a role of infectious agents in the initiation
of ICTD is still accumulating and gaining
importance.
4. Clinical chemistry
The information gained bv clinical bio-
chemistry parameters can reveal so-called
“disease-activity” by measuring sedimenta-
tion rate, serum concentration of eertain
“acute phase” proteins (aj-antitrypsi'n, oro-
somucoid, fibrinogen, haptoglobin). In IC
TD these parameters are clinically useful,
because experience has given them empiri-
cal value. Their biological role is unknown,
and it would indeed be of interest to in-
vestigate and clarify their true role during
the course of acute illness and exacerbation
episodes. They participate in any acute dis-
ease process associated with inflammation,
not only immunological inflammation, but
their synthesis, catabolism and regulation
is not known sufficiently well to make
them of major importance in clinical dia-
gnosis and control. Quantitative determina-
tion of plasma and exudate concentrations
of immunoglobulins of the various classes
likewise gives a rather non-specific infor-
mation. Empirically it is known that ele-
vated IgG is a typical feature of some
ICTDs, but after all, the serum concentra-
tion of an immunoglobulin indicates only a
selected, one-moment value of a dynamic
balance between synthesis and catabolism/
loss of the Ig in question, and since this
balance is subject to the continuous in-
fluence of numerous non-defined factors,
the informative value of quantitative Ig-
determinations is limited. In some diseases
complement concentration in serum and
tissue fluids is associated with immune
complex dependent complement consump-
tion, and analysis of selected factors of the
complement system in these biological ma-
terials may show a good correlation to
clinical exacerbations and remissions. But
more exact information on ICTD can in-
deed be gained by analytical registration
of immunologically specific materials from
patients with ICTD.
5. Specific immunology: Imnrunoglobulins/
lymphocytes
Very pertinent to the title of this review,
the field of specific immunological investi-
gation in ICTD has undergone a considera-
ble development and is still expanding
profusely. An advanced scientific mapping
out of immunoglobulin production, struc-
ture and function has been applied in
several investigations of ICTD. And this
has led to new and profound insight in dis-
ease pathobiology and has also contributed
several immunological methods, that can
be used in clinical work and are highly
useful and even indispensable as diagnostic
tools. This important field is close to the
core of the immunology of ICTD, and a few
selected subjects will be commented on
below.
Immune assays that can detect relevant
information in ICTD may reveal either
immunity to foreign, not-self antigen or to
self antigen belonging to tissues or pro-
ducts of the body itself. Not-self immunity
is obviously associated with several ICTDs
and reveals in several cases information on
etiology or pathogenesis of the disease.
The role of streptococcal infection in rheu-
matic fever is obvious; the association bet-
ween genital infection with gonococci and
secondary allergic arthritis is equally ob-
vious. And recent information on Epstein-
Barr-associated antibody and antigen in
rheumatoid arthritis may eventually be-
come of similar significance. Arthritis as-
sociated with infection with Yersinia ente-
rocolitica has recently had increasing publi-
city, although the importance of this micro-
organism as cause of ICTD is so far un-
settled. New evidence suggests, that so-