[Previous Months][Date Index][Thread Index][Join - Register][Login]
[Message Prev][Message Next][Thread Prev][Thread Next]

RE: [IP] Re (IP) Type 1 and 2--antibodies



I work for a reference laboratory that routinely performs autoantibody
testing for many autoimmune diseases such as IDDM.  Hope this clears up any
confusion for those of you interested.  Any specific questions may be
directed to me personally at email @ redacted

Approximately 15% of all diabetic patients exhibit insulin-dependent
diabetes mellitus (IDDM), also known as Type I diabetes.  IDDM reflect the
autoimmue destruction of insulin-producing beta cells of the islets of
Langerhans in the pancreas.  Although an immunofluorescent assay to detect
islet cell autoantibodies is highly snesitive for predicting and diagnosing
IDDM, its widespread utility is limited by poor precision and the need for
human pancreatic tissue.

Clinical studies have shown that most islet cell autoantibodies are directed
aganinst one of two major islet cell antigens, glutamic acid decarboxylase
(GAD) and the tyrosine phosphatase termed islet antigen-2 (IA-2).  GAD
antibodies are found in 70-80% of newly diagnosed IDDM patients, but are
also found occasionally in other organ specific autoimmune diseases.
Approximately 10% of first degreee relatives of IDDM patients exhibit GAD
antibodies, and 50% of these seropositive relatives will develop IDDM within
5 years.

IA-2 antibodies are found in 60-70% of newly diagnosed IDDM patients, and
are more specific for IDDM than GAD antibodies.  Approximately 5% of first
degree relatives of IDDM patients exhibit IA-2 antibodies, and 80% of these
seropositive relatives will develop IDDM within 5 years.

Investigations of the relationship between GAD antibody detection and IA-2
antibody detection is sera from IDDM patients revealed only partial overlap;
that is, some sera contained GAD antibody only, some sera contained IA-2
antibody only, and some sera contained both antibodies.  More importantly, a
positive result for at least one of these autoantibodies was found in over
90% of IDDM patients.

Thus, a combination of GAD antibody and IA-2 antibody testing provides
greater sensitivity for IDDM detection than measurement of either of these
autoantibodies alone.  Additional studies have shown that the sensitivity of
this combination testing approach is comparable to or better that the
sensitivity of the islet cell autoantibody assay.

GAD antibodies and IA-2 antibodies are measured using radioimmunoassays
(RIA).

Susan S.
IDDM 16 years\MM pump 2 weeks

-----Original Message-----
From: email @ redacted [mailto:email @ redacted]On Behalf
Of Ted Quick
Sent: August 15, 1999 5:30 AM
To: email @ redacted
Subject: Re: [IP] Re (IP) Type 1 and 2--antibodies


gianna marzilli wrote:
>
> is there a difference between  islet and autoimmune antibodies? -Gianna

Perhaps. Thing is that autoimmune antibodies may refer to more than islet
antibodies, since the autoimmune system can destry other things besides
Beta (islet) cells. Of course around here that's a little less likely than
elsewhere, seeing what our main subject is....

Ted Quick
email @ redacted
----------------------------------------------------------
Insulin Pumpers website http://www.insulin-pumpers.org/
for mail subscription assistance, contact: HELP@insulin-pumpers.org

----------------------------------------------------------
Insulin Pumpers website http://www.insulin-pumpers.org/
for mail subscription assistance, contact: HELP@insulin-pumpers.org