When the ANA was negative my rheumy ordered an ANA8 ELISA The test was run on
differant occassions and I presented positive with RNP. Mixed Connective Tissue Disease
is the only connective tissue disease for which only one specific antibody(RNP) is needed
to make a diagnosis. I also tested positive for ssDNA and that antibody will show up positive
10-20% of the time in MCTD.
MCTD is an overlap of three differant connective diseases. In my case they are lupus,
scleroderma and RA. The most common combination is lupus, scleroderma and polymyositis.
It is a systemic condition
I had clinical features of all three autoimmune diseases, swollen joints on both hands, feet.
elbows knees all bilateral, rashes, Raynauds, and a biopsy confirmed the scleroderma.
Every connective tissue disease has their own antibodies. Diagnosis is not a simple procedure
because there are so many illnesses that have simular synptoms.
In checking for a CTD these antibodies should be checked ssDNA,dsDNA,Sm,RNP,
SSA(ro), SSB(LA), histone, Scl 70. Some doctors will not check for these unless you have
a positive ANA. Not everyone with a positive ANA has a CTD and sometimes a person with
a negative ANA has a CTD, confusing isn't?
Fibromyalgia, MCTD (Lupus, Scleroderma & RA) Raynaud's, Osteoporosis,