Undifferentiated Connective Tissue Disease

Study: Rheumatic Diseases and ABO Blood Types

A 2017 study in Turkey sought to find a link between particular blood types and the incidence of rheumatic disease. Rheumatic disease includes over 200 conditions that cause pain in your joints, connective tissue, tendons, and cartilage; many of these conditions are autoimmune diseases such as rheumatoid arthritis, Sjogren’s Syndrome, and systemic lupus erythematosus.

The researchers assessed 823 patients, with the following distribution of blood types: 42.5% patients had type A blood, 33.2% had type O blood, 15.4% had type B, and 8.9% had type AB. Each patient in the study had at least one of the following nine rheumatic diseases:

Behçet’s disease

Familial Mediterranean fever (FMF)

Rheumatoid arthritis (RA)

Spondyloarthropathy

Systemic lupus erythematosus (SLE)

Systemic sclerosis (SSc)

Sjogren’s syndrome (SjS)

Undifferentiated connective tissue disease

Vasculitis

Their study found that there was a significant difference in the distribution of blood types among those with rheumatic diseases. The most common autoimmune diseases among those with type A blood were: rheumatoid arthritis, spondyloarthropathy, vasculitis, Behçet’s disease, and undifferentiated connective tissue disease.

The most common autoimmune diseases among those with type O blood were: systemic lupus erythematosus, systemic sclerosis, and Sjogren’s syndrome. The researchers also noted that SLE, SSc and SjS are the connective tissue disorders frequently observed with antinuclear antibodies (ANA). The rheumatic disease familial Mediterranean fever was also found to be most common in those with type O blood.

Those with blood type AB were observed to be the least likely to suffer from rheumatic disease. However, it should be noted that type AB blood is also the most rare blood type in general, and represented the smallest amount of patients studied.

In addition, it was found that there was a significant difference in the distribution of Rh factor in rheumatic diseases. Of those with rheumatic diseases, 92.2% patients were Rh positive and only 7.8% patients were Rh negative. However, it should once again be noted that a positive Rhesus Factor (Rh+) is also more common among the general population than a negative Rhesus Factor (Rh-).

Is there a link between autoimmune disease and blood type?

So, if you have blood types A or O, does this mean you are more likely to get an autoimmune disease? The researchers who conducted this study concluded: “…we believe that the higher incidence of different rheumatic diseases in different blood types is associated with different genetic predispositions.”

In other words, since blood type is inherited (i.e. genetic), the results of the study point to a likely connection between certain genes and the increased predisposition for developing an autoimmune or rheumatic disease.

Do you know your blood type?

I, for one, do not know my own blood type. This is somewhat ironic, since I’ve undergone many blood tests as part of my Sjogren’s syndrome diagnosis, as well as for monitoring my liver enzyme levels while taking certain medications to control my autoimmune symptoms.

I actually did ask my primary care doctor what my blood type was the last time he ordered a test, and he advised that finding out your blood type is not a common part of the blood testing routine, and thus, he didn’t know what mine was.

If you have an autoimmune disease (or multiple diseases), and you know your blood type, comment below and let us know, are your condition and blood type consistent with the results of this study?

*Congenital Heart Block (CHB) is a rare but serious condition that occurs more frequently in newborns born to mothers with autoimmune disease.* *Image courtesy of Insider.com.*

What is Congenital Heart Block?

According to the National Organization for Rare Disease, Congenital Heart Block, or CHB for short, is the interference of the transfer of electric nerve impulses that regulate the pumping of the heart muscle.

As long as electrical impulses are transmitted normally between the heart’s chambers – the atria and the ventricles – the heart contracts normally, allowing for blood to be pumped throughout the body. If the transmission of the signal is impeded, the blocked electrical transmission is known as heart block, or atrioventricular (AV) block.

Though heart block can happen to anyone of any age, it is called congenital heart block if it occurs in a fetus or newborn up to 28 days old.

Why Does CHB Occur in Children Born to Women with Autoimmune Disease?

Autoimmune-associated CHB has been found in a variety of maternal autoimmune disorders, including Sjogren’s syndrome, systemic lupus erythematosus, rheumatoid arthritis, antiphospholipid syndrome (APS), mixed connective tissue disorders, and undifferentiated connective tissue disease.

It is believed that CHB may result when maternal antibodies cross the placenta, enter the fetus, and attack the fetal cardiac conduction system. The antibodies that were originally produced by the mother’s body to fight infections mistakenly recognize parts of the fetal heart’s conduction system as foreign; for this reason, the immune system attacks and damages the tissues, resulting in inflammation and scarring, which in turn leads to faulty conduction.

What Is the Risk of Congenital Heart Block if I Have an Autoimmune Disease?

A 2017 study conducted by Chinese medical professionals Kai-Yu Zhou and Yi-Min Hua of the West China Second University Hospital, Department of Pediatric Cardiology, revealed that more than half of CHB cases (between 60 and 90%) are associated with maternal autoimmune disease.

Among the general population, CHB occurs in 1 out of every 20,000 live births – an incidence of only 0.00005%. The study found that autoimmune-associated CHB, however, occurs at much more frequent rates, affecting between 2–5% pregnancies with positive anti-Ro/SSA and La/SSB antibodies. The study also found that when a woman had a child with CHB, the recurrence rate of CHB was 12–25% for a subsequent pregnancy.

Mortality Rate & Treatment for Congenital Heart Block

The perinatal mortality rate of a newborn with CHB is up to 30%, and even higher in the presence of endocardial fibroelastosis (EFE) or dilated cardiomyopathy (DCM), which are other potential complications associated with CHB.

If CHB is detected in utero by a fetal electrocardiography (ECG) and echocardiography, your OB/GYN may prescribe an adrenocorticosteroid such as dexamethasone, which works to decrease inflammation and the number of circulating maternal antibodies in the fetus.

Once born, other studies have shown that between that 64 and 70% of CHB survivors require surgery to permanently implant a pacemaker, a medical device which stimulates the heart to contract so that it can pump blood.

How to Prevent Congenital Heart Block

A 2016 report by the American College of Rheumatology states that there are no official guidelines about the prevention, screening, and treatment of CHB due to maternal Ro antibodies.

However, in the same report, it was stated that in a survey of 330 women with autoimmune conditions, 67% were told by their rheumatologists to use hydroxychloroquine (also known as Plaquenil) to prevent CHB. In addition, 62% were told to start the drug prior to pregnancy, in order to prevent the condition from developing.

Another study published in The Journal of the American College of Cardiology stated that hydroxychloroquine reduces the recurrence of CHB below the historical rate by more than 50%, further demonstrating the promise of this drug in the prevention of CHB.

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