Platelet Counts, Thrombocytopenia, and Lupus

Lupus can have far reaching impacts throughout the body. Low platelet count, also known as thrombocytopenia, is a common symptom.

Platelets are cells in the bloodstream that clump together on injury to prevent bleeding. Platelets are produced in the bone marrow and are found throughout the body. In people with high levels of inflammation in their body or cardiovascular issues, they can also clump together in the blood vessel itself and block blood flow.

Many people with systemic lupus erythematosus (SLE) have low platelet counts, a condition also known as thrombocytopenia.

The condition of thrombocytopenia is defined as a platelet count of less than 150 x 10³ per microliter of blood. Symptoms of low amounts of platelets in the body include:

• Wounds that bleed too much  for too long
• Enlarged spleen
• Heavy menstrual flows
• Fatigue
• Easy bruising with large and dramatic bruises, also known as purpura
• Bleeding without injury in delicate areas such as the gums or nose
• Tiny reddish-purple spots called “petechiae” that cluster on the skin like a rash

Most of the time, thrombocytopenia isn’t even suspected until a routine blood count test discovers it. When thrombocytopenia shows up early, the SLE symptoms will often become severe, with potentially worse outcomes. It’s not a sure thing, but it does make platelet count worth keeping an eye on for people with lupus. However, many people with lupus have some sort of blood issue, either thrombocytopenia or anemia. 

Causes of Thrombocytopenia

The causes of low platelet count can be from disease or from medication. These causes lead to:

• Swelling of the spleen
  • The spleen processes blood cells including platelets. When processing slows, swelling occurs.
• Slowed production of platelets
  • Platelets are produced in the bone marrow. Production can slow below the rate at which cells are lost everyday, leading to low platelet counts
• Due to conditions in the body, platelets are destroyed at a higher rate than usual.

Lupus, like all autoimmune diseases, is a condition defined by the immune system misidentifying and attacking the body’s health cells. This can include platelets.

Not all people with lupus produce platelet-specific antibodies, also known as anti-GPIIb/IIIa and anti-TPOR antibodies. However, these auto-antibodies can trigger the body to attack and destroy platelets. These antibodies can be detected through antibody profiles and blood tests, so thrombocytopenia can be predicted. 

SLE activity in the spleen and bone marrow can cause low platelet counts, and can affect the bloodstream, too, and that will also influence the platelet counts. Along with anemia and leukopenia (low white blood cell count), thrombocytopenia is a common symptom of lupus. Lupus can also cause inflammation throughout the body which can cause anemia and clotting, which both reduce platelet counts.

A Relationship Between Lupus and Platelets?

Interestingly, platelets may have revealed a new target for treating lupus. Recent research found that people with SLE have high amounts of mitochondrial DNA in their bloodstream.

Mitochondrial DNA is the DNA found in the mitochondria, which are the part of the cell that is responsible for breaking down simple sugars and producing energy, among other things. How mitochondria or its DNA affects lupus is unclear. However, high amounts of it in the bloodstream often go along with a clotting problem. It is also generally known that the mitochondria work improperly in autoimmune diseases, and it may have to do with the genetics of the mitochondria.

Although the relationship between autoimmune disease and mitochondrial DNA is unclear, platelets may be key to figuring it out.

Treating Low Platelet Counts and Lupus

In an emergency, platelets can be added to the body through blood or platelet transfusions. However, more long-term thrombocytopenia treatments include both medications and surgery, and it has some overlap with lupus treatments in general.

Corticosteroids are first-line treatment for autoimmune thrombocytopenia, as are monoclonal antibodies like rituximab and azathioprine (which are all used to treat lupus in general). Intravenous gammaglobulin is a treatment specific for thrombocytopenia, and removing a swollen spleen can relieve the platelet problem, too.

Notably, Non-steroidal anti-inflammatory drugs (NSAIDs) can cause an inability to clot and can lead to internal bleeding. These should be discontinued unless a doctor approves them. Alcohol use also makes both thrombocytopenia and lupus worse, so reducing alcohol consumption can be way to treat the condition.