Home Blood Disorders In SLE
Robert S. Schwartz, M.D.
Professor of Medicine, Hematology-Oncology Division
New England Medical Center, Boston, MA

Hematologists, specialists in disorders of the blood, are often helpful in the medical management of patients with systemic lupus erythematosus (SLE).  Indeed, it is not unusual for the initial signs of lupus to appear in the blood.  In some patients with lupus, a blood disorder is the primary symptom of the disease.  The major hematological symptoms of SLE are: anemia, thrombocytopenia (low platelet count), clotting disturbances, and low white blood cell counts.  Each of these problems is discussed further.

The most common hematological abnormality in SLE is anemia, a reduction in the number of red blood cells.  Anemia is recognized by any of the following tests: the hematocrit, the hemoglobin concentration in blood, or the red blood cell count.  About half of the patients with active lupus are anemic.  The severity of the anemia is usually proportional to the activity level of a person's lupus.  Fatigus, suffered by many patients with active lupus, can be attributed in part to anemia.

Anemia is not a specific condition, but has many causes.  In a person with lupus, anemia may be caused by chronic inflammation, prolonged uremia, iron deficiency, or hemolytic anemia.

Inflammation is an important cause of anemia in lupus patients.  Prolonged inflammation hinders the production of red blood cells by the bone marrow, the tissue hidden within bones that produces blood cells.  Iron, which is essential for the production of hemoglobin, (the red pigment in cells), is not handled normally during inflammation and accumulates unused in the marrow tissue.  Therefore, treatment with iron is useless in anemia due to inflammation.  Only alleviation of the inflammatory condition restores normal red blood cell production.

Prolonged uremia due to impaired kidney function may also cause anemia in persons with lupus.  Unlike the anemia of chronic inflammation, anemia caused by prolonged uremia can be treated with angrogens (male hormones) or erythropoietin, the recently developed hormone that stimulates red cell production.  Occasionally, severe forms of anemia induced by chronic uremia require blood transfusions.

Iron deficiency, another common cause of anemia, is due to loss of blood from the body.  Women with heavy or frequent menstrul periods may become iron deficient.  Drugs used in the treatment ofl upus, such as aspirin and Prednisone, can irritate the stomach and cause internal bleeding, thus resulting in iron-deficient anemia.  In some cases, the seepage of blood from the stomach  causes the stools to turn black.  If this occurs, a person should immediately contact his or her physician.  In other cases the blood loss is inapparent and detectable only by special examination of the stool (the guaiac test).  Any anemic patient should have a test for blood loss from the stomach or intestines, since the source of bleeding requires identification and treatment.  In contrast to anemia caused by chronic inflammation, treatment with iron tablets rapidly corrects iron-deficient anemia.

The normal red blood cell lives for about 120 days after it emerges from the bone marrow and enter the blood circulation.  Some people with lupus can develop a kind of anemia called hemolytic anemia. This is a condition in which the red blood cells are prematurely destroyed.  Instead of the usual life span of 120 days, the red blood cells in hemolytic anemia may live only ten to fifteen days.

There are many causes of hemolytic anemia, but the most common form of the condition in people with lupus is due to antibodies directed against red blood cells.  This is called autoimmune hemolytic anemia.  In this condition, auto-antibodies interact with the red blood cells causing their removal by scavenger cells (macrophages) i nthe spleen or the liver.  Steroids such as Prednisone are usually effective in treating this type of anemia.  Some patients do not respond satisfactorily to this type of treatment and may require surgical removal of the spleen (splenectomy).  If the anemia is severe, a blood transfusoin may be necessary.

Blood platelets (thrombocytes) are tiny particles in the blood that are essential for blood clotting. A deficiency of platelets, called thrombocytopenia, leads to excessive bruising of the skin or bleeding from the gums, nose, or intestines.  Petechiae, pinpoint hemorrhages in the skin, are a typical sign of thrombocytopenia.  There are many causes of thrombocytopenia, so examination of the bone marrow may be necessary to clarify the diagnosis.  A bone marrow test is done by taking a sample of the bone marrow through a needle.

The most common cause of thrombocytopenia in persons with lupus is immune thrombocytopenia.  Often referred to as "ITP", this is caused by antibodies against platelets.  Indeed, ITP may be the dominant or even sole symptom of lupus in some patients.  In rare cases, ITP and autoimmune hemolytic anemia occur together.  The antibodies destroy the platelets in a maner similar to the destruction of red blood cells in autoimmune hemolytic anemia.  ITP is usually treated with steroids (Prednisone), but a splenectomy may be necessary in some cases.

During pregnancy, anti-platelet antibodies can cross the placenta, enter the baby's blood and cause thrombocytopenia.  However, almost all babies with low platelet counts can be successfully delivered, either vaginally or by Caesarian section.  Good prenatal care and the assistance of a pediatrician at the time of delivery are important for any pregnant woman with thrombocytopenia.

THE LUPUS ANTI-COAGULANT

Some patients with SLE produce an antibody that affects a blood clotting test called the partial thromboplastin time ("PTT").  This antibody is called the lupus anti-coagulant.  The term anti-coagulant usually refers to an agnet which interferes with normal blood clotting mechanisms and results in abnormal or heavy bleeding.  The lupus anti-coagulant is almost never associated with abnormal bleeding, even after injury or surgery.  On the contrary, some patients with the lupus anti-coagulant tend to form clots abnormally, especially in veins, which results in a condition called venous thrombosis.  There is currently no explanation for this paradox.

Venous thrombosis may require treatment with anti-coagulant drugs such as Heparin and Coumadin, particularly in cases associated with pulmonary embolus.  Pulmonary embolus is a condition in which fragments of the venous clot enter the circulation and lodge in the lungs.  The lupus anti-coagulant can alos be detected in cases of recurrent fetal loss.  When this occurs, the pregnancy is interrupted by a spontaneous abortion, usually during the first four months.  Whether the lupus anti-coagulant in fact causes so-called habitual spontaneous abortion is not yet known.  The best treatment for such cases of recurrent fetal loss is still subject to question.  Antibodies against other kinds of blood clotting factors may occur in people with lupus, but they are quite rare.

GRANULOCYTOPENIA AND LYMPHOCYTOPENIA

Either of the two principal types of white blood cells (granulocytes and lymphocytes) may be reduced in systemic lupus erythematosus, causing granulocytopenia (low granulocyte count) and lymphocytopenia (low lymphocyte count).  As a rule, these abnormalities are harmless and do not cause symptoms.  Occasionally, however, severe granulocytopenia can occur and result in susceptibility to bacterial infection.  Severe granulocytopenia is usually caused by a reaction to medication.  Cessation of the causative drug and treatment with antibiotics is necessary of there is infection.

BLOOD TRANSFUSIONS

There is widespread concern about the transmission of Acquired Immune Deficiency Syndrome (AIDS) by blood transfusions.  The development of tests for antibodies against the virus which causes AIDS has greatly improved the situation.  Today, all blood donors are screened for such antibodies.  Any blood from a "positive" donor is discarded/  The safest donor is the recipient, but the storage of one's own blood for later transfusion is not always pratical.  The ideal circumstance for "auto-transfusion" is a planned surgical operation.  In some blood banks, it is possible to designate a blood donor (usually a family member), but that may not be possible if the potential donors have blood types that are incompatible with that of the patient.  Recent investigations suggest that pre-operative treatment with erythropoietin can avoid the need for transfusions in patients undergoing elective surgery.  The casual use of blood transfusions, without due consideration of risk and benefits, is certainly to be avoided.