Since lupus can have many clinical and laboratory manifestations, cells and clotting factors that circulate in the blood are common concerns in manifestations and can be very important. Hematologists, who are specialists in blood disorders, are often asked to be involved in the evaluation and treatment of patients with systemic lupus erythematosus (SLE).

Blood is made up of cells and a protein rich liquid containing many substances including antibodies which are a major concern in lupus. Blood tests are important procedures done on lupus patients to diagnose and measure the activity status of the disease. Blood tests periodically done in a lupus patient are complete blood count (CBC), complement components such as C3, while the diagnosis is aided by antinuclear antibody (ANA), and anti-dsDNA or anti-Sm  antibody blood tests.

The principal hematological (blood) issues of interest are: Anemia (low hemoglobin or red blood cells), leucopenia (low white blood cells), or thrombocytopenia (low platelet counts).

The most common blood disorder is anemia, affecting about half of all people with active lupus. Anemia can be measured and discussed in several different ways, including a low red blood cell count, low hemoglobin, or low hematocrit. In the most important sense, anemia means too little hemoglobin. Hemoglobin is the protein inside red cells that carries oxygen from the lungs to all the tissues of the body. Fatigue, a very common lupus symptom, is generally the first and most common symptom of anemia.

Normal red blood cells live only 120 days (about four months) and must constantly be produced by the bone marrow. The commonest explanation for anemia is reduced red cell production. This may be due to inflammation; kidney problems (when the kidneys do not produce enough of the hormone, erythropoietin, that stimulates the marrow to make more red cells); iron deficiency (without which hemoglobin cannot be made—iron deficiency may result from menstrual bleeding or from intestinal bleeding due to non-steroidal anti-inflammatory drugs); or direct depression of the bone marrow by certain lupus drugs (such as azathioprine or cyclophosphamide). Intestinal bleeding can be obvious if the stool is red, maroon, or pitch black in color, but often bleeding is so slow and gradual that special stool tests are needed to detect it.

Less often, anemia is due to the premature destruction of red cells. This is called hemolytic anemia, or simply hemolysis . Sometimes, patients with hemolysis will appear slightly jaundiced, and in this situation, a yellowish tinge to the skin and eyes does not mean a liver problem. Hemolysis is most commonly due to antibodies that attach to red cells, causing the cells to be eliminated from the circulation. When coupled with thrombocytopenia (a low platelet count), this can mean a condition named thrombotic thrombocytopenic purpura (TTP for short).

The treatment of anemia in lupus depends on its cause. Inflammation can be reduced with drugs such as prednisone. For iron deficiency, iron given orally, such as ferrous sulfate or ferrous gluconate, is almost always effective. In the case of bleeding, the source should be determined in order to correct the problem. Folic acid also helps the bone marrow to make more red blood cells. There are more ways of treatment, doctor should be consulted.

White blood cells are actually made up of several different types of cells, including neutrophils (also called granulocytes), lymphocytes, and monocytes. They are involved in a person's defenses against infection. A reduction in the number of white blood cells is called leukopenia; a particular reduction in granulocytes is called neutropenia (or granulocytopenia).

Leukopenia and neutropenia are very common in active lupus, but rarely are white cell counts low enough to lead to infection. Counts may be lowered by azathioprine, cyclophosphamide, and some other drugs. Therefore, white cell counts are always monitored during treatment with these agents. If counts go too low, the prescribed drug is usually stopped briefly or the dosage is reduced. When infections occur in lupus, they are more often related to alterations in the body's immune system that are not reflected in routine blood counts.

Blood platelets are tiny pieces of megakaryocytes, which reside in the bone marrow. A low platelet count is termed thrombocytopenia. As the platelet count falls, bruising, tiny red bleeding points in the skin called petechiae (especially on the lower legs), nosebleeds, or other bleeding may occur. Although there are many possible causes of thrombocytopenia, in lupus it is almost always due to antibodies. A low platelet count may briefly be aggravated by infection. Whereas thrombocytopenia is common in lupus, only occasionally does serious bleeding result. On rare occasions, a person with lupus may have antibodies against both red blood cells and platelets.

Most people with lupus who have mild to moderate thrombocytopenia do not need treatment. When necessary, prednisone and intravenous gammaglobulin (called IV Ig) are commonly used. Other drugs, such as azathioprine or rituximab, also can help. As in hemolysis due to antibodies, thrombocytopenia can sometimes be relieved by splenectomy. The doctor will advise whether non-steroidal anti-inflammatory drugs (NSAIDs) can be used safely when thrombocytopenia is present.

Paradoxically, thrombocytopenia may be associated with increased clotting or coagulation instead of bleeding. This is seen in a condition known as Antiphospholipid Syndrome or APS. APS may occur in patients with or without SLE, and may also occur even without thrombocytopenia.   Two blood tests most often used to diagnose APS  are the anticardiolipin test and the lupus anticoagulant test.

Bone Marrow Testing

Blood cells are made in the bone marrow, but most blood cell problems in lupus occur after the cells leave the marrow and enter the blood stream. Thus, most hematological questions in lupus can be answered from the results of blood tests alone. Occasionally, however, a bone marrow test provides important information to help in planning treatment.

REFERENCES:

·          Lupus Foundation of America Inc. “Blood disorders”, <http://www.lupus.org/webmodules/webarticlesnet/templates/
new_aboutaffects.aspx?articleid=98&zoneid=17>

·          LupusUK: “Lupus and Blood Disorders Factsheets” <http://www.lupusuk.com/factsheets/blooddisorders.pdf>