HSBTE. LE Cells Phenomenon: Phenomenon of LE cell, its differentiation from tart cell. Demonstration of LE cells by various methods. Clinical significance. DMLT IVth Semester Unit IV.

Phenomenon of LE cell

The LE (lupus erythematosus) cell phenomenon is associated with autoimmune disorders. It involves a specific type of cell called the LE cell. The LE cell is a neutrophil (a type of white blood cell) that has phagocytosed (engulfed) its cell nucleus. This phenomenon is linked to the antinuclear antibodies (ANAs)  present in the blood.

The following steps explain the LE cell phenomenon.

1. Formation of LE Cells: Degenerative connective tissues release protein in blood that acts as an antigen. The human body produces autoantibodies against this antigen. Autoantibody reacts with the lymphocyte nucleus and sensitizes the nuclear body. Thus this antibody is called anti-nuclear antibody (ANA).

Neutrophils are part of the immune system. Neutrophils engulf this antibody-coated nuclear material. This is called LE cells.

2. Ingestion of Nucleus: The neutrophil digestive enzymes could not break down the nuclear material properly.

3. Formation of Incomplete Phagolysosome: The ingested material remains intact within the neutrophil. This forms an inclusion called an "incomplete phagolysosome”.

4. Characteristic Appearance: The stained LE cell under the microscope appears as a neutrophil with a clear, "ghost-like" nucleus inside. Romanowky stain is used to stain LE cells.

The LE cell phenomenon is a diagnostic marker for the disease systemic lupus erythematosus (SLE). However, the LE cell phenomenon may be observed in other autoimmune diseases also.

Differentiation of LE cells from Tart Cell

The term "tart cell" is not well-recognized or widely used in clinical medicine. However, the tart cell phenomenon refers to a condition in which neutrophils contain large basophilic granules. This is associated with myelodysplastic syndromes (MDS). MDS is a group of disorders characterized by abnormal development and maturation of blood cells in the bone marrow. The differentiation between LE cells and Tart cells would be as per below.

1. LE Cell (SLE)

• · associated with autoimmune disorders, particularly SLE.

• · Neutrophils phagocytose their own nuclear material.

• · Diagnostic of autoimmune conditions.

• · Typically seen in the peripheral blood.

2. Tart Cell (MDS)

• · Hypothetically associated with myelodysplastic syndromes.

• · Neutrophils phagocytose their own nuclear material.

• · Associated with abnormal cell development in the bone marrow.

• · Not a widely accepted term in current medical literature.

Demonstration of LE cells by various methods

The demonstration of LE (lupus erythematosus) cells is a laboratory technique used to identify and characterize these cells. LE cells are associated with autoimmune disorders, especially systemic lupus erythematosus (SLE). The primary method for demonstrating LE cells involves preparing a blood smear and using specific staining techniques.

The following steps explain LE cell demonstration in the laboratory

1. Defibrination of blood: Collect 10 mL blood in a 50 mL conical flask containing 20 to 30 glass beads (3 to 5 mm diameter). Shake the conical flask gently for 15 minutes to defibrinate the blood. Keep aside for 15 minutes at 37ͦC.

2. Rotation: Transfer blood and a few beads into a test tube and mix it for 30 minutes using a rotor. Allow to stand at 37ͦC.

3. Centrifugation: Centrifuge it at 3000 rpm for 10 minutes. Transfer the buffy coat to Wint robe's hematocrit tube and again centrifuge for 10 minutes

4. Blood Smear Preparation: Transfer the buffy coat to a small tube and add an equal volume of plasma. Mix well. Prepare a thin smear on a glass slide. Dry the smear rapidly.

• i. Staining Techniques: Use the Wright-Giemsa staining method to stain and visualize the LE cells. These stains provide contrast and highlight cellular structures. This makes it easier to identify abnormalities.

• ii. Microscopic Examination: Examine the stained blood smear under a microscope.

• iii. Identification of LE Cells: LE cells are identified by their characteristic appearance. An LE cell is a neutrophil that has phagocytosed its nucleus. This results in a clear or "ghost-like" appearance of the nucleus within the cytoplasm of the neutrophil. Blue to magenta-colored LC cells inside neutrophils.

• iv. Confirmation of Diagnosis: The presence of LE cells in the blood smear is an indication of autoimmune activity.

Other Methods for LE Cell Demonstration

1. Slide Agglutination Test: In this test, patient serum is mixed with a suspension of fixed neutrophils. If LE cells are present, agglutination (clumping) of the neutrophils occurs.

2. Indirect Immunofluorescence: This technique involves exposing patient serum to tissue sections, and the binding of autoantibodies that can be visualized using fluorescently labeled antibodies.

3. Latex Agglutination Test:

Mix Latex particles coated with neutrophil antigens with patient serum.

The appearance of agglutination indicates the presence of autoantibodies.

Clinical significance of LE Cell Phenomenon

The presence of LE cells in the laboratory findings provides valuable diagnostic information and contributes to the overall understanding of the patient's autoimmune condition. The following are the clinical aspects of the LE cell phenomenon

1. Diagnostic Marker for SLE: The primary clinical significance of the LE cell phenomenon is its association with SLE. The presence of LE cells in the peripheral blood, along with other clinical and laboratory findings helps in the diagnosis of SLE.

2. Complementary to Other Diagnostic Tests: It is used in conjunction with other diagnostic methods, such as anti-nuclear antibody (ANA) testing, immunological assays, and clinical criteria, for a more comprehensive diagnosis of SLE.

3. Autoantibody Production: The LE cell phenomenon reflects the production of autoantibodies, especially anti-nuclear antibodies (ANAs). These antibodies target components of the cell nucleus, such as DNA and nuclear proteins.

4. Indicator of Autoimmune Activity: The presence of LE cells indicates ongoing autoimmune activity. The immune system produces antibodies that target the body's cells and tissues.

5. Disease Monitoring: The monitoring of LE cells and other laboratory markers is useful for assessing disease activity and response to treatment in patients suffering from SLE.

Limitations and Evolving Practices: The use of the LE cell phenomenon as a diagnostic tool has diminished over time. More specific and sensitive tests have been developed for the diagnosis of autoimmune disorders, including SLE. Modern diagnostic approaches often involve a combination of clinical criteria, immunological assays, and molecular testing.

Dr Pramila Singh