Lupus Erythematosus cells

The Lupus Erythematosus cells (LE) phenomenon is a hallmark of systemic lupus erythematosus (SLE), an autoimmune disease. LE cells are neutrophils or other white blood cells that have phagocytized nuclear material from other cells, characteristic of SLE. The presence of LE cells is used as a diagnostic feature for this condition.

LE Cells Phenomenon and Demonstration Methods

1. Table of contents

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   LE Cell Phenomenon

Pathogenesis

• Autoimmune Mechanism: In systemic lupus erythematosus (SLE), the immune system produces antibodies against its tissues, particularly against nuclear components of cells. These autoantibodies (antinuclear antibodies, ANAs) target and bind to the nuclear material of cells, leading to cell damage and debris.
• Formation of LE Cells: Neutrophils or other leukocytes phagocytize the nuclear debris from damaged cells. This internalization of nuclear material results in the formation of LE cells, which their distinctive appearance under the microscope can identify.

Morphological Features

• Appearance: LE cells typically have a central, round structure within their cytoplasm, representing the ingested nuclear material. This structure is often surrounded by a halo of cytoplasm.
• Types:
  • Classical LE Cells: Neutrophils or macrophages with distinct nuclear debris.
  • Tart Cells: Macrophages with ingested material with a “tart” appearance, resembling a “cup” shape.

2. Methods for Demonstration of LE Cells

LE Cell Test Method

1. Preparation:
   • Sample: Collect fresh blood samples in anticoagulant tubes (e.g., EDTA).
   • Reagents: Prepare a reagent mixture or use a control known to contain LE cells (such as blood from an SLE patient).
2. Procedure:
   • Mixing: Combine the patient’s blood with a reagent that enhances LE cell formation (e.g., a solution containing human serum).
   • Incubation: Incubate the mixture for 1-2 hours at room temperature, allowing LE cells to form.
   • Slide Preparation: Prepare a smear from the incubated mixture onto a glass slide.
3. Staining:
   • Stain Choice: Use Wright’s stain or Giemsa stain.
   • Staining Process: Apply the stain to the smear and allow it to develop. This will enhance the visibility of the cellular morphology.
4. Microscopy:
   • Examination: View the stained slide under a light microscope at high magnification (1000x with oil immersion).
   • Identification: Look for neutrophils or other leukocytes with characteristic central nuclear material.

Indirect Immunofluorescence

1. Preparation:
   • Sample: Obtain a blood sample or prepare tissue sections.
   • Reagents: Use fluorescently labelled anti-nuclear antibodies.
2. Procedure:
   • Slide Preparation: Prepare slides with patient samples or cultured cells.
   • Incubation: Incubate the slides with fluorescently labelled anti-nuclear antibodies that bind to nuclear material.
3. Observation:
   • Microscopy: Examine the slides under a fluorescence microscope.
   • Fluorescence Detection: LE cells will show bright fluorescence due to the bound antibodies, indicating the presence of nuclear material.

Immunoassays for Antinuclear Antibodies (ANA Test)

1. Preparation:
   • Sample: Collect blood from the patient.
   • Reagents: Use ELISA kits or other immunoassay methods to detect ANAs.
2. Procedure:
   • Testing: Perform ELISA or immunofluorescence according to the assay’s instructions.
   • Detection: Measure the levels of ANAs in the blood, as elevated levels indicate SLE and correlate with LE cell presence.
3. Interpretation:
   • Results: Positive ANA tests, especially with a homogeneous or speckled pattern, support the diagnosis of SLE.

Peripheral Blood Smear with Special Stains

1. Preparation:
   • Sample: Collect blood in anticoagulant tubes.
   • Reagents: Prepare stains such as Wright’s, Giemsa, or May-Grünwald-Giemsa.
2. Procedure:
   • Slide Preparation: Prepare a blood smear on a glass slide.
   • Staining: Apply the chosen stain and allow it to develop.
3. Microscopy:
   • Examination: Examine the stained slide under a light microscope.
   • Identification: Look for characteristic LE or tart cells based on morphology.

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3. Advantages and Limitations

LE Cell Test Method

• Advantages: Direct observation of LE cells; historically significant for diagnosing SLE.
• Limitations: Requires fresh samples and careful preparation; less specific than modern methods.

Indirect Immunofluorescence

• Advantages: Highly sensitive and specific; can detect a wide range of nuclear autoantibodies.
• Limitations: Requires specialized equipment and expertise; can be expensive.

Immunoassays for ANAs

• Advantages: Provides quantitative results and is widely used in diagnostic laboratories.
• Limitations: Elevated ANAs can occur in various autoimmune disorders, not just SLE.

Peripheral Blood Smear with Special Stains

• Advantages: Simple and inexpensive; useful for initial screening.
• Limitations: Less precise than specialized methods; can be affected by sample quality and staining techniques.