Does prednisone (corticosteroid) affect the focus score in a lip biopsy for Sjogren's syndrome?

Prednisone's Impact on Lip Biopsy Focus Score in Sjögren's Syndrome

Yes, prednisone can significantly affect the focus score in lip biopsies for Sjögren's syndrome diagnosis, potentially leading to false negative results, and should be discontinued at least 6 weeks prior to biopsy whenever possible.

Mechanism and Evidence

Corticosteroids like prednisone have immunosuppressive effects that directly impact the lymphocytic infiltration measured in salivary gland biopsies:

• Corticosteroids can reduce the lymphocytic infiltration in salivary glands, which is the primary histological feature measured by the focus score 1
• A case study demonstrated that high-dose corticosteroid treatment resulted in improvement of both clinical symptoms and histological parameters in repeated salivary gland biopsies, suggesting these changes are reversible 1
• Immunosuppressive medications taken for >6 weeks prior to biopsy may affect biopsy results, potentially leading to false negatives 2

Clinical Implications

Impact on Diagnostic Accuracy

• The focus score (FS) is calculated by counting the number of foci (aggregates of ≥50 mononuclear cells) per 4 mm² of glandular tissue 3
• A focus score ≥1 is considered diagnostic for Sjögren's syndrome 3
• Prednisone can reduce the number and size of lymphocytic foci, potentially reducing the focus score below diagnostic thresholds

Research Findings

A randomized, double-blind, placebo-controlled study examining prednisone (30 mg on alternate days for 6 months) found:

• Prednisone treatment failed to improve histological parameters of salivary glands in primary Sjögren's syndrome 4
• However, prednisone did significantly decrease serum total protein, IgG, IgA, and sedimentation rate 4
• Despite not improving histology over 6 months of treatment, the immunosuppressive effects could still mask initial diagnostic findings

Recommendations for Clinical Practice

Before Scheduling a Lip Biopsy

• Determine if the patient is currently taking prednisone or other immunosuppressive medications
• If possible, discontinue prednisone at least 6 weeks prior to the biopsy to avoid false negative results 2, 5
• For patients who cannot discontinue prednisone due to other medical conditions, document the dosage and duration of treatment when submitting the biopsy

Interpreting Results in Patients on Prednisone

• Consider the potential for false negative results in patients who have been on prednisone
• A negative biopsy in a patient on prednisone should be interpreted with caution, especially if other clinical and serological findings suggest Sjögren's syndrome
• The correlation between clinical presentation (sicca symptoms) and positive serology becomes stronger when excluding patients on immunosuppression for more than 6 weeks prior to biopsy (P = .011) 5

Alternative Diagnostic Approaches

For patients who cannot discontinue prednisone:

• Place greater emphasis on other diagnostic criteria for Sjögren's syndrome, including:
  • Serological markers (anti-SSA/Ro and anti-SSB/La antibodies)
  • Objective measures of ocular and oral dryness
  • Clinical symptoms

Common Pitfalls to Avoid

• Failing to account for prednisone use when interpreting negative lip biopsy results
• Not documenting corticosteroid use in the pathology requisition
• Relying solely on lip biopsy results for diagnosis in patients on immunosuppressive therapy
• Inconsistent application of the grading system for focus score calculation, which can result in misdiagnosis in up to 45% of specimens 6

Remember that consistent application of the grading system is essential to avoid incorrect diagnosis 6. When evaluating patients with suspected Sjögren's syndrome who are on prednisone, consider the full clinical picture rather than relying exclusively on lip biopsy results.