Flow cytometry phenotypization of thyroidal lymphoid infiltrate and functional status in Hashimoto's thyroiditis
Pio Zeppa1, Gilda Marino, Maria Lepore
1Department of Anatomic Pathology and Cytopathology, Faculty of Medicine and Surgery, Università di Napoli Federico II, Naples, Italy. zeppa@unina.it
Insights
Thyroidal lymphoid infiltrate (TLI) analysis in Hashimoto's thyroiditis (HT) reveals distinct T-lymphocyte profiles. A CD4/CD8 ratio less than 1:1 is associated with hypothyroidism, potentially indicating increased apoptosis and thyroid damage.
Area of Science:
- Immunology
- Endocrinology
- Pathology
Background:
- Hashimoto's thyroiditis (HT) is an autoimmune disease characterized by thyroidal lymphoid infiltrate (TLI).
- Understanding the relationship between TLI and thyroidal functional status (TFS) is crucial for managing HT.
Purpose of the Study:
- To evaluate the differences in TLI within thyroid tissue based on thyroidal functional status in patients with Hashimoto's thyroiditis.
- To correlate specific immune cell populations and ratios with hyperthyroid, euthyroid, and hypothyroid states.
Main Methods:
- Flow cytometry (FC) was used to analyze TLI in thyroid fine-needle cytology samples from 57 HT patients.
- Immune cell markers (CD3, CD4, CD5, CD8, CD10, CD19, kappa, lambda light chains) were assessed.
- Thyroidal functional status was determined by serum TSH, FT3, and FT4 levels.
Main Results:
- T-lymphocytes were detected in all patients, while B-lymphocytes were present in 77%.
- A CD4/CD8 ratio less than or equal to 1:1 showed a significant association with hyperthyroid and hypothyroid states (p < 0.01).
- Specific CD4/CD8 ratios varied across euthyroid, hyperthyroid, and hypothyroid classifications.
Conclusions:
- An intrathyroidal CD4/CD8 ratio < 1:1 may indicate intense apoptosis in early HT, potentially followed by CD4/CD8 balance restoration.
- Persistent increased intrathyroidal CD8 levels might correlate with significant thyroidal damage and an elevated risk of developing hypothyroidism.
Objective:
To evaluate the thyroidal lymphoid infiltrate (TLI) in thyroidal functional status (TFS) for differences among patients with Hashimoto's thyroiditis (HT).
Study Design:
Flow-cytometry (FC) was applied to thyroidal fine-needle cytology samples in 57 patients. TLI was analyzed using a fluorescence-activated cell sorter (FACS) scan and fluorescence antibodies CD3, CD4, CD5, CD8, CD10, and CD19 and kappa and lambda light chains. TFS was determined by serum thyroid-stimulating hormone (TSH), FT3 and FT4 immunoassays, in specific clinical settings, to classify the cases as hyperthyroid, euthyroid and hypothyroid. FC assessment was then compared with the corresponding TFS.
Results:
B-lymphocytes were present in 44 cases (77%). T-lymphocytes were present in all the cases; CD4/CD8 = 2:1 ratio was observed in 16 euthyroid, 1 hyperthyroid and 3 hypothyroid; CD4/CD8 > or = 3:1 ratio in 22 euthyroid, 2 hyperthyroid and 2 hypothyroid cases; CD4/CD8 < or = 1:1 ratio in 1 euthyroid, 3 hyperthyroid and in 7 hypothyroid cases. Grouping hyperthyroid and hypothyroid cases, a significant association was observed with the CD4/CD8 < or = 1:1 ratio (p < 0.01).
Conclusion:
Intrathyroidal CD4/CD8 < 1:1 ratio might be the expression of intense apoptosis in the early phases of HT, generally followed by the restoration of CD4/CD8 balance; persistence of increased intrathyroidal CD8 might be related to intense thyroidal damage and thus an increasing risk of hypothyroidism.
