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
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.
