Individually-tailored thyroxine requirement in the same patients before and after thyroidectomy: a longitudinal study.

OBJECTIVE: Thyroxine (T4) requirement after total thyroidectomy for differentiated thyroid carcinoma (DTC) is a debated issue. As most of the studies in the area have been retrospective and/or performed with heterogeneous therapeutic approaches, we designed our study to determine T4 requirement in the same patients and treatment settings, before and after total thyroidectomy. DESIGN, PATIENTS AND METHODS: This was a longitudinal study including 23 goitrous patients treated with T4 in an individually tailored fashion. All patients exhibited a stable TSH (median TSH = 0.28 mU/l) at a stable T4 dose for at least 1 year before surgery (median T4 dose = 1.50 µg/kg per day). The patients underwent total thyroidectomy based on cancer suspicion or compressive symptoms. Eventually diagnosed as having DTC (pT1b-pT2N0) and following surgical and radiometabolic treatment, they were treated with the same pre-surgical doses of T4. RESULTS: Three months after surgery,using the same pre-surgical dose, median TSH increased up to 5.38 mU/l (P<0.0001) and so the T4 dose had to be increased (median T4 dose = 1.95 µg/kg per day; +30%; P < 0.0001). Once divided by patients' age, we observed that, after thyroidectomy and maintaining the same pre-surgical dose, serum TSH significantly increased both in younger and in older patients (median TSH = 4.57 and 6.11 mU/l respectively). Serum TSH was restored to the pre-surgical level by increasing the dose up to 1.95 and 1.77 µg/kg per day (+25 and +21%) respectively. CONCLUSIONS: Following the same treatment regimen, a thyroidectomized patient requires one-third higher therapeutic T4 dose than before surgery. Despite this increase, the dose of T4 needed in our patients remains significantly lower than that previously described in athyreotic patients.

Increased interleukin-4-positive lymphocytes in patients with Hashimoto's thyroiditis and concurrent non-endocrine autoimmune disorders.

A prevalent T helper type 1 (Th1) subset of lymphocytes has been described in Hashimoto's thyroiditis (HT), but whether a similar polarization may characterize HT when associated with non-endocrine autoimmune disorders (NEAD) is not known. The aim of the present study was to analyse the intracellular Th1 and Th2 distinctive cytokines in patients with isolated HT or associated with non-endocrine autoimmune disorders. Intracellular cytokine expression was assessed in peripheral blood lymphocytes (PBL) of 68 out-patients (females = 55; males = 13; median age = 6 years) with HT : 33 had isolated HT and 35 had a concurrent NEAD. The percentage of interferon (IFN)-γ and interleukin (IL)-2 Th1- and IL-4 Th2-positive cells was measured by flow cytometric analysis. We found an increased percentage of IL-2-positive cells in all patients, without differences between patients with isolated HT or associated with NEAD. IFN-γ(+) cells were also increased in both groups, but the median percentage of those with isolated HT was lower than in patients with HT+NEAD (19·0 versus 29·9%; P = 0·0082). An increased number of IL-4-positive cells was observed in three of 33 (9·1%) patients with isolated HT and in 25 of 35 patients with NEAD [71%; P < 0·0001; relative risk (RR) = 3·18]. The median values of IL-4(+) cells (HT = 5·0% versus HT + NEAD = 16·8%) confirmed this large difference (P < 0·0001). A clear-cut increase of IL-4(+) lymphocytes characterizes patients with autoimmune thyroiditis who have associated non-endocrine autoimmune disorders. These findings may represent an initial tool to detect patients with autoimmune thyroiditis in which additional non-endocrine autoimmune disorders may be awaited.

The presence of non-segmental vitiligo modifies intracellular cytokine subsets in patients with chronic lymphocytic thyroiditis.

Chronic lymphocytic thyroiditis and vitiligo often occur in association and seem to be characterized by a prevalent Th1-driven autoimmune process. The aim of this study is to analyze selected intracellular Τh1 and Th2 cytokines in patients with Hashimoto?s thyroiditis when associated with non-segmental vitiligo. We analyzed intracellular interleukin-2, interferon-gamma (Τh1) and interleukin-4 (Th2), in peripheral blood lymphocytes of 23 patients with isolated Hashimoto?s thyroiditis (group A) and of 11 patients with Hashimoto?s thyroiditis associated with non-segmental vitiligo (group B). Peripheral blood lymphocytes were stimulated and incubated with specific monoclonal antibodies. Intracellular cytokines were assayed by flow cytometric analysis. Interleukin-2 and interferon-gamma positive cells were increased in almost all patients but the median values were similar in patients with isolated Hashimoto?s thyroiditis and in those with concurrent vitiligo. In contrast, the number of patients with increased interleukin-4 positive cells was higher in patients with thyroiditis and vitiligo (9/11) than in those with isolated thyroiditis (2/23; p<0.0001). The median values of IL-4 positive cells in the two groups confirmed this difference (A: 5.8 percent, vs B: 20.6 percent; p=0.0011). Increased interleukin-4 positive lymphocytes characterize Hashimoto?s thyroiditis when associated with non-segmental vitiligo, suggesting a modified balance from highly prevalent Th1 to mixed Th1/Th2 subset.