Intrathyroidal accumulation of T cell phenotypes in autoimmune thyroid disease

Comprehensive immunophenotypic analysis reveals the pathological involvement of Th17 cells in Graves' disease

Graves' disease (GD) is an organ-specific autoimmune disease, but there are a few studies that have evaluated how immunophenotypes are related to clinical symptoms and intractable pathology, or the effects of treatment on immunophenotypes. We performed peripheral blood immunophenotyping in GD. We assessed the proportion of functional subsets of T helper cells (such as Th1, Th17, Treg and Tfh cells), B cells (Naïve, IgM memory, Class-switched, IgD⁻CD27⁻ double negative and Plasmablasts cells), Monocytes, Dendritic cells and NK cells, and evaluated the relationship of immunophenotypes with clinical indices, disease activity, risk of relapse, and changes in immunophenotypes after treatment with antithyroid drugs. The activated Th17 cells, activated T follicular helper (Tfh) cells, and IgD⁻CD27⁻ double-negative B cells were higher in newly onset GD compared with healthy participants. Th17 cells were associated with thyroid autoantibodies, thyroid function, thyroid enlargement, and Graves' Recurrent Events After Therapy (GREAT) score; while double-negative B cells were associated with thyroid autoantibodies. Treatment with antithyroid drugs decreased the activated Tfh cells in parallel with the improvement in thyroid function. However, activated Th17 cells were not associated with clinical improvement and remained unchanged. Peripheral blood immunophenotyping identified the differential involvement of T and B cell subsets in the pathogenesis of GD. Abnormalities in the differentiation of Th17, Tfh, and double-negative B cells reflected the clinical pathology associated with autoantibody production and excess thyroid hormones. And Th17 cells are significantly associated with the marker for resistance to treatment. These results suggest the involvement of Th17 cell activation in the intractable pathology associated with potential immune abnormalities in GD.

Clinical trial registration: #UMIN000017726 (Date: June 1st, 2015).

Dual-Directional Immunomodulatory Effects of Corbrin Capsule on Autoimmune Thyroid Diseases

Purpose. To investigate the effects of Corbrin Capsule (CS-C-Q80), a drug derived from Cordyceps sinensis (Berk.) Sacc., on autoimmune thyroid diseases (AITD). Methods. 44 Patients with Graves's disease (GD) and 56 patients with Hashimoto's thyroiditis (HT) were randomly assigned to treatment group (GD-Tx and HT-Tx) or control group (GD-Ct and HT-Ct). The control groups were given methimazole or levothyroxine only while the treatment groups were given Corbrin Capsule (2.0 g tid) besides the same conventional prescriptions as control groups. Thyroid hormones, thyroid antibodies, and T lymphocyte subsets were quantified at baseline and 24 weeks posttreatment. Results. Significant drop of serum anti-TPO-Ab levels was observed in both GD-Tx and HT-Tx groups. Before treatment, GD patients had higher helper T cells compared to cytotoxic T cells, while HT patients suffered from a nearly inverted proportion of helper T/cytotoxic T cells. There was a significant drop of the helper T/cytotoxic T cells ratio in GD-Tx to the median of the normal ranges after Corbrin treatment for 24 weeks, while that in HT-Tx was elevated. Conclusion. Corbrin Capsule could restore the balance between helper T and cytotoxic T cells in both GD and HT patients with dual-directional immunomodulatory effects. And it could significantly reduce the autoantibody levels in both GD and HT.

Analysis of changes in the percentage of B (CD19) and T (CD3) lymphocytes, subsets CD4, CD8 and their memory (CD45RO), and naive (CD45RA) T cells in children with immune and non-immune thyroid diseases

Graves' disease (GD) is an autoimmune thyroid disease caused by immunological abnormality. The immune cells (lymphocytes T and B) which infiltrate the thyroid gland play a key role in the development of autoimmune thyroid disease (AITD). The aim of this study was to evaluate the differences between distribution of T (CD3) lymphocytes, subsets CD4, CD8, and their memory (CD45RO), and naive (CD45RA) T cells and B (CD19) lymphocytes in the peripheral blood of patients with Graves' disease (GD) (n = 33, mean age 15.9 +/- 5.9 years) and non-toxic nodular goiter (NTNG) (n = 25, mean age 15.2 years), in comparison to age- and sexmatched healthy control subjects (n = 25, mean age 15.9 years). The percentages of peripheral blood lymphocyte subsets were analyzed by three-color flow cytometry using a Coulter EPICS XL cytometer. In the untreated Graves' patients we observed an increase in the percentage of CD19+ (p<0.007, p<0.003), CD4+ (p<0.004, p<0.017), CD4+CD45RO+ (p<0.04, NS), CD4/CD8 ratio (p<0.002, p<0.001) and a decrease in the percentage of CD8+ (p<0.02, p<0.02), CD4+CD45RA+ (p<0.04, p<0.03) cells in comparison to the healthy control subjects and euthyroid Graves' patients. These abnormalities were absent in children with non-toxic nodular goiter. In addition, the levels of CD3+, CD4+CD8+, CD8+CD45RO+ T cells and CD8 lymphocytes co-expressing CD45RA and CD45RO antigens were similar in all groups and no statistically significant differences were found in comparison to the healthy controls. In the untreated Graves' patients we found a positive correlation between serum levels of fT4 and fT3 and the percentage of CD19+ lymphocytes (r = 0.45, p<0.01, r = 0.37, p<0.04), between serum level of fT4 and the percentage of CD4CD45RO (r = 0.4, p<0.02) lymphocytes and between concentration of TRAb and CD4+ (r = 0.38, p <0.04) and CD19+ (r = 0.39, p<0.016) cells. Statistically significant negative correlations existed between TRAb, TPO-Ab or TG-Ab concentration in blood serum and the percentage of CD8+ lymphocytes (r = -0.55, p<0.002; r = -0.41, p<0.02; r = -0.51, p<0.004), and between fT4 concentration and the percentage of CD8+ (r = -0.39, p<0.02) lymphocytes. No such correlation was detected in patients with non-toxic nodular goiter. We conclude that the abnormal distribution of B lymphocytes, memory and naive T cell subsets in the peripheral blood in children and adolescents with untreated Graves' disease suggests their role in the development of autoimmunity. The normalization in the percentage of these immune cells after thyrostatic treatment in comparison to newly diagnosed patients confirms the immunomodulatory effect of methimazole therapy.

T-cell receptors and autoimmune thyroid disease--signposts for T-cell-antigen driven diseases

The human autoimmune thyroid diseases (AITDs) are characterized by profuse infiltrates of both CD4+ and CD8+ T cells. The intrathyroidal T-cell-receptor repertoire in Graves' disease, more than in Hashimoto's disease, has been shown to be biased as evidenced by phenotypic analysis and by the use of a restricted T-cell-receptor variable (V) gene repertoire seen in both TCR alpha and beta chains. Evidence for a bias in the T-cell repertoire has also been observed in animal models of induced and spontaneous autoimmune thyroiditis. We found a similar phenomenon of autoimmune thyroid-related T-cell bias in thyroid-humanized scid mice. In these studies we transplanted lymphocyte-depleted thyrocytes and autologous peripheral lymphocytes from AITD patients with a basement membrane preparation which allowed the formation of an artificial thyroid which we have called an "organoid". T-cell clonal expansion was present in these artificial mixed-cell organoids which appeared to mimic the in vivo process. Such clonal expansion was suggestive of an antigen-driven immune response and could also be identified in thyroid tissue from patients with Graves' disease. Our data on scid mice grafted with human mixed-cell thyroid organoids, therefore, suggested that the major antigens driving T-cell selection in patients with AITD were most likely to be thyroid specific. These antigens include thyroglobulin, thyroid peroxidase, and the receptor for thyroid stimulating hormone (TSHR) on the surface of thyroid epithelial cells and we found significant T-cell proliferation to synthetic TSHR peptides in patients with AITD as compared with normals. Our search for a TCR recognition motif for the autoantigen TPO did not reveal any specific sequence motifs. Instead, analysis of the physico-chemical characteristics i.e. hydrophobicity of the amino acids in the CDR3 (N) region of the TCR alpha chain, revealed a strong negative linear correlation between strength of stimulation and the average hydrophobicity of N-region amino acids. This led us to hypothesize that lower affinity T-cell clones were commonly more hydrophobic in their CDR3 alpha region amino acids in keeping with potential crossreactivity of such T cells as a consequence of promiscuous, hydrophobic CDR3 regions. This phenomenon would be analogous to polyreactive, natural autoantibodies which tend to be crossreactive and 'sticky'. Thus, the physico-chemical characteristics of the TCR alpha CDR3 region supported the interaction with antigen/MHC by potentially cross-reactive T cells of low affinity. It would seem likely that such low-affinity autoreactive T-cell populations serve as a pool of potentially pathogenetic cells. These cells would be able to respond to an insult which, via a number of possible mechanisms such as molecular mimicry, would initiate a thyroid lymphocytic infiltration in an antigen-driven fashion with intrathyroidal T-cell expansion and a marked bias in the utilization of T-cell-receptor V genes.

Immunologic effects of human peripheral and intrathyroidal lymphocytes on xenotransplanted human thyroid tissue in athymic nude mice

T cells are intimately involved in the etiology and pathogenesis of human autoimmune thyroid disease. In order to further elucidate the immunologic mechanisms leading to Graves' disease (GD), we investigated the effects of human lymphocytes derived from patients with autoimmune and nonautoimmune thyroid diseases on human thyroid tissue xenotransplanted into nude mice. Eight weeks after transplantation of thyroid tissue from 26 patients with nonautoimmune thyroid disease (nontoxic nodular goiter [NTG]) into nude mice, peripheral (PBL) and intrathyroidal lymphocytes (ITL) from 14 patients with NTG and 12 patients with GD were engrafted into the animals. ITL and PBL subsets were analyzed by flow cytometer before engraftment. Two days after lymphocyte engraftment, the thyroid transplants were examined histologically (HE) as well as immunohistologically by staining with monoclonal antibodies directed against CD3 (T-cell activation and signal transduction), immunoglobulin G (IgG), HLA class II and CD31 (human endothelium). After injection of GD lymphocytes, thyroid transplants contained significantly more CD3, HLA class II, and CD4 expressing cells. Engrafted PBL and especially ITL from patients with GD specifically migrated into human thyroid transplants but not into the mouse thyroids, induced expression of class II products and led to IgG production by plasma cells. Persistence of human endothelium has been proven by positive CD31 staining. In conclusion, our data demonstrate that an organ-specific immune response is induced only by GD lymphocytes that migrate specifically into the thyroid transplants. Persistence of human endothelial cells in the transplants suggests that homing in this in vivo model reflects the situation in GD patients.

Perforin expression by thyroid-infiltrating T cells in autoimmune thyroid disease

Infiltration of the thyroid gland by lymphocytes is a hall-mark of autoimmune thyroid disease; it is particularly evident in Hashimoto's thyroiditis but is also seen in most patients with Graves' disease. Infiltrating cells are comprised primarily of T lymphocytes, of which only a minority appears to be activated. Their precise pathogenic role is largely unknown. Since perforin has been a marker for functionally activated cytotoxic T cells in situ we elected to assess the presence of perforin-containing cells in thyroid-infiltrating lymphocytes and establish their phenotype. Cells were isolated from seven subtotal thyroidectomy specimens, five from patients with Graves' disease and two with Hashimoto's thyroiditis. The novel findings were as follows: CD4+ perforin-containing T cells occurred only in Hashimoto's glands, suggesting a class II-restricted component of cytotoxicity; in Graves' disease, and to a lesser extent in Hashimoto's, perforin-expressing cells were primarily T cell receptor alpha beta- CD4-CD8- (double negative); double negative perforin-containing cells in peripheral blood of normal individuals were largely gamma delta + T cells. In Hashimoto's samples, the predominant population of T cells expressing perforin was CD8+. By comparison, in studies of the synovial fluid of knee joints from patients with rheumatoid arthritis only a minor population of the perforin-containing cells was double-negative. The data suggest significant differences in cytotoxic autoimmune mechanisms between the two autoimmune thyroid diseases. Functional characterization of double-negative T cells is necessary to define their role in autoimmunity.

Lymphocytic traffic and homing into target tissue and the generation of endocrine autoimmunity

Endocrine autoimmunity is known to be characterized by the presence of specific autoantibodies and from the histopathological point of view by lymphocytic infiltration in the target tissue. The presence of mononuclear cell infiltrates is the pathological hallmark of most endocrine diseases characterized by an autoimmune process directed against antigens expressed on endocrine cells. Infiltrating cells can usually be detected by biopsy or by using other, non-invasive, techniques. However, in endocrine tissue such as the islets of Langerhans and the adrenal glands it is difficult to perform biopsies and diagnosis of the autoimmune process is dependent mainly upon detection of specific autoantibodies. A crucial aspect of endocrine autoimmunity and of all processes of organ specific autoimmunity is why and how lymphocytes migrate from primary lymphoid tissue to their specific targets. This occurs mainly through contact with specific adhesion molecules which enable lymphocytes to adhere to the endothelial vessels in close proximity to the target tissue. In this review we discuss the homing of peripheral mononuclear cells into target endocrine tissues and the mediating role of adhesion molecules.

Intrathyroidal lymphocyte subsets, including unusual CD4+ CD8+ cells and CD3loTCR alpha beta lo/-CD4-CD8- cells, in autoimmune thyroid disease

Intrathyroidal lymphocyte subsets were analysed in 13 euthyroid patients with autoimmune thyroid disease by two-colour flow cytometry and compared with subsets in peripheral blood. In both Graves' and Hashimoto's diseases, proportions of intrathyroidal CD5- B cells were higher than in peripheral blood. The numbers of such cells were correlated with serum levels of anti-thyroid microsomal antibodies. Proportions of T cells bearing alpha beta chains of T cell receptors (TCR alpha beta+ T; T alpha beta) and CD16+CD57+ natural killer (NK) cells were lower in the thyroid, but proportions of CD3hiTCR alpha beta-TCR gamma delta+ (T gamma delta) cells were not different. Proportions of CD4+Leu-8- helper T cells and CD4+CD57+ germinal centre T cells were higher and proportions of CD4+Leu-8+ suppressor-inducer T cells and CD8+CD57+ or CD8+CD11b+ suppressor T cells were lower than in the blood in both diseases. Proportions of CD5+ B cells were high in Graves' disease, and proportions of CD8+CD11b- cytotoxic T cells were high in Hashimoto's disease. Unexpectedly, CD4+CD8+ cells and CD3loTCR alpha beta lo/-CD4-CD8- cells were present in thyroid tissues of both diseases. These findings suggest that: (i) an imbalance in the numbers of regulatory T cells and of NK cells that had appeared in the thyroid resulted in the proliferation of CD5- B cells, which were related to thyroid autoantibody production; (ii) CD5+ B cells and cytotoxic T cells are important for the different pathological features in Graves' and Hashimoto's diseases, respectively; and (iii) intrathyroidal CD4+CD8+ cells and CD3loTCR alpha beta lo/-CD4-CD8- cells may be related to the pathogenesis of autoimmune thyroid disease.

Evidence for selective accumulation of intrathyroidal T lymphocytes in human autoimmune thyroid disease based on T cell receptor V gene usage

We have investigated the T cell receptor V alpha and V beta gene family usage by T lymphocytes infiltrating affected thyroids in patients with autoimmune thyroid disease. We show that the intrathyroidal T lymphocytes from patients (n = 6) with autoimmune thyroid disease display a widespread usage of V beta gene families with an average of 14.4/19 V beta gene families similar to the peripheral T lymphocytes of the same patients. Because we recently reported that the utilization of V alpha gene families is markedly reduced within these mitogen-stimulated intrathyroidal T cell populations, as well as within intact tissue from similar patients (n = 4) (overall mean of 4.0/18 families detected), these results indicate that in thyroids of patients with autoimmune thyroid disease the lymphocytes are selectively accumulating based on their V alpha rather than V beta elements. This preferential hTcR V alpha and widespread V beta gene usage was not mimicked in most 7-d autologous mixed lymphocyte reactions using non-T cell stimulators (n = 6) or EB-virus immortalized autologous B cell lines (n = 3). Hence, the selective V gene utilization by intrathyroidal T cells is likely to be secondary to multiepitopic thyroidal autoantigens activating thyroid infiltrating T cells or to the presence of a superantigenlike thyroidal self-antigen, capable of determining a selective infiltration or activation of a variety of T lymphocytes on the basis of their V alpha gene usage.

T cells and human autoimmune thyroid disease: emerging data show lack of need to invoke suppressor T cell problems

Human T cells recognize self and foreign antigens when such antigens are processed into small peptides and bound to molecules coded for by genes of the HLA region on chromosome 6. The part of the T-cell surface which is responsible for such recognition is a set of molecules coded for by a variety of genes and known as the T-cell-receptor complex. In animal models, T cells are able to transfer autoimmune thyroiditis and T cells have, therefore, long been implicated in the etiology of human autoimmune thyroid disease (AITD). Information gained from the study of intrathyroidal T cells and thyroid antigen-specific T-cell clones has shown that in patients with Graves' disease, mainly helper T-cell clones have been obtained, whereas in autoimmune (Hashimoto's) thyroiditis cytolytic T-cell clones may be predominant. Such thyroid antigen-specific T cells have now been shown to recognize one or other of the three major thyroid-specific antigens; thyroglobulin, thyroid peroxidase, or the TSH receptor and efforts are currently in progress to characterize the T-cell epitopes of these major thyroid autoantigens. Recent findings of restricted T-cell receptor V gene use amongst intrathyroidal T cells confirm the primary role of T cells in human thyroid autoimmune processes leading to AITD. However, the mechanisms whereby such autoreactive T cells escape deletion and anergy, and how they become activated, remain uncertain. There is compelling evidence that the thyroid cell itself, by expressing HLA molecules, and presenting antigen directly to the T cells, may initiate disease, perhaps after an external insult.

Preferential use of T-cell receptor V genes in human autoimmune thyroid disease

We review here our analyses of hTcR V gene activity within the thyroid glands of patients with autoimmune thyroid disease. Our data, based on thyroid aspiration specimens, indicate that early in the onset of Graves' disease there is a marked restriction in both hTcR V alpha and V beta gene families utilized by intrathyroidal T-cells. Later, however, and as seen in surgical thyroid specimens from patients with long term disease, there appears to be a loss of V beta restriction for unclear reasons. In contrast, patients with Hashimoto's thyroiditis are usually diagnosed later in the natural history of the disease and appear to show much less hTcR V gene family restriction. The mechanisms driving the use of few and many hTcR V genes within the thyroid gland are likely to be complex and may reveal important insights into disease pathogenesis.

Intrathyroidal activated (Ia+) T-lymphocyte CD+ subsets and B cells in Graves' hyperthyroidism respond rapidly to propylthiouracil therapy: demonstration using fine needle aspirates and two-colour laser flow cytometry

Using a rapid (whole blood lysis) single laser microfluorocytometric technique that permitted the simultaneous analysis of two monoclonal antibody surface markers tagged with different fluorescent dyes, the intrathyroidal (IT) and peripheral blood (PB) activated [Ia+ = DR+] T-lymphocyte CD3+ subsets and [F(ab')2+] B cells were studied in hyperthyroid patients with Graves' disease (GD) before and after 1-4 months of propylthiouracil (PTU) therapy. IT lymphocytes were obtained by serial fine needle aspiration. In untreated patients a marked quantitative (approximately < 10 fold) increase in activated (Ia+ CD3+) T-lymphocytes as well as CD4+ and CD8+ subsets, for IT compared to PB sites, was found. The percentages of Ia+ CD4+ and Ia+ CD8+ within Ia+ CD3+ were not significantly different between the two sources of T cells. F(ab')2+. B cells were significantly increased (approximately 2-3 fold) in IT compared to PB. In hyperthyroid GD patients, PTU therapy induced rapid and specific changes within the Ia+ CD3+ subsets, namely a reduction in the Ia+ CD4+ subset and an increase in the Ia+ CD8+ subset, resulting in a marked decrease in the Ia+ CD4+/Ia+ CD8+ ratio. These changes occurred in association with a reduction in serum T4 and T3 concentration. No significant changes could be detected within the total (predominantly non-activated) CD3+, CD4+ or CD8+ lymphocyte subsets within PB and only a small decrease in the CD4+/CD8+ ratio was demonstrated in IT, following PTU treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

The SCID-hu mouse and thyroid autoimmunity: characterization of human thyroid autoantibody secretion

Severe combined immunodeficient (SCID) mice were injected with peripheral blood mononuclear cells (PBMC) from normal individuals and 14 out of 18 had detectable serum human (h) IgG (maximum levels providing a mean +/- SEM 934 +/- 213 micrograms/ml) and IgM (253 +/- 93 micrograms/ml) at 3-6 weeks after transplantation. Serum human immunoglobulin levels were maximum 6-12 weeks after transplantation and declined to low levels over the subsequent 5 months. Human B cells constituted up to 10% and human T cells up to 40% of cells in the peripheral circulation and spleens of these animals 2-3 weeks after transplantation, PBMC, or intrathyroidal (IT) lymphocytes, from 6 patients with Graves' disease and high serum levels of thyroid autoantibodies were transplanted into 30 SCID mice (Graves' SCID-hu). Although serum human immunoglobulins were observed in only low amounts in the animals receiving IT lymphocytes (n = 4), increased levels of hIgG or hIgM were more easily detectable in 19 Graves' SCID-hu mice that received PBMC. The Graves' SCID-hu mice had significantly lower mean levels of hIgG and hIgM than those observed following transplantation of normal PBMC (mean maximum 328 +/- 113 and 32 +/- 21 micrograms/ml, respectively). Six of these 19 mice had detectable human autoantibody to thyroid peroxidase (TPO, as microsomal antigen) between 3 and 8 weeks after transplantation, with titers ranging from 0.05 to 0.39 (normal SCID-hu serum less than 0.02 ELISA Index). No abnormal thyroid hormone (T4 and T3) levels or thyroiditis was seen when compared to normal SCID-hu mice. Immunization of reconstituted SCID mice with recombinant immunoactive human TPO antigen failed to initiate anti-TPO in normal PBMC-treated mice nor did it increase the titer of human anti-TPO in the anti-TPO positive animals. In conclusion we successfully established human thyroid autoantibody secretion in the SCID-hu mouse and characterized the transient nature of the model. Further studies will be required to achieve successful antigen presentation in this system.

Evidence of limited variability of antigen receptors on intrathyroidal T cells in autoimmune thyroid disease

BACKGROUND

Patients with autoimmune thyroid diseases, including Graves' disease and Hashimoto's disease, have marked lymphocytic infiltration in their thyroid glands. We examined the gene for the variable regions of the alpha-chain of the human T-cell receptor (the V alpha gene) in intrathyroidal T cells to determine whether the infiltration is a secondary heterogeneous immune response or a more restricted, and therefore primary and presumably pathogenetic, reaction to thyroid autoantigens.

METHODS

We used the polymerase chain reaction to detect small numbers of T cells expressing the variable region of the V alpha gene. Different oligonucleotides were used to amplify complementary DNA for the 18 known families of the V alpha gene in intrathyroidal T cells from 9 patients with autoimmune thyroid disease. We compared the findings with the results in patients with nonautoimmune thyroid disease as well as those in normal subjects.

RESULTS

We found marked restriction in the expression of T-cell-receptor V alpha genes by T cells from the thyroid tissue of patients with autoimmune thyroid disease. An average of only 5 of the 18 V alpha genes were expressed in such samples, as compared with 17 V alpha genes expressed in peripheral-blood T cells from the same patients. No such restriction was found in thyroid tissue from patients with nonautoimmune thyroid disease. The predominantly expressed V alpha genes differed from patient to patient, however, with no clear association with the type of disease.

CONCLUSIONS

Intrathyroidal T-cell accumulation in autoimmune thyroid disease is highly restricted and points to the primacy of T cells in causing thyroid disorders. These results present the possibility of using antibodies to the T-cell receptor for the specific inhibition of abnormal T-cell function in autoimmune thyroid disease.