Effect of macrophage depletion on immune effector mechanisms during corneal allograft rejection in rats.

PURPOSE: In rats, corneal allograft rejection is delayed for at least 100 days by clodronate liposomes. These liposomes selectively deplete macrophages. To investigate the immunologic basis for absence of graft rejection in treated rats, the effect of these liposomes on the generation of cytotoxic T lymphocytes (CTLs) and antibody production after orthotopic corneal allotransplantation was determined. METHODS: Transplantations of corneal buttons from PVG rats were performed in AO rats. After surgery, one group received clodronate liposomes subconjunctivally at five time points, and the other group remained untreated. On postoperative day (POD) 3, 7, 12, or 17, rats were killed, the presence of CTLs was investigated at three different anatomic locations, and antibodies against donor antigens were tested. RESULTS: No significant differences were found between the groups tested 3 and 7 days after surgery. But on POD 12 (the time of onset of rejection in the untreated group) and on POD 17, the CTL activities detected in the submandibular lymph nodes (P < or = 0.008) and the spleen (P < or = 0.009) were significantly less in the treated groups compared with the untreated groups. In the untreated groups complement-independent antibodies were present only on POD 17, whereas no antibodies were found in the treated rats. CONCLUSIONS: Local treatment with clodronate liposomes was shown to downregulate local and systemic CTL responses and to prevent the generation of antibodies. Local depletion of macrophages in the initiation phase of the immune response appears to lead to a less vigorous attack on the grafted tissue and therefore to promote graft survival.

Changes in cytokine mRNA levels in experimental corneal allografts after local clodronate-liposome treatment.

PURPOSE: Corneal allograft rejection in rats can be prevented by subconjunctival injections of liposomes containing dichloromethylene diphosphonate (clodronate-LIP), which selectively eliminate macrophages. In this study, the effect of clodronate-LIP treatment on cytokine mRNA levels in corneal allografts was examined. METHODS: AO rats received corneal grafts of PVG rats. Rats were either not treated or injected subconjunctivally with clodronate-LIP on the day of transplantation and on postoperative days (PODs) 2, 4, 6, and 8. RNA was isolated from the graft and rim of corneas at different times after transplantation and from normal controls. Interleukin (IL)-1beta, IL-1 receptor antagonist (IL-1RA), IL-2, IL-4, IL-6, IL-10, IL-12p40, tumor necrosis factor (TNF)-alpha, TNF-beta/lymphotoxin (LT), interferon (IFN)-gamma, monocyte chemotactic protein 1 (MCP-1), and macrophage inflammatory protein 2 (MIP-2) mRNA levels were analyzed by semiquantitative reverse transcription-polymerase chain reaction (RT-PCR). RESULTS: Corneal rejection, observed in all untreated rats by POD 12, was associated with increased mRNA levels of all cytokines investigated in grafts and rims. Clodronate-LIP treatment prevented allograft rejection and strongly decreased the levels of IL-1beta, IL-1RA, IL-2, IL-4, IL-6, IL-10, IFN-gamma, TNF-beta/LT, MCP-1, and MIP-2 mRNA in grafts and IL-1 beta, IL-2, IL-4, IL-6, and IFN-gamma mRNA in rims. Interleukin-12p40 mRNA levels were unaltered in clodronate-treated rats, except for a transient increase in grafts at POD 3. TNF-alpha mRNA levels were increased by clodronate-LIP in grafts and rims early after transplantation (PODs 3 and 7). Despite a normal appearance, long-term accepted corneal grafts (POD 100) contained mRNA for IL-10, IL-12p40, TNF-alpha, MCP-1, and MIP-2. CONCLUSIONS: Clodronate-liposome treatment markedly altered the mRNA levels of all cytokines investigated in corneal allografts. These results may explain in part the mechanism by which clodronate-LIP treatment prevents corneal allograft rejection.

Are cytokine patterns in aqueous humour useful in distinguishing corneal graft rejection from opacification due to herpetic stromal keratitis?

PURPOSE: Intra-ocular cytokine profiles were determined to study the immunological mechanisms of corneal graft opacification due to rejection and/or herpetic stromal keratitis (HSK). METHODS: Sera and aqueous humour (AH) were sampled shortly after the onset of corneal graft opacification, group I (n=18). In eyes with clear grafts, samples were taken 5 months after transplantation, group II (n=59). Samples of non-inflamed eyes, prior to cataract surgery, were used to determine baseline cytokine levels, group III (n=49). Total protein (TP) levels were measured with Bradford reagent and interleukin (IL)-6, IL-10, IL-4 and interferon (IFN)-gamma with ELISAs. RESULTS: All patients who's corneal grafts showed clinical evidence of graft opacification due to rejection and/or HSK were sampled. In the AH-samples of group I, increased levels of TP were found in 60% (9/15), IL-6 in 79% (11/14), IL-10 in 39% (7/18) and IL-4 in none (0/12). IFN-gamma was detected in 19% (3/16), in the case of HSK only. In contrast, samples obtained from patients with clear grafts in group II showed increased levels of TP in 36% (20/55), IL-6 in 14% (8/57) and IL-10, IL-4 or IFN-gamma in none (n=58). CONCLUSIONS: During corneal graft rejection and/or HSV-infection, increased levels of TP and IL-6 in AH confirmed anterior chamber inflammation with breakdown of the blood-aqueous barrier. Based on the data presented, cytokine patterns in the AH do not appear to distinguish corneal opacification due to graft rejection from that due to herpes keratitis.

Cytotoxic T lymphocytes and antibodies after orthotropic penetrating keratoplasty in rats treated with dichloromethylene diphosphonate encapsulated liposomes.

PURPOSE: To investigate the immunological basis for the prolonged corneal allograft survival after subconjunctival injections of liposomes filled with dichloromethylene diphosphonate (Cl2MDP-LIP). METHODS: F344 rats received orthotropic DA corneal grafts. One group of rats was treated with subconjunctival injections of Cl2MDP-LIP on days 0, 2, 4, 6 and 8 postoperatively, the control groups received no treatment. Nineteen or 42 days postoperatively cytotoxic T lymphocyte (CTL) activity was measured in the lymph nodes draining the grafted and the contralateral eyes, in the spleen and the mesenteric lymph nodes. Sera taken at the same time points were tested for presence of lytic alloantibodies. RESULTS: On day 19 CTL activity in submandibular lymph nodes draining the grafted eyes was similar in the 2 groups. In the mesenteric lymph nodes high CTL activity was found in the untreated rats and low in the Cl2MDP-LIP rats. The spleen showed high CTL activity in the untreated group but no activity in the liposome group. Forty two days postoperatively a decline in CTL activity was seen in both groups. Complement dependent anti-donor antibodies were absent in the Cl2MDP-LIP group at both time points whereas antibodies were present on days 19 and 42 in the untreated group. CONCLUSIONS: Repeated subconjunctival injection of Cl2MDP-LIP restricts the induction of cellular cytotoxicity against donor antigens to the regional lymph nodes and suppresses cytotoxic antibody formation.

Cytokine mRNA expression during experimental corneal allograft rejection.

Allograft rejection is the main cause of corneal graft failure. T lymphocytes and macrophages have been implied to be involved in corneal rejection, but little is known about the molecular mechanism in this process. In this study, cytokine mRNA expression in the cornea was analysed during experimental corneal transplantation. The donor and acceptor corneas of two groups of rats were studied after receiving an allo- (PVG to AO rat) or autograft (AO rat). For controls, central buttons and peripheral corneal rings of the non-transplanted contralateral eyes were used. At different post-operative days (1, 3, 7, 12 and 19), the corneas were removed and subjected to mRNA isolation. All corneal samples underwent semi-quantitative reverse transcriptase-polymerase chain reaction analysis for interleukin-1 beta, interleukin-1, receptor antagonist, interleukin-2, interleukin-4, interleukin-6, interleukin-10, tumor necrosis factor-alpha, interferon-gamma, monocyte chemotactic protein-1 and macrophage inflammatory protein-2 mRNA expression. Corneal rejection, characterized by opaque corneas with prominent neovascularization, was always diagnosed around day 12. Contralateral, non-grafted corneas showed constitutive mRNA expression for interleukin-1 receptor antagonist and in a few samples also monocyte chemotactic protein-1 and macrophage inflammatory protein-2 mRNA was found. Both allo- and autografts expressed mRNA for the cytokines found in contralateral, non-grafted tissue, as well as for interleukin-1 beta, interleukin-6, interleukin-10 and tumor necrosis factor-alpha. In allografts, the mRNA levels for these cytokines remained constant throughout all post-operative days, with increased interleukin-6 mRNA expression after post-operative day 12. The analysis of the autografts revealed high cytokine mRNA levels until post-operative day 3 or 7, which decreased from then on, except for interleukin-1 receptor antagonist. mRNA for interleukin-2, interleukin-4 and interferon-gamma was not observed in autografts at any time point and in allografts, until post-operative day 12. Interleukin-2 and interferon-gamma mRNA showed maximal expression on POD 12, while in autografts, a marked decrease was observed after POD 3. IL-10 mRNA levels decreased immediately after POD 1 in autografted eyes. For TNF-alpha, an increased mRNA expression starting on POD 7 was found in recipient rings of allografted eyes, while in autografts a weak expression was seen in some samples. MIP-2 transcription increased on PAD 12, while in autografts, its expression was not markedly different from that detected in the contralateral, non-grafted peripheral cornea.

Prevention of corneal allograft rejection in rats treated with subconjunctival injections of liposomes containing dichloromethylene diphosphonate.

PURPOSE: The drug dichloromethylene diphosphonate (CL2MDP) encapsulated in liposomes depletes macrophages but not other immunocompetent cells. The authors investigated whether subconjunctival injection of CL2MDP containing liposomes (CL2MDP-LIP) could prolong survival of corneal allografts in rats. METHODS: Male Fisher rats received orthotopic corneal grafts of Dark Agouti origin. Rats were treated postoperatively with subconjunctival injections of 0.1 ml CL2MDP-LIP at the time of transplantation and on days 2, 4, 6, and 8 after transplantation. Control groups received either liposomes containing phosphate-buffered saline subconjunctivally at the same time points or no additional treatment. Corneal grafts were evaluated every other day and were scored for neovascularization, opacity, and edema. Immunohistologic evaluation was performed 12 and 19 days after surgery. RESULTS: Corneal grafts in both control groups were rejected within 17 days. In the Cl2MDP-LIP treated rats, grafts were not rejected during the maximum follow-up of 100 days. Cellular infiltration in these grafts was clearly reduced. There was also a strong reduction in neovascularization of the cornea. CONCLUSIONS: Rejection of orthotopic allogeneic corneal grafts could be prevented by repeated subconjunctival injection of Cl2MDP-LIP.

Circulating cornea-specific antibodies in corneal disease and cornea transplantation.

In order to establish the significance of circulating cornea-specific antibodies, we determined the presence of anti-corneal antibodies in the serum of 100 patients with corneal disease and in 50 healthy controls, and subsequently followed the pattern of antibody reactivity in 46 patients who underwent corneal transplantation. An indirect immunofluorescence test on cryostat sections of rabbit corneas was used for screening. The reactivity against two known bovine corneal epithelial proteins was also tested: a 54-kD protein (BCP 54) and an 11-kD protein (BCP 11/24). No significant difference in the presence and specificity of anti-corneal antibodies was observed between the group of patients with corneal disease, taken as a whole, and the healthy controls. Patients with keratoconus or non-immunological graft failure, however, were significantly more often positive for anti-corneal antibodies. Neither the presence of antibodies prior to corneal transplantation nor their appearance post-transplantation had a predictive value for corneal graft survival.

Site-dependent distribution of macrophages in normal human extraocular muscles.

PURPOSE: Clinical data indicate that extraocular muscles have different susceptibilities for some orbital immune disorders depending on their anatomic location. The resident immunocompetent cells may be important mediators in the local pathogenesis of such disorders so the distribution of these cells was studied in extraocular muscles obtained from normal human donors. For comparison skeletal muscles were studied. METHODS: The cell distributions were analyzed quantitatively in cryostat cross-sections subjected to a two-step immunoperoxidase method using monoclonal antibodies against T cells, B cells, macrophages and several other markers for cell differentiation or activation. The macrophage distribution was analyzed in more detail using on-line semiautomatic image analysis equipment (VIDAS, Kontron, Elektronik GmbH, Eching, Germany). RESULTS: Extraocular muscles contain numerous macrophages, fewer human leukocyte antigenD-related (HLA-DR) positive cells and T cells, whereas B cells are absent. The numeric density of all cell types, and macrophages in particular, is much higher in extraocular muscles than in skeletal muscles. In extraocular muscles the majority of T cells are positive for the CD8 antigen (suppressor/cytotoxic), in skeletal muscle CD4 positive T cells (helper) predominate. CONCLUSIONS: Extraocular muscles contain many more CD8-positive cells and macrophages per square millimeter than skeletal muscles. Of all the cell types studied, only the macrophage distribution differs significantly among the normal extraocular muscles: the medial and inferior recti muscles contain about twice as many macrophages as the lateral rectus and superior oblique muscles. Their mean sizes (area) or shape distributions however, appear to be similar.

Site-dependent effects of experimental hypo- and hyperthyroidism on resident macrophages in extraocular muscles of rats: a quantitative immunohistochemical study.

It has been suggested that the effects of dysthyroidism on resident immunocompetent cells of the extraocular muscles may play a role in the pathogenesis of Graves' ophthalmopathy. The distribution of such cells was therefore studied in extraocular muscles of rats that were made hyper- or hypothyroid by the oral administration of thyroxine or propylthiouracil respectively. Skeletal muscles were studied for comparison. The cell distributions were analysed in cryostat cross-sections subjected to a two-step immunoperoxidase method using well-characterized monoclonal antibodies against T cells, B cells, macrophages and MHC class II antigens. The extraocular muscles of control (euthyroid) rats contained numerous macrophages, fewer MHC-II positive cells and T cells and no B cells. Differences in the distribution of immunocompetent cells were found in control rats, between skeletal and extraocular muscles as well as within the various recti eye muscles. This particular tissue distribution resembles that previously reported for human extraocular and skeletal muscles. Quantitative analysis showed that experimental dysthyroidism only affected cell populations in the extraocular muscles. Significant effects on the number of macrophages were observed in the inferior rectus muscle of both hypo- and hyperthyroid rats, this was most pronounced in the orbital layer of the muscles. Both hyper- and hypothyroidism appear to affect local cell distributions in a tissue-specific manner. The presently observed site-dependent effects of dysthyroidism on local immunocompetent cell populations may have relevance for the differential involvement of muscular tissues in Graves' ophthalmopathy.

Corneal autoimmunity in a patient with relapsing polychondritis.

We report our experiences with a patient with relapsing polychondritis, in whom circulating antibodies against corneal epithelium were determined by immunofluorescence before and after medical treatment. The results provide further evidence for an autoimmune pathogenesis of the disease.

Potential antigen-presenting cells in normal extraocular muscles demonstrated with double immunoenzyme staining.

Antigen-presenting cells are of crucial importance for the initiation and regulation of regional immune responses. In a previous study, indirect morphological evidence that morphologically normal human orbital tissues contain HLA-DR-positive macrophages, which may represent antigen-presenting cells, has ben obtained. In the present study, these cells were characterized in detail using double immunoenzyme staining techniques with monoclonal antibodies directed against several well-characterized monocyte/macrophage markers and against HLA-DR gene products. The orbital muscular tissues appear to contain numerous HLA-DR, monocyte/macrophage marker double-stained cells, which are considered to be potential antigen-presenting cells. The cells are widely distributed in the connective tissue of all the orbital muscular tissues studied and consist of several subsets with different phenotypes. Furthermore, site-specific differences were shown between recti muscles and the levator/Müller's muscles with respect to the distribution of HLA-DR and one monocyte/macrophage marker (OKM5). Many of the orbital antigen-presenting cells appear to be of the dendritic type and are considered to be of major importance in regulating local orbital immunity.

Dendritic cells and class II MHC expression on thyrocytes during the autoimmune thyroid disease of the BB rat.

The BB rat is a well-established model for spontaneous thyroid autoimmune disease. Since antigen presentation in thyroid autoimmunity is still a matter of debate, we studied the presence of antigen-presenting dendritic cells in the thyroid of the BB/O rat during the development of the disease in relation to the presence of other leucocytes and the aberrant expression of class II MHC determinants by thyrocytes. Thyroid glands, as well as thyroid-draining lymph nodes, were investigated in enzyme histochemistry and immune histochemistry. The appearance of anti-colloid antibodies in the circulation at 6 weeks of age was accompanied by an increase in the weight of the thyroid-draining cervical lymph nodes, which contained many anti-thyroglobulin-producing plasma cells. The only noteworthy event in the thyroid gland in this early stage of the disease was an increase in the number of dendritic cells. T cells, B cells, and plasma cells were virtually absent from the thyroid, and thyrocytes were invariably negative for class II MHC determinants. Only after 18 weeks of age, when large accumulations of dendritic cells, B lymphocytes, and T lymphocytes were seen in 40% of the BB thyroids, could some class II MHC positive thyroicytes be observed. At this stage the thyroid also contained some anti-thyoglobulin-producing plasma cells. Our observations suggest that dendritic cells play a role in antigen presentation in the early stages of the thyroid autoimmune response.

Human tumor and normal tissue reactivity of the anti-(breast cancer) monoclonal antibody BA-Br-3 and its similarity to the anti-(epithelial membrane antigen) monoclonal antibody E29.

A mouse monoclonal antibody (BA-Br-3) raised against the breast carcinoma cell line CAMA-1 was previously shown to react with a greater than or equal to 300-kDa globule-like glycoprotein from human milk fat also expressed in the cytoplasm and on the surface of human carcinoma cells of different histological types. In this report the reactivity of this mAb with a large number of normal and malignant human tissues was analyzed using immunoperoxidase techniques. When tested on sections of both fresh-frozen tissues and formalin-fixed, paraffin-embedded tissues, BA-Br-3 reacted with a formalin-resistant antigenic determinant expressed by normal and malignant epithelial cells. Preferential reactivity was observed at the apical portion of ductal epithelial cells in normal breast and in glandular epithelia distributed in several other organs. Reactivity with mucin-like secretions in the lumina of ducts was also found. BA-Br-3 reacted mostly in heterogenous staining patterns with 88% of 49 breast carcinoma specimens tested, regardless of their histological type or whether they were primary or secondary neoplasms. Testing of epithelial malignant tumors other than breast carcinomas with this antibody showed that 127 of 151 (84%) were also reactive. mAb BA-Br-3 and E29 (a commercially available anti-(epithelial membrane antigen) shared very similar staining patterns and distributions of reactivity with breast and other epithelial tumors. However, BA-Br-3 showed a significantly higher percentage of reactivity with melanoma (33% versus 6%, P = 0.003) and a trend toward a higher percentage of reactivity with sarcoma (55% versus 27%, P greater than 0.05). This antibody, therefore, defines a molecule that is a member of the mucin-like epithelial membrane antigen family. Further studies are warranted to determine its usefulness in antibody-directed cancer diagnosis, prognosis, and immunotherapy.

Antibodies to 'second colloid antigen.' A study on the prevalence in sporadic forms of congenital hypothyroidism.

Antibodies against the so called 'second colloid antigen' (CA2 antibodies) occurred in 51% of the mothers of hypothyroid children detected by screening for neonatal congenital hypothyroidism in Quebec (N = 49) and in The Netherlands (N = 26). In The Netherlands where corresponding neonatal serum was available, 31% (8 of 26) of the infants with congenital hypothyroidism were positive for antibodies against the second colloid antigen. When during follow-up, 3 to 5 years after diagnosis, the mothers and their children were investigated, 46% (7 of 15) of the mothers were positive for antibodies against the second colloid antigen, whereas 29% (4 of 14) of the hypothyroid children were also positive. Various control groups did not show more than a 12% positivity. This presence of thyroid-reactive antibodies in a proportion of the hypothyroid children 3 to 5 years after diagnosis is not compatible with a mere transplacental passage; it indicates that the antibodies must be produced by the mothers and by the children themselves. We conclude that a thyroid autoimmune response occurs in a considerable part of infants with congenital hypothyroidism and their mothers and that this immune response seems to persist in both of them for years.

Immunoglobulins of patients with idiopathic Addison's disease block the in vitro action of adrenocorticotropin.

The presence of serum immunoglobulins (Ig) blocking ACTH-induced adrenal DNA synthesis and/or cortisol production was studied in 25 patients with idiopathic Addison's disease. For this purpose guinea pig adrenal segments kept in organ culture were exposed to ACTH and graded concentrations of patient IgG. After a 5-h culture period the cortisol present in the culture fluid was measured by RIA, and DNA synthesis in the adrenal cells was measured using Feulgen densitometry on frozen sections of the cultured adrenal segments. Addition of ACTH alone in concentrations of 0.1-10 pmol/L to the culture system stimulated in vitro cortisol secretion; the maximal stimulation was 63 +/- 35% (+/- SD; n = 5) at a concentration 0.1 pmol/L. ACTH also increased (in concentrations of 1 fmol/L to 1 pmol/L) the percentage of fasciculata cells in S-phase from 0-4% (nonstimulated) to 5-12%. IgG preparations from all but 2 of the 25 patients with idiopathic Addison's disease blocked these in vitro ACTH-induced adrenal responses in a dose-dependent fashion. IgG from 2 patients with tuberculous adrenalitis, 1 patient with secondary adrenal insufficiency, and 7 normal subjects had no blocking activity. Among 5 non-Addisonian autoimmune endocrinopathy patients who had adrenal cytoplasmic autoantibodies, 4 had no ACTH-blocking IgGs. Two of 9 patients with miscellaneous adrenal disorders (Cushing's disease, pigmented adrenal micronodular dysplasia, and adrenal nodules) had ACTH-blocking activity. These results demonstrate the existence of IgGs blocking the in vitro effects of ACTH and suggest their involvement in the pathogenesis of idiopathic Addison's disease.

Clinical criteria for the assessment of disease activity in Graves' ophthalmopathy: a novel approach.

Patients with serious inflammatory Graves' ophthalmopathy should be treated with anti-inflammatory drugs or radiotherapy to prevent complications like fibrosis, while those with non-inflammatory ophthalmopathy may be treated by surgery immediately. It is often difficult, however, to distinguish inflammatory from non-inflammatory Graves' disease. We therefore present a simple clinical classification here to differentiate between these two conditions. This classification is based on the classical signs of inflammation--pain, redness, swelling, and impaired function. After two consecutive clinical examinations an 'activity score' can be determined, ranging from 0 to 10 points. In a retrospective study testing the efficacy of this classification we found that patients with an activity score of 3 or more at the beginning of therapy responded well to anti-inflammatory drugs, while those with a lower activity score mostly did not. Comparing the pretreatment activity score with the degree of enlargement of the extraocular muscles on the CT scan, we found a significant correlation between these two parameters: the higher the activity score, the more the enlargement of the muscles. We conclude that this classification facilitates the proper selection of patients for treatment.

Temporal relationship between onset of Graves' ophthalmopathy and onset of thyroidal Graves' disease.

The temporal relationship between the onset of Graves' ophthalmopathy and the onset of thyroidal Graves' disease was evaluated in 125 consecutive patients with Graves' ophthalmopathy. Thyroidal Graves' disease--past or present--was clinically evident in 99 patients (79%): hyperthyroidism in 3 cases. Thyroid disease preceded the eye disease in 37 patients, it occurred simultaneously with the eye disease in 39 patients, and it developed after the eye disease in 23 patients (in 16 cases within one yr after the onset of eye disease). The age at the onset of thyroid disease (38.7 +/- 12.9 yr) was lower than the age at the onset of ophthalmopathy (41.8 +/- 12.5 yr; p less than 0.001). Among the 26 clinically euthyroid patients (21%) laboratory evidence of thyroidal Graves' disease was found in 14 cases (11%): abnormal TRH test, n = 9; normal TRH test but abnormal T3-suppression test, n = 4; normal TRH and T3-suppression tests but positive thyroid stimulating antibodies, n = 1). We conclude that Graves' ophthalmopathy as a rule develops at a time when thyroid autoimmunity also exists. This strongly suggests a common factor in the pathogenesis of thyroidal and ocular expressions of Graves' disease.

Immunoglobulins of patients with Cushing's syndrome due to pigmented adrenocortical micronodular dysplasia stimulate in vitro steroidogenesis.

The putative stimulation of adrenal steroid production by immunoglobulins (Igs) of five patients with pigmented adrenocortical micronodular dysplasia and clinical Cushing's syndrome was investigated. Ascorbate depletion, a process linked to steroid production, was measured by a cyto-chemical bioassay employing guinea pig adrenal explants in organ culture and exposed to IgG from the patients and normal subjects. We also measured cortisol production by these segments during a 5-h culture period using a RIA. For positive reference values we studied the effects of ACTH-(1-39), ACTH-(1-24), ACTH-(11-24), and ACTH-(18-39) on in vitro ascorbate depletion and cortisol production. Both ACTH-(1-39) and ACTH-(1-24) depleted ascorbate and stimulated cortisol production in adrenal cells. The dose-response kinetics of the peptides were bell-shaped; maximal responses were reached in both instances at 1 fmol/L to 10 pmol/L. In all tests, stimulation of in vitro cortisol production was paralleled by ascorbate depletion. ACTH-(18-39) also stimulated ascorbate depletion and cortisol production, but at one concentration only (100 fmol/L), and TSH and LH had no effect. Protein-A-Sepharose-purified IgG preparations of the five patients stimulated ascorbate depletion and/or cortisol production in a dose-dependent fashion; however, the responses occurred over a narrow concentration range (15-150 micrograms IgG/mL culture fluid). These observations support the hypothesis that the hypercortisolism of the syndrome of pigmented adrenocortical micronodular dysplasia is due to circulating Igs that stimulate adrenal steroidogenesis.

Therapeutic outcome of prednisone medication and of orbital irradiation in patients with Graves' ophthalmopathy.

Response to treatment was evaluated prospectively in 58 patients with Graves' ophthalmopathy. Prednisone, administered to 44 patients, resulted in a favourable response in 29 patients (66%): excellent in 3, good in 10 and fair in 16 subjects; 15 patients (34%) did not respond. Orbital irradiation was administered to 39 patients of whom all except 4 had been treated previously with steroids. Six months later, 25 patients (64%) had responded favourably (excellent in 0, good in 9 and fair in 16 subjects) and 14 patients had not responded (36%). A favourable response to prednisone or irradiation was reflected in a general shift to lower grades in each of the classes 2-6 of the NOSPECS system. Responders were not different from non-responders with regard to age, sex, NOSPECS classification, ophthalmopathy index, interval between the onset of eye disease (or of thyroid disease if present) and the start of treatment, or the presence of thyroid disease. In conclusion, (1) the ratio of responders to non-responders is 2:1 for both prednisone treatment and orbital irradiation in Graves' ophthalmopathy, (2) the response is seen in all classes of the NOSPECS system, and (3) the response is not dependent on age, sex, severity or duration of eye disease, or the presence of thyroid disease.

Intrathyroidal dendritic cells.

The presence, marker pattern, and ultrastructure of antigen-presenting dendritic cells were studied in normal thyroid glands from 9 subjects (6 obtained at surgery; 3 at autopsy) and in the thyroid glands form 13 patients with Graves' hyperthyroidism, 10 patients with simple nontoxic goiter, and 1 patient with Hashimoto's disease (all obtained at surgery). The immunohistochemical characterization of the cells was carried out using the monoclonal antibodies OKIa (class II MHC determinants), RFD1 and L25. These latter monoclonal antibodies react strongly with active dendritic cells in T-cell areas of secondary lymphoid organs (the interdigitating cells in lymph nodes and spleen). Antigen-presenting dendritic cells were defined as cells with an eccentric reniform nucleus, long cytoplasmic protrusions, and strong membrane-bound class II MHC positivity combined with little or no cytoplasmic acid phosphatase activity. According to these criteria normal human thyroid tissue contained a few dendritic cells; they were localized outside the thyroid follicles. These dendritic cells in normal thyroid tissue lacked the marker molecules identified by the monoclonal antibodies RFD1 and L25. In fact, the majority of the dendritic cells were strongly positive for the C3bi receptor (identified by the monoclonal antibody FK 24), which indicates a more monocyte/macrophage character of the cell. In Hashimoto's goiter, Graves' disease, and sporadic nontoxic goiter (which we consider an autoimmune thyroid disease) the numbers of dendritic cells were higher compared to those in the normal gland, and these dendritic cells were clearly positive for RFD1 and L25. The cells were often seen in contact with a few intrathyroidal lymphocytes, forming small lymphoid cell clusters. They were also found in the T-cell zones of larger well organized intrathyroidal lymphoid structures (focal thyroiditis). On ultrastructural examination the dendritic cells in Graves' glands, Hashimoto's goiter, and sporadic nontoxic goiter were similar to the interdigitating cells present in secondary lymphoid organs. The data suggest active involvement of dendritic cells in the immune process in the thyroids of patients with autoimmune thyroid disease.