Prognostic factors in the radiotherapy of Graves' ophthalmopathy.

Between April 1968 and February 1988, 311 patients with symptomatic and progressive Graves' ophthalmopathy were treated with megavoltage orbital radiotherapy. The patients were divided into three groups: I (156 patients) treated with 20 Gy/2 weeks; II (69 patients) treated with 30 Gy/3 weeks, and III (a most recent set of 86 patients) received 20 Gy/2 weeks. The degree of eye involvement was evaluated numerically before and after therapy for each of five parameters: soft tissue signs, proptosis, eye muscle impairment, corneal involvement, and sight loss. Pre-treatment and current thyroid diagnosis and status were also noted. To evaluate the effects of radiotherapy alone, follow-up was terminated at the time any eye surgery was done; for those not treated surgically the minimum follow-up was 12 months. Because there were significant demographic differences between the patient groups, the results of each group were analyzed separately. A stepwise linear regression analysis was performed to determine if there were any significant variables affecting outcome. Based on these data formulae were derived which enable outcome to be predicted in any patient. Before therapy more than 90% of patients in all groups had soft tissue and eye muscle involvement, whereas 65-75% had proptosis and about half 50% had some degree of sight loss. Radiotherapy arrested progression of ophthalmic parameters in all but 1-6% of the patients. Objective and symptomatic improvement was noted for all parameters assessed, but there was marked individual variability. The best responses were noted for soft tissue, corneal involvement, and sight loss; however over half the patients had some improvement in eye muscle function and proptosis. Factors which resulted in less favorable outcome included male gender, advanced age, need for concurrent therapy for hyperthyroidism, and no history of hyperthyroidism. No complications have been observed. No significant differences in outcome were observed between the two dosage schedules. Following radiotherapy 29% of patients subsequently underwent some form of eye surgery, mostly eye muscle surgery to correct diplopia. After radiotherapy corticosteroid therapy was stopped without relapse in 76%. Orbital radiotherapy can result in improvement in signs and symptoms of Graves' ophthalmopathy in the majority of patients. For the remainder of patients the disease manifestations can be stabilized to allow functional surgical correction.

Biological activity of autoantibodies associated with Graves' dermopathy.

To test the hypothesis that Graves' dermopathy is due to cross-reactivity of thyroid autoantibody(ies) with a cellular target in pretibial skin, we tested the serum and serum immunoglobulin fraction of 20 such patients for their effects on the metabolic activities of cultured thyrocytes (rat FRTL cells), human pretibial skin fibroblasts, and human fibroblasts of other origins. The incorporation of 3H-labeled thymidine, amino acids, and glucosamine into DNA, protein, and glycosaminoglycans, respectively, was measured. TSH and the serum of each of the 20 patients with Graves' dermopathy markedly stimulated the synthesis of DNA, protein, and glycosaminoglycans by FRTL cells, but not by fibroblasts, whereas assays of serum from 38 of 40 patients with Graves' disease without dermopathy did not stimulate these processes in FRTL cells more than normal serum. Stimulatory activity was associated with immunoglobulins. Serum dermopathy-associated antibodies disappeared with the disappearance of the skin lesions. These results suggest that the serum of patients with dermopathy contains antibodies that recognize a component of the TSH receptor different from that recognized by serum of Graves' patients without dermopathy, the former acting in some manner to induce lesions in pretibial skin. The skin target remains unidentified.

Pathogenesis and treatment of pretibial myxedema.

Pretibial myxedema is considered an autoimmune complication or association of Graves' disease, Hashimoto's thyroiditis, and primary myxedema. The mechanism of lesion formation is unknown; the most plausible theory is that it arises as a result of a target cell in the skin, probably the fibroblast, being stimulated to produce abnormally high amounts of glycosoaminoglycans (especially hyaluronic acid) by autoantibodies directed against a thyroid antigen(s)--that is, by a cross reaction. One or more intermediary humoral agents may be involved in pathogenesis. The reason for the localization to the pretibial region is unknown; there is evidence that most patients with the disorder have similar abnormalities in the preradial skin. The condition may persist for months or years but often regresses spontaneously, accompanied by a parallel decline in, or disappearance of, serum anti-TSH-receptor autoantibody levels. Skin biopsies reveal evidence of increased amounts of hyaluronic acid and damage to collagen and elastic fibers. Local symptomatic treatment with corticosteroids is effective in most cases with slight to moderate severity of skin involvement. Repeated treatments are advised until such time that a spontaneous clinical remission occurs.

Monoclonal antithyroglobulin antibodies derived from immunizations of mice with human eye muscle and thyroid membranes.

A mouse hybridoma clone secreting an immunoglobulin M monoclonal antibody (K-5-4), which reacted with human thyroglobulin (Tg), was obtained from spleen cells of mice immunized with crude membranes of human eye muscle tissues (Em). Its binding to Tg could be inhibited by another monoclonal anti-Tg (F1-11-1) derived from spleen cells of mice immunized with human thyroid cell membranes, but K-5-4 did not inhibit the binding of F1-11-1 to Tg. This finding suggests that K-5-4 may react with a site on the Tg molecule which is susceptible to conformational changes, such as that induced by binding of another anti-Tg antibody at another site on Tg. K-5-4 reacted with human, mouse, rat, guinea pig, bovine, and porcine Tg. Binding and immunohistological staining experiments failed to detect binding of K-5-4 to Em tissue. The very low frequency of one Tg-reacting hybridoma from 6 X 10(8) spleen cells fused after Em immunization contrasts with the relative ease with which monoclonal anti-Tgs were generated from spleen cells of mice immunized with crude human thyroid membranes. In the latter case, 1 anti-Tg hybridoma was generated for every 100,000 spleen cells fused, and an extensive library of monoclonal anti-Tgs was collected. Some of these antibodies were specific for human Tg only, while others cross-reacted with Tg of other animal species. None had the species reativity pattern of K-5-4. The anti-Tgs were used to affinity purify human Tg directly from supernatant of thyroid homogenate; the purified Tg was, in turn, used to affinity purify human polyclonal but monospecific anti-Tg directly from serum of patients in a simple and rapid procedure. We conclude that the monoclonal anti-Tgs are useful reagents in isolating and purifying Tg and anti-Tg.

Limitations of creatinine as a filtration marker in glomerulopathic patients.

To determine the reliability of creatinine as a measure of the glomerular filtration rate (GFR), we compared the simultaneous clearance of creatinine to that of three true filtration markers of graded size in 171 patients with various glomerular diseases. Using inulin (radius [rs] = 15 A) as a reference marker, we found that the fractional clearance of 99mTc-DTPA (rs = 4 A) was 1.02 +/- 0.14, while that of a 19 A rs dextran was 0.98 +/- 0.13, with neither value differing from unity. In contrast, the fractional clearance (relative to inulin) of creatinine (rs = 3 A) exceeded unity, averaging 1.64 +/- 0.05 (P less than 0.001), but could be lowered towards unity by acute blockade of tubular creatinine secretion by IV cimetidine. Cross-sectional analysis of all 171 patients revealed fractional creatinine secretion to vary inversely with GFR. This inverse relationship was confirmed also among individual patients with either deteriorating (N = 28) or remitting (N = 26) glomerular disease, who were studied longitudinally. As a result, changes in creatinine relative to inulin clearance were blunted considerably or even imperceptible. We conclude that true filtration markers with rs less than 20 A, including inulin, are unrestricted in glomerular disease, and that creatinine is hypersecreted progressively by remnant renal tubules as the disease worsens. Accordingly, attempts to use creatinine as a marker with which to evaluate or monitor glomerulopathic patients will result in gross and unpredictable overestimates of the GFR.

Clinical experience with sensitive thyrotropin measurements: diagnostic and therapeutic implications.

A two-site immunoradiometric assay for serum thyrotropin (TSH) was modified to improve the analytical sensitivity. The sensitivity achieved (detection limit, approximately 0.1 microU/ml; lower limit of quantitative measurement, approximately 0.4 microU/ml) was comparable to that of the best competitive binding research assays, yet this assay can be performed routinely. Serum TSH was 1.82 +/- 0.69 (mean +/- s.d.) (range 0.4-3.4 microU/ml) in healthy individuals and 1.83 +/- 0.90 microU/ml (range 0.7-3.7 microU/ml) in patients with nonthyroidal disorders. By contrast, 97% of clinically hyperthyroid patients (Graves' disease, toxic nodular goiter) with high serum free T4 (FT4) and T3 had suppressed serum TSH values, i.e., less than 0.3 microU/ml. Among patients with euthyroid Graves' ophthalmopathy or nontoxic goiter those clinically suspected of mild hyperthyroidism had TSH values less than 0.3 microU/ml, while those judged euthyroid had normal values. A large proportion of thyroid patients on antithyroid drugs (poorly to well-controlled) had suppressed TSH. Of Graves' patients in remission (normal FT4 and T3), 75% had normal TSH, but individual levels changed significantly over time, suggesting that a progressive decline in TSH may be useful in predicting recurrences. In hypothyroid patients taking L-T4, serum TSH was subnormal in patients with elevated FT4, but TSH was also low in six patients clinically suspected to be thyrotoxic despite normal FT4 and T3 and in 32% of asymptomatic patients with normal thyroid hormone levels. Conversely, 23% of thyroid cancer patients who had undergone thyroidectomy were taking insufficient L-T4 to completely suppress TSH secretion. In 25 individuals who underwent thyrotropin releasing hormone (TRH) stimulation tests, the baseline serum TSH value correlated well with the peak serum TSH value post-TRH (r = 0.85). We conclude that sensitive TSH measurements could establish or confirm the diagnosis of hyperthyroidism in equivocal cases, replace most TRH-stimulation tests and be of value in optimizing L-T4 suppression therapy for thyroid cancer patients post-thyroidectomy.

Helper and suppressor activities of lymphocyte subsets on antithyroglobulin production in vitro.

We studied the regulatory activities of T cells on specific antithyroglobulin (anti-Tg) and nonspecific immunoglobulin secretion in cultures of peripheral blood lymphocytes (PBL) of five patients with autoimmune thyroid diseases and high levels of serum anti-Tg. PBL were separated into a non-T population, including B-cells and monocytes, and a T-cell population by rosetting with sheep red cells. T-Cells were further separated into T helper (Th) and T suppressor (Ts) subsets by a panning technique using the monoclonal antibodies anti-Leu 3a and anti-Leu 2a, respectively. The three sets of cells, i.e. B, Th, and Ts, from patients and from normal individuals were cocultured in various combinations and stimulated with the polyclonal stimulant pokeweed mitogen. A sensitive plaque assay was used to enumerate cells producing anti-Tg and protein A-binding immunoglobulins. The PBL of both patients and normal individuals had Tg-specific suppressor cells. Ts-cells from patients in syngeneic or allogeneic combinations with B- and Th-cells at a ratio of 1:1:1 suppressed the pokeweed mitogen-induced anti-Tg response to 41 +/- 8% (+/-SE) and 50 +/- 20% of the control value, respectively, while Ts from normal individuals suppressed the response to 7 +/- 3% of the control value. The suppressive effect of the Ts-cells from patients and normal individuals on nonspecific immunoglobulin secretion was similar (reduced to 10-15% of control). Thus, there appeared to be a deficiency in Tg-specific suppressor activity in PBL of patients. On the other hand, Th-cells from patients (syngeneic or allogeneic) cocultured with patient B-cells produced a greater anti-Tg response than Th-cells from normal individuals. The helper activities of Th-cells of patients and normal individuals on nonspecific immunoglobulin secretion were similar. Thus, there appeared to be an increase in Tg-specific helper activity in PBL of patients.

Radiotherapy of lymphoid diseases of the orbit.

Thirty-two patients with orbital pseudotumor (18), reactive lymphoid hyperplasia (2), atypical lymphoid infiltrate (4) or malignant lymphoma (8) were treated in the Division of Radiation Therapy at Stanford University between January 1973 and May 1983. Of the 20 patients with pseudotumor or reactive lymphoid hyperplasia, 10 had unilateral lesions and 10 had bilateral lesions. Biopsy samples were obtained in 15 patients; in five patients with bilateral disease the diagnosis was made on the basis of computed tomography (CT) and clinical findings. The majority of patients were referred because of disease refractory to treatment with corticosteroids. The patients were given a mean dose of 2360 rad using complex, individualized megavoltage techniques including lens shielding. Radiotherapy was well tolerated with no significant acute or late complications. Fifteen patients had complete resolution of symptoms after treatment; five had continued symptoms. Of the 12 patients with malignant lymphoma or atypical lymphoid infiltrate, four had systemic lymphoma with orbital involvement and eight had orbital involvement only. The diagnosis was made by biopsy in all patients and immunophenotyping was done in six cases, of which 5 were monoclonal. Patients were evaluated with a chest radiograph, lymphogram or abdominal CT, bone marrow biopsy and orbital CT. A mean dose of 3625 rad was delivered to the orbit only. Most of the patients received complex megavoltage treatment using bolus. All patients in this group had a complete response and local control. There were no relapses in those with localized disease. Two patients developed cataracts. Carefully planned orbital radiotherapy provides local control without symptomatic sequelae for orbital masses ranging from pseudotumor to malignant lymphoma.

Peripheral blood lymphocytes from normal individuals can be induced to secrete immunoglobulin G antibodies against self-antigen thyroglobulin in vitro.

Autoantibodies to the self-antigen thyroglobulin (Tg) are usually not found in sera of normal individuals, but are often present in sera of patients with autoimmune thyroid diseases. To determine if the presence of such autoantibodies could be due to the abnormal appearance of self-reactive B cells, which are otherwise absent in normal subjects, or to an alteration in the mechanisms regulating such B cells, peripheral blood lymphocytes (PBL) from normal individuals and patients with autoimmune thyroid diseases were cultured and stimulated in vitro with the polyclonal stimulant pokeweed mitogen (PWM). A modified plaque assay was used to enumerate cells secreting protein A-binding immunoglobulins (Igs) and specific antibodies against Tg. PBL from all individuals tested, including normal subjects (n = 26), could be induced by PWM to produce antibodies against Tg in vitro and these antibodies were of IgG isotypes. PBL from patients with detectable serum anti-Tg had more inducible cells secreting anti-Tg [27,000 +/- 10,700 (+/- SD)/10(6) PBL] than those from patients with autoimmune thyroid diseases, who had no detectable serum anti-Tg (8,000 +/- 5,000), and those from normal individuals (7,200 +/- 4,200). The demonstration of inducible mature (IgG) anti-Tg-producing cells in normal individuals suggests that subclinical autoimmunity against certain self-antigens may be a normal phenomenon in man and that its escalation into clinical autoimmune conditions is prevented through regulation of the specific self-reactive cells.

An improved assay for thyrotropin-binding blocking activity in serum of patients with Graves' disease.

An improved assay for detecting blocking or inhibitory activity on TSH-binding (TBBA) in neat serum of patients with Graves' disease is described. The assay is sensitive, reproducible, simple, and quick. Crude membranes prepared from guinea pig fat (FCM) were used as the source of TSH receptors. One major feature of the assay is the use of small amounts of FCM to increase assay sensitivity. The sensitivity of the assay was found to be inversely proportional to the amount of FCM used. Using a quantity of 10-20 micrograms crude FCM achieved a satisfactory balance between assay sensitivity and accuracy. The assay employs two sequential one-hour incubations at room temperature, first incubating the FCM with the serum sample, followed by removal of excess sample and washing, and then incubating the exposed FCM with 125I-TSH for quantitative determination of specific TSH binding. The assay is recommended as a standard method for measurement of blocking activity in serum of specific TSH binding. Seventy-four percent of the patients with Graves' disease showed positive blocking activity while all normal individuals and patients with Hashimoto's thyroiditis and with nonautoimmune thyroid disorders were negative.

Membrane-binding antibodies in patients with Graves' disease and other autoimmune diseases.

Abnormally high levels of activity (BA) of immunoglobulins (Igs) to membranes containing TSH receptors were observed in patients with Graves' disease. The assay to detect such BA used guinea pig fat as the membrane source. [125I]Protein A was used to develop the binding antibodies (in serum or IgG). The assay was able to detect specific BA in microgram quantities or less of IgG in about 50% of the sera of patients with Graves' disease. The presence or amount of serum BA did not correlate consistently with either the presence in serum of TSH binding inhibitory Ig or the clinical estimate of thyrotoxicity in Graves' disease. High levels of BA were frequently found in sera of patients with other autoimmune diseases, such as Hashimoto's thyroiditis, rheumatoid arthritis, mixed connective tissue disease, and systemic lupus erythematosus. However, BA found in the latter disorders frequently was positive not only when using fat cell membranes but also when using liver kidney, or skeletal muscle membranes. The assay may detect a heterogeneous population of Igs binding specifically to membranes and may reflect a general state of autoimmunity.

Reliability and reproducibility of interpretation of 99mtechnetium pyrophosphate myocardial scintigrams.

The interpretations of 156 99mtechnetium pyrophosphate myocardial scintigrams by four observers were analyzed in order to determine the reliability and reproducibility of the subjective process of reading scintigrams. The scintigrams were scored on an integral scale from 0 to 4, depending upon the degree of myocardial radionuclide accumulation, and the site and nature of uptake were specified. Exact agreement upon score was generally poor but approximate concurrence of interpretation was good (90.4 and 92.5% inter- and intra-observer agreement, respectively). There was somewhat less agreement on scintigrams with the higher scores of 3 and 4 (83.3 and 78.0%, respectively). A high level of concurrence upon the differentiation between diffuse and localized uptake, and upon the site of uptake, was found. We conclude that only approximate rather than exact agreement of individual readers' interpretations can be expected in this subjective technique, that scintigrams with higher degrees of radionuclide accumulation produce slightly greater observer disagreement, and that variability of interpretation could account for some of the diagnostic inaccuracy of 99mtechnetium pyrophosphate myocardial scintigraphy.

Appearance of Graves' disease on orbital computed tomography.

Extraocular muscle enlargement was symmetrical in 70% and asymmetrical in 30% of patients with Graves' ophthalmopathy. True unilateral muscle involvement occurred in 6%. Computed tomography (CT) showed bilateral orbital involvement in 50% of patients presenting clinically with unilateral eye signs. In patients without a clinically apparent ophthalmopathy, CT demonstrated muscle enlargement in 40%. The medial and inferior rectus muscles were the most frequently and most severely involved. Orbital radiation therapy can result in a decrease in size of involved muscles.

A solid phase, sandwich-type radioimmunoassay for antithyroglobulin: elimination of false positive results and semiquantitative measurement of antithyroglobulin in the presence of elevated thyroglobulin.

Thyroid disorders can be associated with elevated concentrations of serum antithyroglobulin antibodies (anti-Tg) and/or thyroglobulin (Tg), but none of the available anti-Tg assays deals with anti-Tg measurements in the presence of abnormally high Tg levels. The competitive binding radioassay produces falsely elevated values for anti-Tg if serum Tg is elevated and either falsely elevated or depressed values if both Tg and anti-Tg are abnormally high. The falsely elevated anti-Tg values can be identified by measuring the formation of Tg[125I]anti-Tg complexes in the supernatant of the anti-Tg assay (supernatant assay). For screening purposes, we modified the original anti-Tg RIA into a solid phase, sandwich-type RIA. Anti-Tg in serum or standard is first bound to plastic cups coated with Tg and then quantitated by binding of [125I]Tg. This assay has a detection limit of 2 U/ml serum, intra- and interassay coefficients of variation of 9--15%, and a normal range of less than 2 U/ml. When sera with normal Tg concentrations were analyzed, the results for anti-Tg obtained by the competitive binding RIA and the new sandwich RIA were comparable as far as positives and negatives were concerned, and the numerical values for positive sera correlated moderately well (r = 0.79); the sandwich assay, in general, gave lower values for anti-Tg. The major advantages of the sandwich anti-Tg RIA are the elimination of false positive results and its applicability to sera containing high levels of both Tg and anti-Tg. In the latter case, the results indicate the level of free anti-Tg present, as opposed to antibody present in the form of Tg-anti-Tg complexes.

Allogeneic cytolysis of reconstituted membrane vesicles.

The successful use of lipid bilayer model membranes as targets for cytotoxic lymphocytes is described. Lipid vesicles were made from a mixture of dipalmitoyl lecithin, dimyristoyl lecithin, and cholesterol. Membrane proteins of LSTRA or EL4 tumor cells (as source of H-2 antigens), human eye muscle membrane proteins (as supporting proteins), and 51Cr marker were inserted into the lipid vesicles. Incubation of the reconstituted vesicles with lymphocytes sensitized in mixed lymphocyte cultures against allogeneic cells resulted in the specific release of intravesicular 51Cr. Vesicle damage was mediated by thymus-derived lymphocytes. H-2 antigens could be incorporated into vesicles without eye muscle proteins. However, immune damage of the vesicles could not be demonstrated when vesicles inserted with H-2 antigens in the absence of eye muscle proteins were used as targets.