Heterogeneity of 125I-labeled human thyroglobulin preparations

This study was undertaken to evaluate the heterogeneity and stability of 125I-labeled human thyroglobulin (Tg) tracers. Tg, labeled with 125I by either a Chloramine T (CT) or a Glucose Oxidase/Lactoperoxidase (GO) method, showed considerable heterogeneity of labeled components, the relative proportions of which were a function of the Tg preparation and the iodination method used. The four largest components had apparent molecular weights as follows: A = 1 200 000 Da; B = 670 000 Da; C = 530 000 Da and D = 290 000 Da. Both B and C were immunoactive. B was considered to be 19S Tg. A non-specific binding difference, (NSB delta) between nonhuman matrices used for diluting standards and human sera was found for the partly immunoactive aggregate component A, (5-20%) and the nonimmunoactive component D, (20-50%), but was minimally present for components B and C (less than 5%). The [125I]19S Tg(B), stored at -70 degrees C, showed rapid spontaneous decomposition with time (50% lost by 8 days), with generation of C, D and iodide. The loss of B was related to specific activity and was least in GO labels. 125I labeling of Tg by GO produced tracers with better immunoactivity, stability and lower NSB delta than comparative CT tracers. Definitive purification and repurification of [125I]Tg tracers before use is necessary in order to remove degradation products with the potential to compromise the accuracy and specificity of serum Tg radioimmunoassay (RIA) measurement.

Autoimmunity and pregnancy

The general effect of pregnancy on autoimmunity remains controversial. In the majority of cases, pregnancy may have no effect on the disease, while on other occasions, pregnancy induces exacerbations that may be especially pronounced in the immediate post-partum period. The reasons for this preponderance are still unclear. Another important aspect of autoimmune diseases during pregnancy entails the passive transfer of the disease into the fetal compartment. It seems that until the pathogenesis and a better specific therapy for autoimmune diseases are clearly defined, careful clinical and immunologic observation of each mother-infant pair will be invaluable.

Pseudotumor cerebri and thyroid-replacement therapy in patients affected by differentiated thyroid carcinoma

The pseudotumor cerebri, a neurological syndrome clinically characterized by headaches, vomiting and bilateral papilledema, occurred in two patients, previously subjected to total thyroidectomy for differentiated thyroid carcinoma, after initiation of levothyroxine replacement therapy. In patients with thyroid cancer, subjected to thyroidectomy and then thyroid hormone replacement therapy, the possible development of pseudotumor cerebri syndrome should be considered and differentiated from CNS symptoms due to brain metastases.

Reciprocal changes of serum thyroglobulin and TSH in residents of a moderate endemic goitre area

Subjects living in iodine deficient areas were reported to have elevated serum thyroglobulin (Tg) concentrations. This finding was interpreted as related to thyroid stimulation. Discrepant results, however, were found when serum Tg concentrations were correlated either with serum TSH or with goitre size. In this study we investigated the relationships between goitre size, serum Tg and serum TSH in 488 unselected adult subjects living in an endemic area of North-Western Tuscany (Garfagnana district). The control group comprised 352 subjects residing in a non-endemic area. In the endemic area a high prevalence of goitre was found (80.1%), thyroid enlargement being slight to moderate in the majority of cases and very large only in six subjects. Serum Tg concentrations increased and serum TSH levels decreased with the size of goitre. Statistical analysis by the chi-square cross correlation test showed that the converse changes of serum Tg and serum TSH in relation to goitre size were highly significant. These findings indicate that the increase of serum Tg occurring in endemic goitrous subjects may be related to factors other than TSH stimulation. Functional autonomy of the thyroid may account for the finding of low serum TSH and elevated serum Tg values in patients with large goitres. The present data do not exclude the possibility that the release of Tg is influenced by TSH stimulation, but indicate that other factors may be responsible for the increased levels of Tg found in endemic goitre.

Polyglandular autoimmune syndromes

Dysfunction of multiple endocrine glands may develop as the result of hypopituitarism, various infiltrative disorders, or an organ-specific autoimmune mechanism. When dysfunction of two or more endocrine glands occurs in association with circulating organ-specific antibodies directed against the involved glands, the term polyglandular autoimmune syndrome is applied. Characteristics of polyglandular autoimmunity include specific patterns of disease association and frequently a family history of similar involvement. The principal endocrine components of these syndromes are adrenal insufficiency, autoimmune thyroid disease, insulin-dependent diabetes mellitus, and premature gonadal failure. In addition, primary hypoparathyroidism is a key feature of one form of polyglandular autoimmunity that occurs in children. Several nonendocrine organ-specific autoimmune disorders are also associated with polyglandular autoimmunity, of which pernicious anemia is the most frequent. The underlying abnormality responsible for polyglandular autoimmunity is most likely a defect in T suppressor cell function, but there is evidence that aberrant expression of HLA DR antigens also plays an important role in the pathogenesis of these disorders.

Proliferation of T8-positive cytolytic T lymphocytes in response to thyroglobulin in human autoimmune thyroiditis: analysis of cell interactions and culture requirements

These experiments were designed to analyze the involvement of T-lymphocyte subpopulations in autoimmune thyroid disorders such as Graves' Disease (GD) and Hashimoto's Disease (HD). In a first set of experiments, lymphocytes isolated from thyroid infiltrates or from peripheral blood of GD and HD patients were analyzed for the expression of various surface antigens. While HLA-DR + T cells were numerous among thyroid infiltrating T lymphocytes in both groups of patients, the proportions of T8 + cells (as defined by their reactivity with the B 9.4 monoclonal antibody specific for T8 surface molecule) were strikingly different in HD and GD. In the latter group of patients only 19% of infiltrating T cells were T8 +, whereas these cells represented approximately 50% in four HD patients. Given the previous demonstration that all T cells expressing T8 antigen are cytolytic T lymphocytes (CTL) or their precursors (CTL-P) in conjunction with the fact that lymphocytes from HD or GD patients are known to proliferate in vitro in response to human tg (Htg), we further analyzed the T-cell subset(s) responsible for in vitro proliferation to Htg. In these experiments, peripheral blood T lymphocytes purified from patients with GD or HD were cultured with 1 microgram/ml Htg and irradiated autologous T-depleted mononuclear cells as the source of antigen presenting cells (APC). The proportions of T8 + cells declined considerably during culture in GD patients, but at Days 6 to 9, T8 + cells represented as much as 51% of cultured T lymphocytes from patients with HD. Moreover, the majority of T8 + cells were medium-large size lymphoblasts. Removal of Htg at Day 6 resulted in both abrogation of proliferative responsiveness and in decreases of T8 + percentages. Further analysis of the cell interactions leading to T8 + cell proliferation in response to Htg showed that helper/inducer T cells, as defined by 5/9 antigen expression, were strictly required. Collectively, these features are reminiscent of the T-cell involvement in experimental autoimmune thyroiditis of mice and stress for the first time the potential role of CTL in tissue damage occurring in Hashimoto's thyroiditis.

Natural history of primary myxedema

It is generally admitted that primary myxedema in adults is the outcome of autoimmune atrophic thyroiditis. The present review traces the natural history of this process from its incipient biologic and genetic anomalies up to its protracted asymptomatic course, clinical development, and eventual lethal complications. The apprehension of preclinical hypothyroidism may change a clinician's outlook on early diagnosis and therapy.

The pathogenesis of Graves' ophthalmopathy

The pathology of the orbital changes in Graves' ophthalmopathy (GO) has been discussed in detail. The target tissue is the eye muscle and the damage probably results from autoimmune processes. Cell-mediated immune responses have been demonstrated and an antibody to eye muscle is detectable in 70% of patients. There is no direct evidence for an effect of thyroid hormones or TSH on orbital tissues in GO. The relation between GO and autoimmune thyroid disease is discussed. Present evidence suggests that in GO autoimmune responses are directed to orbital tissue antigens and do not cross-react with thyroid antigens. Clinical studies suggest that all patients with hyperthyroidism have some abnormality of eye muscle, whereas not all patients with ophthalmopathy have evidence of thyroid disease. It is not possible at the present time to be certain whether GO is an integral part of Graves' disease or a separate entity.

The pathogenesis of Graves' disease

The abnormally increased thyroid activity that is characteristic of Graves' disease is caused by immunoglobulins which specifically interact with the thyroid cell and stimulate it. Increases and decreases in thyroid activity in Graves' disease can be clearly related to rise and fall of these immunoglobulin-mediated activities. The level of immunoglobulin stimulatory activity can be used for prediction of the likelihood of neonatal Graves' disease and of recurrence of disease after cessation of treatment with antithyroid drugs. Investigation of patients with Graves' disease and their families has led to identification of particular human leukocyte antigens and genetically linked markers on immunoglobulins which both appear to incur increased susceptibility to certain autoimmune diseases. Differences in immune function, when compared with control populations, have been found in patients with these genetically linked markers. Protection against autoimmune disease is maintained by purposeful inhibition of any self-directed activity within each function of the immune system and by the controlling interaction of other immune functions. No single deficiency of immune function can be selected as giving the major risk of autoimmune disease, but rather a sum of relative defects resulting in an increased risk. In some patients with Graves' disease the self-protection mechanisms regain sufficient control of the immune functions to reduce the activity of the autoimmune disease, and the patient may achieve clinical remission. Often, however, there is evidence that abnormal immune activity directed against thyroid tissue has persisted with liability to recurrence of the Graves' disease.

Post-partum hyperthyroidism

The importance of recognizing the frequent occurrence of the destructive (i.e. PPT) and stimulatory (i.e. PGD) causes of PH have been discussed. The estimated prevalence of PH in several geographical regions of Japan, North America and Europe ranges from 2.0-5%. Although the autoimmune basis for GD has been well-established, the clinical and laboratory features of PPT as well as the alterations of humoral and cellular thyroidal immune parameters, the typical needle biopsy evidence of lymphocytic infiltration, and the association with HLA and Gm allotypes associated with the PPT syndrome, favour the view that it is also likely a variant form of subclinical ATD which becomes transiently more active post-partum. Post-partum transient hyperthyroidism with or without transient or permanent hypothyroidism and relapse of GD thyrotoxicosis have been observed in patients with or without a previous history of GD. Hence, an RAIU test is the preferred diagnostic test in differentiating between these two entities, especially in the absence of associated stigmata of GD. When the RAIU test is suppressed, other causes such as thyrotoxicosis factitia and iodine exposure should be excluded. Without an RAIU test, only a rapid and spontaneous resolution of post-partum hyperthyroidism, accompanied by laboratory confirmation of a subsequent hypothyroid phase, can indirectly facilitate the differentiation between PGD and PPT. In the first trimester of pregnancy, an increased FT4I has been proposed as a risk factor for PGD and an increased AMA titre for PPT. Depending upon clinical manifestations, severity, patient and physician preferences, PGD can be treated by one of several choices of conventional therapy. The transient thyrotoxic phase of PPT when relatively asymptomatic may require no therapy, but when symptomatic, only conservative therapy with beta-adrenergic blockers, sedatives and/or tranquilizers is indicated. Close follow-up and long-term surveillance of mothers with PH due to PPT is essential for early detection and management of a possible subsequent hypothyroid phase, which may be symptomatic, but is seldom permanent. Treatment of recurrent episodes of PPT is controversial. Thyrotoxic symptoms are usually mild and transient and can best be managed by symptomatic therapy as indicated. In a few exceptional patients with recurrent episodes, prophylactic treatment with corticosteroid may be warranted but thyroidectomy and ablative radioactive iodine therapy is seldom justified.(ABSTRACT TRUNCATED AT 400 WORDS)

Correlation of thyroglobulin measurements and radioiodine scans in the follow-up of patients with differentiated thyroid cancer

Correlation of radioiodine (131I) scans and serum thyroglobulin (Tg) concentrations were performed in the follow-up of 85 differentiated thyroid cancer patients who had undergone total thyroidectomy. Tg results were also compared with the control group of 33 thyroidectomized patients with no evidence of thyroid carcinoma and normal values for Tg established. Excellent correlation between Tg and scans was noted in patients with scan evidence of metastasis distant from the neck. Poor correlation was present in patients with scan evidence of local neck metastasis only, thyroid bed activity, and those with mediastinal activity. In addition, in 8% of the patients, the Tg assay could not be performed because of interfering antibodies. The conclusion is that elevated Tg concentration is a good indicator of metastasis outside of the neck as detected by 131I scans. Caution should be used when Tg alone is used in evaluating local neck metastasis demonstrated on scans. The significance of mediastinal activity warrants further investigation.

T-lymphocyte subsets in idiopathic dilated cardiomyopathy

Idiopathic dilated cardiomyopathy (IDC) is a common clinical problem in Africa. To determine if there is a defect of immune regulation in patients with IDC, the percentage of total T-cells (OKT3 positive), helper/inducer cells (OKT4 positive) and suppressor/cytotoxic cells (OKT8 positive) were measured using monoclonal antibodies in 20 patients with IDC and in 20 age-matched normal control subjects. The percentage of helper/inducer cells was significantly higher in the IDC patients (45 +/- 2% mean +/- standard error) than in the normal subjects (33 +/- 2%) and 8 of the 20 IDC patients had a helper/suppressor cell ratio (OKT4/OKT8) higher than the normal range. Of the 8 patients with this abnormality, 7 were studied within 3 months of the onset of their illness. Results suggest that an excessive immune reaction is part of the pathogenesis of IDC in Africans.

[Diagnostic procedure in suspected functional disorders of the thyroid gland]

In an attempt to derive diagnostic concepts for thyroid diseases we present pathophysiological models for the prevalent thyroid disorders. 'Euthyroid goiter' is a disease mainly caused by iodine deficiency but an additional immunopathogenesis was recently proposed. The 'immunthyropathy' is the thyroid disease with orbitopathy and other extraglandular immunological manifestations. A complete model of the immunological phenomena which begin with a tolerance defect is given, and both the T-cell, and B-cell-mediated pathways are detailed. The complex interaction of immunoglobulins at the thyroid-stimulating hormone receptor and their dependency on human leukocyte antigen loci are presented. The peripheral metabolism depends ultimately upon a prevalence of thyroid gland stimulation (thyrotoxicosis) or glandular destruction (hypothyroidism) and this is true for overt thyroid disease under antithyroid drug therapy or any other therapy. Euthyroidism during 'immunethyropathy' is presented as an equilibrium between thyroid stimulation and destruction. This concept allows an exact description of the thyroid disease and the resulting clinical situation provided that established laboratory tests are used as suggested by the model. 'Disseminated thyroid autonomy and autononous thyroid adenoma' develops during goitrous thyroid disease as a consequence of uncoupling of thyroid cellular growth stimulation, iodine utilization, and thyroid hormone synthesis. The polyclonal origin seems more frequent than monoclonal foci. The size of autononous tissue and individual iodine supply determines the endocrine function in this disease. The TRH test monitors with great sensitivity subtle increases in T4 or T3 production and indicates critical clinical situations earlier than the scintiscan.(ABSTRACT TRUNCATED AT 250 WORDS)

T-cell sensitization to autologous thyroid cells and normal non-specific suppressor T-cell function in Graves' disease

We have employed a syngeneic system utilizing thyroid cell monolayers initiated following thyroid surgery co-cultured with autologous T cells to demonstrate T cell autosensitization in patients with Graves' disease. Antigen-induced blastogenesis was monitored using 24 h [3H]thymidine uptake. Control experiments with 5 d cultured normal human thyroid cells from tissue around benign adenomata showed no evidence of syngeneic T cell autosensitization. Human thyroid cells alone were unable to incorporate [3H]thymidine in the presence of bTSH. In three of four experiments with Graves' thyroid cells there was significant induction of autologous T cell blastogenesis with a mean stimulation index of 220%. In parallel experiments we explored the non-specific helper and suppressor T cell function of these and similar patients with Graves' disease. In normal controls (n = 6) increasing numbers of T cells added to a constant number of B cells (consisting of a T cell depleted peripheral mononuclear cell preparation) showed a marked helper effect measured as increasing IgG secretion. As the ratio of T:B cells increased above 4:1 there was a suppression of IgG secretion. One of two hyperthyroid Graves' patients was observed to have deficient T cell function as demonstrated by lack of IgG suppression. The remaining five patients (all but one of whom were euthyroid at the time of testing) had results similar to the controls indicating normal suppressor T cell function in this disease. Such data showed that patients with Graves' disease possessed circulating T cells which exhibited autosensitization to syngeneic thyroid cell surface antigens, a phenomenon not demonstrable in control individuals. Furthermore, this specific T cell autosensitization did not interfere with non-specific T cell function as judged by its influence on IgG secretion.

T cell and T cell subset determination in normal peripheral blood: comparison of the indirect immunofluorescence and lymphocytotoxicity techniques

We compared a simple complement-dependent lymphocytotoxicity test with a widely used indirect immunofluorescence procedure to enumerate total T, T helper, and T suppressor lymphocytes in normal blood samples. Results with the two techniques were closely similar.

Autoimmune thyroid disease: purification and phenotypic analysis of intrathyroid T cells

A phenotypic analysis of T cells infiltrating the thyroid of patients with autoimmune thyroid disease (both Graves' disease and Hashimoto's thyroiditis) was performed. T lymphocytes were purified from mononuclear cells extracted from surgically removed tissue. The following markers were evaluated: la antigens, MLR4 antigen (expressed on activated T cells) 5/9 antigen (expressed on a subset of lymphocytes containing the whole "helper-inducer" activity in vitro), Fc gamma-receptors, B9 antigen (expressed by cytotoxic, or precursor of cytotoxic, T cells). We observed increased percentages of 5/9-, MLR4- and la-positive T cells with respect to peripheral blood in both HT and GD: on the contrary, in specimens from nonautoimmune thyroid diseases mononuclear infiltrate was minimal, and even T cell evaluation was not possible. In addition, B9- and Fc gamma-positive T cells were increased in Hashimoto's, but not in Graves' thyroid tissue, thus suggesting a different role of cytotoxic effector mechanisms in the two diseases.

Enzyme-linked immunosorbent assay for determination of thyroglobulin autoantibodies. Comparison with RIA and haemagglutination

An enzyme immunoassay (ELISA) has been developed for the detection of human autoantibodies to thyroglobulin (TgAb). The ELISA assay was compared to the previous routine method, the tanned red cell (TRC) method and a radioimmunoassay (RIA) technique for thyroglobulin autoantibodies. Sera from 163 healthy non-hospitalized persons, 31 patients with Hashimoto's thyroiditis, 13 patients with Graves disease, 136 patients with thyroid cancer and 365 sera consecutively received for thyroid autoantibody screening were examined for TgAb in the three methods. The nosological sensitivity for ELISA methods was comparable to that of RIA and higher than that of TRC. The ELISA method was accurate, precise, objective, inexpensive and well suited for quantitative routine determination of TgAb.

Antithyroid drugs

Over the past four decades, a great deal has been learned about the pharmacology and mechanisms of action of antithyroid drugs. Their ability to inhibit hormone biosynthesis involves complex interactions with thyroid peroxidase and thyroglobulin, many of which are still poorly understood. Their spectrum of activity is much wider than previously thought, and a number of clinically important extrathyroidal actions have been identified. Despite a greater appreciation for the intricacies of antithyroid-drug pharmacology, controversies still surround the use of these agents in the treatment of thyrotoxicosis. These controversies are apt to continue until the pathophysiology of Graves' disease is fully elucidated.

A mature thymocyte-like phenotypic pattern on human cord circulating T-lymphoid cells

Cord blood samples from healthy full-term newborns were tested with antimature and antiimmature lymphoid-cell monoclonal antibodies, as well as more traditional markers, in order to identify the phenotype of circulating precursor cells. The results demonstrated that human cord blood contains a lower number of OKT3+, E-rosetting mature T cells than adult blood, very high levels of OKT10+ cells, and few OKT9+, OKT8+ OKT3-, and OKT4+ OKT3- cells. Although the finding of OKT9+ and OKT10+ cord circulating cells could be indicative of cell activation, double marker studies in newborn blood pointed to phenotypically immature lymphoid subsets at different stages of maturation, according to Reinherz's hypothesis. In addition, the absence of nuclear Tdt-positive and hot-rosetting cells, together with the fact that most of these are OKT3+, OKT10+, OKT4+, or OKT8+ cells, suggests that the surface phenotype of newborn lymphocytes is similar to that of mature thymocytes.

Immunohistochemical and ultrastructural studies on the exenterated orbital tissues of a patient with Graves' disease

The exenterated orbital contents obtained post mortem from a 47-year-old man who had an eight-month history of treated hyperthyroidism and a two-month history of visual complaints were examined histopathologically, immunohistochemically, and by electron microscopy. All of the extraocular muscles were massively enlarged, due to early diffuse endomysial fibrosis, mucopolysaccharide deposition, and a predominantly perivascular lymphocytic and plasmacytic infiltration. Histochemical stains revealed that the intramuscular mucopolysaccharides were weakly sulfated and polycarboxylated, establishing that they were products of fibroblastic activation rather than derived from mast cells. Subsarcolemmal deposits in the myofibers were shown by electron microscopy to be collections of glycogen rosettes with intermixed lipid deposits. These inclusions were interpreted as secondary phenomena due to abnormal muscle energetics from restrictions in contractility, and not as evidence of a primary degeneration of the extraocular muscle fibers themselves. The sarcomeric organization of the striated muscle cells was undisturbed, and therefore the pathologic changes occurred int he interstitial space of the endomysium. A monoclonal antibody specific for neurofilaments (antibody 4.3 F9) revealed, in comparison with normal controls, a preferential loss of large-type axons of the proximal segment of the orbital portion of the optic nerve as well as in the intracanalicular portion. The axonal loss was associated with a mildly increased number of astrocytes as demonstrated by an antibody against glial fibrillary acidic protein. The meninges of the optic nerve, the orbital fat, and the tendons of the extraocular muscles were uninflamed. The foregoing findings are compatible with a compressive optic neuropathy mediated by the massively swollen extraocular muscles impinging upon the optic nerve at the orbital apex.

Metastatic medullary and undifferentiated thyroid cancers are not associated with elevated levels of serum thyroglobulin

It is now well accepted that serum thyroglobulin (Tg) determination is a specific marker of disease activity in well-differentiated thyroid cancer after total thyroidectomy. In this study we examined 15 thyroidectomized patients with metastases from medullary thyroid cancer and 10 patients with metastases from undifferentiated thyroid cancer, to determine whether serum Tg measurement could be useful also in these types of thyroid tumors. In contrast with differentiated thyroid cancer, which had high levels of circulating serum Tg, patients with medullary and undifferentiated thyroid cancer had undetectable or low levels of serum Tg. Thus, serum Tg measurements are not useful in the diagnosis of metastatic disease in these patients.

Serum thyroglobulin in patients with autonomous thyroid nodules

To investigate further the relationship between thyroid hormones and thyroglobulin (TG) secretion, total and free thyroid hormone levels, TSH and its response to TRH and serum TG concentrations were determined in 61 patients with solitary autonomous thyroid nodules. Thyroid function varied widely from euthyroidism to clearcut thyrotoxicosis. Serum TG levels were significantly higher in patients than in normal controls. Individually they were above the normal range (greater than 50 ng/ml) in 95% of the patients, as well as in those with normal total and/or free thyroid hormone levels. Patients with high total and/or free thyroid hormone levels had higher TG concentrations than euthyroid patients. TG concentrations were significantly correlated with FT3 values. They were higher in patients in whom TSH was unresponsive to TRH than in the responsive groups. TG was also slightly higher in patients with hot nodules than in those with warm nodules. These data seem to indicate that TG is secreted along with thyroid hormones in the absence of any stimulatory action. It also is a sensitive index of thyroid hyperfunction. Twenty patients were controlled 6 months after nodulectomy. TG levels, though significantly lower than in the preoperative state, were still higher than in normal subjects. This increase was attributed to persistent hyperthyroidism in two patients only. The observation that the increase in TSH after TRH stimulation in post-operative patients was greater than that found in normal controls led us to believe that in most cases the high TG levels after surgery are due to stimulation of the normal thyroid tissue by rebound TSH secretion.

Serum thyroglobulin in newborns' cord blood, in childhood and adolescence: a physiological indicator of thyroidal status

Serum thyroglobulin (Tg) was measured in the cord blood of 635 newborns and serum thyroxine (T4) reverse triiodothyronine (rT3), TSH and T3 were measured in about 200 of them. Cord Tg was detectable in all newborns with a mean +/- SE value (50 +/- 1.3 ng/ml) higher than that found in the serum of adult subjects (n = 144; Tg = 13 +/- 1.1; p less than 0.0001). Cord Tg had a log-normal distribution. A low, but positive correlation was found between cord Tg and cord TSH (n = 242; r = 0.17; p less than 0.05) but not with cord T4 or cord rT3. Gestational age was negatively correlated with cord Tg or cord rT3 (rS = 0.97; p less than 0.01; rS = -0.89; p less than 0.02, respectively) while was positively correlated with cord T4 or cord TSH (rS = 0.85; p less than 0.05; rS = 0.86; p less than 0.01, respectively). Birth weight, maternal diabetes, induction of labor with oxitocin, cesarian section and newborns' illness showed no influence on cord Tg levels when considered alone, but decreased cord Tg levels were found in ill newborns delivered by cesarian section. On the contrary, increased cord Tg levels were present in cord blood of newborns who developed hypoglycemia soon after birth and in small for gestational age newborns. In 24 newborns studied daily for the first 6 days of life, serum Tg was always detectable with mean values not different from those found in the cord blood.(ABSTRACT TRUNCATED AT 250 WORDS)

A new sensitive immunosorbent radioassay for the detection of circulating antibodies to polypeptide hormones and proteins

A solid-phase immunosorbent radioassay for the detection of circulating antibodies to protein hormones is described. The assay is based on the binding of the homologous 125I-labelled antigen to the antibodies which are then bound to anti-IgG antibodies covalently coupled to Sepharose. It can easily be applied as a complement to any radioimmunoassay for the detection of circulating antibodies to the ligand measured. The assay system avoids falsely elevated values due to interference of high serum concentrations of the antigen. The assay was applied to measure antibodies to FSH, LH, TSH, GH, prolactin, insulin and thyroglobulin (Tg). Among patients with chronic thyroiditis Tg antibodies were found in 100% of the sera. In diffuse toxic goitre 73% of the patients had detectable Tg antibodies. Insulin antibodies were present in 82% of the sera from patients with insulin treated diabetes. No antibodies were found against the other protein hormones tested.

Analysis of lymphocyte subsets in patients with aplastic anaemia

Lymphocyte subsets have been measured in the blood of 28 patients with aplastic anaemia. The mean helper/inducer:suppressor/cytotoxic T lymphocyte ratio (1.24 +/- 0.74) was significantly decreased in the total population in comparison to mean ratios in a normal population (1.78 +/- 0.57) and in patients with other haematological diseases (1.82 +/- 0.92). A reversed ratio (less than or equal to 1) was present in a large proportion (53%) of aplastic patients, due both to an absolute deficiency of helper/inducer lymphocytes and an increase in suppressor/cytotoxic lymphocytes. Increased HLA-DR expression, evidence of lymphocyte activation, was present in seven of 12 patients evaluated and was confined to the suppressor/cytotoxic lymphocyte population. In the bone marrow, the percentage of lymphocytes was increased two-fold compared to normal bone marrow but the ratio of T cell subsets was not abnormal. Two of four patients evaluated after haematopoietic recovery following ATG treatment showed a return to normal of the T4/T8 ratio; in two others a low T4/T8 ratio persisted despite recovery. These results indicate that lymphocyte subset imbalance and lymphocyte activation are present in many patients with aplastic anaemia, either as a contributing factor or as a result of bone marrow failure.

A syndrome of arterial-occlusive retinopathy and encephalopathy

An analysis of two new cases and four previously reported cases produced evidence for a syndrome of arterial-occlusive retinopathy and encephalopathy. All six patients were women; they ranged in age from 21 to 40 years. The clinical features of this condition include multiple branch retinal arterial occlusions and encephalopathy in which behavioral and memory disturbances predominate early. Hearing loss is frequent. Except for cerebrospinal fluid pleocytosis and an increased cerebrospinal fluid protein level, there are few laboratory or radiographic abnormalities. The disease may be responsive to corticosteroid therapy. There are some similarities between this syndrome and systemic lupus erythematosus but it appears to be a distinct disease entity. A comparison of the retinal findings with those described in experimental allergic encephalitis suggests that this may be a virally induced immune-mediated disease. Although only four clearly documented examples of this syndrome have been reported, we suspect that cases may have been overlooked because of failure to recognize arterial branch occlusions in the peripheral retina.

Pregnancy in association with a newly diagnosed cancer: a population-based epidemiologic assessment

Cancer patients who were pregnant at the time of cancer diagnosis were identified by the National Cancer Registry of the German Democratic Republic for the years 1970 through 1979. A total of 355 such cases occurred in women aged 15-44, and during the same period 2, 103, 112 live births were registered. Rank by site in order of decreasing frequency was cervix, breast, ovary, lymphoma, melanoma, brain and leukemia. On the basis of general female population rates, 555.8 cases were expected, giving a significantly reduced observed to expected ratio (O/E) of 0.64. O/E ratios rose with age. The O/E for invasive carcinoma of the cervix was significantly elevated at 1.15; carcinoma in situ of the cervix occurred significantly less frequently than expected (O/E = 0.57). For breast, brain, melanoma and leukemia, significantly fewer cases were observed than expected. Explanations considered for the low number of pregnancy-associated incident cancer cases include underreporting of pregnancy-associated cancer, altered tumor progression in pregnancy or decreased fertility in women with early neoplastic disease.

Lymphocyte subclasses in pregnancy induced hypertension

Peripheral blood lymphocyte subclasses were studied by flow cytofluorimetry and monoclonal antibodies in 21 women with Pregnancy Induced Hypertension (PIH), 20 healthy women in their third trimester of pregnancy and in 20 nulliparous, nonpregnant women. The cells were stained with the monoclonal antibodies OKT3, OKT4 and OKT8 to define total T cells, T helper cells (Th) and T suppressor-cytotoxic cells (Ts/c) respectively. B lymphocytes were defined by their surface immunoglobulin. Absolute numbers of total T cells and Ts/c cells were significantly decreased (p less than 0.05) in patients with PIH compared to either control group. The proportion of B lymphocytes was significantly (p less than 0.01) increased and absolute numbers were marginally increased. These findings reflect an immune disturbance which may be of prime importance in the pathogenesis of this disease.

Evidence for an effect of antithyroid drugs on the natural history of Graves' disease

In the United Kingdom, about half the patients with Graves' disease who are given antithyroid drugs are still in remission one year after treatment is stopped. The most widely held view is that such remission rates are due only to the biochemical effects of the drugs, the disease either spontaneously remitting or abating when the immune system is no longer subject to the stimulatory effects of excessive thyroid hormone. We review here the accumulating evidence against both of these alternatives. In contrast, there is now a large body of work which shows that thyrotrophin receptor antibody levels, central to the aetiology of Graves' hyperthyroidism, fall during antithyroid treatment and that remission may be related to this fall in a fashion which is dependent on the dose and duration of treatment. This immunosuppressive effect is supported by experimental data and on the basis of these results we propose that antithyroid drugs may modify the natural history of Graves' disease and contribute to the remission which occurs in a proportion of treated patients.

Thyroglobulin-induced T-cell in vitro proliferation in Hashimoto's thyroiditis: identification of the responsive subset and effect of monoclonal antibodies directed to Ia antigens

Recently it was reported that the peripheral blood and thyroid gland of patients with Hashimoto's thyroiditis contain activated (Ia+ and/or MLR4+) T cells and high levels of 5/9+ ("helper") T lymphocytes. In normal individuals the 5/9 monoclonal antibody recognizes a T-cell fraction that includes all T lymphocytes with inducer activities. Here, circulating 5/9+ and 5/9- T lymphocytes were isolated from patients with Hashimoto's disease, and the proliferative response induced by human thyroglobulin was investigated. The results show that the total thyroglobulin-induced lymphocyte DNA synthesis is confined to the 5/9+ T-cell fraction. Further subfractionation of 5/9+ into MLR4+ and MLR4- cells clearly indicates that no substantial differences exist in their proliferative capacities. Whether 5/9, MLR4, and Ia antigens, all expressed on the thyroglobulin-responsive T-cell subset, are involved in thyroglobulin-induced cell proliferation, was also analyzed. Although both 5/9 and MLR4 monoclonal antibodies had no effect, complete inhibition of antigen-induced blastogenesis was observed upon addition of monoclonal antibodies (D1/12 and BT2/9) directed to common determinants of Ia antigens. This inhibitory effect was also observed when T or non-T fractions were separately incubated with the monoclonal antibodies before culture. These results indicate that in humans, as in animals, the major histocompatibility complex may play a role in autoimmune thyroiditis. The data show that (a) the thyroglobulin-induced proliferative response is confined to a subset (5/9+) of T lymphocytes and (b) Ia antigens are involved in thyroglobulin-induced lymphocyte DNA synthesis in Hashimoto's disease.

A clinical epidemiologic study of thyroid carcinoma in Malmö, Sweden

The annual incidence of clinically diagnosed TC in Malmö was, on an average, 2.4 per 100,000 population during the years 1960-1977. This was 1.2 per 100,000 population lower than the corresponding incidence in the whole of Sweden as reported by the National Cancer Registry. The main reason for the difference was suggested to be inclusion in the official figures of autopsy cases and of cases with a benign diagnosis, rather than a true difference in the prevalence of TC. During the later part of the study an increase in the incidence of differentiated TC of approximately 70% was noted. This was considered to be due to increased health awareness and the availability of medical care, because only the number of tumors with less advanced growth increased. The average annual mortality from TC in Malmö was 0.9 per 100,000, which was 0.4 per 100,000 lower than the corresponding official rate in all of Sweden. The difference was suggested to be mainly due to inclusion in the official figures of persons not dying of TC. The mortality did not change significantly during the period of investigation. The percentage distribution by histologic type of tumors clinically diagnosed (N = 104) was as follows: papillary cancer, 65%; follicular, 21%; medullary, 4%; and anaplastic, 12%. The prognosis as estimated by the life table method was worst for patients with anaplastic TC, followed by those with follicular, papillary, and medullary TC. The validity of using the relationship of the tumor to the thyroid capsule (i.e., intrathyroidal and extrathyroidal growth) as a basis for classification into tumor stages was supported in the present study: the mortality in patients with intrathyroidal tumors was lower than in those with extrathyroidal tumors. The definition of occult TC--TC not larger than 1.5 cm, without regard to the relation to the thyroid capsule--was considered inappropriate and a change in the conception of occult TC was proposed. The presence or absence of node metastases in TC did not seem to have major significance for the prognosis. The significance of age for survival was strongly supported in our study. Deaths from TC clinically diagnosed before the age of 60 were infrequent, whereas the disease after this age increasingly often was fatal. This was partly due to a late onset of anaplastic TC and partly to a higher mortality in older than in younger patients with papillary or follicular TC.(ABSTRACT TRUNCATED AT 400 WORDS)

T-lymphocyte subsets in the aqueous humor and peripheral blood of patients with acute untreated uveitis

We evaluated T-lymphocyte subsets in 18 patients with active untreated uveitis and in 20 controls by monoclonal OKT (Ortho-Kung-T cell) antibodies. Both OKT4- and OKT8-positive cells were detected in the aqueous humor of patients with uveitis. The percentage of OKT4-positive cells (21.1 +/- 7.4) was larger than that of OKT8-positive cells (15.2 +/- 5.3) and the OKT4-OKT8 ratio was 1.40 +/- 0.3. A comparison of aqueous humor and peripheral blood cells from patients with uveitis showed diminished frequencies of OKT4- and OKT8-positive cells. The OKT4-OKT8 ratios were not significantly different. A comparison of peripheral blood cells from patients with uveitis and from controls showed that patients with uveitis had lower OKT4-OKT8 ratios. Lower percentages of OKT4-positive cells were also observed in the peripheral blood cells of patients with uveitis.

Further studies on immunological parameters in gestational trophoblastic neoplasia

The total blood lymphocyte counts, T-cell counts, B-cell counts, percentage of T cells bearing Fc receptors for IgG (TG), lymphocyte responses to phytohaemagglutinin and concanavalin A and serum IgA levels were measured in 15 patients with hydatidiform mole, 32 patients with malignant trophoblastic disease, 30 pregnant controls, and 34 normal non-pregnant controls. The mean percentage of TG was similar in all four groups but the mean absolute number of TG in patients with malignant trophoblastic disease was significantly lower than that in normal non-pregnant controls, due to the lower mean lymphocyte count and T-cell count in the former group. An immune profile score based on the T-cell count, B-cell count, lymphocyte response to mitogens, and serum IgA level was useful in predicting the subsequent development of malignant trophoblastic disease in patients with hydatidiform mole but was not helpful in predicting resistance to chemotherapy in malignant trophoblastic disease.

Short-term and long-term effects of estrogen on lymphoid tissues and lymphoid cells with some remarks on the significance for carcinogenesis

Estrogens have long been thought to play a role in regulating the immune system. The difference in some types of immune responses between males and females is well-known, as is the pronounced thymic involution induced by exogenous estrogens. Estrogens stimulate some aspects of macrophage activity and, depending on dose and mitogen, inhibit or stimulate lymphocyte proliferative response in vitro. Another example is the estrogen effect on the delayed type hypersensitivity response. A broad review is given of such estrogen effects on lymphoid tissue and immune response. Most of the studies published so far are phenomenological. However, the recent description of estrogen receptors in the thymus and in some lymphocyte subpopulations, as well as a deeper understanding of regulating factors in the immune system, open the possibility of a more detailed understanding of the estrogen mechanism of interference. Estrogen effects in adults are reversible. After treating neonatal mice with the synthetic estrogen diethylstilbestrol (DES), disturbances are induced in lymphocyte populations and lymphocyte functions which are permanent and irreversible. Lymphocytes from adult, neonatally DES-treated female mice have a reduced mitogen response to ConA and LPS (T and B cell mitogen) and the delayed type hypersensitivity response is depressed. A detailed analysis demonstrated a decreased T helper cell population. The activity of Natural Killer cells is permanently reduced and this functional impairment is related to a decreased number of these cells, in turn determined at the bone marrow level. The same animals have an increased sensitivity to chemical carcinogens (methylcholanthrene) and they spontaneously develop epithelial changes in the uterine cervix which morphologically are similar to adenocarcinoma. The association between estrogen-associated malignancy and estrogen effects in lymphocyte functions deserves further study.

B- and T-lymphocytes in ocular disease

Ocular inflammatory diseases and ocular adnexal lymphoid tumors have become less obscure and intimidating by virtue of our ability to study the infiltrates in these various diseases for their B-lymphocyte and T-lymphocyte composition. Comparisons are also possible between lymphocytic profiles in the peripheral blood and the precise composition of the in situ infiltrates within the ocular tissue themselves. The availability of monoclonal antibodies, which can determine T-lymphocytic subsets such as T-helper cells and T-suppressor/cytotoxic cells, natural killer cells, and monocytes-histiocytes, has provided a powerful technology for the delineation of the distinctive immune composition of the inflammatory infiltrates, as well as any possible disturbances in T-cell immunoregulation. B-lymphocytes produce immunoglobulins, which may be misdirected as autoantibodies in local or systemic autoimmune diseases. Immunoglobulin-mediated and therefore B-cell derived conditions include vasculitis, progressive cicatricial ocular pemphigoid, Mooren's corneal ulcer, scleritis, and hay fever and vernal conjunctivitis. Other diseases in which B-lymphocytes, their immunoglobulin products or immune complexes formed with presently unknown antigens are potentially at fault are chronic non-specific uveitis; iridocyclitis in Behcet's syndrome; Fuch's heterochromic syndrome, ankylosing spondylitis, and Reiter's syndrome; Graves' disease; and idiopathic inflammatory orbital pseudotumor and myositis. T-cells do not produce immunoglobins, but rather secrete lymphokines or interact directly with receptors or determinants on viruses or target tissues (eg. immunosurveillance against neoplasia); it is possible that some autoimmune diseases are the result of neo-antigens on the surfaces of host tissues that have been coded for by a cryptic inciting virus. T-cell diseases include phlyctenulosis graft rejections, graft versus host disease, and possibly sympathetic ophthalmia and temporal arteritis. Natural killer cells are involved in many of the same diseases as cytotoxic T-cells, except that the former require no period of sensitization (natural immunity), whereas cytotoxic T-cells must undergo an antigen-specific blast transformation (acquired immunity of the delayed hypersensitivity type). In many diseases in which B-cell derived auto-antibodies are at fault, there may be local tissue or systemic T-cell imbalances, with a reduction in T-suppressor cells and a relative augmentation in T-helper cells, thereby facilitating production of misdirected auto-antibodies.(ABSTRACT TRUNCATED AT 400 WORDS)

Serum tissue polypeptide antigen (TPA) in thyroid cancer

Serum tissue polypeptide antigen, (TPA), carcinoembryonic antigen (CEA), calcitonin (CT) and thyroglobulin (Tg) have been measured by specific radioimmunoassays in 174 patients with various types of thyroid cancer previously submitted to thyroidectomy. Elevated serum TPA concentrations were found in 12 of 13 patients with local invasion or distant metastases from undifferentiated thyroid cancer or thyroid lymphosarcoma, while serum Tg and CEA values were normal or undetectable. In 123 patients with well differentiated thyroid cancer serum TPA was usually normal regardless of the presence or absence of functioning metastases. On the contrary, 14 of 15 patients with "dedifferentiated" metastases from previously differentiated thyroid cancer had elevated serum TPA values, while serum CEA was normal and serum Tg variable. Serum CT was confirmed as the most sensitive marker of metastatic medullary thyroid carcinoma, but elevated serum TPA values were also found in most of these cases. The present data indicate that serum TPA provides a new humoral marker in the follow-up of undifferentiated and "dedifferentiated" thyroid carcinoma and may also be usefully employed as an additional marker for medullary thyroid carcinoma.

Immunohistochemical characterization of intrathyroid lymphocytes in Graves' disease. Interstitial and intraepithelial populations

The phenotypic cell surface markers of the lymphocytes present in thyroid tissue from four patients with Graves' disease were quantitatively analyzed using the avidin-biotin immunoperoxidase technique. As control specimens, normal perinodular tissues from three patients who had benign thyroid nodules resected were also studied. In contrast to normal thyroid tissue, which contained very few T cells and no B cells, thyroid tissue of all four patients with Graves' disease contained a lymphocytic infiltrate, and this could be divided into two populations of lymphocytes. The first population was located in the follicular epithelium and expressed a cytotoxic-suppressor T cell marker (Leu2a). On the average, these cells were 4.2 times as numerous in Graves' tissues as in normal tissues (p less than 0.05). Most of these cells did not express Leu1, a pan-T cell marker. The second population was found in the interstitial tissues, often within lymphoid aggregates, and 70 to 83 percent of the cells expressed Leu1. The majority of these cells expressed a helper-inducer T cell marker, Leu3a; Leu3a/Leu2a ratios within aggregates ranged from 1.9 to 2.1. The number of B cells present was small, ranging from 5.8 to 12.1 percent of the interstitial lymphocytes. These findings are consistent with the involvement of both helper-inducer and suppressor-cytotoxic T cells in a localized autoimmune reaction directed, at least in part, against the thyroid follicular epithelial cells.

The influence of common variables on T cell subset analysis by monoclonal antibodies

Normal values for T cell subsets as defined by the most commonly used monoclonal antibodies of the OKT series were determined in a group of 142 unrelated normal individuals. In most age classes females had significantly greater portions of OKT3 and OKT4 antigen bearing lymphocytes and accordingly a higher T4/T8 index. The range of individual normal values within the control population was remarkably wide. Intra-individual differences between the T subset composition remained rather constant over a period of 2 months. Time of day, food absorption and physical exercise had no influence on the results of subset analyses. Storage of the blood sample and freezing of isolated lymphocytes can result in significantly reduced OKT3 and OKT4 positive cell numbers. If lymphocytes were isolated soon after the blood was taken and resuspended in a stabilization medium they exhibited only minimal change.

Value of the estimation of thyroglobulin levels in the surveillance of treated differentiated thyroid carcinoma

Thyroglobulin levels were measured, without interruption of hormone treatment, in 115 patients who had undergone thyroidectomy for differentiated carcinoma. Thyroglobulin levels were invariably high in patients with iodine fixing metastases. The estimation of thyroglobulin was found to be more sensitive than the detection of metastases by their uptake of 131 iodine. A new protocol is suggested for monitoring treated differentiated carcinoma.

Analysis of T cell subsets in Graves' disease: alterations associated with carbimazole

Conflicting data on subpopulations of peripheral blood lymphocytes in patients with autoimmune disease largely reflect variations in methods of study. An investigation was therefore conducted aimed at avoiding this difficulty. Serial samples of peripheral blood mononuclear cells from 42 patients with hyperthyroid Graves' disease were collected at monthly intervals before, during, and for 12 months after a six month course of carbimazole. Samples were stored in liquid nitrogen until completion of the study, when they were thawed and all samples from each patient analysed within the same assay using mouse monoclonal antibodies to human cell subsets and a fluorescence activated cell sorter. Proportions of cytotoxic/suppressor (OKT8) positive cells before treatment (mean 17.4 (SEM 0.8)%) were significantly lower (p less than 0.001) than those in normal controls (29.8 (1.9)%; n = 10) and returned to normal by the end of treatment. In contrast, the proportions of activated T cells (OKIa-OKM1) were significantly raised before treatment as compared with normal (14.4 (0.6)% versus 4.6 (0.8)%; p less than 0.001) and fell to normal by the end of treatment. Proportions of OKT3 and OKT4 positive T cells remained unchanged throughout treatment and in the succeeding 12 months. In patients who relapsed after treatment there was a rise in the proportion of activated T cells and a fall in OKT8 positive T cells, which returned towards normal with retreatment. The explanation for the alterations in numbers of circulating T cells remains to be determined but they may provide a means for predicting more accurately the outcome of Graves' disease after treatment with carbimazole.

Subpopulations of lymphocytes in maternal peripheral blood during pregnancy

The fetus can be considered an allograft with up to one-half of its MHC antigens being potentially recognized by the mother as foreign. This study compares expression of OKT3, OKT4, OKT8, Kappa, Lambda and Ia antigens on lymphocytes in the peripheral blood of normal non-pregnant women, normal pregnant women, patients who are chronic spontaneous aborters and pregnant insulin-dependent diabetic women. Monoclonal antibodies and cytofluorometric analyses were used for these determinations. There were no significant differences (P = 0.01) between these groups for T-cell markers. A statistically significant (P = 0.001) increased ratio of cells bearing surface immunoglobulin to those expressing Ia antigen (K&L/Ia) was observed between normal non-pregnant controls and women with a history of chronic spontaneous abortion. It is concluded that T-lymphocytes in the peripheral blood do not demonstrate a phenotypic abnormality that would account for the non-rejection of the fetal allograft; however, women with chronic spontaneous abortion may have abnormal B-cell differentiation or T-cell activation that mediates chronic spontaneous abortion.

Serum thyroglobulin determinations in the differential diagnosis of congenital hypothyroidism

The value of serum thyroglobulin (Tg) determination in the differential diagnosis of congenital hypothyroidism was assessed by serum Tg measurements in 14 patients with proven congenital hypothyroidism, in 3 subjects with transient perinatal hypothyroidism, in 3 newborns with congenital thyroxine binding globulin (TBG) deficiency and in 34 normal controls. Serum Tg was undetectable in all 6 cases with thyroid agenesis, normal or moderately elevated in the 4 cases with ectopic thyroid, markedly increased in the 4 cases with dyshormonogenic goiter and normal in the 3 cases with transient hypothyroidism and in the 3 with TBG deficiency. The present data indicate that serum Tg measurements may be useful in the differentiation of athyreotic hypothyroidism from other conditions of congenital hypothyroidism.

Correlation of plasma hormone levels and peripheral circulating lymphocyte subpopulations during human pregnancy

Using monoclonal antibodies (OKT3, OKT4, OKT8) peripheral blood lymphocyte subsets were determined in 40 normal primiparous pregnant women and compared with those of 31 nonpregnant controls. In pregnant women plasma concentrations of estradiol, progesterone, human placental lactogen (HPL), beta subunit of human chorionic gonadotropin (beta HCG), and alpha-fetoprotein were measured by means of radioimmunoassay. We studied if correlations between peripheral lymphocyte subsets and plasma hormone levels might exist. We observed in pregnant women from 10 to 40 wk of amenorrhea a decrease in the percentage of OKT3 and OKT8 cells, and during the course of pregnancy an increase in the percentage of OKT4 cells. This increase inversely correlated with plasma beta HCG levels and directly correlated with plasma HPL levels.

Humoral and cell-mediated immune responses to herpesvirus antigens during pregnancy--a longitudinal study

Humoral and cellular immune responses were studied during the second trimester, third trimester, and postpartum periods in 11 pregnant women and in nonpregnant control women. Complement fixing (CF) and indirect hemagglutinating antibody (IHA) titers for herpes simplex type 1 (HSV-1), herpes simplex type 2 (HSV-2), and cytomegalovirus (CMV) were determined. Cellular response was measured by [3H]thymidine uptake by stimulated lymphocytes. Phytohemagglutinin (PHA), HSV-1, HSV-2, and CMV antigens were used as stimulants. No differences in the mean titers of CF and IHA antibodies were found. The cellular response to PHA had a transient decrease (P less than 0.02) during the third trimester. The cellular response to CMV was significantly lower during the second and third trimesters. A diminished response to HSV-1 antigen was observed during the second and third trimesters; the cellular response to HSV-2, though reduced, was not significantly altered during pregnancy. These data indicate a suppression of cellular responses to various herpesviruses and PHA during pregnancy.