Effects of androgens on T and B lymphocyte development

The sexually dimorphic nature of normal immune responses and the remarkably higher incidence of autoimmune diseases in females have suggested a role for gonadal steroid hormones as modulators of immune system function. We have investigated the effects of androgens on the development of lymphocytes in the thymus and bone marrow. Expression of the androgen receptor, the ligand-activated transcription factor that mediates hormone actions, has been documented in lymphoid and nonlymphoid cells of thymus and bone marrow, but not in mature peripheral lymphocytes. This expression pattern suggests that the major impact of androgens must be on the developmental maturation of T and B lymphocytes rather than on the mature effector cells. Recent experiments have explored whether developing lymphoid precursors are the direct targets of androgen action or whether supporting cells, such as thymic epithelial cells and bone marrow stromal cells, are required for the receptor-mediated effects of androgens on lymphoid cell development. Bone marrow transplantation techniques using an androgen-resistant mouse strain permit the creation of chimeric mice with androgen receptor-defective lymphoid or epithelial/stromal cellular compartments. Hormonal manipulation experiments in these chimeric animals have suggested that thymic epithelial cells and bone marrow stromal cells are mediators of androgenic effects on immature lymphocytes. The long-range goal of these studies is to understand the basis for the disproportionate occurrence of autoimmune diseases in females.

Bone marrow stromal cells mediate androgenic suppression of B lymphocyte development

Castration of normal male mice induces expansion of the bone marrow B cell population, an effect that can be reversed by androgen replacement. We employed in vitro cultures and two in vivo models to investigate whether androgens exert these effects directly on marrow lymphoid precursors or whether actions on marrow stromal elements are required. Immature B cells from normal mouse bone marrow were not responsive to the suppressive effect of androgens unless they were cocultured with marrow stromal cells or with supernatants from androgen-treated stromal cells, suggesting that the androgen effects are exerted through marrow stromal elements by production of a diffusible mediator. Further experiments revealed that bone marrow stromal cells produced TGF-beta in response to dihydrotestosterone (DHT), and neutralization of TGF-beta in the DHT-treated stromal cells reversed the suppressive effects. The stromal cell requirement for androgen-mediated effects was confirmed in vivo by experiments using chimeric animals created by bone marrow transplantation in which androgen receptor expression was restricted to either the stromal or lymphoid cells of the bone marrow. Androgens only affected B cell development in chimeric mice with androgen-sensitive stromal cells. These experiments suggest that effects of androgens on developing B cells are mediated through androgen receptors in bone marrow stromal cells. TGF-beta is a candidate mediator for these hormonal effects.

Utility of magnetic resonance imaging in the evaluation of patients with inflammatory myopathies

Magnetic resonance imaging (MRI) and P-31 magnetic resonance spectroscopy (P-31 MRS) provide unique, quantitative data that cannot be obtained from routine laboratory tests. MRI is the method of choice for imaging of muscle abnormalities. It is also a very sensitive technique for localizing nonhomogeneous inflammation in inflammatory myopathies such as dermatomyositis, juvenile dermatomyositis, amyopathic dermatomyositis, polymyositis, and inclusion body myositis. During treatment of inflammatory myopathies, the extent and severity of inflammation may decrease at varying rates, but weakness and fatigue remain serious clinical problems. The metabolic abnormalities detected with P-31 MRS are more persistent and can be used for objective patient evaluation after the disappearance of inflammation and normalization of serum levels of muscle enzymes. With P-31 MRS, biochemical defects are quantitated, including low levels of ATP and phosphocreatine (PCr) and elevated concentrations of ADP and inorganic phosphate (Pi), which may all be related to weakness and fatigue. Thus, MRI and P-31 MRS are useful in assessing the status of patients with inflammatory myopathies during treatment with prednisone and immunosuppressive drugs.

Amyopathic dermatomyositis

Amyopathic dermatomyositis is a variant of dermatomyositis that is characterized by the typical skin rash but without the muscle abnormalities. It has been proposed that the amyopathic and myopathic forms of dermatomyositis exist on a continuum, a concept that is supported by family and genetic studies and the observation that a small proportion of amyopathic patients transform to a frankly myopathic state. The amyopathic state is defined by a lack of muscle weakness and through diagnostic tests, including serum muscle enzymes, electromyogram studies, and muscle biopsies, that are usually normal or show only minimal abnormalities. Despite the lack of weakness, many patients complain of debilitating fatigue. More sensitive measures of muscle function, such as P-31 magnetic resonance spectroscopy, suggest that muscle metabolism is abnormal in amyopathic patients. The amyopathic form is more commonly seen in adults than in children, although juvenile cases are reported. Some early series suggested no association with underlying malignancies, but recent reports indicate that malignancies occur. Determining whether a patient has amyopathic rather than myopathic disease may have prognostic implications.

Androgen receptors in thymic epithelium modulate thymus size and thymocyte development

Castration of normal male rodents results in significant enlargement of the thymus, and androgen replacement reverses these changes. Androgen-resistant testicular feminization (Tfm) mice also show significant thymus enlargement, which suggests that these changes are mediated by the androgen receptor (AR). The cellular targets of androgen action in the thymus are not known, but may include the lymphoid cells (thymocytes) as well as nonlymphoid epithelial cells, both of which have been believed to express AR. In the present study immunohistochemical analysis and hormone binding assays were used to demonstrate the presence of AR in thymic epithelial cells. The physiological significance of this epithelial cell AR expression was defined by further studies performed in vivo using chimeric mice, produced by bone marrow transplantation, in which AR expression was limited to either lymphoid or epithelial components of the thymus. Chimeric C57 mice engrafted with Tfm bone marrow cells (AR(+) epithelium and AR(-) thymocytes) had thymuses of normal size and showed the normal involutional response to androgens, whereas chimeric Tfm mice engrafted with C57 bone marrow cells (AR(-) epithelium and AR(+) thymocytes) showed thymus enlargement and androgen insensitivity. Furthermore, phenotypic analyses of lymphocytes in mice with AR(-) thymic epithelium showed abrogation of the normal responses to androgens. These data suggest that AR expressed by thymic epithelium are important modulators of thymocyte development.

Chest pain in asbestos-exposed individuals with benign pleural and parenchymal disease

Many asbestos-exposed individuals complain of chest pain for which there is no clear explanation. To determine whether chest pain is associated with the presence of benign pleural or parenchymal disease on chest radiograph, we studied 1,280 subjects undergoing surveillance because of prior asbestos exposure at Wittenoom, Western Australia. All subjects completed the Rose questionnaire on chest pain and this revealed 556 subjects (43%) who experienced some chest pain. A posterior-anterior chest radiograph was performed at the same clinic visit and was subsequently graded independently by two experienced readers for diffuse parenchymal disease and pleural disease. Logistic regression models adjusted for sex, age, and cumulative asbestos exposure indicated that the presence of chest pain was significantly associated with the presence of both benign pleural disease and diffuse parenchymal disease. Further analysis after stratification of chest pain into nonanginal and anginal pain showed that there was a significant association between anginal pain and the presence of pleural and parenchymal asbestos-induced radiologic abnormalities and an association of nonanginal pain with parenchymal disease. We conclude that radiographic evidence of either parenchymal or pleural disease in subjects exposed to asbestos is significantly related to the presence of chest pain, particularly anginal pain.

Muscle abnormalities in juvenile dermatomyositis patients: P-31 magnetic resonance spectroscopy studies

OBJECTIVE

To characterize metabolic abnormalities in the muscles of children with the juvenile variant of dermatomyositis (JDM) by the use of noninvasive P-31 magnetic resonance spectroscopy (MRS).

METHODS

Thirteen patients with JDM (ages 4-16 years) were studied. Biochemical status was evaluated with P-31 MRS by determining the concentrations of the high-energy phosphate compounds, ATP and phosphocreatine (PCr), ratios of inorganic phosphate (Pi) to PCr (Pi:PCr ratio), levels of free cytosolic ADP, and phosphorylation potentials (PPs) during rest, exercise, and recovery.

RESULTS

Significant metabolic abnormalities were observed in the thigh muscles of 10 severely affected patients during rest, 2 graded levels of exercise, and recovery. Mean ATP and PCr levels in the muscles of JDM patients were 35-40% below the normal control values (P < 0.003). These data, along with elevated Pi:PCr ratios, higher ADP levels, and abnormal values for PPs, indicated defective oxidative phosphorylation in the mitochondria of diseased JDM muscles. MRS findings were normal in 2 additional patients who had improved with prednisone treatment and in 1 patient who had no muscle weakness (amyopathic variant of JDM).

CONCLUSION

JDM patients can be monitored with noninvasive P-31 MRS without sedation. Biochemical defects in energy metabolism are concordant with the weakness and fatigue reported by JDM patients. Quantitative MRS data are useful for evaluating patients and optimizing drug treatment regimens.

Treatment of rheumatoid arthritis with a DR4/1 peptide

OBJECTIVE

To determine the safety and potential clinical efficacy of primary and booster injections of a DR4/1 peptide in patients with active rheumatoid arthritis (RA) despite methotrexate therapy. METHODS. Subjects with active RA were enrolled in a randomized, placebo controlled, double blind, dose-escalating clinical trial of synthetic DR4/1 peptide containing the shared epitope. The primary injection of the DR4/1 peptide in alum adjuvant was administered at one of 3 doses, 1.3, 4.0, and 13 mg, followed by up to 3 or 4 booster injections every 6 or 8 weeks at the same dose. The primary outcomes were the occurrence of adverse effects and changes in measures of immune function. Clinical efficacy was assessed using the American College of Rheumatology 20% criteria for clinical improvement.

RESULTS

Fifty-three patients were entered into the trial, including 44 who completed the study. In the absence of any observations of a dose response to the DR4/1 peptide injections, the 3 dosage groups were combined for subsequent analysis into 3 groups: patients receiving DR4/1 peptide injections every 6 weeks, patients receiving DR4/1 peptide injections every 8 weeks, and a placebo group. At all doses and each dosing interval the primary and booster injections of synthetic DR4/1 peptide were well tolerated and did not produce any significant changes in lymphocyte counts or evidence of generalized immunosuppression. Analysis of clinical efficacy showed that the 6 week group had trends toward improvement in disease measures.

CONCLUSION

Primary and booster injections of the DR4/1 peptide containing the shared epitope were safe and did not broadly suppress immune function.

Leflunomide for the treatment of rheumatoid arthritis

Leflunomide treatment appears to offer an alternative to methotrexate and sulfasalazine and is a welcome addition to the therapeutic armamentarium for treating active RA. Leflunomide treatment for more than 12 months results in clinically meaningful improvements in disease-specific measures of physical function. The phase 3 trials have shown leflunomide to be as effective as methotrexate and sulfasalazine and an option for initial DMARD therapy. As with all new agents, the long-term safety and value of leflunomide will be determined by use in the clinic.

Skeletal muscle abnormalities in patients with fibromyalgia

Widespread muscle pain and tender points are the most common complaints of fibromyalgia patients, and the underlying mechanisms responsible for these symptoms have been studied intensively during the past decade. It has been suggested that fatigue and pain may lead to decreased levels of physical activity in many patients. The resulting deconditioned state may itself contribute to muscle abnormalities. Associated symptoms such as disturbed sleep, anxiety, depression, or irritable bowel also may have a negative impact on muscle function and level of daily activities. The important interactions between the central nervous and musculoskeletal systems may involve another element, the neuroendocrine stress-response system. This review will consider both the current state of knowledge and also future studies which might be designed to answer more effectively the outstanding questions regarding the underlying pathogenesis of fibromyalgia.

Analysis of 31P MR spectroscopy data using artificial neural networks for longitudinal evaluation of muscle diseases: dermatomyositis

Classical myopathic dermatomyositis (DM) is a chronic autoimmune disease characterized by an erythematous rash and severe, proximal muscle weakness. A disease variant, amyopathic DM, presents with the typical rash but without clinical evidence of muscle weakness. Prednisone and immunosuppressive drugs alleviate symptoms in many patients. Accurate longitudinal evaluations of patients are important to limit serious side effects of these drugs, including osteoporosis, cataracts, and growth inhibition. Metabolic abnormalities detected with 31P magnetic resonance spectroscopy (MRS) provide the best quantitative data for evaluating these patients. With 31P MRS, the levels of inorganic phosphate (Pi), phosphocreatine (PCr), ATP, and phosphodiesters (PDE) were determined in the quadricep muscles of patients during rest and exercise. Artificial neural network (ANN) analyses of these data were previously used for accurate classification of patients with myopathic or amyopathic DM and normal controls. In the present investigation, an artificial neural network was employed for further analysis of the 31P metabolite levels in quantitative, longitudinal evaluations of the extent (percent) of clinical improvement or deterioration during treatment with prednisone and immunosuppressive drugs. The ANN results showed that adult patients in a severe myopathic state could improve with treatment to a clinical status of amyopathic DM. In contrast, severely weak juvenile patients in the myopathic state recovered to normal status. One juvenile patient did not improve and remained in the myopathic state. Additionally, a serious clinical relapse in an amyopathic patient was predicted with serial ANN analyses well in advance of the actual clinical event. These network analyses show potential utility for clinical applications in muscle diseases.

Use of P-31 magnetic resonance spectroscopy to detect metabolic abnormalities in muscles of patients with fibromyalgia

OBJECTIVE

To investigate the metabolic and functional status of muscles of fibromyalgia (FM) patients, using P-31 magnetic resonance spectroscopy (MRS).

METHODS

Twelve patients with FM and 11 healthy subjects were studied. Clinical status was assessed by questionnaire. Biochemical status of muscle was evaluated with P-31 MRS by determining concentrations of inorganic phosphate (Pi), phosphocreatine (PCr), ATP, and phosphodiesters during rest and exercise. Functional status was evaluated from the PCr/Pi ratio, phosphorylation potential (PP), and total oxidative capacity (Vmax).

RESULTS

Patients with FM reported greater difficulty in performing activities of daily living as well as increased pain, fatigue, and weakness compared with controls. MRS measurements showed that patients had significantly lower than normal PCr and ATP levels (P < 0.004) and PCr/Pi ratios (P < 0.04) in the quadriceps muscles during rest. Values for PP and Vmax also were significantly reduced during rest and exercise.

CONCLUSION

P-31 MRS provides objective evidence for metabolic abnormalities consistent with weakness and fatigue in patients with FM. Noninvasive P-31 MRS may be useful in assessing clinical status and evaluating the effectiveness of treatment regimens in FM.

Androgens accelerate thymocyte apoptosis

Mechanisms of androgen-induced thymic involution are largely undefined. We have found that significant decreases in thymic size occur 2-4 h after a dose of testosterone is administered to castrated male mice. This rapid rate of change suggests a role for androgen-induced apoptosis in modulating the size and composition of the thymus. Using thymic organ cultures to define these effects of androgens, we found that dihydrotestosterone treatment of thymus tissues from females or from castrated males results in enhancement of thymocyte apoptosis. Intact (androgen-replete) or testicular feminization, Tfm/Y (androgen-resistant) mice failed to show apoptotic change with androgen treatment, although the apoptotic response to glucocorticoids was present, suggesting a requirement for a functional androgen receptor. Acceleration of thymocyte apoptosis by androgens may mediate processes of thymocyte selection, with the potential to impart gender-specific characteristics on the peripheral T cell repertoire.

Vitamin A and cancer prevention I: observations in workers previously exposed to asbestos at Wittenoom, Western Australia

Our aim was to describe a vitamin A-based cancer prevention program for former asbestos workers and to check for possible harmful effects by comparing rates of disease and death in study subjects with subjects who chose not to join. All subjects had been occupationally exposed to crocidolite at Wittenoom Gorge between 1943 and 1966; 1,677 subjects indicated interest in the program and 1,203 joined between June 1990 and May 1995. Comparison subjects consisted of 996 former workers known to be alive in Western Australia in 1990 who did not join the program. Program subjects were provided with annual supplies of vitamin A (either synthetic beta-carotene or retinol), help in quitting smoking and dietary advice. The comparison group received only mail contact. Both groups were followed up to December 1994 for vital status and cancer information, and rates of cancer and death from various causes were compared. Mortality in both groups was higher than expected (standardised mortality ratio 1.23 in program subjects and 1.67 in comparison subjects). After adjustment for age, smoking and asbestos exposure, the relative rates in participants compared with non-participants was below I for all examined cancers and causes of death. For mesothelioma and lung cancer, group differences increased with time from entry, whereas other differences dissipated with time. No significant side effects were reported. In conclusion, program participants had significantly lower mortality than non-participants, but the rates of the 2 groups converged with time.

Androgens alter B cell development in normal male mice

Castration of normal male mice leads to splenic enlargement and expansion of the B cell population. Since the spleen does not express receptors for androgens, these changes are most likely mediated by effects of androgens on other target organs. Two potential sites of androgen-mediated effects on B cells are evaluated in these studies: thymus and bone marrow. We first confirmed other findings indicating that castration of normal male mice results in expansion in the numbers of bone marrow B cells and then extended these observations by showing that these changes were reversible following androgen replacement. B cell expansion in castrate marrow and spleen was not altered by prior thymectomy, suggesting that thymic androgen receptors are not involved in the observed effects. Androgen receptors were found to be present in both immature B cells and marrow stromal cells by immunoblotting and ligand binding assays. The results suggest a direct modulatory role for androgens on B cells within the bone marrow compartment.

Inflammatory myopathies: issues in diagnosis and management

The techniques of magnetic resonance imaging and spectroscopy have been shown to have utility in the diagnosis and management of inflammatory muscle diseases. But perhaps more important have been the new insights into the pathophysiology of these diseases which MR studies, along with new immunologic data on autoantibodies and cellular infiltrates, have afforded. Pathologic subsets of inflammatory muscle disorders have been identified, suggesting, for example, that PM and DM are distinct disorders, thereby challenging the idea that these are relatively homogeneous syndromes. Further insights into disease pathogenesis which are likely to emerge from these new findings may allow identification of etiologic factors and improved approaches to treatment.

Schistosoma mansoni: susceptibility differences between male and female mice can be mediated by testosterone during early infection

In murine Schistosoma mansoni infections, fewer adult worms develop in male than in female mice infected with the same number of cercariae. To evaluate a potential role for testosterone in this phenomenon, testosterone levels were manipulated in groups of CBA/J mice that were then infected and monitored for survival rates, worm burdens, organomegaly, and egg production. By 16 weeks of infection, more than 80% of mice in groups with low levels of testosterone (untreated females, castrated males, or carrier-treated castrates) were dead, while less than 40% of those in groups with high levels of testosterone (sham-castrated males, testosterone-treated castrates, or testosterone-treated female mice) succumbed to infection. The mean number of worms recovered from mice in the low testosterone level groups was comparable among groups, and significantly greater than that from those in high-testosterone-level groups. The degree of organomegaly observed correlated strongly with worm burden, but the number of hepatic eggs per female worm did not differ significantly between groups. When male mice were castrated or sham-castrated 5 weeks after S. mansoni infection, no significant differences in host survival occurred. Furthermore, female mice treated with testosterone demonstrated reduced worm burdens if the testosterone was given 10 days prior to infection but not if the testosterone was given 10 days or 5 weeks after infection. Thus, the host sex bias observed in parallel-infected male and female mice appears to be related to the presence of male gonadal tissue or testosterone early in infection, during the development of immature schistosomules.

Muscle abnormalities in scleroderma

Weakness and fatigue are common symptoms in patients with scleroderma and may be due at least in part to underlying abnormalities of muscle. Various modalities, including electromyography, histologic examination of biopsy specimens, MR imaging, and MR spectroscopy are useful in defining muscle abnormalities in these patients. Recent studies using P-31 MR spectroscopy and near infrared spectroscopy demonstrate the presence of underlying metabolic abnormalities that may contribute to the clinical findings of weakness and fatigue.

A double-blind, placebo-controlled study of anti-CD5 immunoconjugate in patients with rheumatoid arthritis. The Xoma RA Investigator Group

OBJECTIVE

To evaluate the efficacy of an anti-CD5 ricin-linked immunoconjugate (CD5-IC) in patients with rheumatoid arthritis (RA).

METHODS

A total of 104 evaluable patients were enrolled in a multicenter, double-blind, multiple-dose, placebo-controlled study of CD5-IC.

RESULTS

Treatment with CD5-IC in doses up to 8 mg/m2/day for 4 days in 1 month failed to produce marked or prolonged T cell depletion and was no more effective than placebo in ameliorating disease manifestations. An unexpectedly high placebo response was observed in 48% of the patients. Adverse events were correlated with the dose of CD5-IC, but the treatment was generally well-tolerated.

CONCLUSION

At the doses used in this study, CD5-IC was ineffective for treating RA.

Evaluation of muscle diseases using artificial neural network analysis of 31P MR spectroscopy data

Dermatomyositis is an autoimmune disease characterized by an erythematous rash and severe muscle weakness. 31P Magnetic resonance spectroscopy (MRS) provides quantitative data for longitudinal monitoring of disease status and responses to immunosuppressive therapy. A disease variant, amyopathic dermatomyositis, presents with a typical rash but no clinical muscle weakness. However, metabolic abnormalities in the oxidative capacity of muscles of amyopathic patients during exercise were detected with 31P MRS. Because MRS provided the best quantitative data for evaluating dermatomyositis, the 31P metabolic parameters derived from the MR spectra were further processed using an artificial neural network (XERION). The neural network analyses provided additional clinical information from the weighted correlations of multiple 31P parameters, namely, inorganic phosphate, phosphocreatine, ATP, phosphodiesters, and selected ratios. This investigation analyzes the relative importance of the various metabolic parameters for accurate patient characterization and provides insights into the pathogenesis of the disease.

Case report: testosterone treatment of systemic lupus erythematosus in a patient with Klinefelter's syndrome

Systemic lupus erythematosus occurs with much greater frequency in females than in males, and in some reports, researchers suggested that treatment with androgenic hormones might have therapeutic effects in this disease. The authors report a case of systemic lupus erythematosus in a hypogonadal male with Klinefelter's syndrome who was treated with testosterone in doses sufficient to normalize the serum level of this hormone to the adult male range. Hematologic and serologic abnormalities, including elevated levels of anti-DNA antibodies and depressed complement levels, returned to normal within 9 months of increasing the testosterone dose. The findings in this patient indicate that androgenic steroids can exert significant effects on immune parameters, and suggest that effects of androgens on the immune system may contribute to the sexual dimorphism of autoimmune disease.