Association between Systemic Lupus Erythematosus, Rheumatoid Arthritis, Hyperprolactinemia and Thyroid Autoantibodies

Thyroid Autoimmunity and Subclinical Hypothyroidism in Prolactinoma: A Case Control Study

Background

This study was aimed at determining the frequency of thyroid autoimmunity and subclinical hypothyroidism in patients with hyperprolactinemia due to prolactinoma compared to well-matched healthy controls.

Methods

This was a cross-sectional study wherein 78 treatment naïve prolactinoma patients and ninety-two healthy control subjects were recruited. Serum prolactin (PRL), thyroid-stimulating hormone (TSH), total thyroxine (T4), circulating anti-thyroid peroxidase (anti-TPO), and anti-thyroglobulin (anti-Tg) antibody levels were measured in all study subjects. Progression of the antibody-positive population to subclinical hypothyroidism was determined.

Results

The median PRL level among patients was 166 ng/ml (IQR 85-467) compared to 11.4 ng/ml (IQR 8.5-15.9) in controls (P < 0.001). There was no significant difference in levels of T4 (P = 0.83) and TSH (P = 0.82) between the cases and controls. Overall, 25% of patients had the presence of anti-thyroid antibodies as compared to 20% of controls (P = 0.56). SCH was more common in antibody-positive hyperprolactinemia subjects compared with antibody-positive controls.

Conclusion

We did not find an increased prevalence of thyroid autoimmunity among untreated prolactinoma patients compared to healthy controls. At the same time, subclinical hypothyroidism was more common in thyroid antibody-positive patients with hyperprolactinemia than positive controls.

The prevalence of thyroid autoantibodies in autoimmune connective tissue diseases: a systematic review and meta-analysis

AIM

Patients with autoimmune connective tissue disease (ACTD) may have anti-thyroid peroxidase antibody (TPOAb) and anti-thyroglobulin antibody (TgAb). This study aimed to compare the prevalence of thyroid autoantibodies in ACTD patients and controls.

METHODS

All case-control studies published between 1980 and 2019 in English were searched from Medline, Embase, Web of Science, PubMed databases for meta-analysis and subgroup analyses.

RESULTS

Total 10,321 ACTD cases and 12,949 healthy controls were included, and the prevalence of thyroid autoantibody positivity was higher in ACTD patients than in controls. Subgroup analysis revealed positive association between TgAb and ACTD in populations from all continents including European, Asian, African, and American. In addition, we found positive association between TgAb positivity and most ACTD cases including RA, SLE, pSS, and UCTD, positive association between TPOAb positivity and all ACTD cases including RA, SLE, pSS, SSc, and UCTD, and positive association between TPOAb positivity and ACTD in European, Asian, and African but not in American populations.

CONCLUSION

Thyroid autoantibodies are more prevalent in ACTD patients than in healthy controls. It is important to screen patients with ACTD for the presence of thyroid autoimmunity, and perform thyroid function tests in clinical evaluation of ACTD patients.

Evaluation of autoantibodies and immunoglobulin G subclasses in women with suspected macroprolactinemia

BACKGROUND

Macroprolactin mostly composed of an immunoglobulin G (IgG) and a monomeric prolactin (PRL) represents the major circulating PRL form in the patients with macroprolactinemia that are usually asymptomatic and may not require treatment. In this study, we aimed to evaluate the prevalence of antithyroid and antinuclear antibodies, as well as the IgG subclass distributions in the patients suspected for macroprolactinemia.

METHODS

From January to July in 2018, totally 317 patients with elevated PRL were subjected to the polyethylene glycol (PEG) precipitation assay. The patients with recovery rates of ≤60% were subjected for IgG subclass determination and autoantibody testing including thyroid peroxidase antibody (aTPO), antithyroglobulin antibody (aTG), and antinuclear antibodies (ANA).

RESULTS

The higher the post-PEG PRL recovery rates, the less typical hyperprolactinemia symptoms and the higher prevalence of autoantibodies were observed. The IgG1 and IgG3 were the predominant subclasses in the PRL-IgG complexes according to the immunoprecipitation experiments.

CONCLUSION

The patients with post-PEG PRL recovery rates of <40% and 40%-60% were likely to represent two distinct populations of different clinical presentations. The prevalence of autoantibodies and IgG subclasses distribution suggested their pathogenic significance in the development of macroprolactinemia.

Association of raised levels of IL-4 and anti-TPO with hyperprolactinemia

BACKGROUND AND OBJECTIVE

The modulatory role of prolactin in autoimmune regulation is well established. Hyperprolactinemia is often associated with autoimmune disease like systemic lupus erythematosus and autoimmune thyroid diseases. The objective was to compare levels of direct and indirect autoimmune factors in different categories of hyperprolactinemia cases and predict the direction of association between hyperprolactinemia and autoimmune factors, if any.

METHODS

A total of 102 hyperprolactinemia cases (>100 ng/mL serum prolactin level) were included along with 24 controls. Among 102 hyperprolactinemia cases, there were 36 idiopathic cases, 19 pituitary adenoma cases, 36 drug-induced cases, and 11 cases associated with other secondary/systemic diseases (chronic renal failure, chronic hepatic failure, etc).

MEASUREMENTS

Direct autoimmune markers, IL-2, IFN-γ, IL-4, and IL-5, were measured in serum by ELISA. Indirect autoimmune markers, anti-TPO, anti-tg, anti-CCP, VDRL, platelet count, and aPTT, were measured as per laboratory-defined protocol.

RESULTS

Serum levels of IL-4 and anti-TPO were significantly high in idiopathic hyperprolactinemia cases. Serum IL-4 levels were also significantly high in pituitary adenoma cases, drug-induced cases, and in cases with other secondary causes of hyperprolactinemia. Serum anti-TPO levels were also significantly high in drug-induced hyperprolactinemia cases.

CONCLUSION

No significant difference in autoimmune factors is observed between macroprolactinemia and true hyperprolactinemia. Serum IL-4 and anti-TPO were high in all categories of hyperprolactinemia. This suggests a possible association of hyperprolactinemia with autoimmune conditions (high IL-4 and anti-TPO), mostly subclinical. Thus, hyperprolactinemia case with serum prolactin level >100 ng/mL may require long-term follow-up for the development of autoimmune disease in future.

Circulating levels of prolactin are elevated in patients with rheumatoid arthritis: a meta-analysis

BACKGROUND

Prolactin (PRL), an inflammatory hormone with cytokine properties, has long been proposed to play a crucial role in the pathogenesis of autoimmune disorders, including rheumatoid arthritis (RA). However, the circulating levels of PRL in RA were discordant among published studies.

METHODS

PubMed, Embase, and The Cochrane Library database were systematically searched from inception up to 30 June 2018. The available studies were obtained from the initial search in accordance with the rigorous inclusion and exclusion criteria. Relevant data from the included literatures were extracted. Methodological quality was evaluated in order to refine the final search results. All statistical analyses were conducted using software STATA version 12.0.

RESULTS

Of 698 articles were yielded for eligibility, a finally analysis involving 628 RA cases and 430 controls from 14 published studies were included. When compared to healthy controls, there was a significantly higher level of circulating PRL in patients with RA with a pooled SMD of 1.08 (95% CI = 0.41 to 1.74, P< 0.001), particularly in Asians, age ≥50, enzyme-linked immunosorbent assay (ELISA) group and subjects with erythrocyte sedimentation rate (ESR) ≥25 mm/h.

CONCLUSIONS

Our meta-analysis demonstrates a significantly higher level of circulating PRL in RA patients when compared to healthy controls, and it was associated with region, age, measurement type and ESR.

Circulating prolactin level in systemic lupus erythematosus and its correlation with disease activity: a meta-analysis

Objective

This study aimed to evaluate the relationship between circulating prolactin level and systemic lupus erythematosus (SLE), and to establish a correlation between plasma/serum prolactin levels and SLE activity.

Methods

We performed a meta-analysis comparing the plasma/serum prolactin levels in patients with SLE to controls, and examined correlation coefficients between circulating prolactin level and SLE disease activity.

Results

Twenty-five studies with a total of 1056 SLE patients and 426 controls were included. Prolactin levels were significantly higher overall in the SLE group than in the control group (standardized mean difference (SMD) = 0.987, 95% CI = 0.512–1.463, p = 4.7 × 10−5). Stratification by ethnicity showed significantly elevated prolactin levels in the SLE group in Asian, Latin American, and mixed populations (SMD = 0.813, 95% CI = 0.137–1.490, p = 0.018; SMD = 0.981, 95% CI = 0.307–1.655, p = 0.004; SMD = 1.469, 95% CI = 0.443–2.495, p = 0.005, respectively), but not in the European population. Subgroup analysis by sample size showed significantly higher prolactin levels in the SLE group by small ( n < 30) and large sample numbers ( n > 30). Meta-analysis of correlation coefficients showed a significantly positive correlation between circulating prolactin level and SLE activity (correlation coefficient = 0.379, 95% CI = 0.026–0.487, p = 4.0 × 10−9). Circulating prolactin levels were positively associated with SLE activity in European, Asian, and mixed populations (SMD = 0.532, 95% CI = 0.443–0.609  p < 1.0 × 10−8; SMD = 0.427, 95% CI = 0.240–0.583, p = 2.4 × 10−5; SMD = 0.433, 95% CI = 0.212–0.591, p = 2.7 × 10−5, respectively).

Conclusions

Our meta-analysis demonstrated that circulating prolactin levels are higher in patients with SLE, and that a significantly positive correlation exists between prolactin levels and SLE activity.

The higher incidence of autoimmune thyroid disease in prolactinomas than in somatotrophinomas

OBJECTIVE

Many studies have shown that prolactin (PRL) plays an important role in autoimmune diseases. The aim of this study was to compare the current frequency of autoimmune thyroid disease (ATD) in prolactinomas with another type of functional pituitary adenoma (FPA), somatotrophinoma. Another aim of the study was to evaluate possible factors related to thyroid autoimmunity and the process of ATD in FPAs.

METHODS

We retrospectively evaluated the presence of thyroid peroxidase antibody (TPOAb) and thyroglobulin antibody (TgAb) and thyroid morphologic findings in our patients with FPA (78 with acromegaly and 83 with prolactinoma). The relationship of autoantibody positivity with baseline PRL levels, activity of acromegaly, and treatment of dopamine agonists (DA) and hypogonadism was also assessed. Patients with ATD and hypothyroidism due to autoimmune thyroiditis were also evaluated.

RESULTS

ATD (Hashimoto's thyroiditis) was detected more frequently in patients with prolactinoma than in patients with acromegaly (33% and 17%, respectively; p=0.01). Thyroid autoantibody positivity was found more frequently in females in the whole group (p=0.02) and in the acromegaly group (p=0.008). There was no difference according to sex among the patients with prolactinoma (p=0.800). ATD was found not to be related with baseline PRL levels, treatment of DA, and presence of hypogonadism (p=0.232, p=0.435, p=0.464, respectively) in the prolactinoma group, and activity of acromegaly, presence of hypogonadism in the acromegaly group (p=0.753, p=0.654, respectively). Autoimmune hypothyroidism was more frequent in the prolactinoma group than in the acromegaly group among patients with thyroid autoantibody positivity (p=0.004).

CONCLUSION

Thyroid autoantibodies should be evaluated both at the time of diagnosis and during the course of treatment in patients with prolactinoma, and thyroid function tests should be closely monitored in patients with autoantibody positivity.

The role of the prolactin/vasoinhibin axis in rheumatoid arthritis: an integrative overview

Rheumatoid arthritis (RA) is a chronic, autoimmune, inflammatory disease destroying articular cartilage and bone. The female preponderance and the influence of reproductive states in RA have long linked this disease to sexually dimorphic, reproductive hormones such as prolactin (PRL). PRL has immune-enhancing properties and increases in the circulation of some patients with RA. However, PRL also suppresses the immune system, stimulates the formation and survival of joint tissues, acquires antiangiogenic properties upon its cleavage to vasoinhibins, and protects against joint destruction and inflammation in the adjuvant-induced model of RA. This review addresses risk factors for RA linked to PRL, the effects of PRL and vasoinhibins on joint tissues, blood vessels, and immune cells, and the clinical and experimental data associating PRL with RA. This information provides important insights into the pathophysiology of RA and highlights protective actions of the PRL/vasoinhibin axis that could lead to therapeutic benefits.

Increased risk of thyroid autoimmunity in rheumatoid arthritis: a systematic review and meta-analysis

Thyroid autoimmunity, which is the most common immune-mediated disease, is frequently together with other organ- as well as nonorgan-specific autoimmune disorders. Meanwhile, rheumatoid arthritis (RA) is a chronic immune-mediated inflammatory disorder that mainly results in cartilage destruction as well as synovial joint inflammation, and both the adaptive and innate immune responses involve in the progression of this disease. Considering that autoimmune elements may be common characteristics of thyroid autoimmunity and RA, it is likely that both disorders may coexist within some patients. A great number of studies have researched whether an association between thyroid autoimmunity and RA exists; however, the results of these studies have been inconsistent. Most of these studies have included relatively small sample sizes, which have rendered them insufficiently powerful to determine whether there is a relationship between RA and thyroid autoimmunity. The main objective of this meta-analysis was to provide reliable estimates of the extent of any association between thyroid autoimmunity and RA by combining the primary data from all related studies. Literature databases, including the Embase, Medline, Web of Science, Chinese Wanfang, and CBM databases, were searched for studies published from January 1980 to May 2014, with a language restriction of English and Chinese. A total of 1,021 RA cases and 1,500 healthy controls were included in this study. From these data, the odds ratios (OR) and the corresponding 95 % confidence intervals (95 % CI) were calculated. The results of the meta-analysis showed that the prevalence of thyroid autoantibody positivity in patients with RA was higher than that in healthy controls (TgAb: OR 3.17, 95 % CI 2.24-4.49; TPOAb: OR 2.33, 95 % CI 1.24-4.39). The results of this meta-analysis suggest that thyroid autoimmunity is more prevalent in patients with RA than in the control population.

Serum macroprolactin levels in pregnancy and association with thyroid autoimmunity

BACGROUND

To assess the contribution of macroprolactin to high serum prolactin levels and their association with thyroid status and thyroid autoimmunity during pregnancy.

METHODS

138 pregnant women who suspected of having thyroid dysfunction were studied and divided into three groups according to the thyroid status; group 1; euthyroidism (n 40), group 2; hypothyroidism (n 54), and group 3; hyperthyroid (n 44). Polyethylene glycol (PEG) precipitation method was used for detection of macroprolactin. A percentage recovery of 40 % or less is considered as macroprolactinemia. If macroprolactin was negative, the percentage of monomeric prolactin recovery (monoPRL %) after PEG precipitation was used for comparison between the groups.

RESULTS

Macroprolactinemia was found in two patients (1.4 %) one from hypothyroid and other from euthyroid group. Basal prolactin levels in these patients were 400 and 403 ng/mL respectively. Referring to all patients, there was no correlation between PRL, macroPRL or monoPRL % with thyroid hormone status and also with the serum levels of thyroid antibodies (p > 0.05). A positive correlation was observed between the serum levels of PRL with TSH (p = 0.014 and r = 0.219), while a negative correlation was found with FT4 (p = 0.011 and r = -0.227).

CONCLUSIONS

Despite the fact that serum prolactin levels were found to be high during pregnancy, the contribution of macroprolactin was found to be insignificant in our study. Unlike other auto immune diseases, we could not find any relationship between thyroid autoimmunity and PRL, macroPRL or monoPRL %. These results confirmed that measured prolactin was quite homogeneous during pregnancy.

Are there any causes for increased thyroid volume in women with prolactinoma?

PURPOSE

The aim of this study was to evaluate thyroid volume in women with prolactinoma and investigate the relationship between anabolic hormones [insulin, insulin like growth factor (IGF-1), estrogen] and thyroid volume in the patients.

MATERIAL-METHOD

Sixty-three euthyroid women with prolactinoma and 60 healthy euthyroid women were included. Serum prolactin (PRL), thyroid-stimulating hormone (TSH), thyroxine (free T4), free tri-iodothyronine (free T3), insulin resistance (IR) which was estimated by the homeostasis model assessment, thyroidal microsome (anti-TPO), antithyroglobulin antibodies (TgAb), estradiol (E2), and insulin like growth factor (IGF-1) were evaluated, and thyroid volume was calculated by B-mode doppler USG.

RESULTS

The mean thyroid volume was significantly higher in women with prolactinoma (82.5±15.1mL) than in healthy women (76±15.1mL)(P=0.014), but no correlation was found between thyroid volume and serum PRL levels (P=0.967). There were also no differences between thyroid volume, anabolic hormones (E2, IGF-1), and insulin resistance in women with prolactinoma (P=0.776, P=0.786, P=0.647, respectively).

CONCLUSIONS

Our study did not show an association between anabolic hormones and increased thyroid volume in women with prolactinoma.

Patients with systemic lupus erythematosus have higher prevalence of thyroid autoantibodies: a systematic review and meta-analysis

Background

Thyroid autoimmunity is considered the most common type of organ-specific autoimmune disorder and can be associated with other autoimmune endocrine disorders or non-endocrine diseases. Systemic lupus erythematosus is a prototypical autoimmune disorder with multifactorial etiology. The pathogenesis and development of the disease may result from a loss of immune tolerance and the resulting synthesis of autoantibodies against nuclear antigens. Autoimmune factors may be common features of both thyroid autoimmunity and systemic lupus erythematosus, making it likely that both conditions may coexist within some patients.

Methods and Findings

A number of studies have investigated whether an association between thyroid autoimmunity and systemic lupus erythematosus exists. However, the results of these studies have been inconsistent. Furthermore, most of these studies have had relatively small sample sizes, which have rendered them insufficiently powerful to determine whether there is an association between systemic lupus erythematosus and thyroid autoimmunity. The main objective of this meta-analysis is to provide reliable estimates of the extent of any association between thyroid autoimmunity and systemic lupus erythematosus by combining the primary data from all relevant studies. Literature databases were searched, including the Medline, Embase, Web of Science, Chinese Wanfang and CBM databases, from January 1970 to May 2014. A total of 1076 systemic lupus erythematosus cases and 1661 healthy controls were included in this study. From these data, the odds ratio (OR) and the corresponding 95% confidence interval (95% CI) were calculated. The meta-analysis results showed that the prevalence of thyroid autoantibody positivity in patients with systemic lupus erythematosus was higher than in healthy controls (TgAb: OR = 2.99, 95% CI = 1.83–4.89; TPOAb: OR = 2.20, 95% CI = 1.27–3.82, respectively).

Conclusion

The results of this meta-analysis suggest that thyroid autoimmunity is more prevalent in patients with systemic lupus erythematosus than in a control group.

Thyroid autoimmunity in patients with hyperprolactinemia: an observational study

Objective : To establish whether there is a relationship between hyperprolactinemia and primary thyroid disorders, focusing on patients with autoimmune features. Materials and methods : The medical records of 100 patients with hyperprolactinemia (HPRL) were retrospectively examined. Records of thyroid ultrasonography (USG), basal serum levels of thyroid stimulating hormone, circulating free thyroxine, free triiodothyronine, antithyroglobulin (anti-Tg), and antithyroperoxidase (anti-TPO) antibodies were analyzed. In 100 control subjects, matched by age and gender with HPRL patients, thyroid USG, thyroid function tests (TFTs), and autoantibody panel were obtained. Results : The median PRL in patients was 93 ng/mL (range: 37-470). Twenty-five patients (25%) and 22 controls (22%) had positive anti-Tg and/or anti-TPO titers (P = 0.739). The median serum PRL was 98 (37-470) ng/mL in patients with positive thyroid autoantibodies, and 92 (40-470) ng/mL in patients who were negative (P = 0.975). Among the individuals with autoantibody positivity TFTs abnormalities were more frequent in HPRL patients (60%, out of 25 patients, 14 with subclinical hypothyroidism and one with hyperthyroidism) than in controls (9.1%, out of 22 patients, 2 with subclinical hyperthyroidism) (P < 0.001). Twenty-seven patients with HPRL and 31 controls had goiter (27 vs. 31%, P = 0.437). Forty-six patients (46%) and 50 (50%) controls had one or more of the features of thyroid disorder, which were goiter, positive thyroid autoantibody, and thyroid function abnormality (P = 0.888). Conclusion : HPRL may be associated with more severe thyroid dysfunction in patients with thyroid autoimmunity.

Concomitant myasthenia gravis and macroprolactinoma: the immunomodulatory role of prolactin and its potential therapeutic use

Considerable evidence attests to the role of the hypothalamic-pituitary endocrine axis (HPA) in the maintenance of normal immunocompetence. The immune and neuroendocrine systems are integrally linked and coordinated with bidirectional communication maintaining immune balance. Any disturbance of the normal function of the HPA may significantly alter native immunocompetence and therefore be associated with the development of disorders which have a clearly established autoimmune basis. Molecular and functional evidence shows prolactin, produced by the anterior pituitary, to be a cytokine, exerting its effect via both paracrine and endocrine mechanisms [1]. Its involvement in the activation of multiple immune responses may adversely upregulate certain autoimmune diseases. Myasthenia gravis (MG) has long been recognized as an autoimmune disorder. In this mini review, we present the coterminous presentation of MG and prolactin-secreting macroadenoma. We review published cases in the world literature, discuss pathological mechanism, and consider future targeted therapies.

Hyperprolactinaemia associated with increased thyroid volume and autoimmune thyroiditis in patients with prolactinoma

OBJECTIVE

The aim of this investigation was to evaluate the effects of hyperprolactinaemia on thyroid function, volume and nodularity in patients with prolactinoma.

CONTEXT

Hyperprolactinaemia has been associated with various autoimmune diseases; however, the data on the correlation between the level of prolactin (PRL) and thyroid disorders have not been adequately clarified.

DESIGN

Case-control study.

PATIENTS

Forty-eight subjects with new diagnosis of hyperprolactinaemia (group 1) and 39 subjects undergoing treatment for prolactinoma (group 2) were recruited from our outpatient clinic. Fifty-two healthy subjects were included as a control group (group 3).

MEASUREMENTS

The serum PRL, thyroid-stimulating hormone (TSH), thyroxine (free T4), thyroidal microsome (anti-TPO) and antithyroglobulin antibodies (TgAb) levels were evaluated, and ultrasonographic thyroid volume was calculated.

RESULTS

The frequencies of positive anti-TPO and TgAb were significantly higher in group 1 than in groups 2 and 3 (P = 0·008). Also, the percentage of patients with thyroid heterogeneity were significantly higher in groups 1 and 2 than in group 3 (P < 0·05). The percentage of patients with thyroid nodules were higher in group 1 than in groups 2 and 3 (p1-2 = 0·03, p1-3 = 0·05 and p2-3 = 0·637). The mean thyroid volume was significantly higher in group 1 (P = 0·001), and a positive correlation was found between thyroid volume and the level of PRL (r = 0·616; P = 0·0001). Prolactin had a significant effect on the total volume according to stepwise multiple linear regression analysis (adjusted R(2) is 0·268; P < 0·0001).

CONCLUSIONS

Patients with hyperprolactinaemia have significantly increased thyroid volume, thyroid autoimmunity and nodule prevalence.

Idiopathic transverse myelitis and neuromyelitis optica: clinical profiles, pathophysiology and therapeutic choices

Transverse myelitis is a focal inflammatory disorder of the spinal cord which may arise due to different etiologies. Transverse myelitis may be idiopathic or related/secondary to other diseases including infections, connective tissue disorders and other autoimmune diseases. It may be also associated with optic neuritis (neuromyelitis optica), which may precede transverse myelitis. In this manuscript we review the pathophysiology of different types of transverse myelitis and neuromyelitis optica and discuss diagnostic criteria for idiopathic transverse myelitis and risk of development of multiple sclerosis after an episode of transverse myelitis. We also discuss treatment options including corticosteroids, immunosuppressives and monoclonal antibodies, plasma exchange and intravenous immunoglobulins.

Prolactin and autoimmunity

The relationship between prolactin and the immune system has been demonstrated in the last two decades, opening new windows in the field of the immunoendocrinology. Prolactin has an important role in the innate and adaptive immune response. Increased prolactin levels have been described in autoimmune diseases such as systemic lupus erythematosus, rheumatoid arthritis, Sjögren syndrome, and systemic sclerosis among others. Hyperprolactinemia is associated with active disease and organ involvement in systemic lupus erythematosus. Therefore, prolactin is an integral member of the immunoneuroendocrinology network and seems to have a role in pathogenesis of autoimmune diseases. Few controlled studies of dopamine agonist treatment in humans with autoimmune disease have been conducted only in systemic lupus erythematosus patients, which support the potential efficacy of such agents even during pregnancy and postpartum. Further studies are necessary to elucidate the mechanisms by which prolactin affects autoimmune disease activity, increase the inflammatory mechanism, and determine the role of anti-prolactinemic drugs to regulate the immune/inflammatory process.

Prolactin and autoimmunity

The relationship between prolactin and the immune system has been demonstrated in the last two decades, opening new windows in the field of the immunoendocrinology. Prolactin has an important role in the innate and adaptive immune response. Increased prolactin levels have been described in autoimmune diseases such as systemic lupus erythematosus, rheumatoid arthritis, Sjögren syndrome, and systemic sclerosis among others. Hyperprolactinemia is associated with active disease and organ involvement in systemic lupus erythematosus. Therefore, prolactin is an integral member of the immunoneuroendocrinology network and seems to have a role in pathogenesis of autoimmune diseases. Few controlled studies of dopamine agonist treatment in humans with autoimmune disease have been conducted only in systemic lupus erythematosus patients, which support the potential efficacy of such agents even during pregnancy and postpartum. Further studies are necessary to elucidate the mechanisms by which prolactin affects autoimmune disease activity, increase the inflammatory mechanism, and determine the role of anti-prolactinemic drugs to regulate the immune/inflammatory process.

Fatigue in patients with rheumatic diseases

Fatigue is a prominent symptom in many rheumatic diseases. Numerous factors contribute to cause fatigue, which can be a source of frustration for the patients and physicians, as the treatment often fails to produce the desired improvement. Diagnostic guidelines direct insufficient attention to the various semiological patterns of fatigue seen in rheumatic diseases. This update describes three main patterns of fatigue, depending on whether the source is physical or mental: muscle weakness in patients with neuromuscular disease; asthenia related to organic disease with excessive energy expenditure, deficient energy production (e.g., endocrine disorders), or inadequate recovery; and weariness due to the impact of stress and depression on quality of life. The prevalence of each pattern in various rheumatic diseases is discussed. This update underlines the practical benefits provided by a detailed semiological analysis of fatigue in patients with rheumatic disease and emphasizes the marked predominance of weariness due to stress and depression, on which the personality of the patient and inadequacy of social support systems may exert a major influence. Serotonin reuptake inhibitors (SSRIs) may be valuable in patients with fatigue not only because they improve the mental status, but also via their recently demonstrated anti-inflammatory effects.

Characterization of macroprolactin and assessment of markers of autoimmunity in macroprolactinaemic patients

OBJECTIVE

It has been reported that macroprolactin is a complex of PRL and an immunoglobulin G (IgG). This study further characterizes macroprolactin and evaluates for other markers of autoimmunity using a cohort of macroprolactinaemic sera. PATIENTS AND NORMAL SUBJECTS: Following treatment of hyperprolactinaemic sera (n = 58) with polyethylene glycol (PEG), PRL values fell from 524-13 546 mU/l (Range) to 452-8455 mU/l, while in macroprolactinaemic sera (n = 41), PRL concentration fell from 525-5747 to 98-378 mU/l (PEG treated normoprolactinaemic reference range, 68-230 mU/l in males, 70-390 mU/l in females).

DESIGN

PRL was measured in sera prior to and following gel filtration chromatography, ultrafiltration, treatment with protein A-sepharose, protein G-sepharose, antihuman IgG-agarose and sodium thiocyanate (NaSCN). The binding of radio-labelled PRL in macroprolactinaemic sera was also measured. Sera were assayed for antithyroid and antinuclear antibodies. C-reactive protein (CRP) and CD5 positive B cells were also measured. Comparisons were made between values obtained in normal, hyperprolactinaemic and macroprolactinaemic sera. Results Macroprolactinaemic sera indicated the presence of an IgG molecule and/or IgG fragments with one or more molecules of PRL. In 97% of the sera macroprolactin had a molecular weight of 204 kDa. Treatment of macroprolactinaemic sera with NaSCN caused dissociation of macroprolactin, releasing monomeric PRL. Macroprolactinaemic sera did not yield evidence of an increase in markers of autoimmunity when compared with hyperprolactinaemic or normal sera.

CONCLUSIONS

Comprehensive analysis of macroprolactin confirmed its composition as an IgG molecule or fragment with a PRL molecule. The occurrence of macroprolactin does not appear to be associated with autoimmunity.

Increased incidence of autoimmune thyroiditis in patients with antipsychotic-induced hyperprolactinemia

Prolactin (PRL) elevation in patients with prolactin-secreting pituitary tumors has been linked to increased prevalence of thyroid autoantibodies. However, the effects of antipsychotic drug-induced hyperprolactinemia (HPRL) on development of thyroid autoimmunity and also of other autoimmune phenomena have not been previously studied. To examine whether serum PRL levels were associated with the prevalence of thyroid autoantibodies in patients with schizophrenia receiving long-term antipsychotic treatment, we determined serum PRL, thyrotropin, free thyroxine levels, and the presence of antithyroid peroxidase and antithyroglobulin antibodies in 75 consecutive, clinically stable schizophrenic outpatients who had been on stable doses of antipsychotics for at least 3 months, and had no history of overt thyroid disease. We found that the prevalence of hyperprolactinemia was significantly higher in patients positive for thyroid autoantibodies, when compared with patients negative for them (p=0.045). Serum levels of prolactin were also significantly higher in patients with positivity for thyroid autoantibodies (p=0.039). In separate analyses for genders, a trend-level relationship was observed in females between increased levels of prolactin and the presence of thyroid autoantibodies (p=0.060). Our findings suggest that through the associated HPRL, long-term antipsychotic treatment can induce thyroid autoimmunity. Future research is required to investigate, whether other autoimmune processes might be triggered by antipsychotic drug-induced HPRL, and to what extent the immune alterations reported in patients with schizophrenia are related with this phenomenon.

Effect of long-term cabergoline therapy on the immunological pattern and pituitary function of patients with idiopathic hyperprolactinaemia positive for antipituitary antibodies

OBJECTIVE

The occurrence of antipituitary antibodies (APA) in patients with idiopathic hyperprolactinaemia (IH) and the effects of dopamine agonists on these antibodies and long-term pituitary function outcome have been so far not evaluated. This longitudinal study was aimed at investigating, in patients with IH the occurrence of APA and the effect of cabergoline on the pituitary function and behaviour of APA.

DESIGN

Sixty-six patients with IH were studied. APA (by indirect immunofluorescence) and pituitary function were investigated every year for 3 years.

RESULTS

Seventeen patients resulted APA positive (Group 1) and 49 APA negative (Group 2). Eight patients of Group 1 (Group 1a) and 24 of Group 2 (Group 2a) were asymptomatic and then not treated; instead, nine patients in Group 1 (Group 1b) and 25 in Group 2 (Group 2b), showing symptoms of hyperprolactinaemia, were treated with cabergoline for 2 years. Among the untreated patients, during the follow-up, those with APA positive (Group 1a) showed an increase of APA titres and PRL levels with partial pituitary impairment in some of them; instead those with APA negative (Group 2a) persisted negative with normal pituitary function despite persistent hyperprolactinaemia. Among the treated patients, those with APA positive (Group 1b) showed normalization of PRL levels, APA disappearance and recovery of pituitary function (when initially impaired) during cabergoline treatment, persisting also at last observation (off-therapy). Instead all patients of Group 2b persisted with APA negative during the follow-up with normalization of PRL levels and stable normal pituitary function during cabergoline therapy but showing a further increase of PRL at the last observation.

CONCLUSIONS

The presence of APA in some patients with IH suggests a possible occurrence of autoimmune hypophysitis at potential/subclinical stage; an early and prolonged cabergoline therapy could interrupt the progression to an overt clinical stage of the disease. However, the small amount of patients investigated suggests caution against generalization of our assumption and prompts to further controlled studies on a more numerous population to verify these conclusions.

Thyroid dysfunction in patients with systemic lupus erythematosus (SLE): relation to disease activity

We examined the prevalence of thyroid dysfunction and the production of anti-thyroid antibodies (ATA) in patients with systemic lupus erythematosus (SLE) and assessed the association between ATA production and SLE disease activity status. Seventy-seven patients who met the American College of Rheumatology classification criteria for SLE participated in the study. Fifty-two individuals served as a control group. Demographic, clinical information and SLE disease activity (SLEDAI) status were collected from all patients. The sera of all participants were tested for free thyroxine (FT4), thyroid-stimulating hormone (TSH), anti-thyroglobulin (ATg) and anti-thyroid peroxidase (TPO). A SLEDAI score of > or =6 was considered clinically significant. The results of the thyroid function tests and ATA were compared between the study group and the control group. ATA levels were compared between the patients with a SLEDAI score of > or =6 to those with a SLEDAI score of <6. Hypothyroidism was detected in 11.6% of SLE patients compared to 1.9% in the control group. None of the patients or controls had evidence of hyperthyroidism. No statistically significant difference was observed in the levels of ATg or TPO between the study group and the control group. No correlation was found between ATA levels and the degree of the disease activity. Among the different variables tested in this study, hypothyroidism was the only significant abnormal finding in SLE patients. No association was found between the SLEDAI score and the prevalence of ATA production. Larger controlled, longitudinal studies are necessary to confirm these findings and elucidate the role played by ATA in the pathogenesis of thyroid dysfunction in SLE patients.