Revisitation of autoimmune hypophysitis: knowledge and uncertainties on pathophysiological and clinical aspects.

PURPOSE: This publication reviews the accepted knowledges and the findings still discussed on several features of autoimmune hypophysitis, including the most recently described forms, such as IgG4 and cancer immunotherapy- related hypophysitis. METHODS: The most characteristic findings and the pending controversies were derived from a literature review and previous personal experiences. A single paragraph focused on some atypical examples of the disease presenting under confounding pretences. RESULTS: Headache, visual field alterations and impaired pituitary secretion are the most frequent clinical findings of the disease. Pituitary biopsy, still considered the gold diagnostic standard, does not always receive consent from the patients. The role of magnetic resonance imaging is limited, as this disease may generate images similar to those of other diseases. The role of antipituitary and antihypothalamus antibodies is still discussed owing to methodological difficulties and also because the findings on the true pituitary antigen(s) are still debated. However, the low sensitivity and specificity of immunofluorescence, one of the more widely employed methods to detect these antibodies, may be improved, considering a predetermined cut-off titre and a particular kind of immunostaining. CONCLUSION: Autoimmune hypophysitis is a multifaceted disease, which may certainly be diagnosed by pituitary biopsy. However, the possible different clinical, laboratory and imaging features must be considered by the physician to avoid a misdiagnosis when examining a possibly affected patient. Therapeutic choice has to be made taking into account the clinical conditions and the degree of hypothalamic-pituitary involvement, but also considering that spontaneous remissions can occur.

Longitudinal behavior of autoimmune GH deficiency: from childhood to transition age.

BACKGROUND: Some cases of apparently idiopathic GH deficiency (GHD) may be caused by pituitary autoimmunity. OBJECTIVE: To study the variations in pituitary function and antipituitary antibodies (APA) from childhood to transition age in patients with apparently idiopathic GHD. DESIGN: We conducted a longitudinal study. PATIENTS AND METHODS: Pituitary function and APA detection by immunofluorescence were investigated in 24 childhood patients with isolated GHD before starting recombinant GH therapy and after the stopping of this therapy in transition age. Sera of patients positive for APA were processed by double immunofluorescence to identify their pituitary target. RESULTS: At diagnosis, 16 out of 24 patients were APA positive targeting only somatotrophs (group 1), while the remaining eight were APA negative (group 2). When retested off therapy, 12 out of 16 patients in group 1 persisted being APA positive, while the remaining four became negative with recovery of pituitary function. All patients in group 2 persisted being APA negative but still showing GHD. Of the 12 patients persistently APA positive, eight with confirmed GHD showed APA still targeting somatotrophs, whereas four showed APA targeting only gonadotrophs associated with isolated hypogonadotropic hypogonadism (HH). CONCLUSION: Patients with APA at middle but not at high titer in childhood may show a remission of autoimmune GHD in childhood after GH replacement therapy. As APA may shift their target in transition period, an early characterization of APA by double immunofluorescence is advisable in APA positive GHD patients showing delayed puberty, to allow an early diagnosis and an appropriate therapy, thus preventing the progression toward HH.

Pregnancy may favour the development of severe autoimmune central diabetes insipidus in women with vasopressin cell antibodies: description of two cases.

Recently, an increased incidence of central diabetes insipidus (CDI) in pregnancy, and less frequently in the post partum period, has been reported, most probably favoured by some conditions occurring in pregnancy. This study was aimed at investigating the influence of pregnancy on a pre-existing potential/subclinical hypothalamic autoimmunity. We studied the longitudinal behaviour of arginine-vasopressin cell antibodies (AVPcAbs) and post-pituitary function in two young women with a positive history of autoimmune disease and presence of AVPcAbs, but without clinical CDI, and who became pregnant 5 and 7 months after our first observation. The behaviour of post-pituitary function and AVPcAbs (by immunofluorescence) was evaluated at baseline, during pregnancy and for 2 years after delivery. AVPcAbs, present at low/middle titres at baseline in both patients, showed a titre increase during pregnancy in one patient and after delivery in the other patient, with development of clinically overt CDI. Therapy with 1-deamino-8-d-arginine vasopressin (DDAVP) caused a prompt clinical remission. After a first unsuccessful attempt of withdrawal, the therapy was definitively stopped at the 6th and the 7th month of post partum period respectively, when AVPcAbs disappeared, accompanied by post-pituitary function recovery, persisting until the end of the follow-up. The determination of AVPcAbs is advisable in patients with autoimmune diseases planning their pregnancy, because they could be considered good predictive markers of gestational or post partum autoimmune CDI. The monitoring of AVPcAb titres and post-pituitary function during pregnancy in these patients may allow for an early diagnosis and an early replacement therapy, which could induce the disappearance of these antibodies with consequent complete remission of CDI.

Use of serum pituitary antibodies to improve the diagnosis of hypophysitis.

Lymphocytic hypophysitis is characterized by an extensive infiltration of lymphocytic cells. Pituitary biopsy is the gold diagnostic standard for lymphocytic hypophysitis but the disease occurs with moderate or without pituitary enlargement. The role of antipituitary antibodies (APA) in autoimmune hypophysitis is still discussed due to various methodological difficulties. Indirect immunofluorescence, a widely employed method to detect APA at this time produces highly variable results due to the use of human or animal pituitary substrates. For many years the authors have conducted a re-evaluation of APA by immunofluorescence in patients with other autoimmune diseases and in patients with apparently idiopathic hypopituitarism, using pituitary from young baboons as substrate but considering a predetermined cut-off of the titer and immunofluorescence pattern. This procedure allowed us to find out those with autoimmune pituitary impairment and to foresee the kind of future hypopituitarism in those with pituitary function still normal. Moreover, in APA positive patients, the use of a second step of a double immunofluorescence method allowed identification of the pituitary cells targeted by APA, verifying the correspondence with the kind of hypopituitarism, also when present in subclinical stage. However, to carry out an international workshop comparing the detection of APA by immunofluorescence using different substrates could contribute to verify the best choice to improve the sensitivity and specificity of this method.

Rituximab-induced remission of autoimmune hypophysitis and primary immune thrombocytopenia in a patient with autoimmune polyendocrine syndrome type 4.

Rituximab, a B-cell depleting antibody, has been used for treatment of several autoimmune diseases. We report the effect of rituximab therapy on pituitary and platelet autoimmunity in a 36-yr old patient, positive for antiplatelet and antipituitary (APA) antibodies. The behavior of pituitary function and of APA by immunofluorescence, as well antibodies to platelets and platelet count, were investigated at start and subsequently every six months during Rituximab treatment. Rituximab treatment determined disappearance of antiplatelet antibodies with recovery of normal platelet count and disappearance of APA with recovery of pituitary-gonadal function. Rituximab determined a remission of both autoimmune processes, likely through a T cell inactivation and a depletion of autoreactive B-cells generation responsible for antiplatelet and antipituitary antibody production.

A five year prospective investigation of anterior pituitary function after traumatic brain injury: is hypopituitarism long-term after head trauma associated with autoimmunity?

Traumatic brain injury (TBI) has been recently recognized as a common cause of pituitary dysfunction. However, there are not sufficient numbers of prospective studies to understand the natural history of TBI induced hypopituitarism. The aim was to report the results of five years' prospective follow-up of anterior pituitary function in patients with mild, moderate and severe TBI. Moreover, we have prospectively investigated the associations between TBI induced hypopituitarism and presence of anti-hypothalamus antibodies (AHA) and anti-pituitary antibodies (APA). Twenty five patients (20 men, five women) were included who were prospectively evaluated 12 months and five years after TBI, and 17 of them also had a third-year evaluation. Growth hormone (GH) deficiency is the most common pituitary hormone deficit at one, three, and five years after TBI. Although most of the pituitary hormone deficiencies improve over time, there were substantial percentages of pituitary hormone deficiencies at the fifth year (28% GH, 4% adrenocorticotropic hormone [ACTH], and 4% gonadotropin deficiencies). Pituitary dysfunction was significantly higher in strongly AHA- and APA-positive (titers ≥1/16) patients at the fifth year. In patients with mild and moderate TBI, ACTH and GH deficiencies may improve over time in a considerable number of patients but, although rarely, may also worsen over the five-year period. However in severe TBI, ACTH and GH status of the patients at the first year evaluation persisted at the fifth year. Therefore, screening pituitary function after TBI for five years is important, especially in patients with mild TBI. Moreover, close strong associations between the presence of high titers of APA and/or AHA and hypopituitarism at the fifth year were shown for the first time.

Late primary autoimmune hypothyroidism in a patient with postdelivery autoimmune hypopituitarism associated with antibodies to growth hormone and prolactin-secreting cells.

BACKGROUND: Pituitary and thyroid autoimmunity can be triggered by pregnancy. We report the first association of combined growth hormone (GH) and prolactin secretion deficiency due to autoimmune damage to GH- and prolactin-secreting cells in a patient with postdelivery lactation failure, presenting subsequently with primary autoimmune hypothyroidism. PATIENT FINDINGS: A 34-year-old woman presented with lactation failure following the delivery of her first child. She had a family history of hypothyroidism without a history of pituitary dysfunction. Physical examination did not show any abnormal findings. Laboratory investigations showed normal gonadotropin levels after the restoration of normal menstrual cycles following pregnancy, normal basal and stimulated cortisol levels, but an impaired GH response to insulin-induced hypoglycemia, and low basal prolactin and insulin-like growth factor-1 concentrations. Thyroid function was normal when initially investigated three months after delivery, but five months later, marked primary hypothyroidism (thyrotropin levels >100 mIU/L) occurred. Immunological investigation revealed the presence of antipituitary antibodies, identified by double immunofluorescence and targeting GH- and prolactin-secreting cells. Antithyroid antibodies, in the normal range three months postpartum, became significantly elevated when the hypothyroidism appeared. Autoimmune hypophysitis is responsible for selective or multiple pituitary-hormone deficiencies, sometimes involving thyrotropin secretion and causing secondary hypothyroidism, but usually associated with hyperprolactinemia. To our knowledge, this is the first observation of autoimmune hypopituitarism involving deficient growth hormone and prolactin secretion in a patient with lactation failure after delivery, subsequently followed by severe primary autoimmune hypothyroidism, thus falling into an unusual constellation of autoimmune polyendocrine syndrome type 3. CONCLUSIONS: Considering the well-known relationship between pregnancy and autoimmunity, an early postdelivery immunological and functional investigation in women presenting with disorders of lactation may be useful to detect potential pituitary and thyroid dysfunction even at a subclinical stage.

Subclinical diabetes insipidus.

Subclinical central diabetes insipidus (CDI) can be the outcome of a number of diseases that affect the hypothalamus-infundibulum-post hypophysis axis. One of the most common forms of subclinical CDI is linked to an autoimmune pathogenesis even if other causes may be also responsible. Among these, pregnancy, traumatic and surgical brain injury and some infiltrative, vascular, infectious and neoplastic diseases have been reported with increasing frequency. The natural history of autoimmune CDI seems to evolve through 4 functional stages according to the presence of antibodies to vasopressin-secreting cells (AVPcAb) and the relationship between their behavior overtime, the variations of posterior pituitary function and the characteristics of hypothalamic-hypophyseal region on magnetic resonance imaging. This staging is of crucial importance for the therapeutic strategy, taking into account that some stages could be still reversible. Several medical treatments have been suggested to interrupt the progression toward clinical CDI but the results are still discussed.

Time course of Graves' ophthalmopathy after total thyroidectomy alone or followed by radioiodine therapy: a 2-year longitudinal study.

The findings in hyperthyroid patients with Graves' orbitopathy (GO) of antibodies against antigens shared between the thyroid and orbit, such as the TSH-receptor (TRAb) and a novel protein G2s (G2sAb), suggested a possible common therapeutic strategy. However, the gold therapeutic standard for hyperthyrodism in these patients remains still unsettled and is mainly based on personal experience. Studies on the effect of total thyroidectomy (TT) alone or followed by radioiodine ablation (RAI) of thyroid remnants showed often conflicting results. This longitudinal study was aimed at evaluating the influence of TT alone or followed by post-surgical RAI with respect to methimazole treatment on the activity and severity of GO in patients with hyperthyroidism and GO. Sixty consecutive patients with Graves' disease and mild/moderate GO were studied and grouped as follows: group 1, including 25 patients (16F, 9M) undergoing TT alone; group 2, including 10 patients (8F, 2M) undergoing TT followed by RAI for histological evidence of differentiated thyroid cancer; group 3, including 25 patients (18F, 7M) euthyroid under methimazole therapy, studied as controls. Clinical study of ophthalmopathy and measurements of TRAb and G2sAb were performed in all patients at start of the study (time of TT for group 1 and RAI after TT for group 2 and of the first finding of euthyroidism under methimazole treatment for group 3) and after 6, 12, 24 months. Patients of both groups 1 and 2 showed an early significant decrease and a further progressive reduction of the activity and severity of GO with a disappearance of TRAb and a decrease of G2sAb levels during the follow-up, without statistically significant differences between the two groups. Patients in group 3 showed a much later and less marked improvement of GO with persistence of TRAb and G2sAb positivity, even if with reduction of TRAb levels at 12 and 24 months. Our results suggest that in Graves' patients with large goiter or relapse of hyperthyroidism and mild/moderate GO, TT alone could be an advisable choice to treat hyperthyroidism also improving GO with reduction of cost/benefit ratio.

Detection of antipituitary and antihypothalamus antibodies to investigate the role of pituitary or hypothalamic autoimmunity in patients with selective idiopathic hypopituitarism.

OBJECTIVE: Antipituitary (APA) but not antihypothalamus antibodies (AHA) have been investigated in patients with idiopathic hypopituitarism. This study searched for APA and AHA in some of these patients to investigate whether pituitary or hypothalamic autoimmunity could play a role in their pituitary dysfunction. DESIGN: Sixty-six patients with selective idiopathic hypopituitarism were studied: 27 with ACTH deficiency, 20 with GH deficiency and 19 with hypogonadotropic hypogonadism. Twenty patients with hypopituitarism secondary to hypophysectomy and 50 healthy subjects were enrolled as controls. MEASUREMENTS: Antipituitary and AHA were evaluated by indirect immunofluorescence in sera of patients and controls. Positive sera were retested by a four-layer double immunofluorescence to identify the cells targeted by these antibodies. RESULTS: Antipituitary were present at high titre in 4 of 27 patients with ACTH deficiency (14·8%), 4 of 20 with GH deficiency (26%) and 5 of 19 with hypogonadotropic hypogonadism (21%) and targeted, respectively, corticotrophs, somatotrophs and gonadotrophs. AHA were found at high titre only in 5 patients with ACTH deficiency (18·5%), mostly targeting corticotrophin-releasing hormone-secreting cells; none of these 5 patients resulted positive for antipituitary antibodies. Among the controls, only 1 hypophysectomized patient resulted APA positive at low titre. CONCLUSIONS: Our results suggest that in patients with selective idiopathic hypopituitarism, detection of APA or AHA could better characterize an autoimmune process involving the pituitary or hypothalamus, respectively. In particular, detection of antibodies targeting selectively ACTH-secreting or corticotrophin-releasing hormone-secreting cells may differentiate, respectively secondary from tertiary variants of autoimmune hypoadrenalism.

Predictive role of the immunostaining pattern of immunofluorescence and the titers of antipituitary antibodies at presentation for the occurrence of autoimmune hypopituitarism in patients with autoimmune polyendocrine syndromes over a five-year follow-up.

CONTEXT: Antipituitary antibodies (APA) are frequently present in patients with autoimmune polyendocrine syndrome (APS). DESIGN: The aim was to evaluate the predictive value of APA for the occurrence of hypopituitarism. A total of 149 APA-positive and 50 APA-negative patients with APS and normal pituitary function were longitudinally studied for 5 yr. METHODS: APA, by indirect immunofluorescence, and anterior pituitary function were assessed yearly in all patients. The risk for developing autoimmune pituitary dysfunction was calculated using survival and multivariate analysis. RESULTS: Hypopituitarism occurred in 28 of 149 (18.8%) APA-positive patients but in none of the 50 APA-negative patients. The immunostaining pattern in APA-positive patients involved either isolated pituitary cells [type 1 pattern; n=99 (66.4%)] or all pituitary cells [type 2 pattern; n=50 (33.6%)]. All patients developing pituitary dysfunction throughout the study span had a type 1 pattern. Kaplan-Meier curves for cumulative survival showed a significantly higher rate for developing hypopituitarism in relation to positive APA tests (P<0.005), pattern of immunostaining (P<0.0001), and APA titers (P<0.000001). Cox regression analysis in APA-positive patients with a type 1 pattern demonstrated a significantly (P<0.0001) higher risk for the onset of hypopituitarism in relation to increasing titers of APA. CONCLUSIONS: APA measurement by immunofluorescence may help to predict the occurrence of hypopituitarism but only when considering the immunostaining pattern and their titers. Combined evaluation of these parameters allows identifying patients at higher risk for pituitary autoimmune dysfunction, thus requiring a strict pituitary surveillance to disclose a preclinical phase of hypopituitarism and possibly interrupt therapeutically the progression to clinically overt disease.

Investigation of antihypothalamus and antipituitary antibodies in amateur boxers: is chronic repetitive head trauma-induced pituitary dysfunction associated with autoimmunity?

OBJECTIVE: Current data clearly demonstrate that sports-related chronic repetitive head trauma due to boxing might result in hypopituitarism. However, the mechanism of sports-related traumatic brain injury-induced pituitary dysfunction is still unclear. In order to understand whether autoimmune mechanisms could play a role in the pituitary dysfunction due to sports-related head trauma, we investigated the presence of antipituitary antibodies (APAs) and antihypothalamus antibodies (AHAs) in amateur boxers. PATIENTS AND DESIGN: Sixty-one actively competing (n=44) or retired (n=17) male boxers (mean age, 26 years; range, 17-53) who had been evaluated regarding pituitary functions previously were included in the study. In all boxers and in 60 age/sex-similar normal controls, AHAs and APAs were investigated by an indirect immunofluorescence method. RESULTS: AHAs were detected in 13 of 61 boxers (21.3%), and APAs were detected in 14 of 61 boxers (22.9%), but in none of the normal controls. Pituitary dysfunction was significantly higher in AHA-positive boxers (46.2%) than in AHA-negative boxers (10.4%) (P=0.003). There was a significant association between AHA positivity and hypopituitarism due to boxing (odds ratio: 7.37, 95% confidence interval 1.8-30.8). There was no significant association between APA positivity and hypopituitarism. CONCLUSIONS: This study demonstrates for the first time the presence of AHAs and APAs in boxers who were exposed to sports-related head trauma. Moreover, the present investigation provides preliminary evidence that AHAs are associated with the development of pituitary dysfunction in boxers, thus suggesting that autoimmunity may have a role in the pathogenesis.

Anti-pituitary antibodies in children with newly diagnosed celiac disease: a novel finding contributing to linear-growth impairment.

OBJECTIVES: The possible autoimmune involvement of the pituitary gland in patients with celiac disease (CD) has been suggested but demonstrated in only a few patients on gluten-free diet. We aimed to assess the prevalence and clinical meaning of anti-pituitary antibodies (APA) in children and adolescents with the newly diagnosed CD. METHODS: A total of 119 patients with CD (0.9-15.8 years old) attending the inpatient clinic of University Hospital were recruited for the cross-sectional study. Their height, weight, and body mass index (BMI) were recorded, and insulin-like growth factor-1 (IGF-1) and APA were assayed. APA was also determined in 98 sex- and age-matched controls. RESULTS: APA were detected in 50 patients (42.0%), 15 of them with high titer (30%) and 35 with low titer (70%), and in 2 control subjects at low titer (2%) (P<0.001). IGF-1 was higher in patients with negative than with low titer (P=0.02) or high titer APA (P=0.03). Height was more reduced in high-titer APA patients than in the negative ones (P<0.01). Height was positively correlated with IGF-1 (P<0.01) and negatively with chronological age (P=0.001). IGF-1 was positively correlated with BMI (P<0.001). For height prediction the regression analysis showed the rank order 1 for chronological age and 2 for IGF-1. CONCLUSIONS: In this paper we have shown a remarkable prevalence of positive APA in newly diagnosed CD patients. High APA titers are associated with height impairment, likely mediated by a reduction of IGF-1, thus suggesting that autoimmune pituitary process could induce a linear-growth impairment.

Antipituitary antibodies after traumatic brain injury: is head trauma-induced pituitary dysfunction associated with autoimmunity?

OBJECTIVE: Traumatic brain injury (TBI) is a devastating public health problem that may result in hypopituitarism. However, the mechanisms responsible for hypothalamic-pituitary dysfunction due to TBI are still unclear. Although the antibodies against neurons have been demonstrated in injured animal studies, investigations regarding the occurrence of antipituitary antibodies (APAs) in patients with TBI are lacking in the literature. In order to investigate whether autoimmune mechanisms could play a role in the pituitary dysfunction after TBI, we have planned this study aimed at investigating the presence of APA at the third year of TBI and association between the TBI-induced hypopituitarism and APA. PATIENTS AND DESIGN: Twenty-nine (25 males and 4 females; age 36.5+/-2.3 years) patients who had completed a 3-year follow-up after TBI were included in the present study. APA and pituitary function were evaluated in all the patients 3 years after TBI; moreover, APAs were tested also in sera of 60 age-/sex-matched normal controls. The APAs were investigated by an indirect immunofluorescence method. Results APAs were detected in 13 out of the 29 TBI patients (44.8%), but in none of the normal controls. Pituitary dysfunction development ratio was significantly higher in APA-positive patients (46.2%) when compared with APA-negative ones (12.5%; P=0.04). There was a significant association between APA positivity and hypopituitarism due to TBI (odds ratio: 2.25, 95% confidence intervals 1.1-4.6). Moreover, there was a significant positive correlation (r=0.74, P=0.004) between APA titer ratio and peak GH response to GHRH+GH related peptide (GHRP)-6 test, suggesting that high APA titers were associated with low GH response to GHRH+GHRP-6 test. CONCLUSIONS: This study shows for the first time the presence of the APA in TBI patients 3 years after head trauma. Moreover, present investigation indicates preliminary evidence that APA may be associated with the development of TBI-induced pituitary dysfunction, thus suggesting that autoimmunity may contribute in the development of TBI-induced hypopituitarism. The presence of the association between APA and TBI-induced hypopituitarism may provide a new point of view in this field and promote further clinical and experimental studies.

Immunological and clinical aspects of lymphocytic hypophysitis.

LYH (lymphocytic hypophysitis) is an autoimmune disease of the pituitary gland which can present with varying degrees of pituitary hormonal impairment and/or with symptoms related to pituitary enlargement. In this review, we provide an overview of the epidemiology, diagnosis, pathogenesis, treatment, and the role of organ-specific and antipituitary antibodies as potential markers of LYH. In addition, although the mechanisms underlying LYH are not completely understood, the role of prolactin, which plays an important part in maintaining immune system homoeostasis and is increased in the disease, is considered.

Anti-hypothalamus and anti-pituitary antibodies may contribute to perpetuate the hypopituitarism in patients with Sheehan's syndrome.

OBJECTIVE: While anti-pituitary antibodies (APAs) were detected in some patients with Sheehan's syndrome (SS) suggesting an autoimmune pituitary involvement in the development of their hypopituitarism, hypothalamic cell anti-hypothalamus antibodies (AHAs) have not been investigated so far. DESIGN: The aim of this study was to evaluate the presence of AHA and APA in SS patients to verify whether an autoimmune hypothalamic-pituitary process can contribute to their late hypopituitarism. METHODS: Twenty women with SS with a duration of disease ranging from 3 to 40 years (median 25.5 years) were enrolled into the study. Out of 20 patients, 12 (60%) had panhypopituitarism and the others had partial hypopituitarism well corrected with appropriate replacement therapy. None of them had clinical central diabetes insipidus. AHA and APA were investigated by immunofluorescence method in all patients. In addition, a four-layer immunofluorescence method was used to verify whether AHA immunostained vasopressin-secreting cells (AVP-c) or not. RESULTS: AHAs were found in 8 out of 20 (40%) and APAs in 7 out of 20 (35%) patients with titers ranging from 1:32 to 1:128 and 1:16 to 1:32 respectively; however, in none of these positive patients AHA immunostained vasopressin cells. None of controls resulted positive for both antibodies. CONCLUSIONS: Patients with SS, even many years after the onset of SS, can show antibodies to pituitary and/or hypothalamic but not AVP-secreting cells. Antibodies to unknown hypothalamic cells (releasing factor-secreting cells) other than APAs suggest that an autoimmune process involving both the hypothalamus and pituitary gland may contribute to late pituitary dysfunction in SS patients.

Antipituitary antibodies in idiopathic hyperprolactinemic patients.

Hyperprolactinemia is often observed in lymphocytic hypophysitis (LYH). To clarify the possible autoimmune pituitary involvement in patients with apparently idiopathic hyperprolactinemia we investigated the presence of antipituitary antibodies (APA) in hyperprolactinemic patients with idiopathic hyperprolactinemia and in those with prolactinoma. Sixty-six hyperprolactinemic patients (52 F, 14 M age range 28-42 years, group 1) were studied. Of them, 34 out of 66 showed clinical features of hyperprolactinemia and subsequently underwent cabergoline therapy; the 32 out of 66 patients without symptoms of hyperprolactinemia did not receive cabergoline therapy. Moreover, 32 patients (24 F/8M, age range 23-44 years) with hyperprolactinemia due to microprolactinoma (group 2) were also studied. APA, by immunofluorescence method, and anterior pituitary function were evaluated in both groups of patients. APA were present in 17 out of 66 (25.7%) patients in group 1 with titers ranging from 1/16 to 1/64. All patients of group 2 were considered APA negative because these antibodies were found at low titer (

Antipituitary antibodies against gonadotropin-secreting cells in adult male patients with apparently idiopathic hypogonadotropic hypogonadism.

CONTEXT: Hypogonadotropic hypogonadism (HH) can occur at any stage of life as an isolated congenital or acquired abnormality or within a more generalized pituitary or hypothalamic impairment. However, the defect in patients with idiopathic HH is still unknown. OBJECTIVE: The aim of this study was to investigate the prevalence of antipituitary antibodies (APA) in a group of HH patients with or without Kallmann's syndrome and to characterize their pituitary target. DESIGN: We conducted a cross-sectional cohort study. SETTING: The study was performed at the Endocrinology Unit of the Second University of Naples. PATIENTS: Twenty-one HH patients with normal sense of smell (group 1), 10 patients with Kallmann's syndrome (group 2), 13 patients with HH associated with other pituitary hormone deficiencies (group 3), and 50 normal controls were studied. MAIN OUTCOME MEASURES: APA were evaluated in patients and in controls by indirect immunofluorescence. Moreover, a magnetic resonance imaging (MRI) of the hypothalamic-pituitary region was performed in all three groups of patients. RESULTS: APA were detected at high titer in eight out of 21 patients in group 1 (38%) and in five of 13 in group 3 (38.4%), and at low titers in two out of 10 in group 2 (20%) and in three of 50 controls (6%). In patients of group 1, APA immunostained selectively gonadotropin-secreting cells, whereas in those of group 3, they immunostained other pituitary hormone-secreting cells also. None of patients in group 1 showed alterations on MRI, whereas all patients in group 2 showed aplasia/hypoplasia of the olfactory bulbs/tracts and/or of olfactory sulci. Among the five APA-positive patients in group 3, three had normal MRI, one had findings of empty sella, and one had findings of autoimmune hypophysitis. CONCLUSIONS: Our results suggest that some apparently idiopathic cases of HH, both isolated and associated with other pituitary impairment, can be caused by an early autoimmune process involving the gonadotrophs at pituitary level. Future longitudinal studies are needed to clarify the natural history of this process and the possible effect of early corticosteroid therapy.

Growth hormone impaired secretion and antipituitary antibodies in patients with coeliac disease and poor catch-up growth after a long gluten-free diet period: a causal association?

INTRODUCTION: Coeliac disease (CD) is usually associated with impaired growth in children. A gluten-free diet (GFD) induces a catch-up growth with the recovery of height in about 2 years. AIM AND DISCUSSION: The lack of the height improvement has been related to growth hormone (GH) secretion impairment. CD is an autoimmune disease often associated with other endocrine and non-endocrine autoimmune disease. The aim of this study was to evaluate antipituitary autoantibodies (APA) and antihypothalamus autoantibodies in CD children with poor clinical response to a GFD and growth hormone deficiency (GHD). We diagnosed CD on the basis of specific antibodies and endoscopic biopsies in 130 patients aged 1-15 years. Seven CD children, without catch-up growth after at least 12-months GFD, were tested for GH secretion and, in five out of seven patients, the diagnosis of GHD was made in the absence of metabolic and systemic diseases. RESULTS: APA and antihypothalamus antibodies were detected by the indirect immunofluorescence method in the seven CD children without catch-up growth factor and in 25 CD children without growth impairment matched for sex and age, and in 58 healthy children as control groups. APA resulted positive at high titres in four out of five CD-GHD patients and were also positive at low titres (<1:8) in three of only CD children and in two out of 58 controls. Hypothalamic-pituitary magnetic resonance imaging (MRI) was normal in all patients except in one with cystic pineal. APA have been previously detected not only in adults with GHD, but also in idiopathic GHD children, suggesting the occurrence of an autoimmune hypophysitis in these patients. CONCLUSION: In our study, the presence of APA in CD children without catch-up growth after GFD seems to be able to identify an autoimmune form of hypophysitis involving the somatotrophs cells.

Antipituitary antibodies recognizing growth hormone (GH)-producing cells in children with idiopathic GH deficiency and in children with idiopathic short stature.

CONTEXT: Antipituitary antibodies (APA) recognizing GH-secreting cells may indicate an autoimmune pituitary involvement in adults with idiopathic GH deficiency (IGHD). OBJECTIVE: We aimed 1) to investigate the presence of APA in prepubertal children with IGHD or idiopathic short stature (ISS), identifying the pituitary hormone-producing cells targeted by APA; and 2) to verify whether in patients with ISS the presence of APA could predict the development of GHD. DESIGN: We performed a cross-sectional and partially longitudinal cohort study. SETTING: The study was performed at the Endocrinology Unit and Pediatric Unit of the Second University and University Federico II of Naples, respectively. PATIENTS: Twenty-six children with IGHD (group 1), 60 children with ISS (group 2), 33 children with GHD caused by lesions/abnormalities of the hypothalamus or pituitary (group 3), and 40 controls participated in the study. Nineteen children of group 2 were reevaluated after 2 yr. MAIN OUTCOME MEASURES: IGF-I levels, GH secretion, and APA (by indirect immunofluorescence) were evaluated in all participants. RESULTS: At study entry, APA recognizing GH-producing cells were detected in seven of 26 children in group 1 and in 14 of 60 in group 2. Two years later, all eight initially APA-positive and all 11 APA-negative of the 19 reevaluated patients persisted positive and negative, respectively. The reevaluation of GH secretion in these patients revealed the development of GHD in all but one of the APA-positive children but in none of the APA-negative ones. CONCLUSIONS: IGHD in children can be frequently associated with APA targeting GH-secreting cells; thus, the detection of APA in children with ISS could identify those prone to develop GHD.