Associations with multiple pituitary hormone deficiency in patients with an ectopic posterior pituitary gland

INTRODUCTION: The presence of an ectopic posterior pituitary gland (EPP) on magnetic resonance imaging (MRI) is associated with hypopituitarism with one or more hormone deficiencies. We aimed to identify risk factors for having multiple pituitary hormone deficiency (MPHD) compared to isolated growth hormone deficiency (IGHD) in patients with an EPP. METHODS: In 67 patients (45 male) with an EPP on MRI, the site (hypothalamic vs. stalk) and surface area (SA) [ x (maximum diameter/2) x (maximum height/2), mm(2)] of the EPP were recorded and compared in patients with IGHD and MPHD in relation to clinical characteristics. RESULTS: In MPHD (n = 32) compared to IGHD (n = 35) patients: age of presentation was younger (1.4 [0.1-10.7]vs. 4.0 [0.1-11.3] years, P = 0.005), major incidents during pregnancy were increased (47%vs. 20%, P = 0.02) as were admissions to a neonatal intensive care unit (NICU) (60%vs. 26%, P = 0.04), whilst EPP SA was lower (12.3 [2.4-34.6]vs. 25.7 [6.9-48.2] mm(2), P < 0.001). In patients with a hypothalamic (n = 56) compared to a stalk sited EPP (n = 11): prevalence of MPHD was greater (55%vs. 9%,P = 0.05) and EPP surface area was smaller (17.3 [2.4-48.2]vs. 25.3 [11.8-38.5] mm(2), P < 0.001). In regression analysis, after adjusting for age, presence of MPHD was associated with: major incidents during pregnancy (RR 6.8 [95%CI 1.2-37.7]), hypothalamic EPP site (RR 10.9 [1.0-123.9]) and small EPP SA (RR 2.5 [1.0-5.0] for tertiles of SA). CONCLUSION: In patients with an EPP, adverse antenatal events, size (small) and position (hypothalamic) of the posterior pituitary gland on MRI were associated with MPHD. These findings suggest that adverse factors during pregnancy may be important for the development of an EPP.

Monomerization of dimeric IgG of intravenous immunoglobulin (IVIg) increases the antibody reactivity against intracellular antigens

Intravenous immunoglobulin (IVIg) preparations are derived from pooled plasma from up to 60,000 healthy human donors and reflect the immunologic experience of the donor population. IVIg contains monomeric and dimeric IgG populations which are in a dynamic equilibrium depending on concentration, pH, temperature, donor pool size, time and stabilizers added in order to keep the portion of dimeric IgG below a certain level. In the present study, monomeric and dimeric fractions were isolated by size exclusion chromatography. The dimeric fractions, however, showed a dynamic instability and tended to dissociate. Both dimeric and monomeric IgG fractions were acid treated (pH 4) in order to dissociate the dimeric IgG. Western-blot analysis identified a sub-population of SDS resistant IgG dimers. Furthermore, the reactivities of the fractions were tested against a panel of self- and exo-antigens. There was a marked increase in activity of the dimeric compared to the monomeric IgG fraction against various intracellular self-antigens. Our data indicates that the increased reactivities of pH 4-treated fractions can mainly be attributed to dimer dissociation, as pH 4-treated monomers do not show significantly increased activities against a range of antigens.

Pica and refractory iron deficiency anaemia: a case report

ABSTRACT: INTRODUCTION: Iron deficiency is the most common cause of anaemia worldwide. Pica, the ingestion of substances that are inappropriate for consumption, is associated with iron deficiency and may be under-diagnosed. CASE PRESENTATION: A 34-year-old woman presented with iron deficiency anaemia refractory to treatment for more than a decade. The clinical presentation, endoscopic findings and laboratory investigations were consistent with pica. Subsequent geophysical analysis confirmed that the ingested material was kaolin, a negatively charged silicate. CONCLUSION: Prolonged unexplained iron deficiency anaemia should prompt clinicians to remember and inquire about pica. In our patient, this would have averted numerous unnecessary investigations and prevented a decade-long suffering.

Spinal MRI supporting myelopathic origin of early symptoms in unsuspected cobalamin deficiency

We report two patients with subjectively progressive sensory symptoms and gait disturbance due to cobalamin deficiency, but only slight or absent abnormalities on neurological examination. In both patients, spinal MRI provided evidence for a myelopathic origin of the symptoms, disclosing characteristic T(2) hyperintense signal alterations confined to the posterior columns of the cervical and thoracic spinal cord. The patients illustrate the early clinical presentation of subacute combined degeneration (SCD) with a sensory neuropathy starting with acroparesthesia and Lhermitte's sign. Furthermore, the diagnostic value of spinal MRI for early diagnosis of SCD with characteristic findings is highlighted.

Antiaggregatory and proangiogenic effects of a novel recombinant human dual specificity anti-integrin antibody

BACKGROUND: beta(3)-Integrins are involved in platelet aggregation via alpha(IIb)beta(3) [glycoprotein (GP)IIb-GPIIIa], and in angiogenesis via endothelial alpha(V)beta(3). Cross-reactive ligands with antiaggregatory and proangiogenic effects, both desirable in peripheral vasculopathies, have not yet been described. OBJECTIVES: In vitro and in vivo characterization of antiaggregatory and proangiogenic effects of two recombinant human Fab fragments, with emphasis on beta(3)-integrins. METHODS: Recombinant Fab fragments were obtained by phage display technology. Specificity, affinity and IC(50) were determined by immunodot assays, enzyme-linked immunosorbent assay (ELISA), and Scatchard plot analysis, and by means of human umbilical vein endothelial cells (HUVECs). Functional analyses included ELISA for interaction with fibrinogen binding to GPIIb-GPIIIa, flow cytometry for measurement of activation parameters and competitive inhibition experiments, human platelet aggregometry, and proliferation, tube formation and the chorioallantoic membrane (CAM) assay for measurement of angiogenic effects. RESULTS: We observed specific and high-affinity binding to an intact GPIIb-GPIIIa receptor complex of two human Fab autoantibody fragments, with no platelet activation. Dose-dependent fibrinogen binding to GPIIb-GPIIIa and platelet aggregation were completely inhibited. One Fab fragment was competitively inhibited by abciximab and its murine analog monoclonal antibody (mAb) 7E3, whereas the other Fab fragment bound to cultured HUVECs, suggesting cross-reactivity with alpha(V)beta(3), and also demonstrated proangiogenic effects in tube formation and CAM assays. CONCLUSIONS: These Fab fragments are the first entirely human anti-GPIIb-GPIIIa Fab fragments with full antiaggregatory properties; furthermore, they do not activate platelets. The unique dual-specificity anti-beta(3)-integrin Fab fragment may represent a new tool for the study and management of peripheral arterial vasculopathies.

Innate and adaptive immunity cooperate flexibly to maintain host-microbiota mutualism

Commensal bacteria in the lower intestine of mammals are 10 times as numerous as the body's cells. We investigated the relative importance of different immune mechanisms in limiting the spread of the intestinal microbiota. Here, we reveal a flexible continuum between innate and adaptive immune function in containing commensal microbes. Mice deficient in critical innate immune functions such as Toll-like receptor signaling or oxidative burst production spontaneously produce high-titer serum antibodies against their commensal microbiota. These antibody responses are functionally essential to maintain host-commensal mutualism in vivo in the face of innate immune deficiency. Spontaneous hyper-activation of adaptive immunity against the intestinal microbiota, secondary to innate immune deficiency, may clarify the underlying mechanisms of inflammatory diseases where immune dysfunction is implicated.

Variability of anti-PF4/heparin antibody results obtained by the rapid testing system ID-H/PF4-PaGIA

BACKGROUND: Recent studies have shown that a low clinical pretest probability may be adequate for excluding heparin-induced thrombocytopenia. However, for patients with intermediate or high pretest probability, laboratory testing is essential for confirming or refuting the diagnosis. Rapid assessment of anti-PF4/heparin-antibodies may assist clinical decision-making. OBJECTIVES: To evaluate the performance of rapid ID-H/PF4-PaGIA. In particular, we verified reproducibility of results between plasma and serum specimens, between fresh and frozen samples, and between different ID-H/PF4-polymer lots (polystyrene beads coated with heparin/PF4-complexes). PATIENTS/METHODS: The samples studied were 1376 plasma and 914 corresponding serum samples from patients investigated for suspected heparin-induced thrombocytopenia between January 2000 and October 2008. Anti-PF4/heparin-antibodies were assessed by ID-H/PF4-PaGIA, commercially available ELISAs and heparin-induced platelet aggregation test. RESULTS: Among 914 paired plasma/serum samples we noted discordant results (negative vs. low-titre positive) in nine instances (1%; 95%CI, 0.4-1.6%). Overall, agreement between titres assessed in plasma vs. serum was highly significant (Spearman correlation coefficient, 0.975; P < 0.0001). Forty-seven samples tested both fresh and after freezing/thawing showed a good agreement, with one discordant positive/negative result (Spearman correlation coefficient, 0.970; P < 0.0001). Among 1376 plasma samples we noted a strikingly variable incidence of false negative results (none - 82%; 95%CI, 66-98%), depending on the employed ID-H/PF4-polymer lot. Faulty lots can be recognized by titrating commercial positive controls and stored samples of HIT-patients. CONCLUSION: Laboratories performing the assay should implement stringent internal quality controls in order to recognize potentially faulty ID-H/PF4-polymer lots, thus avoiding false negative results.

Low Mannan-binding lectin serum levels are associated with complicated Crohn's disease and reactivity to oligomannan (ASCA)

OBJECTIVES: Mannan-binding lectin (MBL) acts as a pattern-recognition molecule directed against oligomannan, which is part of the cell wall of yeasts and various bacteria. We have previously shown an association between MBL deficiency and anti-Saccharomyces cerevisiae mannan antibody (ASCA) positivity. This study aims at evaluating whether MBL deficiency is associated with distinct Crohn's disease (CD) phenotypes. METHODS: Serum concentrations of MBL and ASCA were measured using ELISA (enzyme-linked immunosorbent assay) in 427 patients with CD, 70 with ulcerative colitis, and 76 healthy controls. CD phenotypes were grouped according to the Montreal Classification as follows: non-stricturing, non-penetrating (B1, n=182), stricturing (B2, n=113), penetrating (B3, n=67), and perianal disease (p, n=65). MBL was classified as deficient (<100 ng/ml), low (100-500 ng/ml), and normal (500 ng/ml). RESULTS: Mean MBL was lower in B2 and B3 CD patients (1,503+/-1,358 ng/ml) compared with that in B1 phenotypes (1,909+/-1,392 ng/ml, P=0.013). B2 and B3 patients more frequently had low or deficient MBL and ASCA positivity compared with B1 patients (P=0.004 and P<0.001). Mean MBL was lower in ASCA-positive CD patients (1,562+/-1,319 ng/ml) compared with that in ASCA-negative CD patients (1,871+/-1,320 ng/ml, P=0.038). In multivariate logistic regression modeling, low or deficient MBL was associated significantly with B1 (negative association), complicated disease (B2+B3), and ASCA. MBL levels did not correlate with disease duration. CONCLUSIONS: Low or deficient MBL serum levels are significantly associated with complicated (stricturing and penetrating) CD phenotypes but are negatively associated with the non-stricturing, non-penetrating group. Furthermore, CD patients with low or deficient MBL are significantly more often ASCA positive, possibly reflecting delayed clearance of oligomannan-containing microorganisms by the innate immune system in the absence of MBL.

Haematologic data, iron parameters and molecular findings in two new cases of iron-refractory iron deficiency anaemia

Matriptase-2 (Tmprss6), a type II transmembrane serine protease, has an essential role in iron homoeostasis as a hepcidin regulator. Recently, patients with TMPRSS6 mutations and suffering from iron-refractory iron deficiency anaemia (IRIDA) have been reported. We describe two new cases of IRIDA, one patient of Swiss origin and the second of Italian origin. The first case results from a large deletion of 1054 nucleotides corresponding to an in frame deletion of 30 amino acid residues in the low-density lipoprotein receptor-1/-2 (LDLR-1/-2) domains and from a missense mutation in CUB1 (S304L). In the second case, a homozygous G-->C mutation in the last nucleotide of exon 15 and which modified the consensus sequence of the 5' splice donor site of intron 15 (AGgt-->ACgt) was identified. Both patients had a high hepcidin level and low serum iron and transferrin saturation compared to age-matched controls. Continuous perfusion of i.v. iron 4 h/d x 5 d in the first case resulted in a significant rise in haemoglobin. These new cases of IRIDA illustrate the importance of LDLR-1/-2 and CUB1 domains in matriptase-2 function as well as the role of matriptase-2 in hepcidin regulation. Furthermore a deletional form of TMPRSS6 (in LDLR-1/-2 domains) resulting in IRIDA is described for the first time. These cases reinforce the belief that patients suffering from IRIDA have no specific geographical or ethnic distribution and are sporadic secondary to different mutations of the matriptase-2 gene.

Expanding the spectrum of mutations in GH1 and GHRHR: genetic screening in a large cohort of patients with congenital isolated growth hormone deficiency

CONTEXT: It is estimated that 3-30% of cases with isolated GH deficiency (IGHD) have a genetic etiology, with a number of mutations being reported in GH1 and GHRHR. The aim of our study was to genetically characterize a cohort of patients with congenital IGHD and analyze their characteristics. PATIENTS AND METHODS: A total of 224 patients (190 pedigrees) with IGHD and a eutopic posterior pituitary were screened for mutations in GH1 and GHRHR. To explore the possibility of an association of GH1 abnormalities with multiple pituitary hormone deficiencies, we have screened 62 patients with either multiple pituitary hormone deficiencies (42 pedigrees), or IGHD with an ectopic posterior pituitary (21 pedigrees). RESULTS: Mutations in GH1 and GHRHR were identified in 41 patients from 21 pedigrees (11.1%), with a higher prevalence in familial cases (38.6%). These included previously described and novel mutations in GH1 (C182X, G120V, R178H, IVS3+4nt, a>t) and GHRHR (W273S, R94L, R162W). Autosomal dominant, type II IGHD was the commonest form (52.4%), followed by type IB (42.8%) and type IA (4.8%). Patients with type II IGHD had highly variable phenotypes. There was no difference in the endocrinology or magnetic resonance imaging appearance between patients with and without mutations, although those with mutations presented with more significant growth failure (height, -4.7 +/- 1.6 SDS vs. -3.4 +/- 1.7 SDS) (P = 0.001). There was no apparent difference between patients with mutations in GH1 and GHRHR. CONCLUSIONS: IGHD patients with severe growth failure and a positive family history should be screened for genetic mutations; the evolving endocrinopathy observed in some of these patients suggests the need for long-term follow-up.

Mutation analysis of the muscarinic cholinergic receptor genes in isolated growth hormone deficiency type IB

BACKGROUND: Isolated GH deficiency (IGHD) is familial in 5-30% of patients. The most frequent form (IGHD-IB) has autosomal recessive inheritance, and it is known that it can be caused by mutations in the GHRH receptor (GHRHR) gene or in the GH gene. However, most forms of IGHD-IB have an unknown genetic cause. In normal subjects, muscarinic cholinergic stimulation causes an increase in pituitary GH release, whereas its blockade has the opposite effect, suggesting that a muscarinic acetylcholine receptor (mAchR) is involved in stimulating GH secretion. Five types of mAchR (M(1)-M(5)) exist. A transgenic mouse in which the function of the M(3) receptor was selectively ablated in the central nervous system has isolated GH deficiency similar to animals with defective GHRH or GHRHR gene. OBJECTIVE: We hypothesized that mAchR mutations may cause a subset of familial IGHD. PATIENTS/METHODS: After confirming the expression of M(1)-M(5) receptor mRNA in human hypothalamus, we analyzed the index cases of 39 families with IGHD-IB for mutations in the genes encoding for the five receptors. Coding sequences for each of the five mAchRs were subjected to direct sequencing. RESULTS: In one family, an affected member was homozygous for a M(3) change in codon 65 that replaces valine with isoleucine (V65I). The V65I receptor was expressed in CHO cells where it had normal ability to transmit methacholine signaling. CONCLUSION: mAchR mutations are absent or rare (less than 2.6%) in familial IGHD type IB.

Antibody responses induced by long-term vaccination with an octovalent conjugate Pseudomonas aeruginosa vaccine in children with cystic fibrosis

We assessed the serological responses over 10 years to repeated immunization of cystic fibrosis (CF) patients with an O-polysaccharide (OPS)-toxin A conjugate vaccine against Pseudomonas aeruginosa. A retrospective analysis was performed with sera from 25 vaccinated and 25 unvaccinated children treated at the same CF centre and matched for clinical management, age and gender. Yearly immunization led to sustained elevations of serum immunoglobulin G (IgG) antibody levels to all vaccine components. Eighteen unvaccinated patients but only eight vaccinated ones developed chronic pseudomonal lung infections. Infection rapidly caused further marked elevations of polysaccharide- but not toxin A-specific serum IgG in both immunized and nonimmunized patients, indicating that protection did not depend on the quantity of IgG present. However, qualitative analyses revealed that the protective capacity of specific serum IgG antibodies was linked to high affinity and to specificity for OPS serotypes rather than for lipopolysaccharide core epitopes.

Experimental folate and vitamin B12 deficiency does not alter bone quality in rats

Hyperhomocysteinemia (HHCY) has been linked to fragility fractures and osteoporosis. Folate and vitamin B(12) deficiencies are among the main causes of HHCY. However, the impact of these vitamins on bone health has been poorly studied. This study analyzed the effect of folate and vitamin B(12) deficiency on bone in rats. We used two groups of rats: a control group (Co, n = 10) and a vitamin-deficient group (VitDef, n = 10). VitDef animals were fed for 12 wk with a folate- and vitamin B(12)-free diet. Co animals received an equicaloric control diet. Tissue and plasma concentrations of homocysteine (HCY), S-adenosyl-homocysteine (SAH), and S-adenosyl-methionine (SAM) were measured. Bone quality was assessed by biomechanical testing (maximum force of an axial compression test; F(max)), histomorphometry (bone area/total area; B.Ar./T.Ar.], and the measurement of biochemical bone turnover markers (osteocalcin, collagen I C-terminal cross-laps [CTX]). VitDef animals developed significant HHCY (Co versus VitDef: 6.8 +/- 2.7 versus 61.1 +/- 12.8 microM, p < 0.001) that was accompanied by a high plasma concentration of SAH (Co versus VitDef: 24.1 +/- 5.9 versus 86.4 +/- 44.3 nM, p < 0.001). However, bone tissue concentrations of HCY, SAH, and SAM were similar in the two groups. Fmax, B.Ar./T.Ar., OC, and CTX did not differ between VitDef and Co animals, indicating that bone quality was not affected. Folate and vitamin B(12) deficiency induces distinct HHCY but has no effect on bone health in otherwise healthy adult rats. The unchanged HCY metabolism in bone is the most probable explanation for the missing effect of the vitamin-free diet on bone.