The influence of oral insulin on the development of autoimmune diabetes in NOD mice fed a hypoallergenic diet.

BACKGROUND: Autoimmune diabetes can be prevented in animal models by hypoallergenic diets. Moreover, in animal models, oral administration of insulin can suppress the development of autoimmune diabetes and clinical trials on prevention of human Type 1 diabetes by oral administration of insulin are already taking place. However, it has been reported that autoimmune diabetes can be induced by oral administration of an auto-antigen (insulin), and great caution is therefore warranted when applying the oral tolerance approach to prevent Type 1 diabetes. AIM: To evaluate the effect of orally administered insulin on the development of autoimmune diabetes in non-obese diabetic mice fed a hypoallergenic diet. METHODS: Four groups of mice were fed regular mouse chow (group 1, control mice), hypoallergenic diet, using the hydrolyzed infant formula Pregistimil (group 2), and Pregistimil with oral insulin (4 U/l of drinking water, group 3; and 8 U/l of drinking water, group 4). RESULTS: At 210 days of age, 11/20 (55%) mice in group 1 developed diabetes. In contrast, none of the mice from the Pregistimil-fed groups (0/16, 0/14, 0/17) developed the disease (p<0.001). The incidence of infiltrated islets and the severity of insulitis, at age 90 days, was significantly lower in mice fed with the hypoallegenic diet than in controls (p=0.028). CONCLUSIONS: In NOD mice fed a diet that prevents the development of diabetes, oral insulin supplementation appears to be safe, since it does not promote the development of clinical diabetes.

Detection of RAG mutations and prenatal diagnosis in families presenting with either T-B- severe combined immunodeficiency or Omenn's syndrome.

It has been recently shown that mutations in both of the recombination activating genes RAG1 and RAG2 are involved in each of the two different types of severe combined immunodeficiency (SCID) syndromes: T-B- SCID and Omenn's syndrome (OS). The objective of the study was to search for novel mutations in the RAG genes and to offer prenatal diagnosis for families that have been identified as at risk of T-B- SCID or OS. Mutation analyses of polymerase chain reaction products of RAG1/RAG2 genes were performed in 14 cases (T-B- SCID = 6 and OS = 8). Consanguinity was reported in seven (50%) families. Four missense mutations in the RAG2 gene in six of eight OS patients and in four of six T-B- SCID patients were detected. The C1845T transition leading to a Tre215Ile substitution is a novel mutation. All but one of the patients were homozygous for the detected mutations, possibly reflecting the consanguinity in these families and the relative rarity of the disease-causing mutations. In addition, three putative polymorphic sites were found. Prenatal diagnosis was offered to seven families, but three of them declined genetic counseling for religious reasons. In the remaining families, four pregnancies were successfully completed, and in one case, the family chose to have an abortion because of a homozygous mutation. Mutations in RAG1/RAG2 genes were detected in only some of the T-B- SCID or OS patients, and the molecular basis for the remaining cases has yet to be elucidated. Important factors such as religious beliefs need to be considered when offering prenatal diagnosis to certain families.

Familial severe congenital neutropenia associated with infantile osteoporosis: a new entity.

A new entity manifested by severe congenital neutropenia associated with osteoporosis and recurrent bone fracture is described in a family. A possible role for a new recognized cytokine system involved in bone remodeling, the osteoprotegerin/receptor activator of nuclear factor-kappa B ligand, is suggested.

The mutational spectrum of human malignant autosomal recessive osteopetrosis.

Human malignant infantile osteopetrosis (arOP; MIM 259700) is a genetically heterogeneous autosomal recessive disorder of bone metabolism, which, if untreated, has a fatal outcome. Our group, as well as others, have recently identified mutations in the ATP6i (TCIRG1) gene, encoding the a3 subunit of the vacuolar proton pump, which mediates the acidification of the bone/osteoclast interface, are responsible for a subset of this condition. By sequencing the ATP6i gene in arOP patients from 44 unrelated families with a worldwide distribution we have now established that ATP6i mutations are responsible for approximately 50% of patients affected by this disease. The vast majority of these mutations (40 out of 42 alleles, including seven deletions, two insertions, 10 nonsense substitutions and 21 mutations in splice sites) are predicted to cause severe abnormalities in the protein product and are likely to represent null alleles. In addition, we have also analysed nine unrelated arOP patients from Costa Rica, where this disease is apparently much more frequent than elsewhere. All nine Costa Rican patients bore either or both of two missense mutations (G405R and R444L) in amino acid residues which are evolutionarily conserved from yeast to humans. The identification of ATP6i gene mutations in two families allowed us for the first time to perform prenatal diagnosis: both fetuses were predicted not to be affected and two healthy babies were born. This study contributes to the determination of genetic heterogeneity of arOP and allows further delineation of the other genetic defects causing this severe condition.

Alterations of the X-linked lymphoproliferative disease gene SH2D1A in common variable immunodeficiency syndrome.

X-linked lymphoproliferative (XLP) disease is a primary immunodeficiency caused by a defect in the SH2D1A gene. At least 3 major manifestations characterize its clinical presentation: fatal infectious mononucleosis (FIM), lymphomas, and immunoglobulin deficiencies. Common variable immunodeficiency (CVID) is a syndrome characterized by immunoglobulin deficiency leading to susceptibility to infection. In some patients with CVID, a defective btk or CD40-L gene has been found, but most often there is no clearly identified etiology. Here, 2 unrelated families in whom male members were affected by CVID were examined for a defect in the XLP gene. In one family previously reported in the literature as having progressive immunoglobulin deficiencies, 3 brothers were examined for recurrent respiratory infections, whereas female family members showed only elevated serum immunoglobulin A levels. A grandson of one of the brothers died of a severe Aspergillus infection secondary to progressive immunoglobulin deficiency, FIM, aplastic anemia, and B-cell lymphoma. In the second family, 2 brothers had B lymphocytopenia and immunoglobulin deficiencies. X-linked agammaglobulinemia syndrome was excluded genetically, and they were classified as having CVID. The occurrence of FIM in a male cousin of the brothers led to the XLP diagnosis. Because the SH2D1A gene was found altered in both families, these findings indicate that XLP must be considered when more than one male patient with CVID is encountered in the same family, and SH2D1A must be analyzed in all male patients with CVID. Moreover, these data link defects in the SH2D1A gene to abnormal B-lymphocyte development and to dysgammaglobulinemia in female members of families with XLP disease.

Complementation cloning identifies CDG-IIc, a new type of congenital disorders of glycosylation, as a GDP-fucose transporter deficiency.

Congenital disorders of glycosylation (CDG) comprise a rapidly growing group of inherited disorders in which glycosylation of glycoproteins is defective due to mutations in genes required for the assembly of lipid-linked oligosaccharides, their transfer to nascent glycoproteins (CDG-I) or the processing of protein-bound glycans (CDG-II). Previously' a defect in the GDP-fucose import into the lumen of the Golgi was identified in a person with CDG (A.C.) with a general deficiency of fucosyl residues in glycoproteins. This patient presents the clinical features of leukocyte adhesion deficiency type II (LAD II) including mental retardation, short stature, facial stigmata, and recurrent bacterial peripheral infections with persistently elevated peripheral leukocytes. Using a fucose-specific, lectin-staining procedure for detection of fucosylated glycoproteins and a retroviral cDNA library, we isolated a cDNA complementing the fucosylation defect in the patient's fibroblasts. The cDNA encodes a highly hydrophobic protein of 364 amino acids with multiple putative transmembrane domains. Restoration of GDP-fucose import activity in Golgi-enriched vesicles from the patient's fibroblasts verified the GDP-fucose transporter activity of this protein. We identified two missense mutations in the GDP-fucose transporter cDNA of patient A.C. and of two other people with LAD II. Thus complementation cloning allowed us to identify the human GDP-fucose transporter cDNA and GDP-fucose transporter deficiency as a cause for a new type of CDG. Following the recent recommendations for the nomenclature for CDG, this new type is classified as CDG-IIc (formerly LAD II).

Importance of insulin content in infant diet: suggestion for a new infant formula.

Oral insulin promotes intestinal maturation and may prevent diabetes in animal models. The aim of this study was to evaluate the concentration of insulin in human milk and in different infant formulas. Our results show that the concentration of insulin in human milk is significantly higher (60.23 +/- 41.05 microU/ml mean +/- SD) compared with cow's milk (16.32 +/- 5.98 microU/ml mean +/- SD) and that insulin is hardly detectable in infant formulas. We propose the addition of human insulin to infant formula to match its composition more closely to human milk.

Long-term sleep disturbances in adolescents after minor head injury.

It has been demonstrated that patients in the acute phase after minor head injury (MHI) complain of sleep disturbances. The purpose of the present study was to characterize the long-term effects of MHI on sleep in adolescents. Nineteen adolescents who had suffered MHI 3 years before the study and had complained of sleep disturbances completed a sleep questionnaire and were investigated in the sleep laboratory by whole-night polysomnographic recordings and were actigraphically monitored for 5 days at home. Questionnaire results revealed severe complaints regarding sleep behavior. Polysomnographic recordings revealed that in comparison with controls, MHI was associated with lower sleep efficiency (79.8 +/- [9.8]% vs 87.7 +/- [6.8]%; P < 0.005), with more wake time (10.6 +/- [9.0]% vs 3.4 +/- [4.4]%; P < 0.005), and with more awakenings lasting more than 3 minutes (2.1 +/- [1.5] vs 0.6 +/- [0.8]; P < 0.005). These findings were confirmed by actigraphic monitoring that revealed lower sleep efficiency (90 +/- [5]% vs 94 +/- [3]%; P < 0.05), more minutes of wake time (49 +/- [21] min vs 28 +/- [15] min; P < 0.05), and a trend toward more awakenings longer than 5 minutes (1.8 +/- [0.8] vs 1.2 +/- [0.8]; P = 0.063). Our data demonstrated that 3 years after MHI without any discernible clinical sequel, adolescents still complain of sleep disturbances that could be confirmed by both polysomnographic and actigraphic monitoring.

Impairment of the Golgi GDP-L-fucose transport and unresponsiveness to fucose replacement therapy in LAD II patients.

Leukocyte adhesion deficiency type II is an autosomal recessive syndrome characterized by generalized reduction of L-fucose in glycoconjugates; the specific molecular defect is still undefined. The most important clinical symptoms include severe growth and mental retardation and severe immunodeficiency. Patients from two ethnic groups have been reported, i.e. Arab and Turkish. We have observed that GDP-L-fucose transport into Golgi vesicles was specifically impaired in an Arab patient, with a significant reduction of the V:(max) but no significant differences in the K:(m) from control and parents. GDP-L-fucose transport showed simple saturation kinetics in all samples. Transport of UDP-galactose, UDP-N:-acetylglucosamine, and CMP-sialic acid was comparable into vesicles from the Arab patient, parents, and control. These kinetic parameters probably account for the failure to obtain any clinical and biochemical response to fucose therapy in Arab patients. This contrasts both with the distinctive kinetic properties of GDP-L-fucose transport and with the success of fucose therapy, which have been recently reported in one patient of Turkish origin. Accordingly, the biochemical properties of GDP-L-fucose transport into the Golgi are consistent with different variants of leukocyte adhesion deficiency type II that are probably the result of different molecular defects.

Primary immunodeficiency mutation databases.

Primary immunodeficiencies are intrinsic defects of immune systems. Mutations in a large number of cellular functions can lead to impaired immune responses. More than 80 primary immunodeficiencies are known to date. During the last years genes for several of these disorders have been identified. Here, mutation information for 23 genes affected in 14 immunodefects is presented. The proteins produced are employed in widely diverse functions, such as signal transduction, cell surface receptors, nucleotide metabolism, gene diversification, transcription factors, and phagocytosis. Altogether, the genetic defect of 2,140 families has been determined. Diseases with X-chromosomal origin constitute about 70% of all the cases, presumably due to full penetrance and because the single affected allele causes the phenotype. All types of mutations have been identified; missense mutations are the most common mutation type, and truncation is the most common effect on the protein level. Mutational hotspots in many disorders appear in CPG dinucleotides. The mutation data for the majority of diseases are distributed on the Internet with a special database management system, MUTbase. Despite large numbers of mutations, it has not been possible to make genotype-phenotype correlations for many of the diseases.

Insulin in human milk and the prevention of type 1 diabetes.

Although controversial, exclusive breast milk feeding was shown to exert a protective effect in preventing type 1 diabetes. In contrast, an early introduction of cow's milk-based formula in young infants may enhance the risk of disease, especially in genetically susceptible children, presumably by an increase of intestinal permeability to macromolecules such as bovine serum albumin and beta-casein, which may arouse autoimmunity. We have shown that human milk contains insulin in substantial concentrations, while insulin is barely detectable (if at all) in infant formulas. Orally administered insulin was demonstrated to promote gut maturation and to reduce intestinal permeability to macromolecules. Furthermore, oral insulin may induce tolerance to insulin and protect against the development of type 1 diabetes. We herewith raise a hypothesis that human milk is protective against the development of type 1 diabetes by virtue of the effects of its substantial content of insulin.

Novel aspects of phagocytic cell disorders.

This review highlights the various numerical and functional defects in the phagocyte system. It mainly focuses on newly discovered genetic defects in the system and the role played by these defects in the clinical symptoms presented by patients. Novel therapeutic modalities to treat phagocyte abnormalities, which are currently under clinical trials, are also discussed.

Melatonin improves sleep-wake patterns in psychomotor retarded children.

Five children with severe psychomotor retardation (mean age 8.2+/-3.6 years) and irregular sleep-wake patterns underwent 1 week of wrist actigraphic monitoring before and after treatment with 3 mg melatonin. Three underwent multiple measurements of urinary sulfatoxymelatonin levels. Urine sulfatoxymelatonin levels were abnormally low, without any significant day/night differences. Melatonin treatment increased nighttime sleep from 5.9+/-0.8 to 7.3+/-0.5 hours (paired t test, P<0.01) and sleep efficiency from 69.3%+/-6.2% to 88.3%+/-2.3% (P<0.01). Daytime sleep decreased from 3.2+/- 1.2 to 1.7+/-1.2 hours (P<0.05). Thus, no change in 24-hour total sleep time (9.1+/-1.5 vs. 9.0+/-1.6 hours) occurred. Administration of 3 mg melatonin to five severely psychomotor retarded children resulted in a significant improvement in their sleep-wake patterns.

Prenatal diagnosis of X-linked hyper-IGM syndrome by direct detection of mutation Q220X in the CD40L gene using PCR-mediated site directed mutagenesis.

We present the first report of prenatal diagnosis of X-linked hyper-IgM syndrome by PCR-mediated site directed mutagenesis (PSM) in a woman known to carry the Q220X mutation in the CD40L gene. Using the simple PSM assay, the Q220X mutation was identified by chorionic villous sampling (CVS) at 11 weeks' gestation and the pregnancy was terminated.

Integrins: the molecular glue of life.

The molecular interactions responsible for cellular adhesion, either to other cells or to extracellular matrix, are now known to be complex, well orchestrated, and under sophisticated control. Among the participating molecules, integrins serve a notably broad range of biologic processes, including platelet aggregation and leukocyte extravasation. The loss of an adhesion interaction may result in disease, as may the stimulation of excessive adhesiveness.

Leukocyte adhesion deficiency II-from A to almost Z.

Leukocyte adhesion deficiency (LAD) type II is the second human disorder identified which involves the adhesion cascade. While in LAD I the integrin family is defective, in LAD II the selectin system is involved. The syndrome has been described in only five patients and is transmitted as an autosomal recessive trait. The infectious episodes and the severity are much milder than those observed in LAD I, and the only persistent clinical symptom is chronic severe periodontitis. Delay separation of the umbilical cord, which is a hallmark for LAD I, was not observed in any of the LAD II patients. The exact defect in the system is absence of the SLeX, which is an important ligand for the selectin on the leukocyte lead ing to a profound defect in leukocyte rolling, the first step in the adhesion cascade. This causes a marked decrease in chemotaxis accompanied by pronounced neutrophilia. Apart from the leukocyte defect, these patients suffer from severe growth and mental retardation and exhibit the rare Bombay blood group type. The primary defect in the syndrome is in fucose metabolism, with the absence of all fucosylated glycans on cell surface membranes. Recently, it is was found that the defect is in a specific transporter of GDP fucose into the Golgi apparatus, and thus no fucosylation process takes place, and no surface expression can be detected. The exact genetic defect in the transporter is still unknown. Four of the patients were of Arabic origin while the fifth was of Turkish origin. It seems that the primary defect is somewhat different and, therefore, fucose administration was effective in the Turkish child, but did not show any beneficial results in the patients of Arabic origin.