Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0348321 (Haemophilus)
 15,372 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

To investigate whether an underlying defect in antibody (Ab)-forming capacity could contribute to the infection susceptibility of patients with hyper-IgE syndrome, we evaluated 11 such patients for their responses to bacteriophage phi X174 (phi X174), diphtheria and tetanus toxoids, and pneumococcal (Pneumovax) and Hemophilus influenzae vaccines. Three of nine patients immunized with phi X174 had normal primary and secondary Ab responses, five had accelerated declines in their titers after initially normal primary Ab responses and lower than normal secondary Ab responses, and two of the latter patients failed to switch normally from IgM to IgG Ab production. Only one of 10 patients tested had normal Ab responses to diphtheria toxoid, and postimmunization antitetanus titers were abnormally low in five of the 10 patients tested. Serum Abs to H. influenzae polyribose phosphate were protective in seven of the eight immunized patients. Five of the nine patients administered Pneumovax had poor Ab responses to at least one of the pneumococcal serotypes 7, 9, or 14. Abnormal antipolysaccharide responses did not correlate with IgG2 deficiency. All patients responded with protective Ab levels to type 3. Thus, patients with hyper-IgE syndrome are heterogeneous with respect to their Ab-forming capacities. Ab deficiency may contribute to infection susceptibility in some of these patients.
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PMID:Antibody responses to protein, polysaccharide, and phi X174 antigens in the hyperimmunoglobulinemia E (hyper-IgE) syndrome. 182 6

Humoral immune parameters were studied in 13 patients with end-stage renal failure on maintenance hemodialysis. Serum IgA, IgM and IgG concentrations were comparable to control values from 14 healthy blood donors. IgG subclass analysis revealed significantly increased IgG1 levels in the patients when compared to controls (p less than 0.01). In 3 patients, IgG2 deficiency was found, in one case associated with low IgG3 level. Concentrations and subclass composition of naturally occurring antibodies to Haemophilus influenzae type b (Hib) polysaccharide (PS) were measured using an indirect ELISA. In patients IgM and IgG, including IgG1 and IgG2 antibodies to Hib, presented no difference from controls. Subclass analysis of Hib specific IgG antibodies revealed that IgG2 accounted for a substantial amount of the anti-Hib PS antibody response in controls as well as in patients. We conclude that patients on maintenance hemodialysis present imbalances of immunoglobulin levels. However, the antibody response to certain PS antigens could remain unaffected by renal failure.
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PMID:Serum immunoglobulin levels and natural antibodies to Haemophilus influenzae in hemodialysis patients: evidence for IgG subclass imbalances. 223 47

To characterize more fully the immunologic basis for increased susceptibility to infection in patients with low serum concentrations of IgG2, we identified eight infection-prone children, 1 to 2 years of age, with serum IgG2 concentrations greater than 2 SD below the mean for age and followed their serologic and clinical courses for 1 to 3 years. Two of the eight children became clinically and immunologically normal and may have had transient IgG2 deficiency with an exaggerated developmental delay of this late-maturing subclass. The remaining six subjects had persistently subnormal or low-normal serum IgG2 levels and continued to experience frequent infections. All six of these children responded poorly to Haemophilus influenzae type b (Hib) polysaccharide, and four of six responded poorly to Streptococcus pneumoniae type 3 polysaccharide. Both IgG1 and IgG2-specific antibody responses to these vaccines were abnormal. Three of these six children also responded poorly to tetanus toxoid, an antigen that normally induces a predominant IgG1 response. Although five of these six children produced antibodies in response to Hib polysaccharide protein conjugate vaccine, three of four given Hib oligosaccharide CRM conjugate vaccine required booster doses to respond, a pattern of response characteristic of infants less than 6 months of age. Further, although serum concentrations of IgG1 were normal, peripheral blood mononuclear cells from four of six children tested produced extremely small amounts of IgG1 and IgG3 as well as IgG2. Finally, varied patterns of abnormalities of IgG, IgA, IgM, and IgG4 became apparent in five of the six children with persistently low serum IgG2 values. This study demonstrates that subnormal serum concentrations of IgG2 may be associated with varied patterns of immunologic dysfunction, some of which are evolving and may be responsible for increased susceptibility of these children to infection.
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PMID:Subnormal serum concentrations of IgG2 in children with frequent infections associated with varied patterns of immunologic dysfunction. 231 99

Serum IgG contains 4 subclasses, IgG1 (60-66%), IgG2 (20-30%), IgG3 (less than or equal to 5%) and IgG4. Individual subclasses vary with respect to their physicochemical and biological properties. IgG subclass concentrations in serum are age dependent. IgG1 and IgG3 reach near to adult levels around the age of 3, IgG2 and IgG4 after the age of 6. Antibodies of certain specificities generally belong to a certain isotype (subclass) due to the isotype restriction. Patients with subclass deficiencies often suffer from recurrent infections. Those with IgG2 deficiency coften occurring with IgA and IgG4 deficiency) develop recurrent infection of the upper and lower respiratory tract often caused by pyogenic microorganisms (Haemophilus, Pneumo-(occus). Since early initiation of IVIG substitution therapy has a beneficial effect on long term prognosis the importance of early diagnosis is apparent.
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PMID:[Clinico-immunologic aspects of IgG subclass deficiency]. 268 36

Serum IgG contains 4 subclasses, IgG1 (60-66%), IgG2 (20-30%), IgG3 (less than or equal to 5%) and IgG4. Individual subclasses vary with respect to their physicochemical and biological properties. IgG subclass concentrations in serum are age dependent. IgG1 and IgG3 reach near to adult levels around the age of 3, IgG2 and IgG4 after the age of 6. Antibodies of certain specificities generally belong to a certain isotype (subclass) due to the isotype restriction. Patients with subclass deficiencies often suffer from recurrent infections. Those with IgG2 deficiency (often occurring with IgA and IgG4 deficiency) develop recurrent infection of the upper and lower respiratory tract often caused by pyogenic microorganisms (Haemophilus, Pneumococcus). Since early initiation of IVIG substitution therapy has a beneficial effect on long term prognosis the importance of early diagnosis is apparent.
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PMID:[Clinico-immunologic aspects of IgG subclass deficiency]. 305 27

Serum immunoglobulins and IgG subclasses were measured in 30 children with recurrent infections. Seven patients had low IgG2 concentrations (less than 3SD below the geometric mean for age). Four of these seven patients had normal concentrations of IgG, IgA and IgM, and thus would have been considered immunologically normal by routine criteria. The seven children with IgG2 deficiency had more severe infections than the 23 children with normal IgG2. Five children had recurrent pneumonia or sinusitis, one had recurrent invasive Haemophilus influenzae type b infections, and one had severe pneumococcal meningitis. Their immunologic abnormalities were heterogeneous. Two children had isolated IgG2 deficiency, two had IgG2-IgG4 deficiency, one had IgG2-IgG4-IgA deficiency, one had IgG2-IgA deficiency, and one had severe IgG1-IgG2 deficiency with abnormal T cell function and thrombocytopenia. Thus IgG2 deficiency occurs frequently among children with recurrent infections, and is associated with a variety of clinical and immunologic abnormalities.
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PMID:Spectrum of IgG2 subclass deficiency in children with recurrent infections: prospective study. 370 8

We studied 20 children with recurrent sinopulmonary infections and serum IgG levels within the normal range, who had selective IgG-subclass deficiency. Twelve of the children were IgG2 deficient, five were IgG3 deficient, and three were deficient in both IgG2 and IgG3. IgA deficiency was present in 3 of the 20 patients. In the children with IgG2 deficiency, serum antibody concentrations to the capsular polysaccharide of Hemophilus influenzae type B (Hib) were significantly lower than those in age-matched controls, both before and after immunization with the Hib capsular polysaccharide antigen, which elicits antibody predominantly of the IgG2 subclass. In contrast, their serum antibody titers to the tetanus and diphtheria toxoid protein antigens, which elicit antibody predominantly of the IgG1 subclass, were normal in comparison with those of age-matched controls. These results suggest that impairment of the antibody response to specific microbial antigens predisposes patients with selective IgG-subclass deficiencies to recurrent infections. Thus, as an aid in determining therapy, children with recurrent infections and normal total serum IgG should be evaluated for this condition.
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PMID:Recurrent sinopulmonary infection and impaired antibody response to bacterial capsular polysaccharide antigen in children with selective IgG-subclass deficiency. 387 40

Selective IgG subclass (IgGSc) deficiencies are frequently found in association with recurrent infections in childhood. IgG1 deficiency is the most severe and is associated with features typical of panhypogammaglobulinaemia. Immunoglobulin replacement therapy is usually required. IgG2 deficiency is associated with recurrent infections with encapsulated bacteria such as Haemophilus influenzae and Streptococcus pneumoniae. IgG2 deficiency may be transient in children under five years of age and patients improve with antibiotics and immunisation. IgG3 and IgG4 deficiency are commonly found in children with recurrent infections and may indicate a disordered immune system since absence of these antibodies alone appears insufficient to cause symptoms. Children may also have selective IgGSc deficiencies in the absence of recurrent infections. This is explained by compensatory factors in other parts of the immune system. Measurement of IgGSc levels should be based on highly specific polyclonal antisera which show no IgGSc cross-reactivity. Most monoclonal antibodies are unsatisfactory since allotypes are detected variably, leading to excess reporting of IgGSc deficiencies and Mabs cannot be used for nephelometric or turbidimetric methods.
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PMID:IgG subclasses in childhood infections. 761 65

Only a small number of patients with IgG subclass deficiencies (IgGSD) have been observed to have bronchiectasis. Moreover, in the series of patients with bronchiectasis, IgGSD have not been found at any frequency, and the etiology of bronchiectasis remains unclear in 29 to 49% of cases. Serum concentrations of total IgG, IgA, and IgG subclasses as well as pulmonary function were measured in 65 patients (aged: 10 to 74 yr) with bronchiectasis of unknown etiology. An ELISA test was performed to quantify subclasses 1 through 4 using subclass-specific antihuman monoclonal antibodies. IgG subclass estimation in a healthy population with age-stratified normal ranges was derived from 100 adults, 37 children aged between 10 and 12 yr, and 27 adolescents aged between 13 and 16 yr. Serum concentrations of specific IgG antibodies to Haemophilus influenzae type b capsular polysaccharide (Hib-PRP) were also assayed by an ELISA test in 19 of the patients (10 with IgGSD and nine with non-IgGSD) and in 58 healthy individuals before and 3 wk after immunization with Hib-PRP conjugated to meningococcal outer membrane protein complex (OMPC). Thirty-one patients (48%) had low serum concentrations of one or more IgG subclasses (19 IgG2 deficiencies, 2 IgG3 deficiencies, 3 IgG4 deficiencies, and 7 combined subclass deficiencies). All patients showed increased levels of total IgG, IgG1, and IgA, but this rise was significantly higher in patients without IgGSD. Patients with IgGSD showed impaired antibody response to Hib-PRP compared with patients with non-IgGSD and the control group. IgGSD, particularly IgG2 deficiency, are not an unusual cause of bronchiectasis. Therefore, serum levels of IgG subclasses must be assayed whenever other causes of bronchiectasis have been ruled out.
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PMID:IgG subclass deficiencies associated with bronchiectasis. 856 13

Patients with IgG2 deficiency have recurrent sinopulmonary infections caused by Pneumococcus and Hemophilus. Hereditary and selective IgG2 deficiency was suspected in two Japanese siblings whose serum IgG2 levels were under detection limits, while other serum levels of immunoglobulin subclasses were within normal ranges. Expression level of spontaneous germline Cgamma2 transcript was normal, but that of the spontaneous mature Cgamma2 transcript was greatly decreased in the patients' PBMCs, suggesting the presence of a defect at or after the class switch to Cgamma2. We sequenced the Cgamma2 gene region, and in both patients a homozygous one-base insertion (1793insG) was present in exon 4 of the Cgamma2 gene, just upstream from the alternative splice site for M exons. The mutant membrane-bound gamma2 heavy chain loses the transmembrane domain and the evolutionarily conserved cytoplasmic domain. Considering several lines of evidence showing that intact expression of the membrane-bound heavy chain is essential for a normal response of B cells and production of secreted immunoglobulin in mice, we concluded that 1793insG is responsible for selective and complete IgG2 deficiency in these two siblings. This is the first documentation of a mutation in human selective IgG2 deficiency.
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PMID:Molecular basis of selective IgG2 deficiency. The mutated membrane-bound form of gamma2 heavy chain caused complete IGG2 deficiency in two Japanese siblings. 944 2


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