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Biomedical subjects

R A Seger

Publications and source records attributed to R A Seger.

At least 55 records · Page 3Linked to original sources
PubMed1991

Defective activation of the alternative pathway of complement in patients with homozygous C2 deficiency: studies in two unrelated families.

Selective homozygous deficiency of the second component of complement, C2, with increased susceptibility to infection was detected in five children of two unrelated families. Because the haemolytic activity of the alternative complement pathway (AP) was in the low normal range, we evaluated the AP activation pattern. Serum levels of factor B measured immunochemically and the haemolytic function of factor B were low normal. Levels of C3d were not increased. Activation products of factor B were undetectable indicating the absence of in vivo activation of AP. Activation of C3 in vitro by activators of the AP (zymosan A and lipopolysaccharide) was profoundly deficient in homozygous C2 deficiency while heterozygous carriers exhibited intermediate values. There was no correlation between serum levels of factor B and in vitro C3 activation. We conclude that defective AP activation may contribute to increased susceptibility to bacterial infections in some patients with homozygous C2 deficiency.

Child↗
PubMed1991

[Immunologic complications of visceral leishmaniasis].

This study concerns 3 cases of visceral leishmaniasis with various immunological complications. One patients showed a life-threatening activation of macrophages, characterised by haemophagocytosis in the bone marrow, pancytopenia, hypofibrinogenaemia and hypertriglycerideamia. A selective deficiency of IgG subclasses persisting for months was found in all 3 cases, the clinical relevance of which is unclear. One case manifested the already well known transient decrease of cell mediated immunity to antigens. If early detection and correct management is possible, these complications may be prevented and most cases of visceral leishmaniasis be cured.

Animals↗
PubMed1990

Bare lymphocyte syndrome--combined immunodeficiency and neutrophil dysfunction.

A 4-year-old girl presented with recurrent infections. Immunoglobulin deficiency (serum and secretory IgA, serum IgG3) neutropenia and neutrophil dysfunction (defective spontaneous migration and chemotaxis) were found. T-lymphocyte counts were normal and they responded to phytohaemagglutinin but were not stimulated by Concanavalin A, pokeweed mitogen and microbial antigens in vitro. Delayed cutaneous hypersensitivity testing to purified protein derivative and candidin was negative. Despite bacille Calmette-Guérm vaccination and candidiasis, near normal beta-2-micro-globulin and human leucocyte antigen (HLA) class I concentrations were detected on mononuclear cells and phytohaemagglutinin-induced lymphoblasts. HLA class II antigens (HLA-DP, -DQ, -DR) were not expressed. These observations indicated a bare lymphocyte syndrome (BLS) type II. This is the first time neutrophil dysfunction has been noted in association with BLS.

Cell Movement↗
PubMed1989

Stable human immunodeficiency virus encephalopathy in two infants receiving early intravenous gammaglobulin plus antimicrobial prophylaxis.

Two infants with human immunodeficiency virus (HIV) infection, encephalopathy, intrathecal anti-HIV IgG antibody production and (in one case) the presence of HIV antigen received monthly doses of intravenous gammaglobulin (IVGG) and daily antimicrobial prophylaxis starting at the ages of 6 and 9 months respectively. The follow-up over 15 and 12 months revealed a favourable course with remarkable improvement in visuo-spatial functions, receptive language, play behaviour and fine motor skills, as well as in muscle tone, pyramidal tract signs and vigilance in case 1, and near normalization in case 2. Viability of HIV in peripheral blood mononuclear cells, antigen in serum and cellular immunodeficiency, however, all remained unchanged. We suggest that neurological complications of encephalopathy in paediatric acquired immunodeficiency syndrome may have a slower progression when IVGG treatment plus antimicrobial prophylaxis is started early.

Acquired Immunodeficiency Syndrome↗
PubMed1989

IgG2/IgG4 subclass deficiency in a patient with chronic mucocutaneous candidiasis and bronchiectases.

A 22-year-old man with chronic mucocutaneous candidiasis (CMC) and hypothyroidism developed severe bronchiectases following recurrent bronchopneumonia. Immunological investigations revealed IgG2/IgG4 subclass deficiency and absence of antibodies against pneumococcal and Haemophilus polysaccharides. Under regular immunoglobulin substitution every 3 weeks pulmonary symptoms improved markedly.

Adult↗
PubMed1989

Immunological evaluation in the early diagnosis of prenatal or perinatal HIV infection.

A longitudinal evaluation was carried out of the clinical, infective, and immunological progress of 34 children (who were aged 6 to 68 months--mean 25 months at the time of writing) born to 31 mothers infected with human immunodeficiency virus (HIV), over a mean observation period of 13.4 months. Clinical symptoms, not always clearly related to HIV became apparent in 11 children, and preceding immune abnormalities were documented in two of them. In eight children culture for HIV was positive, and six of these were symptomatic. No cancers were diagnosed and none of the children died. Immune abnormalities including hypergammaglobulinaemia, IgG subclass deficiency, low serum IgA concentration, antibody deficiency, a decrease in the number of CD4+(T helper) cells, and defective cellular responses to antigens, were found in seven of the children in whom culture for HIV was positive; in two of four who had symptoms and in all four who were symptom free and in whom culture was negative for HIV but in whom HIV antibodies persisted and who were older than 15 months; and in three of nine who were symptom free and in whom culture was negative with loss of HIV antibodies. We conclude that serological diagnosis alone may be misleading and that additional immunological assessment may help to identify affected children. Analysis of humoral and cellular responses to antigens used for vaccination such as tetanus toxoid by measurement of specific antibodies and skin testing are simple and helpful in clinical practice.

Acquired Immunodeficiency Syndrome↗
PubMed1988

Absence of complement receptor type 3 and lymphocyte function antigen 1 causing deficient phagocyte and lymphocyte functions.

We describe a patient with delayed umbilical cord detachment, recurrent bacterial infections, and inability to form pus, despite persistent leucocytosis. Immunofluorescence studies with specific monoclonal antibodies showed a severe deficiency in the expression of alpha-chains of the receptor for the C3bi fragment of C3, complement receptor type 3, and the lymphocyte function antigen 1 molecule, found on neutrophil, monocyte and lymphocyte membranes. These membrane antigen defects were responsible for abnormalities in adhesive cell functions. Polymorphonuclear leucocytes demonstrated a markedly reduced chemiluminescence response as well as an impaired nitroblue tetrazolium test and superoxide generation to a particulate stimulus (zymosan), while the responses to a soluble stimulus (phorbol myristate acetate) were normal. In addition, random migration und chemotactic response to zymosan-activated serum were impaired. The lymphocytes demonstrated abolished natural killer cell cytotoxicity as well as abnormal humoral immunity and a lack of antibody response to pertussis and tetanus antigens.

Antigens, Differentiation↗
PubMed1986

A study of 25 patients with chronic granulomatous disease: a new classification by correlating respiratory burst, cytochrome b, and flavoprotein.

Twenty-five patients suffering from chronic granulomatous disease (CGD) and their families were investigated. Defects in the superoxide generating system were characterized at the level of the heme-containing cytochrome b and of the FAD-containing flavoprotein, both localized in the plasma membrane of granulocytes. It was confirmed that in most of the typical cases (18 of 22), the complete inability of superoxide generation was associated with the absence of detectable cytochrome b. Mothers but not fathers of such male patients were characterized by a diminished content of cytochrome b, confirming that the affected gene is localized on the X chromosome. In contrast, the granulocytes of four other typical patients (two female and two male) contained normal amounts of cytochrome b, whereas oxidative activity was absent. Since no abnormality of oxidative activity as well as of cytochrome b was found in granulocytes of the mothers and fathers of these patients, an autosomal recessive mode of inheritance of the disease is probable. The flavoprotein deficiency found in the granulocytes of four male patients was always associated with an absence of detectable cytochrome b. This could indicate a structural relationship between flavoprotein and cytochrome b (e.g., a flavocytochrome). Three further patients with mild X-linked CGD contrasted with the patients with severe or classic X-linked disease; the oxidative activity of their phagocytes was diminished but not absent, and the cytochrome b present, albeit in small amounts.

Adolescent↗
PubMed1986

Treatment of pneumococcal postsplenectomy sepsis in the rat with human gamma-globulin.

A rat model was used to evaluate the possible effect on experimental postsplenectomy sepsis of a human gamma-globulin preparation for intravenous use (Sandoglobulin). Sixty splenectomized male Sprague-Dawley rats were given 3 X 10(3) Streptococcus pneumoniae type 1 intravenously. Twelve of the animals received no treatment and all died, in contrast to 12 sham-operated controls which all survived the challenge. The remaining splenectomized rats were divided into four groups, each consisting of 12 animals. One group was given 120 mg human gamma-globulin twice intraperitoneally (0.3 g/kg body wt), at 18 and 42 hr, after challenge; 10 of the 12 survived, in contrast to none of the 12 in the second group receiving 120 mg human albumin instead of gamma-globulin (P = 0.00003). When the injections were delayed to 24 and 48 hr, 9/12 gamma-globulin-treated animals still survived, in contrast to 0/12 in the albumin group. These findings point to new possibilities for treatment and perhaps prevention of overwhelming postsplenectomy sepsis by administration of high doses of gamma-globulins.

Albumins↗
PubMed1985

Chronic granulomatous disease: uptake and intracellular activity of fosfomycin in granulocytes.

In chronic granulomatous disease (CGD) polymorphonuclear leukocytes (PMN) are unable to kill phagocytized catalase-positive bacteria. Therefore, patients with CGD are prone to infections and dependent on antimicrobial agents able to penetrate PMN membranes and to act intracellularly. Owing to their good lipid solubility, trimethoprim/sulfamethoxazole and rifampicin passively diffuse the membrane. In contrast, fosfomycin is transported actively into the cell. In normal PMN, it reaches cellular-to-extracellular ratios of 1.83 after 15 min, in CGD-PMN 2.18 after 30 min. At concentrations between 16 and 200 mg/liter, fosfomycin was able to kill staphylococci surviving within CGD-PMN, thus compensating for the bactericidal deficiency in CGD. A combination of low concentrations of fosfomycin (8 mg/liter) plus rifampicin (0.06 mg/liter) was more effective at the intracellular level than either agent alone. Apart from a stimulation of PMN-chemiluminescence of yet unknown significance, the agent did not interfere with other neutrophil functions. Clinical investigations are indicated to study whether fosfomycin can be added to the small number of antibiotics useful in CGD.

Adolescent↗
PubMed1985

[Progressive-septic granulomatosis: improved prognosis with early diagnosis and targeted therapy. Report of 5 cases].

The clinical and laboratory findings in chronic granulomatous disease are illustrated by five case reports. Biochemical studies of the neutrophil bactericidal defect have revealed several molecular forms of the disease. Specific therapeutic action is nowadays possible, after early diagnosis of the condition by nitroblue-tetrazolium test and chemiluminescence. Infections are treated using antibiotics and antimycotics which penetrate well into granulocytes; additional surgical intervention or granulocyte transfusion may be necessary. Prolonged infection-free periods are achieved under prophylactic sulfamethoxazole/trimethoprim therapy, promising an improved prognostic outlook for patients with chronic granulomatous disease.

Adult↗
PubMed1984

Correlation between serum antibody-levels against group B streptococci and gestational age in newborns.

Sera from 33 newborn infants with gestational ages ranging from 27 to 41 weeks were tested by radioimmunoassay for IgG antibodies to surface antigens of group B streptococci (GBS) types Ia, Ib, II and III. Antibody levels to GBS antigens were positively correlated to gestational age and birthweight. However, only the correlations for anti-Ia and anti-II antibody levels reached statistical significance. Mean antibody concentrations in infants below 34 weeks of gestation were significantly lower for type Ia (P less than 0.001), type II (P less than 0.001) and type III (P = 0.05) than in infants above this limit. These findings might explain the higher rate of serious GBS-infections found among prematures as compared to full-term infants.

Antibodies, Bacterial↗
PubMed1984

Intravenous administration of human IgG to newborn infants: changes in serum antibody levels to group B streptococci.

A human IgG preparation was given intravenously to 36 newborn infants admitted to the neonatal intensive care unit because of suspected septicaemia. IgG was given as a single dose of 0.4 g/kg body weight. Patient serum was obtained immediately before and 30 min after terminating the infusion. Blood was also withdrawn 2 days after giving the IgG in eight of the infants. The sera were tested by radioimmunoassay for IgG antibody levels to surface antigens of group B streptococci (GBS) types Ia, Ib, II and III and to R-protein. The mean increases in anti-type Ia, Ib, II, III and R-protein antibodies 30 min after the end of infusion were 81%, 73%, 49%, 60% and 69% of the preinfusion levels, respectively. This was followed by a rapid decrease during the following 2 days to 25%-32% of the initial increases. Based on the above findings, a controlled trial of passive immunisation in the management of neonatal GBS septicaemia seems justified. The rapid decline in antibody levels would necessitate a second infusion 24 h after the initial immunoglobulin administration if the suspicion of septicaemia persists.

Antibodies, Bacterial↗
PubMed1984

Oral chloramphenicol therapy for multiple liver abscesses in hyperimmunoglobulinemia E syndrome.

In a patient with Hyper-IgE-syndrome multiple liver abscesses developed in spite of prophylactic treatment with trimethoprim and sulfamethoxazol. Ultrasound confirmed the clinical diagnosis and percutaneous needle aspiration under ultrasonographic guidance and culture of the aspirated pus allowed specific antibiotic treatment by oral chloramphenicol alone without surgical drainage. The isolated Staph.aureus strain was resistant to trimethoprim and sulfamethoxazol.

Candidiasis↗