1/6. vaccination responses to capsular polysaccharides of neisseria meningitidis and haemophilus influenzae type b in two C2-deficient sisters: alternative pathway-mediated bacterial killing and evidence for a novel type of blocking IgG.meningitis caused by neisseria meningitidis serogroup W-135 was diagnosed in a 14-year-old girl with a history of neonatal septicemia and meningitis caused by group B streptococci type III. C2 deficiency type I was found in the patient and her healthy sister. Both sisters were vaccinated with tetravalent meningococcal vaccine and a conjugate haemophilus influenzae type b vaccine. Three main points emerged from the analysis. First, vaccination resulted in serum bactericidal responses demonstrating anticapsular antibody-mediated recruitment of the alternative pathway. Second, addition of C2 to prevaccination sera produced bactericidal activity in the absence of anticapsular antibodies, which suggested that the bactericidal action of antibodies to subcapsular antigens detected in the sera might strictly depend on the classical pathway. A third point concerned a previously unrecognized type of blocking activity. Thus, postvaccination sera of the healthy sister contained IgG that inhibited killing of serogroup W-135 in C2-deficient serum, and the deposition of C3 on enzyme-linked immunosorbent assay plates coated with purified W-135 polysaccharide. Our findings suggested blocking to be serogroup-specific and dependent on early classical pathway components. Retained opsonic activity probably supported post-vaccination immunity despite blocking of the bactericidal activity. The demonstration of functional vaccination responses with recruitment of alternative pathway-mediated defense should encourage further trial of capsular vaccines in classical pathway deficiency states.- - - - - - - - - - ranking = 1keywords = antigen (Clic here for more details about this article) |
2/6. meningitis and septicaemia in a child caused by non-typable Haemophilus influenzae biotype III.Since vaccination against haemophilus influenzae type b (Hib) became widespread, other strains of H. influenzae have become more common than Hib as causes of disease in vaccinated children. A four-month-old, appropriately vaccinated infant presented with meningitis and septicaemia caused by H. influenzae biotype III. To our knowledge, this is the first reported case of meningitis caused by this biotype, which is not detectable by Hib antigen tests.- - - - - - - - - - ranking = 1keywords = antigen (Clic here for more details about this article) |
3/6. Intrafamily spread of Haemophilus type b infections.meningitis and epiglottitis are the clinical manifestations of severe Haemophilus influenzae serotype b infection. Compared with meningitis, epiglottitis occurs in older children. When secondary cases occur within the family, the type of clinical manifestation produced by this serotype is generally similar in siblings. This report concerns the unusual occurrence of meningitis developing in older child and epiglottitis developing in the younger one. We discuss the possible explanations for this unusual pattern. We also survey the spread of H influenzae both within and outside the family unit and review the present status of histocompatibility antigens and Haemophilus disease.- - - - - - - - - - ranking = 1keywords = antigen (Clic here for more details about this article) |
4/6. Secondary cases of invasive disease caused by spread of haemophilus influenzae type b.Three 6-year-old girls were admitted to hospital within a period of 9 days because of invasive disease caused by haemophilus influenzae type b (Hib). Two days after the index case contracted bacterial meningitis, her twin sister developed septicemia. Nine days after onset of illness in the index case, a day-care contact developed a febrile illness. The antibiograms of the bacterial strains isolated from cerebrospinal fluid or blood in the first two cases were identical; in the third case, blood cultures were negative but Hib antigen could be detected in serum and in urine. These cases illustrate the contagiousness of Hib disease. All household contacts of a case should be informed about the risk and their protection with rifampicin considered.- - - - - - - - - - ranking = 1keywords = antigen (Clic here for more details about this article) |
5/6. C2 deficiency, moderately low IgG2 concentrations and lack of the G2m(23) allotype marker in a child with repeated bacterial infections.C2 deficiency was demonstrated in an 11-year-old boy with a past history of recurrent purulent otitis media, pneumonia, H. influenzae meningitis and S. pneumoniae septicaemia. The major histocompatibility complex haplotypes present, A10, B18, DR2, BF*S, C2*QO, C4*A4, C4*B2 and A28, B18, DR2, BF*S, C2*Q0, C4*A4, C4*B2, were in accord with previous observations in C2 deficiency. The concentrations of C1q, C5, factor B and factor D were in the low normal range and the hemolytic activity of the alternative pathway was slightly decreased. In addition, the patient showed moderately low IgG2 concentrations and lacked the IgG2 subclass marker G2m(23). The findings indicate that the patient's susceptibility to bacterial infections may be due to C2 deficiency in combination with the presence of an IgG allotype associated with impaired antibody responses to carbohydrate antigens.- - - - - - - - - - ranking = 1keywords = antigen (Clic here for more details about this article) |
6/6. meningitis due to enterotoxigenic bacteroides fragilis.An enterotoxigenic strain of bacteroides fragilis was the sole organism isolated from the cerebrospinal fluid of a two-and-a-half-month neonate who had a medullary-colonic fistula as part of a complex congenital malformation, but no brain abscess. A rapid latex particle agglutination test for detection of bacterial antigen was positive for haemophilus influenzae type b, suggesting that bacteroides fragilis and haemophilus influenzae type b might share some capsular antigens. In order to determine the role of the enterotoxin with respect to virulence of the strain, antibodies to a 20 kDa protein were sought in the patient's serum, but Western blot of the culture supernatant revealed only antibodies to a 45 kDa bacterial protein. The patient was successfully treated with metronidazole and imipenem.- - - - - - - - - - ranking = 2keywords = antigen (Clic here for more details about this article) |