Penelope G. Shackelford

Nitroblue tetrazolium dye test as an aid in thedifferential diagnosis of febrile disorders

Nitroblue tetrazolium (NBT) dye tests were performed upon blood obtained at time of admission or during the course of hospitalization from 247 febrile patients and 20 afebrile individuals. Detailed clinical and laboratory diagnostic evaluation permitted subsequent placement of 181 of the febrile patients into 8 specific groups. Knowledge of only percentage and absolute number of NBT-positive cells permitted reclassification into 4 groups as follows: (1) normal subjects, (2) individuals with viral infection, noninfectious fevers, or partially treated bacterial infection, (3) untreated bacterial infection, and (4) bacterial infection unresponsive to therapy provided. There was generally no correlation between percentage of NBT-positive cells and either white blood cell counts or body temperature recorded at the time blood for the NBT test was obtained. Discriminant analysis was used to prepare a nomogram which permits classification of patients prospectively into one of the 4 groups, if the percentage and absolute number of NBT-positive cells are known.

Spectrum of IgG2 subclass deficiency in children with recurrent infections: prospective study

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.

Hemophilus Influenzae Type B Disease in Children Vaccinated with Type B Polysaccharide Vaccine

We studied 55 cases of invasive Hemophilus influenzae type b disease occurring in children at least three weeks after vaccination with type b polysaccharide vaccine. Their mean age at the time of immunization was 27.8 months (range, 18 to 47). Meningitis developed in 39 patients, of whom 3 died and 6 had neurologic sequelae. We investigated certain host factors that may have contributed to the failure of the vaccine. The geometric mean concentration of antibody to type b polysaccharide in convalescent-phase serum from 31 of the vaccinated patients who had hemophilus disease was significantly lower than that in serum from 25 patients of similar age with the disease who had never been vaccinated (0.59 vs. 3.46 micrograms per milliliter, P less than 0.001). However, only 3 of 46 patients in whom the vaccine failed and who were tested for hypogammaglobulinemia had this finding, and none of 33 children tested for IgG2 had low serum concentrations of this immunoglobulin subclass, which is thought to be important in the immune response to polysaccharide antigens. In addition, all but 1 of the 46 patients in whom the vaccine failed and who were tested for IgG antibody to tetanus toxoid protein, a thymic-dependent antigen, had normal values, and 19 of 20 tested for hemolytic complement activity had normal levels. In white children, the presence of the Gm immunoglobulin phenotype (1,2,3, 17; ;5,13,21) was associated with a sevenfold increase in the relative risk of vaccine failure (P less than 0.003). We conclude that vaccine failure may be related in part to genetic factors, and that most vaccinated children in whom Hemophilus influenzae disease develops have deficient antibody responses to the type b polysaccharide despite normal serum concentrations of immunoglobulin and normal antibody responses to tetanus toxoid.

Concentrations of antibodies in paired maternal and infant sera: Relationship to IgG subclass

Previous studies comparing IgG subclass concentrations in cord and maternal sera have indicated that IgG1 is transported across the placenta to a greater extent than is IgG2. The purpose of our study was to examine the relationship between the transport of IgG1 and IgG2 and the transport of specific antibodies that are relatively restricted to a particular subclass, either IgG1 or IgG2. The concentrations of total serum IgG1 and IgG2 and those of IgG-anti-tetanus toxoid (TT) and anti-group A streptococcal carbohydrate (GAC) were measured in 30 paired maternal and cord sera. Previous studies have shown that anti-TT in adults is predominantly IgG1, whereas anti-GAC is predominantly IgG2. The mean cord/maternal concentration ratios of IgG1 and anti-TT were similar (1.77 +/- 0.56 and 1.93 +/- 0.67, respectively), but differed significantly (P = 0.0001) from those of IgG2 and anti-GAC (0.99 +/- 0.39 and 1.01 +/- 0.45, respectively). We confirmed the difference in cord/maternal concentration ratios of IgG1 and IgG2 antibodies by measuring IgG1 and IgG2 antibodies specific for Haemophilus influenzae type b capsular polysaccharide; the mean cord/maternal concentration ratio of IgG1-anti-Hib PS was significantly higher than that of IgG2-anti-Hib PS (2.23 +/- 0.83 compared with 0.94 +/- 0.49, P = 0.01). These results indicate that placental transport of IgG antibodies is related to their subclass composition.

Urban measles in the vaccine era: A clinical, epidemiologic, and serologic study

A measles epidemic, during which 130 children were hospitalized and six died, occurred in St. Louis City and County during 1970 to 1971. A survey revealed an attack rate of 8.5 per cent in unvaccinated children who had not had natural measles, a rate of 1.7 per cent in children vaccinated after one year of age, but 6.3 per cent for children immunized before age one year. Measles attack rates in vaccinees were independent of time elapsed since immunization. Serum from 8 of 15 children with modified measles had no reduction in acute measles hemagglutination-inhibiting antibody titer after treatment with 2-mercaptoethanol. Twelve children had “atypical measles-rd but six of them had received only live vaccine. Ten per cent of 248 immunized children had hemagglutination-inhibiting titers of

Clinical and Immunologic Characteristics of Healthy Children with Subnormal Serum Concentrations of IgG2

ABSTRACT: To understand the relevance of subnormal serum concentrations of IgG2, we measured IgG2 in serum of 575 healthy children and identified 11 with concentrations > 2 SD less than the mean for age. The levels of IgG2 present were similar to those found in symptomatic children with IgG2 subclass deficiency associated with antibody deficiency. The 11 children ranged in age from 1 to 14 y (mean = 5.7). Detailed clinical information was available on 10 of the 11 children and each was matched for age with two controls. The median number of visits/y to the doctor for infectious illnesses was identical for the two groups (1.0). Nine of the children with subnormal IgG2 were followed for 1 to 5 y (mean = 2.3). All nine children had normal serum concentrations of IgA, IgGl, IgG3, and IgG4 but seven had persistently subnormal or low-normal serum IgG2 concentrations. One of these seven children also had a subnormal serum concentration of IgG, and one had subnormal IgM. Antibody responses to Haemophilus b polysaccharide vaccine were normal in five of six who were immunized. In vitro secretion of Ig by mitogen-stimulated peripheral blood mononuclear cells was measured in six of seven children with persistently subnormal or low-normal IgG2; five showed decreased secretion of IgG2, and two of the five also had subnormal secretion of IgGl and IgG3. An important implication of this study is that the subnormal concentrations of serum IgG2 found in infectionprone children are not a sufficient explanation for their increased susceptibility to infection. The healthy children with low serum concentrations of IgG2 differ from symptomatic children with subnormal IgG2 in that the former have otherwise normal serum Ig concentrations and have normal antibody responses to Hib PS vaccine.

A clinical and serologic study of 103 children with measles vaccine failure.

During the spring of 1971, 103 children with measles vaccine failure were studied. Seventy-six children had typical measles, 15 had mild modified measles, and 12 had an illness resembling the atypical measles syndrome; 6 of these latter 12 patients had previously received only live measles vaccine. Eighty-seven patients had serologic evidence of recent measles infection; 2-mercaptoethanol (2-ME) treatment of the acute-phase sera from these children revealed different antibody patterns by clinical category. The majority of sera from typical measles cases had ≥4-fold reduction in titer with 2-ME treatment, whereas the majority of sera from modified and atypical cases had no reduction in titer with 2-ME treatment. The acute-phase sera of 15 patients with vaccine failure were found to contain only gamma-G measles antibody when separated by sucrose gradient centrifugation. Thirteen of these sera were from children with modified or atypical illnesses. These findings suggest that some vaccine failures occur in patients who were antigenically simulated previously by measles virus and that illness in these children is likely to be less severe.

Subnormal serum concentrations of IgG2 in children with frequent infections associated with varied patterns of immunologic dysfunction

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.

Countercurrent immunoelectrophoresis in the evaluation of childhood infections.

Samples of CSF, serum, and urine from 162 children with a clinical diagnosis of possible bacterial infection were examined by CIE within 1 hr of admission to the hospital. Results obtained were compared to information derived from gram stain and bacterial cultures of these specimens. Thirty-eight of 59 patients with culturally proved bacterial infections had positive CIE determinations at the time of admission. Highest correlation between culture and CIE results was in patients with meningitis due to Hemophilus influenzae type b while poorest correlation was obtained in children with pneumococcal septicemia. PRP within serum or CSF was quantitated on 21 occasions in patients with H. influenzae meningitis. Patients who experienced sequelae of their meningitis had significantly (p less than 0.005-0.025) higher levels of PRP within CSF and serum than those whose recovery was uneventful.

Epidemiologic and bacteriologic evaluation of neonatal necrotizing enterocolitis

The incidence of necrotizing enterocolitis (NEC) in our neonatal unit has varied from 4.7% to zero to 4.4% during three time periods. Simultaneously, significant changes have occurred in the spectrum of bacterial species in the gastrointestinal tract of unaffected infants in the same unit. During the first period of increased attack rate, 82% of gastric and 88% of fecal Enterobacteriaceae were E. coli and K. pneumoniae. When the attack rate decreased the frequencies were 11% (gastric) and 47% (fecal), and P. mirabilis was retrieved with increased frequency. The return of E. coli and K. pneumoniae as the dominant organisms was associated with an increase in NEC. Infants with NEC, compared with controls, had a statistically significant increased frequency of retrieval of E. coli and K. pneumoniae from gastric and fecal samplings. The data suggest an active role for certain enteric bacteria in the pathogenesis of NEC.