Chlamydia trachomatis and parainfluenza 2 virus: a shared antigenic determinant?

A tracheal aspirate from which parainfluenza 2 (PI-2) virus but not chlamydiae was isolated demonstrated positive immunofluorescence of elementary body- and reticulate body-like particles on direct examination with anti-chlamydia monoclonal antibodies (Syva Co.). In subsequent studies, we found this reagent to show specific staining of this strain of PI-2 as well as of 3 of 18 additional PI-2 strains that were evaluated.

Pulmonary assessment of children after chlamydial pneumonia of infancy.

We evaluated the pulmonary status of 18 children 7 to 8 years after their hospitalization for chlamydial pneumonia of infancy. Pulmonary function tests (PFTs) and respiratory questionnaire results in this group were compared with those in a control group of 19 comparable children from the same community, and with values that other investigators have reported for normal children. Significant limitations of expiratory airflow were found (FEV1, FEV1/FVC, PEF, and FEF 25%-75%), as well as signs of abnormally elevated volumes of trapped air (FRC and RV/TLC ratios). These obstructive patterns were responsive to inhalation of isoproterenol. Moreover, a significantly greater number of patients had physician-diagnosed asthma than in the control group. The obstructive PFT abnormalities could not be accounted for by recognized risk factors, such as exposure to smoking at home or family history of atopy. Our results show that chlamydial pneumonia of infancy is associated with PFT abnormalities and respiratory symptoms 7 to 8 years after recovery from the acute illness.

Epidemic measles in Chicago in 1983. Sustained transmission in the preschool population.

We evaluated epidemiologic features of 54 patients with measles seen at Wyler Children's Hospital during a 1983 measles epidemic in Chicago. Forty-one (76%) were less than 5 years old, and 23 (43%) were less than 16 months old. We found evidence of a low rate of measles immunity in preschool-aged children of immunization age immediately before the epidemic; only 62% of 173 emergency room patients this age had antibody on enzyme-linked immunosorbent assay. These observations, together with failure of school-based control measures to significantly affect the observed course of the epidemic, indicate that the preschool population sustained the epidemic. Unimmunized preschool-aged children are important in the current epidemiology of measles, and improved immunization strategies are needed to control measles in this population in Chicago and perhaps other cities.

Salmonella enteritidis bacteremia in childhood.

We have reviewed the clinical course of 32 children with Salmonella enteritidis bacteremia and compared them with 135 children with acute gastroenteritis caused by S. enteritidis at Wyler Children's Hospital over 4.5 years. Analysis of symptoms of infection, the initial laboratory evaluation, the initial impression of the severity of illness, the clinical course, and the eventual outcome showed no differences between children with bacteremia and those with acute gastroenteritis, nor did a comparison between older children (one year of age or older) and younger children, with either bacteremia or acute gastroenteritis, show appreciable differences. We conclude that bacteremia occurring with acute gastroenteritis was clinically elusive and more common than previously recognized. Furthermore, in the absence of documented risk factors, bacteremia occurring with acute gastroenteritis was not associated with any greater morbidity than was acute gastroenteritis occurring alone.

Lymphocyte anergy specific to Toxoplasma gondii antigens in a baby with congenital toxoplasmosis.

A baby's clinical course during her first year of life documented her congenital infection with Toxoplasma gondii. Certain of her peripheral blood lymphocyte subtype numbers and functions were studied at intervals during this year: This patient's lymphocytes did not respond to Toxoplasma gondii antigens when she was 2 or 6 months old but did respond when she was 1 year old. Her lymphocyte anergy appeared to be a specific impairment or delay in lymphocyte blastogenic response to T. gondii antigens as her peripheral blood lymphocytes responded normally to the T-cell mitogen Concanavalin A and to allogeneic lymphocytes in mixed lymphocyte cultures. She had normal numbers of total peripheral blood lymphocytes and normal proportions of peripheral blood T cells with T4 and T8 surface antigens.

Chlamydial colonization of the cervix in pregnant adolescents.

We studied the incidence of Chlamydia trachomatis colonization of the cervix in pregnant adolescents and analyzed the effect of such colonization on pre-, intra-and postpartum events. A significant increase in post-vaginal-delivery endometritis as well as an increase in other sexually transmitted diseases occurred in patients colonized by C. trachomatis.

Excessive numbers and activity of peripheral blood B cells in infants with Chlamydia trachomatis pneumonia.

The peripheral blood lymphocytes of seven infants who had lower respiratory infections caused by Chlamydia trachomatis (chlamydial pneumonia) were studied for abnormalities that may be related to the hyperimmunoglobulinemia characteristic of this infection. Both proportions and numbers of B cells and plasma cells were strikingly elevated in these infants, as indicted by the percentage of peripheral blood mononuclear cells (PBMC) that reacted with fluorochrome-labeled antibodies to human immunoglobulins. Cells expressing IgM and IgD on their surface, and cells possessing IgM and IgG in their cytoplasm were especially increased above levels found in normal adults, infants, and a group of infants with other infections. Cells from infected infants secreted exceptionally large amounts of IgM, IgG, and IgA when cultured in the absence of added mitogens. These data suggest that chlamydial pneumonia induces substantial B-cell activation during a period of development when antibody responses are normally difficult to stimulate.

Defective interfering particles of respiratory syncytial virus.

A multiplicity-dependent interference was observed in respiratory syncytial virus preparations (Randall strain) grown in HEp-2 cells, and the factor mediating this interference was characterized. Cloned virus did not demonstrate this multiplicity-dependent interference, but its replication was shown to be inhibited by the interfering factor by assays of reduction of infectious yield assay, the interferon factor was found to be particulate, to be inactivated by UV irradiation, and not to interfere with the replication of a heterologous virus, vesicular stomatitis virus. These characteristics are compatible with the physical properties and biological behavior of defective interfering particles. Defective interfering particles were generated by four undiluted passages of cloned virus but were not apparent after eight passages at a multiplicity of infection of 0.1.

Chlamydia pneumonia in infants: radiography in 125 cases.

Chlamydia trachomatis was recently discovered to be the causative organism in a distinctive afebrile pneumonia occurring in infants under 6 months of age. Experience with the first 125 cases seen at this hospital during a 3 1/2 year period is reported. Chest radiographs were reviewed of 2,273 infants in this age group with signs of lower respiratory tract infection. The first group comprised 148 patients admitted to the hospital. Chlamydia pneumonia was diagnosed in 41 cases. The second group of 2,125 infants was first seen in the outpatient department where 84 additional cases were detected. From this experience it was concluded that, although there are no radiographic findings specific for Chlamydia pneumonia, a combination of the clinical and radiographic findings strongly suggests the diagnosis before cultures and serum antibody titers are available. Important clinical features include age of onset at 2-14 weeks of age, cough, lack of fever, and elevated serum immunoglobulins. Most chest films show bilateral hyperexpansion and diffuse infiltrates with a variety of radiographic patterns including interstitial, reticular nodular, atelectasis, coalescence, and bronchopneumonia. Pleural effusion and lobar consolidation are not seen. The radiographic changes often suggest a more serious illness than that observed clinically. Radiographic features are described in detail.

Clinical characteristics of the afebrile pneumonia associated with Chlamydia trachomatis infection in infants less than 6 months of age.

Respiratory tract colonization with Chlamydia trachomatis commonly occurs in natally acquired chlamydial infection and is sometimes associated with a chronic, afebrile pneumonia that has relatively distinctive clinical characteristics. To further define the frequency and clinical characteristics of lower respiratory tract disease associated with C trachomatis, we grouped 56 infants aged less than 6 months with afebrile pneumonia according to nasopharyngeal shedding of Chlamydia and viruses and compared their illnesses. Forty-one (73%) were positive for C trachomatis (23 had C trachomatis only, while 18 had C trachomatis plus a virus [cytomegalovirus, respiratory synctial virus, adenovirus, rhinovirus, or enterovirus]), and 15 were C trachomatis negative (nine had a virus only, and six had neither C trachomatis nor virus). The 41 infants with C trachomatis alone or C trachomatis plus a virus were similar clinically and differed significantly from other infants in several ways: (1) onset of symptoms before 8 weeks of age; (2) gradually worsening symptoms; (3) presentation for care at 4 to 11 weeks of age; (4) presence of conjunctivitis and ear abnormalities; (5) chest roentgenograms showing bilateral, symmetrical, interstitial infiltrates and hyperexpansion; (6) peripheral blood eosinophils greater than or equal to 300/cu mm; and (7) elevated values for serum immunoglobulins M, G, and A. Pediatrics 63:192--197, 1979, Chlamydia trachomatis, pneumonia, afebrile pneumonia, interstitial pneumonia.

Treatment of chlamydial pneumonia of infancy.

Infants with untreated chlamydial pneumonia shed Chlamydia trachomatis and are symptomatic for may weeks. We used sulfisoxazole, 150 mg/kg/day, or erythromycin ethyl succinate, 40 mg/kg/day, for approximately 14 days to treat 32 patients with chlamydial pneumonia of infancy, and observed them for nasopharyngeal shedding of C trachomatis and changing clinical status. All infants stopped shedding chlamydiae soon after treatment was started. After treatment, three of the 25 infants tested again became culture positive (but did not have clinical relapse). All infants improved clinically. In 24 (83%) of 29 infants, where the onset of improvement could be times, improvement began within seven days of starting treatment. Progression to complete recovery was observed in 27 of 28 infants examined between two weeks and two months of treatment completion. Neither the existence of concomitant viral infection nor the duration of illness or hospitalization before starting treatment influenced the interval between initiation of treatment and onset of clinical improvement. While these observations do not prove, they are at least compatible with the hypotheses that C trachomatis plays a central etiologic role in this illness and that termination of chlamydial infection is beneficial clinically. Pending the availibility of data from controlled studies, we believe that either of the treatment programs outlined warrant consideration in the clinical management of patients with chlamydial pneumonia of infancy.

Respiratory-tract colonization and a distinctive pneumonia syndrome in infants infected with Chlamydia trachomatis.

To learn if Chlamydia trachomatis causes in young infants a distinctive penumonia characterized by chronic, afebrile course, diffuse lung involvement and elevated serum immunoglobulins G and M, 47 black infants four to 24 weeks of age were examined for nasopharyngeal shedding of C. trachomatis and serum immunofluorescent antibody to lymphogranuloma venereum Type I. Nasopharyngeal C. trachomatis was found in 18 of 20 with the pneumonia syndrome, two of 15 with various other illnesses and 10 of 12 with inclusion conjunctivitis but without lower respiratory illness. Chlamydial antibody titers of infants with the pneumonia syndrome were significantly elevated (geometric mean-1, pneumonia vs. conjunctivitis = 24,833 vs. 1024 P less than 0.001). No other commonly recognized respiratory pathogens were consistently associated with the pneumonia syndrome. We believe these findings demonstrate an association between the distinctive pneumonia syndrome and C. trachomatis. This, in turn, is a particular facet of a more general event consisting of frequent colonization of the respiratory tract by C. trachomatis in natally acquired infection.