Neonatal IgM response to acute infection

Use of polymerase chain reaction and rabbit infectivity testing to detect Treponema pallidum in amniotic fluid, fetal and neonatal sera, and cerebrospinal fluid

The diagnosis of congenital syphilis continues to pose a difficult clinical challenge. Because the serodiagnosis of congenital syphilis has significant limitations, the direct detection of Treponema pallidum in suspect neonatal tissues or body fluids represents a desirable alternate diagnostic strategy. We developed and applied the polymerase chain reaction (PCR) for the detection of T. pallidum in clinical material relevant to the diagnosis of congenital syphilis but which typically contain factors inhibitory for the PCR. Four methods of specimen processing were examined to circumvent PCR inhibition; clinical materials included amniotic fluids, neonatal sera, and neonatal cerebrospinal fluids. The PCR was 100% specific for T. T. pallidum compared with the sensitive rabbit infectivity test (RIT) for all clinical materials tested. For amniotic fluids, the PCR was 100% sensitive when correlated with the RIT but had a lesser sensitivity when applied to sera or cerebrospinal fluids, which typically contain few treponemes. The combined sensitivity of the PCR for all clinical samples was 78%. Positive PCR results also were obtained among some clinical specimens for which RIT was not performed; these results correlated well with either stigmata or risk factors for congenital syphilis. The combined results suggest that the PCR can be a useful adjunct to the diagnosis and clinical management of congenital syphilis and that it will provide a valuable tool for investigations of the pathogenesis of the disorder.

Polymorphonuclear elastase in neonatal sepsis

Quantitative analysis of polymorphonuclear elastase was carried out in 135 newborn infants during the first 28 days of life. In 15 neonates with septicaemia, significantly increased PMN-elastase activity (range 75 to 700 micrograms/l: P less than 0.0001) was observed at the time of recognition of infection. Cut-off level 65 micrograms/l. Normalisation of the elastase activities was observed only under real recovery of the patients. It is concluded that plasma elastase determination serves as a sensitive indicator of systemic infection in neonatology, and as a good parameter for monitoring the course of the disease, because PMN-elastase correlates with the clinical condition of the patient.

Immunoglobulin A and M levels in premature infants with gastroenteritis

Eleven premature babies with an infection of the gastrointestinal tract were followed from birth up to the first month of life in an attempt to correlate the effect of acute localized infections of the gut to IgA and IgM immunoglobulin synthesis. The results were compared to those of 17 prematures comparable in birthweight and gestational age with no clinical or bacteriological evidence of an intestinal infection. There was a significant increase of serum IgA and a slight but not significant increase of IgM level in infected babies as compared to the healthy group of prematures. It is suggested that micro-organisms causing localized infections of the gastrointestinal tract stimulate immunoglobulin A producing sites of the intestinal wall. This results in rapid production of secretory antibody. In the course of this localized infection, replication of bacteria in the lymphoid tissue of the intestinal wall stimulate immunologically competent cells in direct proximity to the alimentary tract, causing increased serum IgA levels.

Diagnostic virology

A review of the indications for viral diagnostic procedures has been presented. Specific diagnosis is unnecessary and impractical in every patient with a suspected viral illness. In certain instances, however, the documentation of a viral disease by culture or serology may be of great value to the patient. The pediatrician must therefore use his judgment as to when to study the patient, and should resist the temptation simply to tell an anxious parent, "Don't worry; it's just a virus".