Inflammatory and immunological markers in preterm infants: correlation with disease.

Newborn infants often suffer from bacterial and viral infections without presenting typical symptoms. Therefore, reliable methods for detecting and monitoring sepsis in the newborn would be beneficial. In older patients C-reactive protein (CRP) and neopterin have proved useful serum markers of infection and inflammation. Both of these markers are regulated by cytokines, and it has been proposed that cytokines themselves could be used to monitor immune activation and infection. This study has examined the levels of CRP, neopterin, soluble IL-2R, tumour necrosis factor-alpha (TNF-alpha) and interferon-gamma (IFN-gamma) in cord blood samples from both premature and term neonates. Having established reference ranges for these analytes, serial measurements were made in babies requiring intensive care support. The results suggest that in preterm infants the simultaneous measurement of CRP and neopterin, and possibly soluble IL-2R, may provide an accurate early diagnosis of sepsis and may be of use in differentiating between bacterial and viral etiologies. In addition, serial measurement of these markers may help in the early diagnosis of necrotizing enterocolitis (NEC).

Class- and subclass-specific pneumococcal antibody levels and response to immunization after bone marrow transplantation.

Immunoglobulin class- and subclass-specific antibodies to a polyvalent pneumococcal capsular polysaccharide vaccine (Pneumovax II) were measured before and after immunization in children, 1 year or more after bone marrow transplantation for a variety of genetic disorders. The median titres of specific IgG, IgG1 and IgG2 pneumococcal antibodies fell significantly (P less than 0.05) from pre-transplantation levels. The levels of pneumococcal antibodies in the patients before immunization were markedly lower than those in control children of comparable age, for antibodies of IgM, IgG, IgG1 and IgG2 classes (P = less than 0.001 in each case). Apart from IgG2 antibodies, the median response to immunization with Pneumovax II was not significantly different from the controls (P greater than 0.05). However, because of the lower pre-immunization levels, the patients did not achieve a high post-immunization-specific antibody titre in any immunoglobulin class or subclass, when compared with normal children. Neither the pre-immunization specific antibody levels nor the response to immunization were affected by splenectomy or the presence of chronic graft-versus-host disease. Immunization of the donor before bone marrow harvest did not influence the level of specific antibody 1 year or more after transplantation. No significant correlation was found between the total serum IgG2, the patients' age at the time of assessment, or time after transplantation, and the IgG2-specific antibody response. The lack of specific antibodies and the poor IgG2 response to pneumococcal antigens may contribute towards the occurrence of infection with Streptococcus pneumoniae in the late post-transplantation period.