Children with severe bacterial infections may benefit from routine immunologic testing following recovery, as early identification of immune abnormalities may inform preventive measures against reinfection. These study findings were published in The Journal of Infectious Diseases.
Children with severe bacterial infections often have underlying comorbidities, anatomical abnormalities, and risk factors associated with compromised immune function. As there remains a paucity of data guiding patient management in this area, a study was designed to assess the role of routine immunologic testing among otherwise healthy children recovering from severe bacterial infection.
Investigators at the University Children’s Hospital in Zurich, Switzerland conducted this retrospective, single-center, cohort study. Patients (N=360) with bacterial pleuropneumonia, meningitis, and/or sepsis were observed between 2013 and 2020. Immunologic data were collected during follow-up visits, including neutrophil count and function, complement activity, and total immunoglobulin (Ig) concentrations. Antibody testing, pocked erythrocyte assessments, and lymphocyte phenotyping via flow cytometry were also performed.
Among patients included in the analysis, the median age was 3.37 (range, 0-15.9) years, 57% were boys, 57% had pleuropneumonia, and 42% were infected with unknown pathogens. Overall, follow-up data were available for 265 patients (74%).
For patients infected with Neisseria meningitidis (n=16) and Haemophilus influenzae (n=14), meningococcal serogroup B (50%) and type b (Hib; 50%) were the most commonly detected of all group isolates. For patients infected with S pneumoniae (n=87), PCV13 serotypes were the most commonly detected (31%).
During the follow-up period, 92% of children completed immunologic testing, of whom 78% had no abnormalities detected. There were 37 patients with immune abnormalities of unclear clinical relevance, including those with mild humoral abnormalities (11%) or unclear abnormalities in the innate immune system (4%).
Stratified by infection, patients with sepsis, septic meningitis, and those younger than 1 year were more likely to have abnormalities suggestive of impaired immune function.
Of note, autoimmune neutropenia following S pneumoniae sepsis was detected in 1 patient.
Among 3 (1%) patients who died, postmortem laboratory findings identified low IgG and/or IgM concentrations or decreases in all lymphocyte subpopulations. However, these findings were not considered significant due to unclear clinical relevance.
Limitations of this study include the retrospective design and the lack of standardized immunologic testing.
According to the investigators, “The recognition of even minor immunological abnormalities can be important, and we there suggest routinely performing inmmunological investigations in children after recovery…”
Strasser S, Relly C, Berger C, Trück J. Structured immune work-up in healthy children with a first episode of severe bacterial infection: a 7-year single-center study. J Infect Dis. Published online April 11, 2023. doi:10.1093/infdis/jiad098