Respiratory infections due to Mycoplasma pneumoniae in infants and children
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Abstract:
Systematic monitoring of infants and children in a day-care center revealed infection with Mycoplasma pneumoniae to be more common than expected. Most of these infections were asymptomatic (74%) or associated with mild, nonspecific coryza and cough. Infected children ranged in age from 2 months to 8 years. Complement-fixing and growth-inhibiting antibodies in serum tended to wane rapidly and reinfection was detected in five children after one and one-half to 3 years. In vitro lymphocyte studies revealed antigen-reactive cells were detectable in few of the children under age 4, but thereafter lymphocyte reactivity was found in 53%. These findings suggest that recurrent, unsuspected M. pneumoniae infections occur during infancy and early childhood and that pneumonic disease, common above age 10 years, is an expression of increasing host immune response to the organism.
Insights
Mycoplasma pneumoniae infections are common in young children, often causing mild symptoms or no symptoms at all. Recurrent infections suggest a developing immune response in children.
Area of Science:
- Pediatrics
- Infectious Diseases
- Immunology
Background:
- Mycoplasma pneumoniae is a common respiratory pathogen.
- Infections in young children are often underdiagnosed due to mild or absent symptoms.
Purpose of the Study:
- To investigate the prevalence and characteristics of Mycoplasma pneumoniae infections in a day-care setting.
- To understand the host immune response to recurrent infections in children.
Main Methods:
- Systematic monitoring of children in a day-care center.
- Serological testing for antibodies (complement-fixing and growth-inhibiting).
- In vitro lymphocyte proliferation assays to assess cellular immune response.
Main Results:
- Mycoplasma pneumoniae infection was more common than anticipated.
- 74% of infections were asymptomatic or mild (coryza, cough).
- Antibody levels waned rapidly, and reinfection occurred within 1.5–3 years.
- Lymphocyte reactivity to M. pneumoniae antigens increased with age, detected in 53% of children over 4 years old.
Conclusions:
- Recurrent, often unsuspected, Mycoplasma pneumoniae infections are prevalent in infancy and early childhood.
- Pneumonic disease, more common in older children, may reflect a maturing host immune response to the organism.