Chlamydia pneumoniae antibody titers in asthmatic children; relation to asthma severity and the dose of inhaled steroids used for control

ABSTRACT

Accumulating evidence suggests that Chlamydia pneumoniae [C. pneumoniae], an intracellular ubiquitous pathogen with an innate propensity to persist and cause chronic infections, may be associated chronic inflammation in asthma. As inflammation has been found to be present in almost all asthmatics, inhaled steroids now, have an established position in the treatment of persistent asthma. However, corticosteroids negatively affect many aspects of cell-mediated immunity and deteriorate the host's ability to eradicate an intracellular pathogen, such as C. pneumoniae. The aim of this work was to investigate the relationship between C. pneumoniae infection and asthma severity as well as the doses of inhaled steroids used for asthma control. An enzyme immunoassay was used to measure the immunoglobulin [Ig] G and IgA antibodies against C. pneumoniae in a study group consisting of 100 asthmatic children with different grades of asthma severity on regular prophylactic inhaled steroids, and 50 non-asthmatic age and sex matched healthy controls. Statistical analysis of the results showed [A]- No significant difference in the mean IgG [t=0.923, P=0.358], and IgA [t=1.233, P=0.22] antibody titers between asthmatic and non-asthmatic children. [B]- In asthmatic children, we found the following [1]- The mean IgG and IgA antibody levels were significantly higher in patients with severe asthma than in patients with mild and moderate asthma [IgG F=197.4, P<0.01and IgA F= 4.67, P<0.05]. [2]- A significant positive correlation between C. pneumoniae IgG and lgA antibody titers and asthma severity [IgG r=0.901, P<0.01; IgA r=0.847, P<0.01], and the frequency of exacerbations [IgG r=0.866, p<0.01; IgA r=0.859, P<0.01]. [3]- A significant negative correlation between the IgG and IgA antibody titers and peak expiratory flow rate [IgG r=0.641, P<0.01 and IgA r=0.859, p<0.01]. [4]- A significant positive correlation between the IgG and IgA antibody levels and the mean dose of inhaled steroids used for control [IgG r=0.861, P<0.01 and IgA r=0.806, P<0.01]