Specific IgA antibodies in Mycoplasma pneumoniae infections

Mycoplasma pneumoniae is the prevalent cause of community acquired pneumonia (CAP), especially in pediatric age. M. pneumoniae infection may presents a severe pulmonary disease whose clinical picture is undistinguishable from that of other pneumotropic agents.A rapid and suitable laboratory diagnosis mainly lies on serological test investigations. A total of 37 consecutive CAP pediatric and adult patients, and 102 subjets with suspected respiratory tract infections (SIR) were enrolled and examined for specific IgA-, IgG-, IgM anti-M. pneumoniae antibodies using a rapid ELISA test (Mycoplasma Chorus-Diesse), and a two step ELISA test (MYP test-Savyon). Agreement of IgA, IgG, and IgM values were 96%, 64%, 100%, respectively. Among CAP patients, IgM was the prevalent marker (23/37); in this population, 12/23 pediatric patients were both IgM and IgA positives. Conversely, among adults, IgA antibodies were the most prevalent infection marker. Pediatric patients of both CAP and SIR population showed a similar serological picture; instead, all adult patients resulted as IgM negatives; IgA and IgG antibodies showed high positive values in 4/8, and in four old patients IgA was the alone infection marker. Although specific IgM antibodies detection remains the main serological sign of recent infection in pediatric age, the presence of IgA antibodies is a suitable tool to revealing the etiology of clinical picture in both pediatric and adult patients.