Antibodies to MYCOPLASMA PNEUMONIAE in serum
Serological diagnosis is based on the detection of titer AT to Mycoplasma pneumoniae in serum. The most widely used method was ELISA.
With the use of ELISA, it is possible to determine the AT classes of IgA, IgM and IgG.This method is more sensitive and specific( 92% and 95% respectively) than others. The titers of Ig IgM and IgG should be determined in the acute period of the disease and after 2-4 weeks. IgM antibodies appear during the first week of the disease and disappear after recovery, but in some cases can persist in the blood up to 1 year. The titer of AT IgG begins to increase somewhat later than IgM, but it remains elevated longer. The IgM titer above 1:10 or 4-fold increase in levels of IgA and / or IgG-AT in paired sera indicates an ongoing infection. Considering the fact that IgM antibodies relatively quickly disappear from the blood, in some cases it is sufficient to detect them in a single sample of serum for the diagnosis of acute infection. The titer of IgA-AT in elderly patients increases more significantly than that of IgM, which must be taken into account in the diagnosis of infection. Upon recovery, IgM antibodies can not be detected in serum, and IgA and IgG-AT content is significantly reduced. Reinfection is accompanied by a rapid rise in the titer of IgA and / or IgG-AT.The time of 4-fold increase in the titer of antimycoplasmic antibodies during sequential examination of blood samples taken in the acute period of the disease and during the convalescence period is 3-8 weeks. The frequency of detection of IgM Ig to Mycoplasma pneumoniae, depending on the day of the disease, is presented in Fig.
Specific Ig IgMs to Mycoplasma pneumoniae are found in 80% of patients on the 9th day after the onset of the first symptoms of the disease.
Fig. The frequency of detection of IgM Ig to Mycoplasma pneumoniae.
Fig. The frequency of detection of IgM Ig to Mycoplasma pneumoniae.
On the 7th-8th day, IgM antibodies are detected in 88% of patients under the age of 20 and in 40% of older patients. In patients with mycoplasma infection over 60 years of age, the titer of Ig IgM may not increase.
Simultaneous detection of IgM and IgG allows detection of up to 99% of all mycoplasma infections( primary and reinfection), and the study of only IgM Ig is 78% of primary diseases.
Definition of AT to Mycoplasma pneumoniae is used for the diagnosis of mycoplasmal infection in chronic inflammatory diseases of the lungs, secondary immunodeficiency states.