Serum immunoglobulin levels in various forms of meningococcal infection and in meningococcus carriers.

The levels of serum IgG, IgA and IgM were examined in 191 adults including 103 patients with various forms of meningococcal infection, 32 meningitis convalescents and 56 carriers, in order to elucidate the causes of different susceptibility to the meningococcal infection. The IgD level was determined in 54 meningitis patients as well as in convalescents and carriers. The amount of immunoglobulins was determined by radial immunodiffusion. The level of IgG at the beginning of the disease in patients with the generalized forms of meningococcal infection (meningitis, meningitis combined with meningococcaemia, meningococcaemia) was found to be considerably lower than in healthy subjects. The levels of all immunoglobulins, particularly of IgA and IgM, increased in the course of the disease. The levels of IgG, IgA and IgM in meningitis convalescents a year after recovery were found to be the same as in the controls. The levels of IgG, IgA and IgM in patients with meningococcal nasopharyngitis were significantly lower than in healthy subjects. The carriers showed a decreasd level of IgA and a considerably increased level of IgG while the levels of IgM and IgD did not differ from the control.