[Determination of IgM antibodies by complement-fixation after serum fractionation by sucrose density gradient in children and adults with evidence of Mycoplasma pneumoniae infection (author's transl)].

Sera from 45 patients with serologic evidence of Mycoplasma pneumoniae infection were fractionated by sucrose gradient centrifugation. The distribution of complement-fixing (CF) antibodies for Mycoplasma pneumoniae within the 19S and the 7S immunoglobulins was determined all patients below 20 years of age and 44% of older patients had 19S specific antibodies. A predominance of 19S relative to 7S CF antibodies was observed in 40% of cases below 20 years and in 18% of cases above 20 years. The meaning of these data is discussed.