Possible polyclonal B cell activation in mucocutaneous lymph node syndrome.

Immunoserological studies on polyclonal B cell activation were carried out on 39 patients with mucocutaneous lymph node syndrome (MCLS) and in age-matched healthy individuals. The incidence of anti-mite, P. acnes (Kato) and EB virus antibodies, recently proposed as aetiological agents by some investigators, was increased in the patient group. Serum immunoglobulin (Ig) M level and IgM-anti-dinitrophenyl (DNP) antibodies, which are considered to be parameters of polyclonal B cell activation, were determined in MCLS cases. The level of serum IgM in MCLS was significantly elevated (0.02 less than P less than 0.05). Levels of anti-DNP antibodies in seven cases of MCLS (18%) were significantly higher than those of the controls (P less than 0.01). Nine of the ten pair sera in MCLS showed a stage-dependent decrease in anti-DNP antibodies. These results suggest that polyclonal B cell activation occurs in MCLS.