Immune histochemical and electron microscopic observations on so-called non-specific mesenterial lymphadenitis

Two cases of so-called mesenterial lymphadenitis in childhood were investigated with the immunoperoxidase technique. One more case was studied electron microscopically. All three cases were morphologically identical. In two cases infection with Yersinia enterocolitica was proven serologically. The majority of the lymphoid cells which filled the strongly distended sinuses represented electron microscopically various steps of the lymphocyte transformation. Immune histochemically, the blasts contained large amounts of immunoglobulins. It is suggested that the mitogen and adjuvant activity of bacterial lipopolysaccharides may substantially be involved in the pathogenesis of the characteristic lesion of the mesenterial lymphadenitis.