Review of some recent observations on 'glandular fever cells'

Pathologists have long been familiar with the curious mononuclear cells which occur in the blood in infectious mononucleosis but until relatively recently most accounts have been largely concerned with morphological aspects. Other methods of investiga-tion-electron microscopy, cytochemistry, auto-radiography, and various immunological procedures-have now been used in more detailed studies of these cells, the results of which provide the main basis for this review. The material is presented in two sections. Part I deals principally with the morpho-logy, ultrastructure, and cytochemistry of the atypical cells, their proliferative activity and possible immunological functions. In Part II, these observa-tions are used in a discussion of three more general topics: the nature of the atypical cells, their possible origin, and their relationship to leukaemic cells. Two problems arise in any study of infectious mononucleosis: the selection of diagnostic criteria and the choice of a suitable name for the atypical cells. There is now reasonable agreement that clinical, haematological, and serological criteria should all be satisfied before the diagnosis of infectious mono-nucleosis is made and this policy has been followed here. The nomenclature of the atypical cells is more difficult. Their occurrence in a wide variety of clinical conditions as well as in normal subjects (Efrati and Rozenszajn, 1960; Giacardy and Giacardy, 1961; Pearmain and Lycette, 1963) illustrates the inade-quacies of 'glandular fever cells ' and of 'virocytes' (Litwins and Leibowitz, 1951); 'atypical lympho-cytes ' may, by implication, be too restrictive a term, and the various hybrid names which abound in the older literature-lymphocytic plasma cells, lympho-monocytes, lymphatic monocytes, etc.-are con-fusing and often conflicting. They are referred to here as 'atypical mononuclear cells', a clumsy term but one which is at least noncommital