A historical basis for modern concepts of the pathogenesis of tuberculosis.

Theories of the pathogenesis of tuberculosis accepted by clinicians in this field, receive no mention or little emphasis in textbooks of pathology. These are: the systemic character of the disease from the initial infection; the role of tissue allergy; the subclinical, benign and lifelong character of most tuberculosis infections, yet liable to an endogenous activation by the influence of stress. These concepts go far back in history, and reference is made to Bayle (1816), Koch (1891), Calmette and Guérin (1906), Von Pirquet (1907) and Ghon (1912). The origin of the pulmonary apical lesion was controversial in the 1920s. Assmann formulated a theory of reinfection, which is opposed to Simon's theory of primary origin, which is gaining acceptance today. Histological studies of early lesions by Vorwald show their haematogenous origin and Sweany's work on late lesions emphasises the instability of tubercle at any age of the lesion. Krauses's survey of the pathogenesis anticipates the modern concept of tuberculosis as being mainly a condition of stress.