Hypereosinophilia in association with pulmonary tuberculosis in a rural population in south India.

In a prospective study conducted in four villages of North Arcot Ambedkar district of Tamil Nadu in south India over a 5 yr period from 1981-86, 279 patients were detected to have pulmonary tuberculosis (PTB). Thirty one of them were found to have associated hypereosinophilia (HE) with total blood eosinophil level of > or = 2000 per cumm; besides cough with expectoration they also complained of dyspnoea and wheeze. Twelve of the 18 patients with intestinal parasites had remission with deworming agents alone. The other 6 non responsive patients like the 13 who did not have parasitic infestation, needed treatment with diethylcarbamazine for eosinopenic remission and thus could be classified as patients of tropical pulmonary eosinophilia (TPE). The association of hypereosinopilic state as a whole as well as TPE with tuberculosis as compared to that prevalent in the general population was found to be highly significant (P < 0.001). The frequent association of TPE with tuberculosis as observed by us suggests the possibility of an early hypersensitivity reaction to mycobacterial antigens triggering a florid TPE state in susceptible patients from an area endemic for filariasis. A similar mechanism may also operate in cases of pulmonary eosinophilia induced by other helminths in areas where they are endemic.