BAGASSOSIS .4. PRECIPITINS AGAINST EXTRACTS OF THERMOPHILIC ACTINOMYCETES IN PATIENTS WITH BAGASSOSIS

Precipitating antibodies against extracts of crude moldy bagasse have previously been detected in the serum of patients with bagassosis and to a lesser extent in the serum of unaffected sugar cane workers. In this report serum specimens obtained from patients with bagassosis and appropriate control groups were analyzed for precipitins against thermophilic fungi and actinomycetes isolated from bagasse. The thermophilic actinomycete Micromonospora vulgaris was found to be an important source of bagassosis antigens. Sixty-four per cent of those with bagassosis of recent onset demonstrated precipitins against this organism and eight M. vulgaris antigens were identified using rabbit antiserum. Patients with bagassosis also demonstrated elevated levels of IgG and IgA and normal IgM levels. Only an occasional unaffected bagasse industry worker or unexposed Louisiana resident demonstrated precipitin arcs against the battery of actinomycete extracts employed and these arcs were generally not as well defined or intense as those developed by serum of patients with overt bagassosis. Precipitin arcs tended to decrease in number and intensity with clinical improvement. A positive precipitin reaction to M. vulgaris in a case of suspected active or recent onset bagassosis was considered to be of presumptive diagnostic significance. © 1969.