Attempts to convert lepromatous into tuberculoid-type leprosy with blood lymphocyte extracts from sensitized donors.

Two groups of lepromatous patients (L type of leprosy) were injected intramuscularly and respectively with the Lawrence's transfer factor (LTF) or a ribonucleic acid (RNA) extracted from viable blood lymphocytes of healthy donors hypersensitive to lepromin (48–72 hr and 20–30 days), tuberculin (PPD), toxoplasmin and histoplasmin. Each patient received a single dose of LTF or RNA obtained from 109 lymphocytes and was carefully observed for a period of 4 months. Histopathology of skin lesions and of lymph nodes were repeatedly performed. The results of intradermal tests with antigens were read at different times up to 120 days after the injection of LTF and RNA. Delayed cutaneous reaction to some antigens was induced in three patients injected with LTF and in two others injected with RNA. The lepromin reaction read at the end of 48–72 hr and after 20–30 days remained negative in all patients during 120 days of observation. Clinical and histopathologic signs of transformation into tuberculoid leprosy could not be observed in the eight patients tested.