Elevated colchicine sensitivity of dermal lymphocytes in mycosis fungoides.

Lymphocytes in chronic lymphocytic leukaemia and in other malignant lymphomas exhibit an extreme sensitivity to colchicine and are cytolysed in vitro by 10(-6) M colchicine. This characteristic can be quantified with the colchicine sensitivity index which is used for diagnostic purposes. We have demonstrated that lymphocytes liberated from skin infiltrates in mycosis fungoides (6 patients) show an elevated colchicine sensitivity of 44 (p < 0.01); in contrast, the index of lymphocytes isolated from dermal infiltrates of reactive inflammatory dermatoses (9 patients) is low, being only 23. Determination of the colchicine sensitivity index can be helpful in the diagnosis of mycosis fungoides.