progressive multiple sclerosis abnormal immune functions in vitro and aberrant correlation with enumeration of lymphocyte subpopulations in a series of 27 consecutive progressive multiple sclerosis ms patients under age 50 we have simultaneously measured 3 in vitro immune functions and 6 markers and compared their results to a group of 21 controls we have confirmed a reduction of concanavalin a con a induced suppression and nk function contrasting with increased igg secretion in response to pokeweed mitogen pwm among 6 monoclonal antibodyrecognized subpopulation leu 1 leu 2 okt8 leu 3 leu 7 and leu 11 only leu 2 lymphocytes were statistically reduced okt8 were slightly reduced leu 3 were slightly increased discriminant analysis revealed that the 3 immune functions together with the results of okt8 and leu 3 enumeration were sufficient to appropriately classify most of the individuals only 3 ms and 4 controls were misclassified correlation analysis suggested disappearance of the doubly labelled okt8leu 7 population in ms patients in ms as opposed to controls con ainduced suppression did not correlate with suppressor cell markers but correlated with nk cell markers suggesting that in ms this population mediates con ainduced suppression igg secretion and con a suppressor cell function were inversely correlated in ms patients but not in controls suggesting that in chronic progressive multiple sclerosis a common abnormality underlies both increased response to pwm and decreased induction of suppression by con a