Changes in the number of complement-binding leucocytes in the peripheral blood of multiple sclerosis (MS) patients: indication to a reduction of EAC3bi-binding T cells in the early acute phase of MS.

Peripheral blood leucocytes (PBL) of multiple sclerosis (MS) patients and healthy controls were examined for their reactivity with EAC3b, EAC3b-beta 1H, and EAC3bi intermediates and C3b- or beta 1H-coated microspheres (ms). A marked decrease was found in the number of EAC3b-beta 1H (P = 0.04) and EAC3bi (P = 0.03) rosettes accompanied with a decrease in the number of total T cells (P = 0.0015), when MS patients were examined within the first 14 days after occurrence of disturbances. On the other hand, when MS patients were examined later than 14 days after onset of disturbances or those with a progressive course were examined, EAC3b-beta 1H (P = 0.0002) and EAC3bi (P = 0.0002) rosettes were markedly increased. In studies where fluorescence-activated cell sorter (FACS) analysis was applied on C3b- and beta 1H-coated ms, similar results were obtained as found with EAC intermediates. Based on previous findings these results strongly suggest that the decrease in EAC3b-beta 1H, EAC3bi, and beta 1H-ms-binding PBL was predominantly due to a loss of beta 1H-binding T cells. A possible relevance of this finding to the demyelinating mechanism(s) is discussed.