Flow cytometric differentiation of Asian and Western types of multiple sclerosis, HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) and hyperIgEaemic myelitis by analyses of memory CD4 positive T cell subsets and NK cell subsets

We examined the alterations of memory CD4⁺ T cell subsets bearing surface receptors linked to either Th1 or Th2 cytokine production as well as natural killer (NK) cell subsets by three color flow cytometry in the peripheral blood from 36 patients with clinically definite multiple sclerosis (MS), 27 patients with HAM/TSP, 13 patients with hyperIgEaemic myelitis who had mite antigen-specific IgE and 25 healthy controls (HC). The patients with MS were clinically classified into an optico-spinal form of MS (Asian type, MS-A) and the conventional form of MS (Western type, MS-W). MS-A showed a significant increase of CD4⁺CD45RA^-CCR5⁺ cells (Th1 cells) through the relapse and remission phases in comparison to HC, while MS-W showed a significant increase of CD4⁺CD45RO⁺CD62L^- cells (Th1 cells) only at the relapse phase. HAM/TSP showed a significant increase of CCR5⁺ and CD62L^- memory CD4⁺ T cells as well as CD30⁺ memory CD4⁺ T cells (Th2 cells) in comparison to HC. On the other hand, a selective increase of CD4⁺CD45RO⁺CD30⁺ cells was found in hyperIgEaemic myelitis. The percentage of mature NK cells (CD3^-CD16⁺CD56⁺ cells) as well as double negative T cells (CD3⁺CD4^-CD8^- cells) decreased significantly in HAM/TSP in comparison to HC. Our findings therefore suggest a flow cytometric analysis of Th1/Th2-associated markers on memory CD4⁺ T cells as well as NK cell subsets to be useful for differentiating various inflammatory neurologic conditions.