Lymphocyte subpopulations of peripheral blood in tsutsugamushi disease.

We examined lymphocyte subpopulations in the peripheral blood and serum concentrations of immunoglobulin (Ig) in 8 patients with tsutsugamushi disease. In 7 of the 8 cases, there was a 4-fold or greater increase in IgG and IgM antibody titers between the initial and convalescent serum specimens. In one case, there was no increase, but IgM antibodies were detected with diagnostically significant antibody titers. The percentages of CD8- and CD2-positive lymphocytes measured before treatment were found to be significantly higher than during the recovery stage of patients with tsutsugamushi disease. The CD4/CD8 ratio in the peripheral blood calculated before treatment was significantly lower than that during the recovery stage. Serum concentrations of IgG and IgM in patients during the recovery stage were significantly higher than pretreatment levels, respectively.