Characterization of atypical lymphocytes and immunophenotypes of lymphocytes in patients with dengue virus infection

To characterize the immunophenotypes of lymphocytes in patients with dengue infection, we performed flow cytometric analysis of peripheral blood mononuclear cells collected from 49 dengue hemorrhagic fever (DHF), 25 dengue fever (DF), and 26 dengue-like syndrome (DLS) cases. The mean total atypical lymphocytes in DHF (916.1 +/- 685.6 cells/microl) and DF (876.2 +/- 801.9 cells/microl) were higher than those of DLS (310.5 +/- 181.4 cells/microl). An atypical lymphocyte count of 10% or higher was a good indicator of dengue infection (sensitivity 50% and specificity 86%). Flow cytometric studies showed that the percentages of atypical lymphocytes correlated with those of CD19+ B lymphocytes and inversely correlated with the percentages of CD69+ lymphocytes. The mean absolute counts of atypical lymphocytes and CD19+ cells on the discharge day were significantly higher than those on the admission day. Low percentages of TdT+ cells were found in all groups of patients. We concluded that atypical lymphocyte and CD19+ cell counts may be a useful diagnostic tool for dengue infection and the recovery from the disease could be judged when numbers of both cell types are significantly elevated.

Epidemiology of invasive meningococcal disease in 13 government hospitals in Thailand, 1994-1999

This study was conducted to elucidate the magnitude of problem and the clinical course of invasive meningococcal infection from 13 government hospitals in Thailand between 1994 and 1999. Thirty-six strains of Neisseria meningitidis were isolated from 16 blood and 24 cerebrospinal fluid specimens; 4 patients had positive culture in both blood and CSF. Of the 16 strains, 9 (56.3%) were serogroup B. Seventy-one and eighty-four percent of the isolates were susceptible to penicillin and cefotaxime/ceftriaxone respectively. Five out of six penicillin-nonsusceptible strains were found to be relatively resistant to penicillin with the MIC of 0.125 microg/ml. Of 33 patients whose medical records were available, 21 were males and 12 were females, with a mean age of 11.2 years. Fifteen patients (45.5%) presented with meningococcemia and 18 patients (54.5%) presented with meningococcal meningitis. Hypotension and purpura were found in 24.2% and 33.3% of patients respectively. The overall mortality rate was 9.1%. In conclusion, meningococcal disease is not common in Thailand, meningococcemia is a life-threatening condition whereas meningococcal meningitis is much less severe. The prevalence of meningococci relatively resistant to penicillin seems to be increasing.