Pj. Hoekstra et al., Elevated D8/17 expression on B lymphocytes, a marker of rheumatic fever, measured with flow cytometry in tic disorder patients, AM J PSYCHI, 158(4), 2001, pp. 605-610
Objective: Elevated D8/17 expression on B lymphocytes is a known susceptibi
lity marker of rheumatic fever. Previous studies have reported higher than
usual D8/ 17 expression on B lymphocytes of patients with tic disorders. Th
e purpose of this study was to assess D8/17 expression on B lymphocytes of
tic disorder patients by using an objective method in which no operator var
iability was involved.
Method: D8/17 expression on B lymphocytes was assessed with flow cytometry
by using an immunoglobulin M (IgM) monoclonal D8/17-specific antibody in an
unselected group of Dutch patients with tic disorders (N=33) and healthy v
olunteers (N=20). Binding of this monoclonal antibody was compared with bin
ding of an irrelevant IgM monoclonal antibody, and the shift in mean fluore
scence intensity of the D8/17-specific antibody compared to that of the irr
elevant IgM monoclonal antibody was used as a measure of D8/17 overexpressi
on. For the patients, Yale Global Tic Severity Scale scores were used to as
sess disease severity.
Results: D8/17 overexpression in the patient group (mean=16.8 arbitrary uni
ts, SD=30.5) was significantly higher than in the comparison group (mean=3.
2, SD= 3.0). A significant minority of the patients (N=13, 39.4%), however,
had levels of D8/ 17 overexpression within the range of that of the health
y comparison subjects. Flow cytometric analysis did not indicate a separate
subpopulation of D8/17-positive B cells.
Conclusions: These data confirm the utility of D8/17 B cell overexpression
as a peripheral blood marker in patients with tic disorders and are compati
ble with a streptococcus-related pathogenesis for at least a subgroup of pa
tients with tic disorders.