Elevated D8/17 expression on B lymphocytes, a marker of rheumatic fever, measured with flow cytometry in tic disorder patients.
OBJECTIVE
Elevated D8/17 expression on B lymphocytes is a known susceptibility marker of rheumatic fever. Previous studies have reported higher than usual D8/17 expression on B lymphocytes of patients with tic disorders. The 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 variability was involved.


METHODS
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 volunteers (N=20). Binding of this monoclonal antibody was compared with binding of an irrelevant IgM monoclonal antibody, and the shift in mean fluorescence intensity of the D8/17-specific antibody compared to that of the irrelevant IgM monoclonal antibody was used as a measure of D8/17 overexpression. For the patients, Yale Global Tic Severity Scale scores were used to assess disease severity.


RESULTS
D8/17 overexpression in the patient group (mean=16.8 arbitrary units, 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 healthy 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 compatible with a streptococcus-related pathogenesis for at least a subgroup of patients with tic disorders.
Child and Adolescent Psychiatry Center, University Hospital, Hanzeplein 1, 9713 GZ Groningen, The Netherlands. pieter.hoekstra@kjpnn.nl
P J
PJ
Hoekstra
J
J
Bijzet
P C
PC
Limburg
M P
MP
Steenhuis
P W
PW
Troost
M D
MD
Oosterhoff
J
J
Korf
C G
CG
Kallenberg
R B
RB
Minderaa
D000293:Adolescent; D000328:Adult; D000911:Antibodies, Monoclonal / Q000276:immunology* / Q000378:metabolism; D000941:Antigens / Q000032:analysis / Q000276:immunology*; D015551:Autoimmunity / Q000276:immunology; D001402:B-Lymphocytes / Q000276:immunology* / Q000378:metabolism; D015415:Biomarkers; D002648:Child; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D007075:Immunoglobulin M / Q000276:immunology; D008297:Male; D011569:Psychiatric Status Rating Scales / Q000706:statistics & numerical data; D012213:Rheumatic Fever / Q000276:immunology; D012720:Severity of Illness Index; D013290:Streptococcal Infections / Q000276:immunology; D013291:Streptococcus / Q000276:immunology; D013981:Tic Disorders / Q000175:diagnosis / Q000276:immunology*
D000911:Antibodies, Monoclonal; D000941:Antigens; D015415:Biomarkers; D007075:Immunoglobulin M