In interpreting the results of recent neuropsychiatric investigations (4), it is important to remember that D8/17 was developed as a trait marker of rheumatic fever susceptibility. Numerous rheumatic fever investigations and our increasing experience with longitudinal D8/17 assessments in patients with OCD and tic disorders (including Tourette's disorder) clearly demonstrate that D8/17 is not a state marker of streptococcal reactivity. Subjects who are initially identified as being D8/17 positive remain in that category even when their antistreptococcal titers fall to normal levels; conversely, numerous subjects have been found to be D8/17 negative despite markedly elevated antistreptococcal antibody titers, as seen in the patients with well-documented acute poststreptococcal glomerulonephritis, in which all patients had decreased complement, high anti-streptolysin O or anti-DNase B titers, and urinary signs of disease, yet had low D8/17 values (1). Because the relative percentage of D8/17+ cells remains constant among individuals across time, it is highly unlikely that the percentage of D8/17+ cells will be found to correlate with symptom severity. In fact, since D8/17 status is reported as a dichotomous variable (positive or negative), it is difficult to envision how it might be used as a "dimensional" variable.