Session Title: Inflammation
Presentation Date: Friday, March 14 – Saturday, March 15, 2009
LYMPHOPENIA IN IDIOPATHIC PARKINSONISM: AN AETIOLOGICAL CLUE
J. Bowthorpe1, A. Charlett2, C. Weller1, R.J. Dobbs3, S.M. Dobbs3
1Institute of Psychiatry, Kings College London, London, United Kingdom, 2Centre for Infections, Health Protection Agency, London, United Kingdom, 3Institute of Psychiatry, Kings College London, Department of Gastroenterology, Kings College Hospital, London, United Kingdom
Introduction: In idiopathic parkinsonism (IP), small studies report reduced blood lymphocyte count.
Methods: We contrast lymphocyte counts in 126 IP probands and 79 probands' spouses with general practitioners' routine requests. With 400 controls, standard-deviation of derived reference-range-limits would be small. Age trends in full-blood-count indices of controls < 46 years proved anomalous: exclusion left 381. Lymphocyte counts were examined for distinct Gaussian-distributions (e.g. a subgroup with infection). A mixture of Gaussian-distributions did not provide a better fit.
Results/discussion: Mean lymphocyte count was 23.8 (95% CI 18.7, 28.7)% lower in probands (p< 0.001, after age and gender adjustment) and 17.3 (10.0, 24.0)% lower in 79 spouses (p< 0.001). An estimated 12.5 (7.2, 19.8)% of probands and 7.1 (2.4, 15.9)% of spouses fell below age-specific contemporaneous reference-range cf. expected 2.5% (p< 0.001), no-one exceeding range. Counts were shifted downwards in probands, spouses and controls cf. conventional lower reference-range-limit (1.3 x109/l) by 30.8 (22.7, 39.9), 10.0 (4.1, 19.5) and 7.3 (4.9, 10.4)%, respectively, frequency of 'lymphopenia' varying between groups (p< 0.001).In probands never exposed to anti-parkinsonian medication (37.3%), the count was 101.0 (89.5, 113.9)% of that in spouses, i.e. significantly lower than in controls. Probands receiving medication had a 11.1 (0.1, 20.8)% lower count (p< 0.05). Including time-from-diagnosis in the model reduced significance of medication-status to 0.1. Time-from-diagnosis was not important independently, in either medicated or un-medicated. Intrinsically-linked effects of exposure and time-lapse maybe surrogate for disease-progression.
Conclusion: Robust finding of reduced lymphocyte count in probands and their spouses indicates a shared environmental influence.