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S056-2

A Psychoneuroimmuno-Imaging Study of Patients with Obsessive Compulsive
Disorder (OCD)

Sundar Gnanavel1, Sundar Gnanavel2, Arpit Parmar1, Pratap Sharan1, Vivekanandan Subbiah1,
Khusbu Agarwal1, Uma Sharma1, Jagannathan Nr1

1All India Institute of Medical Sciences, India 2AIIMS, India

Background/Objective: Invitro studies have demonstrated possible neuro protective effects of the
following pro-inflammatory cytokines: IL-6, IL-1β and TNF-α against glutaminergic excitotoxicity
in brain through different pathways. In the current study, we aim to correlate level of the above
pro-inflammatory cytokines in serum with Glx (glutamate+glutamine) levels in head of caudate
nucleus (in brain) measured using 1H-MRS (Proton Magnetic Resonance Spectroscopy) in patients
with OCD (Obsessive compulsive disorder), a neuropsychiatric illness with a possible multi-factorial
aetiology including immunological and excitotoxic factors.

Method: 30 psychotropic-naïve patients with OCD and an equal number of gender and age matched
normal controls were recruited in the study. A detailed psychiatric assessment was carried out
including sociodemographic and clinical variables (eg. duration of illness and disease severity) using
appropriate questionnaires. A 3T MR imaging and spectroscopy session was carried out in head of
caudate nucleus (implicated in OCD) (TE/TR=80/3000 ms ). Further, absolute quantification of Glx
level was obtained using LC model. Simultaneously, 5 ml of blood sample was collected and
assayed for the above pro-inflammatory cytokines (Siemens, Immulite TM ). The levels of Glx as
measured by 1H-MRS was correlated with the cytokine levels in patients with OCD.

Result: The level of Glx was significantly higher in patients with OCD as compared to controls
(p<0.05). The Glx level negatively correlated with two of the three pro-inflammatory cytokines: IL-6
and TNF-α (r=-0.807, p<0.05; r=-0.838; p<0.05 respectively) while no significant correlation was
demonstrated with IL-1β. The cytokine or Glx levels did not vary with age, gender, duration or
severity of illness.

Conclusion: The findings provide preliminary evidence regarding possible neuroprotective effects of
pro-inflammatory cytokines against glutaminergic excitotoxicity in patients with OCD. Further
studies on a larger sample size and including patients with other psychiatric illnesses like depressive
disorder as controls are required for confirmation of the above findings.

Reference: Systematic review of proinflammatory cytokines in obsessive-compulsive disorder. Gray
SM, Bloch MH. Curr Psychiatry Rep. 2012 Jun;14(3):220-8.
Neuroinflammation and psychiatric illness. Najjar S, Pearlman DM, Alper K, Najjar A, Devinsky O.
J Neuroinflammation. 2013 Apr 1;10:43.