Low NK activity in large autism subgroup

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Low natural killer cell cytotoxic activity in autism: The role of

glutathione, IL-2 and IL-15

Aristo Vojdani, Mumper, Doreen Granpeesheh, Lynne Mielke,

Traver, Bock, Karima Hirani, Neubrander, Kurt N.

Woeller, O'Hara, Anju Usman, Schneider, Hebroni,

Berookhim and Jaquelyn McCandless.

Journal of Neuroimmunology

Volume 205, Issues 1-2, 15 December 2008, Pages 148-154

http://tinyurl.com/oew4ph

Although many articles have reported immune abnormalities in autism,

NK cell activity has only been examined in one study of 31 patients,

of whom 12 were found to have reduced NK activity. The mechanism

behind this low NK cell activity was not explored. For this reason, we

explored the measurement of NK cell activity in 1027 blood samples

from autistic children obtained from ten clinics and compared the

results to 113 healthy controls. This counting of NK cells and the

measurement of their lytic activity enabled us to express the NK cell

activity/100 cells. At the cutoff of 15–50 LU we found that NK cell

activity was low in 41–81% of the patients from the different clinics.

This NK cell activity below 15 LU was found in only 8% of healthy

subjects (p < 0.001). Low NK cell activity in both groups did not

correlate with percentage and absolute number of CD16+/CD56+ cells.

When the NK cytotoxic activity was expressed based on activity/100

CD16+/CD56+ cells, several patients who had displayed NK cell activity

below 15 LU exhibited normal NK cell activity. Overall, after this

correction factor, 45% of the children with autism still exhibited low

NK cell activity, correlating with the intracellular level of

glutathione. Finally, we cultured lymphocytes of patients with low or

high NK cell activity/cell with or without glutathione, IL-2 and

IL-15. The induction of NK cell activity by IL-2, IL-15 and

glutathione was more pronounced in a subgroup with very low NK cell

activity. We conclude that that 45% of a subgroup of children with

autism suffers from low NK cell activity, and that low intracellular

levels of glutathione, IL-2 and IL-15 may be responsible.