ASD (Autism Spectrum Disorder), is a heterogeneous neurodevelopmental disorder in which no etiology is identified in the majority of cases. The proposed mechanism of action of umbilical cord blood stem cells in ASD is not believed to be the replacement of brain cells. Instead, researchers think any potential benefit would occur through paracrine and immunomodulatory effects—that is, the cells release signaling molecules that may influence inflammation, immune function, and neural connectivity. Several mechanisms have been proposed: 1- Modulation of neuroinflammation, 2- Regulation of the immune system, 3- Secretion of neurotrophic factors, 4- Improvement of cerebral blood flow and 5- Effects on neural connectivity. Early open-label trials reported improvements in some children, particularly in social communication. However, stem cell therapies for ASD are generally experimental. Larger, well-designed clinical trials are still needed.

Keywords: Autism Spectrum Disorder; Stem Cells; Mechanism; Clinical Trials

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