Coenzyme Q10 and immunity: A case report and new implications for treatment of recurrent infections in metabolic diseases

• Clinical features of CoQ10 deficiency include encephalomyopathy, multisystemic disease, cerebellar ataxia and nephropathy.
• Immune dysregulation has not been reported as a feature of CoQ10 deficiency.
• After CoQ10 supplementation clinical symptoms and T cell function partially improved in our patient with CoQ10 deficiency.
• The patient’s infectious history further improved with immunoglobulin replacement therapy.
• Diagnosis of CoQ10 deficiency should be considered in patients with metabolic diseases and recurrent infections.

Coenzyme Q10 (CoQ10) deficiency can manifest diversely, from isolated myopathy to multisystem involvement. Immune dysregulation has not been reported as a feature of the disease. We report a four-year old girl with failure to thrive, recurrent infections, developmental delay with hypotonia, and CoQ10 deficiency with impaired immune function, which improved after CoQ10 and immunoglobulin replacement therapy. Immune dysfunction in CoQ10 deficiency should be considered and treated appropriately.