Objective: Reduced levels of serum carnitines (3-hydroxy-4-N-trimethyl-ammonio-butanoate) are found in most patients treated with zidovudine. However, since serum carnitines do not strictly reflect cellular concentrations we examined whether a carnitine depletion could be found in peripheral blood mononuclear cells (PBMC) from AIDS patients with normal serum carnitine levels. In addition, we explored whether it was possible to relate the host's immunoreactivity to the content of carnitine in PBMC and whether carnitine levels can be corrected by oral supplementation of L-carnitine.
Design: Immunopharmacologic study.
Methods: Twenty male patients with advanced AIDS (Centers for Disease Control and Prevention stage IVCI) and normal serum levels of carnitines were enrolled. Patients were randomly assigned to receive either L-carnitine (6 g/day) or placebo for 2 weeks. At baseline and at the end of the trial, we measured carnitines in both sera and PBMC, serum triglycerides, CD4 cell counts, and the frequency of cells entering the S and G2-M phases of cell cycle following mitogen stimulation.
Results: Concentrations of total carnitine in PBMC from AIDS patients was lower than in healthy controls. A significant trend towards the restoration of appropriate intracellular carnitine levels was found in patients treated with high-dose L-carnitine and was associated with an increased frequency of S and G2-M cells following mitogen stimulation. Furthermore, at the end of the trial we found a strong reduction in serum triglycerides in the L-carnitine group compared with baseline levels.
Conclusions: Our data indicate that carnitine deficiency occurs in PBMC from patients with advanced AIDS, despite normal serum concentrations. The increase in cellular carnitine content strongly improved lymphocyte proliferative responsiveness to mitogens. Because carnitine status is an important contributing factor to immune function in patients with advanced AIDS, we therefore believe that L-carnitine supplementation could have a role as a complementary therapy for HIV-infected individuals.