Methods: From our mitochrondia cohort, we selected all patients diagnosed as definitive based on the Walker criteria. Seventy patients were identified, 16 with Leigh, 6 with depletion, 2 with SANDO, 1 with NARP, 1 with MELAS and the rest with unknown syndrome. We performed a laboratory retrospective review, documenting all commercial immune results.
Results: Immunoglobulin and IgG subclass levels were within normal range for >90% of patients. Lymphocyte subset data was present for 44 patients. Although the CD45RO absolute count was within the age-specific normal range, the vast majority (65/71, 92%) of the values were in the lower third of the normal range. However, the %CD45RO was below the lower threshold for normal values (n=60, 85%). Conversely, the CD45RA values were on the upper threshold of normal. Most patients have protective titers to tetanus, diphtheria and pneumococcus.
Conclusions: Most patients with mitochondrial disease do not have perturbed immune development except for reduced CD45RO memory lymphocytes. The clinical significant of this result is unclear, but it suggests that mitochondrial function might be necessary for optimal immune memory development.