A simple and safe technique for longitudinal bone marrow aspiration in cynomolgus and rhesus macaques

• A technique for safe longitudinal bone marrow sampling in macaques
• Longitudinal samples can be taken every 4 weeks without detrimental effects.
• Bone marrow resident plasma cells can be readily measured in aspirates.
• Plasma cell numbers are not negatively affected by repeated sampling.

Longitudinal bone marrow aspirates were obtained aseptically from the humerus of 36 rhesus and 6 cynomolgus macaques by using a 20G spinal needle, introduced through the bone close to the greater tuberosity. All samplings were performed without complications, and the animals showed no signs of pain or infections. The amount of total bone marrow cells obtained from each aspiration varied, in part due to animal-to-animal variation, but the yields were not affected by the sampling frequency or the length of time between each aspiration. The frequency of plasma cells in the bone marrow of each animal was also fairly stable over several longitudinal samplings while a greater, age-dependent, variation was observed between different animals.