- The CB unit with the least HLA disparity (with the patient) will be selected first (i.e., selection priority is 6/6 match > 5/6 match > 4/6 match); additional CB units then may be selected to achieve the required cell dose, as outlined below; if a second unit is required, this unit will be the unit that most closely HLA matches the patient and meets minimum size criteria outlined below of at least 1.5 x 10^7 total nucleated cells (TNC)/kg (i.e. a smaller, more closely matched unit will be selected over a larger, less well matched unit as long as minimum criteria are met)