Changes in the lymphocyte cytoplasmic refractive index following typhoid vaccination.

The refractive index of the circulating blood lymphocytes (LCRI) of healthy young adults vaccinated with typhoid vaccine has been measured by immersion refractometry and phase contrast microscopy. A rise in the LCRI preceeds the rise in the antibody titre by two to three days. A more pronounced rise also occurred in one patient prior to a rejection crises following a kidney transplant.