irradiating the mixture of leukocytes in the presence of a psoralen at {HEAD ~ a temperature} between about 20° C. and {TAIL ~ about 28° C.}; followed by 
between
irradiating the mixture of leukocytes in the presence of a psoralen at { HEAD ~ a temperature } between about 20 ° C. and { TAIL ~ about 28 ° C. } ; followed by
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH