“…Allorosettes were found to appear after renal transplantation [8,[18][19][20], skin transplantation [16,[25][26][27], or immunization with spleen cells [22,34] and tumor cells [7] between isohistogenic strains of rats and mice. Unlike xenorosette formation, allorosettes cannot be produced by red blood cell immunization, and there are no spontaneous A R F C [18,19].…”