Abstract: The present invention provides isolated nucleic acid molecules encoding a variety of V&bgr; genes (e.g., V&bgr;25, V&bgr;26, V&bgr;27, V&bgr;28, V&bgr;29, V&bgr;30 or V&bgr;31) as well as both 5′ and 3′ sequences which flank a T cell receptor &bgr; gene. Also provided are kits of primers and kits of antibodies. Further, the present invention also provides methods for diagnosing organ transplant rejection, as well as methods for determining a correlation between a disease or disease susceptibility and a selected polymorphism.