KLRB1 and HIV infectious disease: In HIV-infected patients, the reduced abundance of Vα7.2-Jα33 mRNA and gDNA, the unchanged frequency of Vα7.2+CD161− cells among CD3+CD4− lymphocytes (despite the loss of Vα7.2+CD161++ cells, which would be expected to increase the relative frequency of this population), and the strong correlation of Vα7.2-Jα33 mRNA levels with the frequency of Vα7.2+CD161++ cells but not total Vα7.2+ cells, all argue that MAIT cells are lost from the blood in HIV infection.