Inhibition of in Vitro Nickel Sulfate Reaction by Anti-HLA-D/DR Antisera. Lack of Demonstrable Suppressor Cells in Peripheral Blood in Nickel Unresponsiveness in Man

A nickel sulfate induced lymphocyte blast transformation reaction in vitro was specifically inhibited by anti-HLA-D/DR antisera, which indicates the requirement of HLA-D/DR antigens in cellular cooperation. Macrophages are effective antigen presenting cells in the in vitro nickel reaction and this step could be the site of an HLA-antigen function in the recognition of “self.” It was shown that macrophages of an HLA identical, healthy sibling could offer proper “help” to macrophage-depleted lymphocytes of the nickel allergic subject in evoking a nickel reaction. Thus, in this respect, the function of macrophages in nickel allergy is not different from that in a nickel-unresponsive state. The nickel unresponsiveness in healthy subjects is probably not due to specific suppressor cells because HLA identical lymphocytes from the healthy siblings could not suppress the nickel induced blast transformation of the nickel allergic siblings. This suggests that a deletion of sensitized clones in the periphery is the more probable mechanism of unresponsiveness in healthy subjects