Lymphocyte transformation test with nickel in hard metal asthma: another sensitizing component of hard metal

To determine cell-mediated immunity to nickel, another matrix in hard metal besides cobalt, lymphocyte transformation tests (LTT) with nickel were carried out in seven hard metal asthma patients all of who had reacted to cobalt chloride in the bronchial provocation tests (BPT). Immunoallergic studies prior to the present study revealed that three of the seven generated a simultaneous positive reaction in the BPT with nickel and the allergosorbent test with nickel-conjugated human serum albumin (Ni-HSA). A stimulation index in LTT indicating a positive response was defined on the basis of results from the studies in the controls. Data revealed that two of the three who showed a combination of positive bronchial and immunological reactions with nickel had a positive LTT with nickel. In the other five, peripheral lymphocytes did not proliferate in response to nickel. Thus it is suggested that cell-mediated immunity to nickel as well as cobalt is implicated in some cases associated with hard metal asthma.