[A study of clinical significance of leukocyte migration inhibition test in drug-induced hypersensitivity pneumonitis].

In 71 patients suspected of drug-induced pneumonitis, the identification of the allergenic drugs were studied by leukocyte migration inhibition test (LMIT). The LMIT was positive in 61 cases (85.9%). Leukocyte migration activating factor (LMAF) was detected in 22 cases (30.9%), and leukocyte migration inhibitory factor (LMIF) in 39 cases (54.9%), which was found significantly higher than LMAF (p < 0.05). There was no considerable difference in the LMIT-positive rate between interstial and eosinophilic pneumonia. The LMIT-positive drugs were detected in 66 of all 180 suspected drugs, in which 33 drugs (50%) were antibacterial agents and 11 were Kampo prescriptions. beta-Lactam antibiotics accounted for about half the number (16 drugs) in antibacterial agents. LMAF was detected more frequently in beta-lactam antibiotics-induced pneumonitis, which LMIF was detected more often in Kampo prescriptions-induced pneumonitis (p < 0.005). Furthermore, the latent period from drug initial to the onset of pneumonitis were about 10 days in beta-lactam antibiotics-induced pneumonitis and a few months in Kampo prescriptions-induced pneumonitis (p < 0.001). Our findings indicate that LMIT is valuable to identify the allergenic drugs in drug-induced hypersensitivity pneumonitis and that delayed-type hypersensitivity (DTH), with which LMIF is related closely, plays a major role in the pathogenesis of this lung lesion. Furthermore, the pathogenic mechanism of beta-lactam antibiotics-induced pneumonitis may be different from that of Kampo prescriptions-induced pneumonitis.