[en] Changes of several immunological parameters in 52 cases of primary lung cancer treated with radiation combined chemotherapy were studied in the present paper. During the treatment, decreasing of absolute lymphocyte counts, PHA skin test reactivity and lymphocyte blastoid transformation with PHA were recognized. The decreasing of immunological capacities tested in the present investigation did not depend on among clinical stages or histologic types. But irradiation to mediastinum affected to immunological abilities. The values in some immunological parameter tested at pre-treatment or at post-treatment suggested the correlation with tumor regression, namely in the cases showed high values in absolute lymphocyte counts and PPD skin test reactivity at the time of pre-treatment and in the cases showed high reactivity in PHA skin test at post-treatment, tumor regression was significantly demonstrated compared with the other cases. The patients showed high values in absolute lymphocyte counts and PHA skin test at pretreatment time or showed high values in lymphocyte blastoid transformation with PHA at post-treatment demonstrated longer survival time. As a result, the test of immunological abilities obtained at pre-treatment time was reliable to forecast tumor regression and survival time. (author)