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In a lot of 452 patients with various forms of tuberculosis, in various locations, the authors have investigated the efficiency of tests currently employed in detecting tuberculin sensitivity (intradermoreaction to PPD, the test to sensitines and the Ustvedt test), in relation with several immunologic tests performed in vitro (index of lymphoblastogenesis to PPD and/or phytohaemagglutinin, leucocyte migration inhibition test, and the rosette test). It was noted that the two groups of investigations give similar results when tuberculin reactions are positive and intense. Under the conventionally admitted threshold of tuberculinic allergy the test of blastic transformation of lymphocytes, and especially the leucocyte migration inhibition tests are still positive and may be considered as a valuable means for measuring infra-tuberculinic allergy, as well as for the diagnosis of latent tuberculous infections.

Cell suspensions obtained from 54 human lymph nodes involved by different pathological conditions were characterized by conventional markers and by the OKT-3, OKT-4, OKT-8, OKIa-1, and OKM-1 monoclonal antibodies. In 18 cases of reactive lymphoid hyperplasia, the majority of lymph node cells were mature T lymphocytes (E-RFC = 56 +/- 9%; OKT-3+ = 63 +/- 10%); among T-cell subsets, OKT-4+ cells were 49 +/- 8% whereas OKT-8+ cells were 21 +/- 8% (T4/T8 = 2.7 +/- 1.1). This distribution of T-cell phenotypes was not similar in the different histological types of reactive lymphoid hyperplasia. In fact, an increase in the percentage of OKT-8+ cells (25 +/- 9%; P less than 0.05) and a decrease in the values of the T4/T8 ratio (2.1 +/- 1.0; P less than 0.05) were observed in 9 cases of reactive lymphoid hyperplasia of follicular type when they were compared to the mixed and sinus types. In 13 lymph nodes involved by B-cell lymphoma, the percentage of T lymphocytes was markedly reduced (E-RFC = 21 +/- 12%; OKT-3+ = 27 +/- 18%) and the percentage of OKIa-1+ cells (51 +/- 15%) was significantly (P less than 0.01) increased as compared to reactive nodes; in addition, in these cell suspensions, an increase in the relative proportion of OKT-8+ cells (T4/T8 = 1.4 +/- 0.7; P less than 0.01) could also be demonstrated. Finally, a clear prevalence of OKT-4+ cells on OKT-8+ cells was demonstrated in 5 cases of tuberculous lymphadenitis (T4/T8 = 3.9 +/- 1.5; NS) and in 18 cases of Hodgkin's disease (T4/T8 = 4.2 +/- 2.0; P less than 0.01). In tuberculous lymphadenitis, a significant increase (P less than 0.01) in the percentage of OKM-1+ cells could also be demonstrated.

While endemic T.B. is undoubtedly receding, sources of infection are still widespread and knowledge of the pathology of the bacillus is still required. A short account of tracheobroncheal lymphadenopathy is accompanied by radiological illustration of personal cases treated without hospitalisation.

In the last few years, we have adopted the following immunological techniques for the study of hilarmediastinal lymphadenopathies: the E and EAC rosette tests (composition of the lymphocyte population) for an evaluation of the general immunological picture, the delayed-type cutaneous tests to reveal the specific picture of cell-mediated immune responses, and the leucocyte migration inhibition test against related and unrelated antigens. This cellular technique was integrated with the determination of precipitating and agglutinating antibodies against the same antigens. Data are reported regarding tubercular and sarcoid lymphadenopathies, Hodgkin's disease, and secondary neoplastic lymphadenopathy with prevalent intratoracic localization. The techniques used demonstrated that tubercular lymphadenopathy is associated with a well defined immunological profile which is both humoral and cellular. Sarcoid lymphadenopathy (thoracic sarcoidosis) showed a specific, well characterized immunological picture as regards cell-mediated immune responses. In Hodgkin's disease (hilarmediastinal lymphadenopathy) the immunological technique showed up a general, depressed immunological picture, particularly as regards the cell-mediated immunitary response, presumably partly due to the treatment given (physical and pharmacological therapy). Secondary neoplastic lymphadenopathy showed a similar pattern, as far as the immunological parameters used until now are concerned. On the basis of experience gained to date, we believe that the immunological techniques can make a contribution to diagnostic and clinical studies of tubercular and sarcoid lymphadenopathies.

To study the cellular component of local immune defence, bronchoalveolar lavage fluid (BALF) was examined in 69 patients: 24 children and adolescents with primary tuberculosis and 45 patients with secondary patterns of tuberculosis complicated by catarrhal and purulent endobronchitis. With no appreciable lesions in the bronchial mucosa the cellular composition of BALF and functions of alveolar macrophages (AM) in patients with primary tuberculosis are determined by the phase of specific process. In secondary tuberculosis associated with endobronchitis, the cellular composition of BALF is mainly determined by the character of bronchial pathology whereas AM function by the patterns of both specific and nonspecific processes.

Monoclonal antibodies and immunoperoxidase staining were used to characterize the cellular subpopulations in lymph nodes from 10 patients with tuberculous lymphadenitis, seven of whom had symptomatic human immunodeficiency virus (HIV) infection. CD4+ cells were significantly fewer in nodes of patients with HIV infection than in those of immunocompetent patients. CD8+ cells were distributed throughout the granuloma in patients with HIV infection, but confined to the periphery in normal hosts. Blastoid Ta1+ cells, putatively antigen-reactive T lymphocytes, were seen in immunocompetent patients but not in those with HIV infection, suggesting that these cells fail to mature appropriately in the latter group. The immunopathological features noted above provide preliminary evidence that the cell-mediated immune response to tuberculosis is abnormal in patients with HIV infection, and may in part explain both the severe and the unusual manifestations of tuberculosis in these individuals.