Histological and histochemical pattern of phytohemagglutinin (PHA) skin test in patients with sarcoidosis.
Phytohemagglutinin (PHA) is a non-specific stimulant of blastogenic transformation and proliferation of T-lymphocytes in vitro. This material has been used for detection of a reduced lymphoblastic transformation in vitro and, as a skin test, for providing information in the evaluation of cellular immunodeficiency in man (BLAESE et al. 1973). As in sarcoidosis the immunological features are "depression of delayed-type hypersensitivity suggesting T-cell anergy and raised serum immunoglobulins suggesting B-cell overactivity", the authors used PHA skin test in comparison with patients with tuberculosis and M. Hodgkin. PHA positive reactions recorded at 72 hrs. were in 95% for sarcoidosis, 90% for tuberculosis and 5% for M. Hodgkin. But the histological and histochemical investigation of cutaneous biopsies demonstrated three significant differences at 72 hrs. in untreated patients with sarcoidosis compared to the material of tuberculosis patients: formation of lymphatic pseudo-follicles, an increased number of arteriovenous anastomoses and appearance of C-mucopolysaccharide (a histochemical marker of connective tissue in sarcoidosis). There were in sarcoidosis, unlike tuberculosis, blast cells, plasmocytes and a number of lymphocytes at 72 hrs. It is difficult for the authors to explain the different behaviour of the PHA skin test in sarcoidosis and tuberculosis. The appearance of the C-mucopolysaccharide might be a result of the raised serum level of IgM in patients with sarcoidosis.
D006025:Glycosaminoglycans / Q000378:metabolism; D006651:Histocytochemistry / Q000379:methods; D006801:Humans; D037102:Lectins / Q000494:pharmacology; D008213:Lymphocyte Activation / Q000187:drug effects; D012507:Sarcoidosis / Q000276:immunology / Q000378:metabolism* / Q000473:pathology; D012882:Skin Tests / Q000379:methods; D013601:T-Lymphocytes / Q000276:immunology
D006025:Glycosaminoglycans; D037102:Lectins