Granulomatous and nongranulomatous lymphadenitis in sarcoidosis. An immunophenotypic study of seven cases

Five cases of prescalenic granulomatous lymphadenitis (GL) and 2 cases of prescalenic nongranulomatous lymphadenitis (NGL) in 7 patients with sarcoidosis were studied with a large panel of monoclonal antibodies (anti-CD 1, CD 3, CD 4, CD 8, CD 14, CD 22, CD 25, HLA-DR, HLA-DQ, HNK-1, R4/23). Immunopathologic analysis was performed by studying three different compartments of GL-granuloma, intergranulomatous area and sinuses - and of NGL - cortex, paracortex and sinuses. Intra- and intergranulomatous T lymphocytes were mainly of the CD 4 type in 4 out of 5 cases; in all the cases less than 25% of T lymphocytes stained also for CD 25. Epithelioid cells were HLA-DR+, HLA-DQ+, CD 14+ and, frequently, CD 1+ and CD 25+, the latter positivity being mainly restricted to the marginally located epithelioid cells. Sinuses were filled with T- and B- cells; sinusal histiocytes were HLA-DR+, HLA-DQ+, CD 14+ and, frequently, CD 1+ and CD 25+. In the cortex and paracortex of NGL, T-cell subsets paralleled the distribution and ratio observed in the intergranulomatous area of GL; furthermore the immunophenotype of NGL sinusal histiocytes roughly overlapped that observed in the same district of GL with a strong CD 1 and CD 25 positivity. These results, besides confirming the global imbalance of the CD 4/8 ratio in all the areas of GL, seem to demonstrate that the prevalence of CD 4+ or CD 8+ T-cells probably reflects different functional phases of the granulomatous process. Furthermore the immunophenotype of epithelioid cells is consistent with their supposed antigen presenting function and suggests that these cells might result from a lymphatic input and transformation of the so-called veiled cells. In conclusion, a certain degree of phenotypic 'continuum' is observed between NGL and GL, thus allowing further insight into the pathogenesis of sarcoid granuloma.