Regulation of immunologic reactivity in sarcoidosis

Immunology of sarcoidosis

Because of its association with cutaneous anergy, sarcoidosis was originally viewed as a defect of cellular immunity. Supporting that misperception were early studies of peripheral blood lymphocytes that found lymphopenia and impaired lymphocyte responses to mitogens and recall antigens. The clue to a vast underlying network of complex hyperactive cellular immune functions was discovered in the paradoxical finding of in vitro spontaneous lymphoblastic transformation and lymphokine production. Subsequently, investigative focus shifted to the activated, proliferating T-helper lymphocytes, the lymphokines of which were found to function in the recruitment and retention of monocytes for granuloma development. T-helper lymphocytes also contributed to the mechanism of hypergammaglobulinemia through their influence on B cells. The most intriguing question about sarcoid immunology is the initiating factor that triggers the T-lymphocyte activation and proliferation in the first place. There is much to suggest that antigen processing and presentation launches the process. Because lymphocyte activation and proliferation antedate granuloma formation at K-S skin test sites and in the lung, we combined the harvesting technique of BAL with the K-S bioassay to show that granulomagenic antigen is being processed by monocyte-macrophages. The finding of autologous monocyte-macrophage granulomagenicity raises the distinct possibility that sarcoidosis is a unique cell-mediated type of autoimmune process. The isolation and identification of the granulomagenic factor is the exciting research frontier ahead.

Sarcoid-like lymphadenopathy mimicking metastatic testicular cancer

A case of nonseminomatous testicular cancer and enlarged mediastinal lymph nodes, which were interpreted as metastases, is reported. When there was no change after two courses of chemotherapy, a mediastinoscopy was performed and the results showed sarcoidosis.

Laboratory diagnosis of ophthalmic sarcoidosis

Because the eye is involved in about 25% of patients with active sarcoid, the ophthalmologist is often the first physician to see these patients. Although clinical findings may suggest sarcoid, laboratory tests (e.g., x-ray, skin tests, blood chemistries, etc.) may be normal or inconclusive. Thus, it is important that the ophthalmologist be aware of the availability and limitations of the various biochemical, immunological, radiological, and histopathological tests that contribute to the early diagnosis of sarcoidosis. The authors review diagnostic procedures and present a flowchart detailing indications for each.

Sarcoid-like lymphadenopathy in malignant teratoma

The reported association between sarcoidosis and malignancy has relevance both to the diagnosis of the cause of lymphadenopathy and possibly also to the prognosis of the malignant disease. A case is reported in which mediastinal lymphadenopathy due to non-caseating epithelioid granulomata caused diagnostic difficulty in the staging investigation of a patient with malignant testicular teratoma.

Association between endogenously activated T cells and immunoglobulin-secreting B cells in patients with active systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is characterized by increased numbers of circulating B cells activated polyclonally to secrete immunoglobulin. Because T cells secrete, or shed, various factors that are functionally important in regulating immunoglobulin production by B cells, a reverse hemolytic plaque assay was developed to quantitate such activated T cells. In this technique, we used a rabbit antiserum raised to supernatants of concanavalin-A--stimulated human lymphocytes. The relevant antigenic specificity of this antiserum is directed toward the shed surface membrane determinant(s) preferentially expressed on activated T cells. Freshly isolated peripheral blood mononuclear cells from 14 SLE patients contained more than 10 times the number of endogenously activated T cells than cells from normal subjects. Within the SLE group, plaque-forming T cells were particularly increased in patients with active disease. By linear regression analysis, a significant positive correlation was revealed between such activated T cells and immunoglobulin-secreting B cells, also measured by a reverse plaque assay (r = 0.83). It appears that both activated B cells and T cells circulate in increased numbers in SLE. Additional investigation will be required to define the molecular nature of the T cell product(s) being measured and to clarify the relationship of these findings to the immunoregulatory abnormalities in this disorder.

Darier's disease: a partially immunodeficient state

Darier's disease (Keratosis follicularis) a dominantly inherited keratinizing disorder of the skin, is associated with the development of severe, progressive viral and bacterial skin infections. We investigated the possibility that an inadequacy of the immune system might be responsible for this tendency. Seven of our 8 patients with Darier's disease showed complete anergy to common skin test antigens and their peripheral blood lymphocytes failed to produce the lymphokine, leukocyte inhibitory factor (LIF) in vitro when stimulated with the same antigens. One Darier's patient and 6 controls showed positivity to at least one skin test antigen and produced lymphokine in vitro to the appropriate antigen. All patients had normal leukocyte and differential counts and normal numbers of circulating T and B cells. All 8 patients with Darier's disease demonstrated no proliferative response to optimal doses of the T cell mitogen Con A while showing normal responses to the T cell stimulant PHA and the T cell dependent B cell stimulant PWM. This previously unreported finding suggests a subtle abnormality of T cells in Darier's and might be a marker for these patients. Serum from 2 patients with Darier's disease did not suppress the in vitro immunologic activity of lymphocytes from normals. Finally, 13-Cis-retinoic acid in dosages adequate to clear their skin disease did not alter the in vivo or in vitro immunologic functions in 3 Darier's patients, suggesting that the immune dysfunction is not a secondary phenomenon.

Clinicopathologic correlations. De subitaneis mortibus. XXV. Sarcoid heart disease

Postmortem findings within the cardiac conduction system are described from the case of a black woman with sarcoid heart disease who died suddenly. Her clinical course had been characterized by recurring ventricular arrhythmias and bouts of syncope. Both the sinus node artery and the atrioventricular (A-V) node artery were sites of focal fibromuscular dysplasia, which thickened slightly the wall of the former but markedly narrowed the lumen of the latter. Small foci of sarcoid infiltration were present in the sinus node and the A-V node. Fatty replacement within the His bundle was attributable to the probable ischemia caused by narrowing of the A-V node artery. Sarcoid granulomata and infiltration with epithelioid cells were present throughout the ventricular myocardium, but were conspicuously less prevalent in the atria. All the large coronary arteries were normal. Many small coronary arteries in the ventricular myocardium were involved by the sarcoidosis and their lumen were narrowed. These findings and analogous ones reported by others are discussed relative to the pathogenesis of syncopal attacks and sudden death which seem to peculiarly prevalent in sarcoid heart disease.