Cellular immunity in polymyalgia rheumatica and giant cell arteritis: lack of response to muscle or artery homogenates

Longitudinal monitoring of circulating immune cell phenotypes in large vessel vasculitis

Giant cell arteritis (GCA) and Takayasu arteritis (TAK) are two types of primary large vessel vasculitis (LVV). LVV is an intractable, rare disease with a high relapse rate. Disease progression in asymptomatic patients is an important issue in the clinical management of LVV. Useful biomarkers associated with clinical phenotypes, disease activity, and prognosis may be present in peripheral blood. In this review, we focused on peripheral leukocyte counts, surface markers, functions, and gene expression in LVV patients. In particular, we explored longitudinal changes in circulating immune cell phenotypes during the active phase of the disease and during treatment. The numbers and phenotypes of leukocytes in the peripheral blood were different between LVV and healthy controls, GCA and TAK, LVV in active versus treatment phases, and LVV in treatment responders versus non-responders. Therefore, biomarkers obtained from peripheral blood immune cells may be useful for longitudinal monitoring of disease activity in LVV.

Peripheral blood lymphocyte subsets in polymyalgia rheumatica

Peripheral blood lymphocytes from 23 patients with polymyalgia rheumatica (PMR) were characterized using monoclonal antibodies and flow cytometry in a two-year prospective study. There were no significant differences in absolute numbers or relative percentages of lymphocytes or CD3+, CD4+, CD8+ T cells or the CD4+ T cell functional subsets, virgin (CD4+CD45RA+) and memory (CD4+CD29+) T cells, in patients before or during corticosteroid treatment compared to controls. Previous reports on decreased levels of CD8+ T cells as a characteristic of PMR/giant cell arteritis was not confirmed. The absolute number and relative percentage of lymphocytes with natural killer cell activity, CD16+ CD56+ cells, were significantly lower in patients with active untreated PMR as well as during corticosteroid treatment compared to controls, but at the two-year follow-up the difference was less marked.

Immunological studies in giant cell arteritis

The results of investigations on the humoral immunological mechanisms are conflicting in giant cell arteritis (GCA) and have not been able to explain the pathological findings in the inflamed arterial wall. Altogether, immunological studies suggest that a cell-mediated immune reaction, possibly against an autologous antigen, occurs locally in the arteritic lesions of GCA. The excellent effect of treatment with glucocorticosteroids on the inflammation in GCA can also be explained by this model. The glucocorticosteroids inhibit the synthesis of interleukin-1 (IL-1) by the macrophages and suppress the IL-2 production from the T cells (Palacios, 1982). The observed HLA-DR expression in the arterial wall can be accounted for by the sum of macrophages and activated T cells, the macrophages being the most probable antigen-presenting cells. The interdigitating reticulum cells observed in some of the GCA patients may also be involved in antigen presentation. What the antigen(s) may be is, however, still unknown, as are the factors initiating the inflammatory process. It has recently been possible to extract T lymphocytes from the inflamed tissue and to culture these cells in vitro. After culture, it is possible to study the gene for the T-cell receptor, and probably even the antigenic specificity of the T cells. I hope that this approach may lead to a better understanding of the pathogenic mechanisms in GCA.

Temporal arteritis: cell composition and the possible pathogenetic role of cell-mediated immunity

A biopsy specimen exhibiting the typical morphologic characteristics of temporal arteritis was studied by using light immunofluorescent, and electron microscopy and immunohistochemical techniques. The granulomatous lesion consisted of clusters of macrophages, epithelioid cells, giant cells, and the peripheral lymphocyte mantle, and was localized mainly in the media. Neutrophils were rare, and fibrinoid necrosis was absent. In immunofluorescent and immunohistochemical studies, no significant deposition of immunoglobulins or complement was observed. Immunohistochemical study with monoclonal antibodies to leukocyte surface antigens demonstrated that the central aggregated granulomatous infiltrate consisted of OKTM1+, Leu-M3+, HLA-DR+ epithelioid macrophages and multinucleated giant cells, whereas OKT8+, HLA-DR+ (suppressor/cytotoxic) T cells predominated in the peripheral lymphocyte mantle. These findings suggest that cell-mediated immunity, especially T cell-regulated granulomatous reaction, may play an important role in the pathogenesis of temporal arteritis. By electron microscopy, smooth muscle cells often exhibited closely attached macrophages, epithelioid cells, and giant cells, and displayed a variety of cell injuries. It therefore seems likely that smooth muscle cells are a primary target of the granulomatous reaction.

T cell subsets and expression of immunological activation markers in the arterial walls of patients with giant cell arteritis

Immunohistochemical features of infiltrating mononuclear cells (MNC) and resident cells were studied in the temporal artery biopsy specimens of 13 patients with histological verified giant cell arteritis (GCA) and in six biopsy specimens from patients with GCA with negative histological findings. Eight temporal artery biopsy specimens from seven patients with unrelated diseases served as controls. In all patients with GCA proved by biopsy an infiltration of T lymphocytes in the arterial wall was observed, most being of the helper/inducer subset. No B lymphocytes, or very few, were seen. Lymphocytes in 10 out of the 13 positive biopsy specimens displayed staining for the class II major histocompatibility complex (MHC) antigen HLA-DR, whereas this was found in only two of eight controls. A minor number of the infiltrating T lymphocytes from seven out of 13 patients with GCA proved by biopsy stained for transferrin receptors, and in six out of the 13 cases they reacted with anti-interleukin 2 receptor antibody. In the arterial wall from all patients with histologically verified GCA we also found an increased number of macrophages, many of them expressing HLA-DR antigens and transferrin receptors. The immunohistochemical pattern of cell phenotypes found in the arterial wall of patients with GCA suggests that the infiltrating T cells are immunologically activated. This finding supports the hypothesis of a predominantly cellular immunological pathogenesis of giant cell arteritis.

Polymyalgia rheumatica and temporal arteritis

Polymyalgia rheumatica and temporal arteritis are a clinical syndrome and clinicopathologic entity, respectively. Polymyalgia rheumatica occurs more commonly than temporal arteritis, with approximately half of all patients with temporal arteritis having the polymyalgia rheumatica syndrome. Both conditions are found in the population over 50 years of age and are associated with an elevated ESR. The etiology of both is unclear, although genetic, and potentially, environmental factors may play significant roles. Both conditions respond to corticosteroid therapy, but patients with temporal arteritis require significantly higher doses to control symptoms and to prevent blindness.

Polymyalgia rheumatica and giant cell arteritis. The dilemma of therapy

Polymyalgia rheumatica, next to rheumatoid arthritis the most common inflammatory rheumatic disorder of the elderly, is a nonspecific clinical syndrome involving pain in the shoulder and pelvic girdles. Giant cell arteritis appears to localize in elastin-containing arteries and can cause similar myalgias. A relationship exists between the two diseases, as evidenced by their frequent coexistence in the same patient. The symptoms of polymyalgia rheumatica respond to low-dose corticosteroid therapy, while giant cell arteritis requires higher doses to prevent blindness due to involvement of the temporal artery. The key decision in therapy, therefore, concerns the dose and duration of use of steroid for polymyalgic symptoms. In this decision, prevention of the catastrophic complications of giant cell arteritis and avoidance of needless side effects of high-dose steroid therapy in the elderly are competing considerations.

Temporal arteritis and renal disease. Case report and review of the literature

Renal abnormalities have been described in a small percentage of patients with temporal arteritis. Transient microscopic hematuria is the most common finding. In rare instances, widespread vasculitis involving renal arteries or microscopic polyarteritis nodosa can be seen. This case report describes the association of temporal arteritis with membranous glomerulonephropathy and the nephrotic syndrome in an elderly patient, an occurrence not previously reported. Whether this association is coincidental or pathogenetically linked remains to be determined.

Decrease of the OKT8 positive T cell subset in polymyalgia rheumatica. Lack of correlation with disease activity

Peripheral T cell populations were investigated in 35 patients suffering from polymyalgia rheumatica. The total number of T cells was low compared with those of a control group of similar age (P less than 10(-3). This decrease was demonstrated by using both classic E-rosette and monoclonal antibody techniques (OKT3, and OKT4 + OKT8) and was shown to be secondary to a selective T8 defect (P less than 10(-9). There was no correlation between the decrease in T8 (a cytotoxic suppressor T cell subset) and steroid therapy, disease activity, and temporal arteritis, nor between this decrease and the T gamma percentage and the presence of circulating immune complexes (CIC). The T gamma cell percentage was low in the patient group (P less than 10(-5) and correlated with the presence of detectable CIC (P less than 0.05). In contrast to the T8 and T gamma defects, concanavalin A-stimulated cells from 5 selected patients were found capable of suppressing in vitro anti-trinitrophenyl response. This suppression was found in both autologous and allogeneic experiments. From these data one can assume that an immune anomaly (T8 defect) could be the origin of CIC and the disease occurrence.

Immunohistologic and cytochemical studies of temporal arteritis

Arteritic lesions from 14 patients with temporal arteritis were studied by cytochemical and immunohistochemical methods to identify the nature of the inflammatory cell infiltrate and to demonstrate immunoglobulin deposition. The infiltrating cells typically seen were histiocytes, giant cells, monocytes, and lymphocytes. The lymphocytes were mainly T cells and the majority of them were of the helper/inducer (Leu-3a) T cell subset, as indicated by monoclonal antibody reactivity. Immunoglobulin deposits on the internal elastica were identified in only 6 patients and neutrophils were either very sparse or absent. These findings are consistent with the hypothesis that cell-mediated immunity may be important in the pathogenesis of temporal arteritis.

Serologic and immunopathologic findings in temporal arteritis

In 104 patients undergoing biopsies for temporal arteritis, lymphocyte characterization identified both T4 helper/inducer and T8 cytotoxic/suppressor lymphocytes in approximately equal numbers. B lymphocytes were absent. Deposition of IgM and IgG was observed in three of 16 positive biopsy specimens. Antinuclear antibodies were present in ten of 16 biopsy-proven cases of temporal arteritis compared with 19 of 55 in the control group with negative biopsy specimens. Anti-smooth-muscle, anti-DNA, and antimitochondrial antibodies were not useful in distinguishing between the two groups.

Immunohistochemical findings in cranial arteritis

The cause of cranial arteritis is unknown, but the demonstration of immunoglobulin and complement in temporal artery biopsies by immunofluorescence suggest that it may be a disease of disordered immunity. Because of the inevitable problems of histologic interpretation associated with the fluorescent technique, 15 temporal artery biopsies from patients with active arteritis were examined by an immunoperoxidase method. Varying amounts of IgA, IgG, and IgM were identified in plasma cells and macrophages. Extracellular IgG was identified in 1 case, but there was no staining for complement. These findings provide no support for the concept of cranial arteritis as a form of immune complex vasculitis.

In vitro cytotoxicity of human endothelial cells in polymyalgia rheumatica and giant cell arteritis

We studied sera from 20 patients with polymyalgia rheumatica (PMR)/giant cell arteritis (GCA), 15 patients with systemic lupus erythematosus (SLE), 15 patients with the CREST syndrome (calcinosis, Raynaud's phenomenon, esophageal dysfunction, sclerodactyly, and telangietasia) and 33 age and sex matched controls for cytotoxicity against human endothelial cells using a 51Cr release assay. We observed increased levels of endothelial cytotoxic activity in the PMR/GCA sera compared with controls (P less than 0.001). This cytotoxicity was predominantly found in the GCA group, where 7 out of 10 patients (70%) demonstrated significant cytotoxicity. Sequential studies showed that the cytotoxic activity returned to normal when the disease was under control. Although 7 SLE and 3 CREST sera had significant cytotoxic activity, as a group they did not differ from controls (P less than 0.05). Pre-incubation with soybean trypsin inhibitor suppressed the cytotoxic activity in the positive sera suggesting the cytotoxicity is mediated via a protease mechanism. Our results demonstrate the presence of a cytotoxic factor in the serum of patients with PMR/GCA which may play an important role in the pathogenesis of the vascular lesions observed in these disorders.

Immune complexes, rheumatoid factors, and cellular immunological parameters in patients with giant cell arteritis

Circulating immune complexes were found in 2 of 15 patients with giant cell arteritis (GCA) by using a solid phase Clq enzyme linked immunoabsorbent assay (ELISA). The prevalence in controls was 5%. Rheumatoid factor could be demonstrated in 2 out of 27 patients and in 11% of the controls by using a similar ELISA technique. The prevalence of T cells in blood was similar in 25 patients with GCA and in controls. The blood lymphocyte blastogenic response to the mitogens, phytohaemagglutinin, concanavalin-A, and pokeweed mitogen did not differ in 25 untreated patients compared with controls. Stimulation of lymphocytes by arterial homogenates was tested in 8 patients. In no case could a significant simulation by obtained. We conclude that immune complexes and rheumatoid factors are present in the same low frequency in GCA patients as in the normal population, and that the studied parameters of cellular immunity appear to be normal.

Circulating immune complexes in giant cell arteritis and polymyalgia rheumatica

Sera from 74 patients with polymyalgia rheumatica or giant cell arteritis or both were tested for immune complexes by using the Raji cell radioimmunoassay. Levels in patients with active disease were higher than in patients whose disease had become inactive. There was no difference in levels of immune complex-like materials between patients with polymyalgia rheumatica alone and those with giant cell arteritis. Density gradient analysis of one serum showed immune complex-like materials mainly in the 19S region. Immune complexes may be important in the pathogenesis of these conditions.