Diminished levels of T cell receptor zeta chains in peripheral blood T lymphocytes from patients with systemic lupus erythematosus.

OBJECTIVE: To examine the expression of molecules known to participate in early T cell receptor (TCR)/CD3 signaling in peripheral blood (PB) T lymphocytes from patients with systemic lupus erythematosus (SLE). METHODS: Signaling molecules were analyzed by immunoprecipitation and Western blotting of unstimulated PB T lymphocyte cell lysates from SLE patients, non-SLE disease controls, and healthy controls. Flow cytometry was used for analysis of the expression of membrane markers in intact cells. RESULTS: PB T lymphocytes from SLE patients showed diminished levels of TCRzeta chains. This was not due to trapping of these molecules in the cytoskeleton, nor was it dependent on the presence of monocyte/macrophages. There was normal expression of CD3epsilon chains and normal assembly of TCR/CD3 complexes in membranes. We observed a lack of expression of TCRzeta chains in in vitro cultures of SLE T cells, and reversal of the defective expression in some patients by culturing T cells in the presence of NH4Cl. CONCLUSION: Blood lymphocytes from SLE patients have a diminished expression of TCRzeta chains that may be related to enhanced degradation in the lysosomal compartment. The defective expression of these molecules may alter signal transduction via the CD3 pathway and contribute to abnormal T cell responses in T lymphocytes from SLE patients.

Abnormal pattern of tyrosine phosphorylation in unstimulated peripheral blood T lymphocytes from patients with systemic lupus erythematosus.

Previous reports have shown abnormal responses mediated via the TCR/CD3 pathway in T lymphocytes from systemic lupus erythematosus (SLE) patients. Recently, we and others have reported augmented TCR/CD3-mediated responses in lupus T cells. It is possible that the pattern of downstream biochemical signals triggered by TCR/CD3 ligation may be altered in T lymphocytes from patients with SLE, thus leading to abnormal distal cell responses. In this paper we have examined the phosphorylation of proteins on tyrosine residues in peripheral blood T lymphocytes from a group of SLE patients and controls. We found a lower frequency of constitutively tyrosine-phosphorylated 119- and 113-kDa substrates and an enhanced frequency of tyrosine-phosphorylated 66- and 25-kDa proteins in unstimulated cultures of SLE T lymphocytes, suggesting an altered pattern of tyrosine phosphorylation in T cells from patients in vivo. Additionally, the protein tyrosine phosphatase (PTP) activity of CD45 immunoprecipitates was lower in unstimulated lupus T cells and was enhanced after stimulation via the CD3 pathway in lupus but not control T lymphocytes. The present results seem to suggest abnormal regulation of in-vivo tyrosine phosphorylation in T cells from patients with SLE.

Protein tyrosine kinase activity in T lymphocytes from patients with systemic lupus erythematosus.

We have recently observed an abnormal pattern of protein tyrosine phosphoryl-ation in resting T lymphocytes obtained from peripheral blood of patients with systemic lupus erythematosus (SLE). To examine whether these findings may be related to dysregulated protein tyrosine kinase (PTK) function, we tested the relative amount and enzyme activity of the main PTKs involved in the earliest signalling steps triggered via the CD3 pathway. Cell lysates from peripheral blood T cells in SLE patients showed lower amounts of p59(fyn) and p56(lck) as shown by immunoblot. In contrast, the amount of ZAP-70, a PTK of the syk family, was comparable in both groups. However, p59(fyn) immuno-precipitates obtained from unstimulated peripheral blood SLE T cells showed enhanced PTK activity as compared to controls, whereas the PTK activity of p56(lck) and ZAP-70 molecules was comparable in both groups. The unchecked activity of the TCR/CD3-associated src kinase p59(fyn) may alter the balance needed for regulated T cell responses in SLE patients.

Restriction fragment length polymorphisms of constant region genes of immunoglobulin lambda chains in Venezuelan patients with systemic lupus erythematosus.

Previous studies suggest a potential association between human immunoglobulin (Ig) genes and susceptibility to systemic lupus erythematosus (SLE). Ig allotypic determinants seem to confer an increased risk for the disease in various ethnic patient populations. In this study we have examined the pattern of restriction fragment length polymorphisms (RFLP) of constant region lambda (C lambda) light chain genes in a group of 78 Venezuelan patients with SLE and 70 healthy controls. The frequency of the 8-kb allele and the 8/8 genotype was significantly lower in normal Venezuelan controls as compared to healthy British Caucasians (P = 0.0002 and 0.0007 respectively). In turn, Venezuelan controls showed a higher frequency of the 18-kb allele and the 18/18 genotype (P = 0.0002 and 0.0052 respectively). However, there were no statistically significant differences in either parameter between Venezuelan SLE patients and healthy controls. Our study argues against a role for lambda light chain constant region genes in predisposition to SLE.

T lymphocytes from patients with systemic lupus erythematosus show increased response to interleukin-2 after costimulation with OKT3 monoclonal antibody and phorbol esters.

In the present study we have examined the potential contribution of IL-2/IL-2R interactions in CD3-mediated responses by T lymphocytes from patients with systemic lupus erythematosus (SLE). T-cells from SLE patients showed normal IL-2 production when activated with OKT3 MAb and submitogenic concentrations of PMA, in cultures in which uptake of endogenous IL-2 was prevented by pretreatment with anti-Tac MAb. In contrast, PHA-induced IL-2 production was lower in patients under the same conditions. Under these stimulatory conditions the proportions of T-cells expressing IL-2R CD25 molecules was comparable in patients and controls. There was earlier and higher binding of exogenously added IL-2 in T lymphocytes from patients activated via the CD3 pathway. Furthermore, these cells responded to IL-2 with stronger proliferative responses than cells from control subjects. These findings may partly explain the increased proliferative responses of SLE T-cells when stimulated via the CD3 pathway.

Increased proportion of responders to a murine anti-CD3 monoclonal antibody of the IgG1 class in patients with systemic lupus erythematosus (SLE).

A group of Venezuelan patients with SLE showed an increased proportion of responders to Leu-4, an anti-CD3 MoAb of the IgG1 class, compared with ethnically matched non-SLE patients and healthy controls. The rate of proliferative responses or IL-2 production induced by MoAb Leu-4, and the helper effect of macrophages from Leu-4 responders on T cells from a third-party donor were comparable in patients and controls. No significant differences in the binding of murine IgG1 molecules by macrophages from SLE patients and controls were observed. The proportion of monocytes/macrophages expressing Fc gamma RI was significantly higher in SLE patients. However, the expression of FcRII, the type capable of supporting Leu-4-mediated responses, and of Fc gamma RIII was comparable in monocytes from SLE patients and controls. Our results suggest that Venezuelan patients with SLE may have a genetic predisposition for the expression of the phenotypic variant of Fc gamma RII capable of binding murine IgG1 molecules.

Enhanced CD3-mediated T lymphocyte proliferation in patients with systemic lupus erythematosus.

Nonfractionated peripheral blood lymphocytes from patients with systemic lupus erythematosus (SLE) showed enhanced proliferative responses when stimulated via the CD3 pathway. In contrast, proliferative responses induced by phytohemagglutinin were diminished in SLE patients. Levels of CD3-induced interleukin-2 production and interleukin-2 receptor expression were comparable with normal levels. Highly purified T cells also showed augmented CD3 responses, but only in the presence of phorbol myristate acetate or a combination of phorbol myristate acetate plus calcium ionophore A23187, and not with calcium ionophore alone. The data suggest integrity of the T cell receptor/CD3 pathway for T cell activation in patients with SLE, as examined in cultures stimulated with specific anti-CD3 monoclonal antibodies rather than with multivalent lectins. An increased response via the CD3 complex could contribute to the autoimmune activity in human SLE.

Auricular chondritis and diffuse proliferative glomerulonephritis in primary Sjögren's syndrome.

Bilateral auricular inflammation with histological changes of relapsing polychondritis was observed in a female patient with primary Sjögren's syndrome. This was accompanied by rapidly progressive renal insufficiency due to diffuse proliferative glomerulonephritis. To our knowledge this is the first well documented case of primary Sjögren's syndrome associated with chondritis and glomerulonephritis, further emphasising the wide spectrum of extraglandular manifestations in this autoimmune disorder.

Down-regulation of immunoglobulin and IgM-rheumatoid factor synthesis by oral treatment of rheumatoid arthritis patients with a nonsteroidal antiinflammatory drug.

We examined the effect of treatment with piroxicam, a nonsteroidal antiinflammatory drug (NSAID), on immunoglobulin (Ig) and IgM-rheumatoid factor (IgM-RF) synthesis in vitro by lymphocytes of patients with rheumatoid arthritis (RA). Oral treatment with piroxicam induced a progressive decrease of spontaneous IgM-RF production by unstimulated lymphocyte cultures during 12 weeks of observation. Also, pokeweed mitogen (PWM)-driven Ig synthesis was significantly diminished and the effect on total IgM production was sustained until the end of the study. This modulation of humoral responses is consistent with the drop in RF sera level. In addition, we also showed that treatment with NSAIDs can decrease RF levels in the synovial space. NSAIDs may have a long-term beneficial effect in patients with RA due to their modulatory role of lymphocyte responses.