Prevalence of Fc‐gammaR chain expression in CD4+T cells of patients with systemic lupus erythematosus

Lead poisoning influences TCR-related gene expression patterns in peripheral blood T-lymphocytes of exposed workers

Previous studies have shown that occupational lead (Pb) exposure might influence human T-lymphocyte function, including such as changes in T-cell receptor (TCR) Vβ and Vγ repertoire and in expression of the TCRζ gene. Thus, the study here further investigated expression of TCRζ-related factors and the FcεRIγ gene (whose product has a functional role complementary to the TCRζ chain) and the Elf-1 gene whose product is involved in regulation of TCR expression. Quantitative real-time RT-PCR was used to measure expression of TCRζ, FcεRIγ, and Elf-1 genes in peripheral blood mononuclear cells (PBMC) isolated from 17 Pb-exposed workers. Samples were collected before and after the workers had undergone chelation therapy regimens. Twenty-three healthy individuals served as controls. The results showed that TCRζ, FcεRIγ, and Elf-1 gene expression in Pb-exposed workers before chelation therapy was significantly lower than in PBMC from healthy individuals. After chelation therapy, expression of TCRζ appeared to trend toward normal levels; in comparison, lower expressions of FcεRIγ and Elf-1 persisted. In conclusion, the previously-documented impairment of T-lymphocyte functions and T- lymphocyte-mediated immune responses seen previously in response to occupational Pb exposure might be attributable, in part, to effects on TCR signaling pathways - including those related to TCRζ and FcεRIγ - and to any down-regulation of membrane TCRζ expression/activity that might be associated with Pb-induced effects on Elf-1 expression.

Prevalence of ZAP-70, LAT, SLP-76, and DNA methyltransferase 1 expression in CD4+ T cells of patients with systemic lupus erythematosus

T cells from systemic lupus erythematosus (SLE) patients exhibit defective function of CD4(+) T cells that can be responsible for improper activation of B cells and antibody biosynthesis against host antigens. We compared the level of ZAP-70, LAT, and SLP-76, transcripts and proteins in CD4(+) T cells from SLE patients (n = 22) and healthy individuals (n = 15). We also determined DNA methyltransferase 1 (DNMT1) protein content in CD4(+) T cells of SLE patients. The CD4(+) T cells were isolated by positive biomagnetic separation technique. The quantitative analysis of messenger RNA (mRNA) was performed by reverse transcription and real-time quantitative polymerase chain reaction (RQ-PCR) SYBR Green I system. The protein level in the CD4(+) T cells was determined by Western blotting analysis. We found that the LAT protein level was significantly higher in SLE CD4(+) T cells than in controls (P = 0.006). Western blot analysis revealed that ZAP-70 protein content in SLE CD4(+) T cells may be reciprocally correlated with disease activity expressed in SLEDAI scale (R = -0.623, P = 0.002) or number of affected organ systems (R = -0.549, P = 0.008). We also observed reciprocal correlation between DNMT1 protein content in CD4(+) T cells and disease activity scored with SLEDAI scale (R = -0.779, P = 0.001) or number of affected organ systems (R = -0.617, P = 0.019), respectively. Our findings might indicate that LAT, ZAP-70, and DNMT1 protein levels in CD4(+) T cells can be associated with SLE disease.

Liver infarction in a woman with systemic lupus erythematosus and secondary anti-phospholipid and HELLP syndrome

We report a 39-year-old primigravida, a case of systemic lupus erythematosus (SLE) and secondary anti-phospholipid syndrome (APS) with a smooth antenatal course who delivered by caesarean for non-reassuring foetal heart rate. On day 2 postoperatively, she developed a sudden severe colicky upper abdominal pain with tachypnoea, dyspnoea, and tachycardia, and blood pressure (BP) reaching 150/95 mmHg. Computed tomography of the abdomen revealed lesions consistent with liver infarction. She developed haemolytic anaemia, elevated liver enzymes, and low platelets (HELLP syndrome); heparin and methylprednisolone were started. On day 3, BP normalized, respiratory symptoms improved but abdominal symptoms persisted. Methylprednisolone was increased to 80 mg/day on day 8 when she had significant clinical response and was discharged on day 16. This case emphasizes that a morbid clinical course including liver infarction should be anticipated in patients with SLE and APS complicated with HELLP syndrome.

FcgammaRIII engagement provides activating signals to NKT cells in antibody-induced joint inflammation

NKT cells promote antibody-induced arthritis, but the mechanism by which NKT cells are activated in this model remains unclear. It has been proposed that Fcgamma receptor (FcgammaR) contributes to NKT cell activation in antibody-induced arthritis. To address this issue, we explored the functions of FcgammaR on NKT cells in antibody-induced arthritis. RT-PCR and flow cytometric analysis demonstrated that NKT cells constitutively express surface FcgammaRIII but not FcgammaRI, -II, or -IV. FcgammaRIII engagement by aggregated IgG on NKT cells enhanced CD25 and CD69 expression, whereas FcgammaR(-/-) mouse NKT cells did not enhance activation. FcgammaRIII engagement on NKT cells enhanced the production of IL-4, IL-10, IL-13, and IFN-gamma, whereas FcgammaR-deficient NKT cells did not alter the production of these cytokines after aggregated IgG treatment. However, FcgammaR-deficient NKT cells were functionally intact in terms of TCR-induced activation. Moreover, adoptive transfer of FcgammaR-deficient NKT cells could not restore inflammation or TGF-beta production in the joint tissues of CD1d(-/-) mice, whereas adoptive transfer of wild-type NKT cells induced arthritis and reduced TGF-beta production in joint tissues. We conclude that FcgammaRIII engagement by IgG in joint tissues provides activating signals to NKT cells in antibody-induced arthritis.