The effects of freeze/thawing on the function and phenotype of CD4(+) lymphocyte subsets in normal individuals and patients with systemic lupus erythematosus.

Several studies report on lymphocyte phenotypic and functional abnormalities in Systemic Lupus Erythematosus (SLE). Freezing and thawing may alter functional and phenotypic properties of cells. We assessed the effect of the freezing/thawing process (F/T) on Th1 (CD3(+)CD4(+)CCR4(-)CXCR3(+)CCR5(+)), Th2 (CD3(+)CD4(+)CCR5(-)CXCR3(-)CCR4(+)), Th17 (CD3(+)CD4(+)CCR6(+)CD161(+)), and Treg (CD3(+)CD4(+)CD25(high)CD127(-)) cell cultures in healthy controls and SLE patients. F/T was associated with decreased frequency of Th2 and Th17 cells in cultures from SLE patients but not from controls. F/T was also associated with increased frequency of apoptotic cells, as measured by annexin V labeling, in all T cell subtypes analyzed, as well as increased cell proliferation, as measured by Ki-67 labeling, in all cells except Th1 from SLE patients. Thus, F/T can have differentiated effects on T lymphocyte subtypes from SLE patients and controls, and can have significant effects on cell death and proliferation. These findings should be carefully considered when designing and interpreting studies on functional and phenotypic aspects of T lymphocytes in SLE.

CD4 T lymphocyte subsets display heterogeneous susceptibility to apoptosis induced by serum from patients with systemic lupus erythematosus.

BACKGROUND: Serum from systemic lupus erythematosus (SLE) patients has been shown to induce T-lymphocyte (TL) apoptosis. Given that different cells of the immune system display different sensitivity to apoptosis, we set to evaluate the in vitro effect of SLE serum on regulatory T-cells (Treg), Th17, Th1 and Th2 from SLE patients and healthy controls. METHODS: Peripheral blood mononuclear cells from SLE patients or normal controls were exposed to a pool of sera from SLE patients or normal controls. Annexin V was used to label cells in apoptosis or necrosis. Annexin V-labeled Treg, Th17, Th1 and Th2 cells were determined using flow cytometry. RESULTS: Total CD3 + and CD4 + cells from SLE patients showed higher frequency of spontaneous apoptosis/necrosis, whereas Th1 cells from SLE patients presented reduced spontaneous apoptosis/necrosis rate as compared with cells from controls. Incubation with SLE serum induced increased frequency of apoptotic/necrotic CD3 + , CD4 + and Th2 cells from normal controls or from SLE patients as compared with cultures incubated with normal human serum (NHS) or without human serum at all. Incubation with SLE serum did not increase the apoptosis/necrosis rate in Th1 or Th17 cells. Treg cells from SLE patients were more prone to apoptosis/necrosis induced by SLE serum than Treg cells from normal individuals. Th1, Th2, and Th17 cells presented increased apoptosis rates in cultures without human serum. CONCLUSION: Our findings indicate that the serum of patients with active SLE stimulates apoptosis of CD4 + T cells in general and exhibit differentiated effects on CD4 + T-cell subsets.

Th17 cells and CD4(+) multifunctional T cells in patients with systemic lupus erythematosus.

INTRODUCTION/OBJECTIVE: Recent evidence suggests that abnormalities involving Th17 lymphocytes are associated with the pathophysiology of systemic lupus erythematosus (SLE). In addition, multifunctional T cells (MFT), i.e., those producing multiple cytokines simultaneously, are present in the inflammatory milieu and may be implicated in the autoimmune process observed in SLE. In the present study, we aimed to characterize the functional status of CD4(+) T cells in SLE by simultaneously determining the concentration of IL-2, IFN-γ and IL-17 in lymphocyte cultures under exogenous and self-antigenic stimuli. PATIENTS AND METHODS: Eighteen patients with active disease, 18 with inactive disease, and 14 healthy controls had functional status of CD4(+) T cells analyzed. RESULTS: We found that SLE patients presented a decreased number of total CD4(+) cells, an increased number of activated T cells, and an increased frequency of Th17 cells compared to healthy controls (HC). MFT cells had increased frequency in SLE patients and there was an increased frequency of tri-functional MFT in patients with active SLE compared with those with inactive SLE. Interestingly, MTF cells produced larger amounts of IFNγ than mono-functional T cells in patients and controls. CONCLUSION: Taken together these data indicate the participation of recently activated Th17 cells and MTF cells in the SLE pathophysiology.

Immune system - part I. Fundamentals of innate immunity with emphasis on molecular and cellular mechanisms of inflammatory response.

The immune system consists of an intricate network of organs, cells, and molecules responsible for maintaining the body's homeostasis and responding to aggression in general. Innate immunity operates in conjunction with adaptive immunity and is characterized by rapid response to aggression, regardless of previous stimulus, being the organism first line of defense. Its mechanisms include physical, chemical and biological barriers, cellular components, as well as soluble molecules. The organism first line of defense against tissue damage involves several steps closely integrated and constituted by different components of this system. The aim of this review is to restore the foundations of this response, which has high complexity and consists of several components that converge to articulate the development of adaptive immune response. We selected some of the following steps to review: perception and molecular recognition of aggressive agents; activation of intracellular pathways, which result in vascular and tissue changes; production of a myriad of mediators with local and systemic effects on cell activation and proliferation, synthesis of new products involved in the chemoattraction and migration of cells specialized in destruction and removal of offending agent; and finally, tissue recovery with restoration of functional tissue or organ.