Familial occurrence of impaired interleukin-2 activity and increased peripheral blood B cells actively secreting immunoglobulins in systemic lupus erythematosus

Immunoregulatory defects in patients with systemic lupus erythematosus in clinical remission

Little is known about the immune system of patients with systemic lupus erythematosus (SLE) during periods of silent disease. To address this issue we analysed lymphoid populations andcytokine production of mononuclear cells obtained from SLE patients in remission. We studied 43 patients with inactive disease, 10 with active disease and 30 controls. Remission was defined as at least 1 year during which lack of clinical disease activity permitted withdrawal of all treatment. Remission length ranged from 1 to 30 years. Flow cytometry and ELISA were used to study lymphoid populations (CD4, CD8 and CD19) and cytokine production (IL-2, 4, 10, 12 and 18). Patients with short remission periods (up to 15 years) exhibited an increased percentage of B cells; production of IL-2, IL-10 and IL-12 was decreased; production of IL-18 was increased. Interestingly, patients from groups with long time of inactive disease had corrected most alterations, but had an impaired IL-18 expression. IL-12 production correlated strongly with the length of the remission period (r = 0.7565). The immune system of patients with inactive lupus has partially corrected the disturbances present during disease activity. This is accomplished gradually, sometimes until counter-regulatory alterations are developed. This may allow patients to remain without disease activity.

Disassociation of sex hormone levels and cytokine production in SLE patients

This study examines whether changes in the cytokine milieu of patients with systemic lupus erythematosus (SLE) are associated with abnormal levels of sex hormone levels in serum. The concentration of 17beta-estradiol (E2), progesterone (Pg) and dehydroepiandrosterone-sulphate (DHEAS) was monitored in sera from 128 lupus patients and 96 controls, and correlated with the activity of their cytokine secreting cells. Results indicate that SLE patients have (i) significantly fewer cells secreting IFNgamma, (ii) increased serum E2 and Pg levels, and (iii) reduced serum DHEAS levels compared to normal controls. However, the observed abnormalities in the cytokine milieu of SLE patients did not correlate with abnormalities in serum sex hormone levels. Instead, the association between IFNgamma production and DHEAS levels evident in healthy controls is absent in SLE patients, suggesting that cells from lupus patients are defective in their ability to produce IFNgamma in response to physiologic stimuli. Similarly, the normal correlation between IL-4 production and E2 levels was lost in patients with severe disease. Thus, while it remains possible that increased E2 and reduced DHEAS levels in lupus patients may help induce cytokine abnormalities early in disease, the subsequent cytokine imbalance does not correlate with sex hormone levels.

Genetic studies of human lupus in families

Systemic lupus erythematosus (SLE) is a complex multigenic disease in which the contributing genetic systems are being rapidly identified. Most of the currently recognized genes have been discovered from case-control association studies, but, increasingly, family linkage studies are being employed to confirm previous genetic associations, to examine their relative contributions, and to identify new susceptibility loci. Most of the loci identified thus far appear to contribute only modest effects on susceptibility overall but rather influence more strongly disease expression and/or severity. MHC class II alleles, for example, seem to show only weak linkage to SLE itself but instead mediate specific T cell driven pathogenic autoantibodies which produce many of the clinical disease features, similar to their effects in many other autoimmune diseases. On the other hand, complete and partial hereditary deficiencies of early complement components are more lupus-specific. Homozygous complement deficiencies, while powerful risk factors, are rare causes of lupus and heterozygous deficiencies exert only modest effects on susceptibility. Other genes, such as low-binding IgG Fc receptor alleles (FcgammaIIa and FcgammaIIIa), appear to promote nephritis by modifying the efficiency of immune complex clearance. A variety of cytokine genes appear also to promote severity, including those for TNFalpha, IL-10, IL1 receptor antagonist, and perhaps others (IL-6, IL-4 and TNFalpha receptor). Family studies and recent genome-wide scans in lupus and other autoimmune diseases support the likelihood that some susceptibility loci, as yet unidentified, predispose to several or many autoimmune diseases. Only thorough the identification and elucidation of function of these many genes is the pathogenic picture of lupus likely to be complete.

Small-bowel involvement in systemic lupus erythematosus: a morphometric and immunohistochemical study

BACKGROUND

We have investigated the intestinal mononuclear cell subpopulations in patients with systemic lupus erythematosus (SLE) and correlated these with the disease activity.

METHODS

Eighteen female outpatients were studied; in 10 of them lupus activity was measured with the Lupus Activity Criteria Count and the SLE Disease Activity Index. Eight patients were in lupus remission. The control group consisted of 10 healthy volunteers. Peroral jejunal biopsy was performed in all individuals, at the angle of Treitz, using a Watson capsule, under X-ray control. Histologic studies analysed the villous to crypt ratio, lamina propria cells, and intraepithelial lymphocyte count. Immunohistochemical evaluation was carried out with the indirect immunoperoxidase technique, using monoclonal antibodies against CD3, CD4, CD8, D1, D7, D9, and M1.

RESULTS

Lamina propria CD3+, CD8+, D7+, and M1+ cells from patients with SLE did not differ significantly from those of controls. CD4+ cells were decreased in all patients with SLE, especially in the clinically inactive patients. D1+ and D9+ cells were also decreased in all patients.

CONCLUSION

The finding of quantitative abnormalities in the cell-mediated immunity of the intestinal mucosa may reflect systemic defects of the immune system in SLE.

Interleukin-2 and systemic lupus erythematosus--fifteen years later

Systemic lupus erythematosus (SLE) is a highly heterogeneous disorder in which multiple immunologic abnormalities have been described. In this review, we thoroughly analyse the impaired T cell production of, and response to, interleukin-2 (IL-2) characteristic of patients with SLE. Since it was first reported, several articles have provided us with enlightening, but somewhat confusing, data that reveal the complexity of the subject. The IL-2 production by T cells is part of a complex network in which a discrete alteration is capable of disrupting the whole system. On the other hand, regulatory mechanisms exist that, in an attempt to compensate the primary alteration, provoke secondary defects. Evidence indicates that this defect is not intrinsic, but rather, results from multiple microenvironmental influences that act on the T cell and modify its activation state and its cytokine production. Abnormalities in co-stimulatory mechanisms and in cytokines that may be related to the IL-2 production deficiency, have been described in patients with SLE. We also consider the information derived from murine SLE models, IL-2 knockout models and reports concerning the immune dysregulation present in patients with SLE.

Dysregulation of interleukin-10 production in relatives of patients with systemic lupus erythematosus

OBJECTIVE

To evaluate interleukin-10 (IL-10) production in relatives of patients with systemic lupus erythematosus (SLE).

METHODS

Production of IL-10 was evaluated in 13 families in which several members had SLE. The constitutive IL-10 production in SLE patients (n = 16) was compared with that in healthy members of these multiplex families (n = 70), in 30 SLE patients who had no relatives with SLE, and in 46 healthy unrelated controls.

RESULTS

The level of IL-10 production did not differ between SLE patients who were members and those who were not members of multiplex families (mean +/- SEM 4,384 +/- 908 pg/ml and 4,709 +/- 560 pg/ml, respectively), but was higher in both groups than in healthy unrelated controls (515 +/- 88 pg/ml). The healthy members of the multiplex families constitutively produced large amounts of IL-10 (3,080 +/- 311 pg/ml; P < 0.001 compared with healthy unrelated controls). This high IL-10 production was independent of age and sex, and was similar in first- and second-degree relatives of SLE patients. The IL-10 was produced both by monocytes and by a subpopulation of B lymphocytes in SLE patients and in their relatives.

CONCLUSION

The dysregulation of IL-10 production previously identified in SLE patients is also present in healthy members of families with several cases of SLE, and it may contribute to the immunologic abnormalities affecting relatives of SLE patients.

Low serum levels of dehydroepiandrosterone may cause deficient IL-2 production by lymphocytes in patients with systemic lupus erythematosus (SLE)

The principal cause of IL-2 deficiency, a common feature of both murine lupus and human SLE, remains obscure. Recent studies of our own as well as others have shown that dehydroepiandrosterone (DHEA), an intermediate compound in testosterone synthesis, significantly up-regulates IL-2 production of T cells, and that administration of exogenous DHEA or IL-2 via a vaccinia construct to murine lupus dramatically reverses their clinical autoimmune diseases. Thus, we have examined serum levels of DHEA in patients with SLE to test whether abnormal DHEA activity is associated with IL-2 deficiency of the patients. We found that nearly all of the patients examined have very low levels of serum DHEA. The decreased DHEA levels were not simply a reflection of a long term corticosteroid treatment which may cause adrenal atrophy, since serum samples drawn at the onset of disease, which are devoid of corticosteroid treatment, also contained low levels of DHEA. In addition, exogenous DHEA restored impaired IL-2 production of T cells from patients with SLE in vitro. These results indicate that defects of IL-2 synthesis of patients with SLE are at least in part due to the low DHEA activity in the serum.

Interleukin-2 activity of colonic lamina propria mononuclear cells in a rat model of experimental colitis

BACKGROUND

Altered interleukin 2 (IL-2) production has been implicated in the pathogenesis of inflammatory bowel diseases.

METHODS

The temporal relationship between IL-2, prostaglandin E2 (PGE2) production, and mucosal injury was evaluated by isolated colonic lamina propria mononuclear cells (LPMC), using the trinitrobenzene sulfonic acid model of rat colitis.

RESULTS

Spontaneous LPMC IL-2 activity was significantly increased in chronic (5 weeks) but not acute (5 days) or resolved colitis groups. IL-2 activity after concanavalin A activation was highest in the groups with resolved and chronic colitis. PGE2 production was significantly increased in LPMC cultures in acute or chronic colitis as well as the ethanol control groups but not the resolved colitis group. The addition of indomethacin to LPMC cultures decreased PGE2 levels in all groups, whereas IL-2 activity increased only for the chronic and resolved colitis groups. No correlation was found between PGE2 and IL-2 production by LPMC.

CONCLUSIONS

In this experimental model, LPMC IL-2 production varied according to the severity and duration of the inflammation. Increased PGE2 production does not appear to be responsible for the IL-2 alterations in colitis.

T-cell receptor alpha/beta chain-CD3 protein complex defect in systemic lupus erythematosus: T-cell function

We describe the first case of systemic lupus erythematosus (SLE) in which peripheral blood T cells were deficient in cell surface expression of T-cell receptor alpha/beta chain (TcR alpha beta) and the CD3 protein. Because of the uncommon phenotype and because of the notion that coexpression of TcR alpha beta and CD3 is essential for antigen-specific T-cell function, in vitro functional assays were performed, showing a highly decreased proliferative response to anti-CD3 antibody and other T-cell mitogens, deficient interleukin-2 (IL-2) secretion, and impaired function to respond in autologous and allogeneic mixed lymphocyte reactions. However, the helper-inducer function of T cells was unaffected by deficient expression of the TcR alpha beta/CD3 protein complex. The relative increase of CD4+ CDw29+ helper-inducer subsets in T cells accounted for elevated secretion of two terminal B-cell stimulating factors, B-cell growth factor (BCGF) and B-cell differentiation factor (BCDF). Hence, our results suggest that the regulation of secretion of lymphokines, IL-2, and BCGF and BCDF is independently controlled in T cells, and this case illustrates the pathologic sequelae of a unique defect in T cells characteristic of SLE.

Cytokines and autoimmune disease

A wide array of cytokines are locally present in autoimmune lesions where they are produced by inflammatory cells or by the target cell of the autoimmune attack. The presence of cytokines at the site of autoaggression reflects ongoing inflammatory and activation processes. These mediators exert proinflammatory effects, contribute to the activation and stimulation of the effector function of T or B lymphocytes, directly participate in target cell destruction, and mediate accompanying local reactions, including fibrotic processes. The release of cytokines into the circulation may explain certain systemic reactions, including fever or changes in the profile of plasma proteins. Many, especially systemic, autoimmune diseases are accompanied by a dysregulation of lymphokine secretion at the level of circulating leukocytes or cells situated outside of the local inflammatory event, thus reflecting regulatory disorders that may either have a genetic or an acquired basis. Decreased production of lymphokines in vitro in response to nonspecific stimuli may be accompanied by an elevated spontaneous release in vivo resulting in an increase of circulating cytokine levels (interleukin 2, tumor necrosis factor-alpha). Secretion of interleukin 1, interleukin 2, and tumor necrosis factors-alpha or -beta, in part, is determined by genetic factors and it is possible that a particular secretor phenotype may predispose to the development of autoimmune lesions. Probably due to their pleiotropic nature, systemic administration of cytokines such as interleukin 1, interleukin 2, tumor necrosis factor, and interferon-gamma may exert either accelerating or suppressive effects on autoimmune diseases. Conversely, agents that block the function of the lymphokine interleukin 2 exert an unequivocal autoimmune disease-inhibiting effect.

Soluble interleukin-2 receptor in sera of patients with Graves' disease

Activation of T lymphocytes has been found to be associated with an increase in soluble interleukin-2 receptor (sIL-2R) levels. The aim of this study was to investigate serum levels of sIL-2R in 20 untreated patients with Graves' disease and to relate these levels to disease activity and to TSH-receptor, anti-thyroglobulin, anti-microsomal and anti-eye muscle antibodies. sIL-2R levels were significantly increased in newly diagnosed Graves' patients compared with controls (667 +/- 270 vs 205 +/- 45 U/ml) (P less than 0.001). The sIL-2R levels were higher in patients with active infiltrative ophthalmology than in those without eye symptoms (810 +/- 313 vs 525 +/- 180 U/ml). All patients were treated with methimazole for at least 12 months. sIL-2R levels were normalized by methimazole treatment in the majority of patients without ophthalmopathy but not in those with ophthalmopathy. In five patients sIL-2R serum levels were studied after interruption of thyrostatic therapy. An increase was observed in three patients and hyperthyroidism subsequently relapsed in two of these. Furthermore, a correlation was found between soluble interleukin-2 receptor levels and TSH-receptor antibodies but not with other immune parameters examined. Serum sIL-2R represents a useful marker of immunological activity in Graves' disease.

Cytokine-independent progression of immunoglobulin production in vitro by B lymphocytes from patients with systemic lupus erythematosus

B lymphocytes from patients with systemic lupus erythematosus (SLE) secreted high levels of immunoglobulin spontaneously when cultured in vitro. Addition of the cytokines interleukin-2, interleukin-4 and interleukin-6 either alone or in combination failed to augment spontaneous immunoglobulin synthesis. Percoll-separated low-density SLE B lymphocytes matured into immunoglobulin-secreting cells also independent of exogenous interleukins. During maturation these cells became enlarged and less dense, and began to express CD23. This was in contrast to normal B cells, which did not secrete immunoglobulin spontaneously but synthesized IgM after interleukin stimulation. These results indicate that in vitro immunoglobulin synthesis by SLE B cells is already initiated in these cells and progresses independently of further stimulatory manoeuvres.