Successful treatment of refractory thrombocytopenia with mycophenolate mofetil in a patient with systemic lupus erythematosus

While mild thrombocytopenia in systemic lupus erythematosus (SLE) is frequently seen in the context of active disease, severe thrombocytopenia causing significant bleeding is not that common. Corticosteroids are considered the first line therapy for severe thrombocytopenia in SLE. Second-line therapeutic agents or splenectomy have been reported to be effective for patients who fail to respond to steroids or those who require moderate doses of steroids to maintain the platelet counts. Recent randomized controlled studies have shown that mycophenolate mofetil (MMF) is an efficacious and safe therapeutic agent in patients with proliferative forms of lupus nephritis. However, little information has been available regarding the role of MMF in the treatment of immune thrombocytopenia complicated with SLE. Hereby I describe a patient with SLE in whom thrombocytopenia was refractory to corticosteroids, intermittent intravenous cyclophosphamide, azathioprine, cyclosporine, intravenous gamma globulin, danazol, and splenectomy, and whose platelet counts eventually normalized during therapy with MMF. In this patient, thrombocytopenia is initially thought to be associated with active SLE involving major organ. However, after immunosuppressive agents were given, the refractory nature of thrombocytopenia seems to be an isolated phenomenon, independently of SLE activity.     

Histiocytic necrotizing lymphadenitis without granulocytic infiltration

Summary Twenty-seven cases of an unusual necrotizing lymphadenitis previously described only in Japan are reported as occurring in West Germany (23 cases), Iran (1 case), Italy (1 case), Korea (1 case) and Spain (1 case). The lesion frequently develops in the cervical lymph nodes of young women. It is characterized by infiltration of the cortex and/or paracortex by large collections of proliferating histiocytes and is devoid of granulocytes. Complete or, more often, incomplete necrosis of lymphoid tissue is seen in all cases. In cases with incomplete necrosis, the histiocytes are interspersed with pyknotic cells and nuclear debris. Based on the histological findings, the term histiocytic necrotizing lymphadenitis without granulocytic infiltration is proposed. Lesions to be considered in a differential diagnosis are malignant histiocytic neoplasms and necrotizing lymphadenitis with granulocytic infiltration, which is seen in lupus erythematosus and bacterial infections. The aetiology of histiocytic necrotizing lymphadenitis without granulocytic infiltration is still unclear. Some clinical and histological features indicate the possibility of an underlying viral infection.This study was supported by the Kind-Philipp-Stiftung     

Interleukin-1 dysregulation is an intrinsic defect in macrophages from MRL autoimmune-prone mice

Macrophages (M?) from pre-diseased autoimmune-prone MRL mice (both MRL/+ and MRL/1pr) dramatically underproduce the cytokine interleukin-1 (IL-1) in comparison to M? from a number of normal strains. In this study we show that IL-1 dysregulation by MRL M? is fully expressed at birth, and that this defect does not change with time or the development of disease. We also constructed adult irradiation chimeras (consisting of A/J → MRL and MRL → A/J mice), and show that M? isolated from these chimeras display a pattern of IL-1 production indistinguishable from that of the donor strain controls. Moreover, when we constructed a mixed chimera (A/J + MRL → A/J), the A/J and MRL M? coexisting within the same animal retained their individual patterns of IL-1 production when isolated by negative selection. Taken together, these results provide the first substantive evidence for an intrinsic defect (IL-1 dysregulation) in M? from MRL autoimmune-prone mice.     

The transmembrane form of TNF-alpha drives autoantibody production in the absence of CD154: studies using MRL/Mp-Fas(lpr) mice

It is generally accepted that the interaction between CD40 and its ligand (CD154) plays a decisive role in contact-dependent help for T and B cells. In CD154-deficient MRL/Mp-Fas(lpr) (MRL/lpr) mice, however, high titres of IgG2a-type autoantibodies against small nuclear ribonucleoproteins (snRNPs) are observed. We successfully isolated two CD154-deficient MRL/lpr Th1 lines, which could provide B cell help for anti-snRNP antibody production. The proliferative responses of the Th1 cell lines were MHC class II (I-Ek)-restricted. Although syngeneic B cell proliferation was induced by Th1 lines in both a contact-dependent and -independent manner, the soluble form of TNF-alpha (sTNF-alpha) was not involved in contact-independent B cell proliferation. On the other hand, both anti-TNF-alpha and TNF-receptor 2 (TNF-R2, p75) monoclonal antibody (MoAb) blocked contact-dependent B cell proliferation, suggesting that the transmembrane form of TNF-alpha (mTNF-alpha)-TNF-R2 co-stimulation participates in B cell activation. Similarly, anti-TNF-alpha and TNF-R2 MoAb inhibited anti-snRNP antibody production in vitro, but anti-CD154 or TNF-R1 MoAb did not. These results indicate that the interaction of mTNF-alpha on activated Th1 cells with TNF-R2 on B cells may be involved in the autoimmunity seen in MRL mice, and that the blockade of CD40-CD154 co-stimulation may not always be able to suppress some Th1-related manifestations of lupus.     

Decreased cell-mediated cytotoxicity against virus-infected cells in systemic lupus erythematosus.

Cell-mediated cytotoxicity, directed against virus-infected tissue culture cells, was studied with peripheral blood mononuclear cells from 11 patients with systemic lupus erythematosus (SLE) and 12 matched, normal subjects in a 51Cr release assay. Baseline (preimmunization) levels of cytotoxicity against target cells infected with influenza A/Victoria, influenza B/Hong Kong, Newcastle disease virus, and herpes simplex virus were significantly decreased in patients with SLE compared to normal subjects (P less than 0.001), although serum antibody levels to the respective viruses were similar in both groups. After intramuscular administration of inactivated influenza A/Victoria vaccine, SLE patients failed to generate elevated levels of cytotoxicity against A/Victoria-infected cells, in contrast to normal subjects. SLE patients responded with levels of serum hemagglutination-inhibition antibody which were similar to those of normal subjects. Thus, SLE patients manifest decreased cell-mediated cytotoxicity against virus-infected target cells, although humoral antibody responses appeared to be intact. Studies of SLE patients with influenza may help to define the role of cell-mediated immunity in the pathogenesis of certain viral infections.     

Presence of antibodies to replication protein A in some patients with systemic lupus erythematosus (SLE)

Presence of antibodies directed against replication protein A (RPA), a DNA binding protein complex composed of three subunits (RPA-70, RPA-32 and RPA-14) was investigated among patients with SLE and other autoimmune diseases using immunoblot analysis to RPA-70 and RPA-32 recombinant proteins. Anti-RPA antibodies were found in two out of 108 sera from SLE patients, one of them showing reactivity against RPA-32 and RPA-70 and the other reacting only against RPA-32. Sera from 108 patients with other autoimmune disorders as well as from 42 healthy control individuals were negative. Thus, the frequency of these antibodies in SLE is estimated to be 2–3%. The study demonstrates that RPA is one target more of the wide array of autoantigens that elicit an immune response in SLE. The presence of anti-RPA autoantibodies seems to be circumscribed to a small number of patients with SLE.     

Subpopulations of CD4+ cells in lpr/lpr mice: differences in expression of T cell receptor/CD3 complex and proliferative responses.

CD4+ cells from autoimmune-prone C57BL/6 lpr/lpr mice contain two subpopulations, B220-CD4+ and B220+CD4+ cells. Highly purified B220-CD4+ cells from C57BL/6 +/+ and lpr/lpr mice were examined by comparing functional characteristics and expression of cell surface antigens and T cell receptor (TcR)/CD3 complex. Both lpr B220+CD4+ and B220+CD4-CD8- cells, most of which were PgP-1 positive, expressed TcR/CD3 complex on the cell surface at lower level as compared with B220-CD4+ cells of age-matched normal mice. In addition, the B2200-CD4+ cells were heterogeneous on the basis of surface expression of PgP-1 and CD3 antigens. Normal levels of TcR C alpha-, C beta- and V beta 8-specific mRNA were found in the B220-CD4+ cells and B220+CD4+ cells as compared with normal B220-CD4+ cells, while V beta 8-specific mRNA was preferentially expressed only by B220+CD4-CD8- cells. Either B220+CD4+ cells and B220+CD4-CD8- cells failed to respond to anti-CD3 monoclonal antibody (MoAb) as assessed by proliferative responses and production of interleukin-2 (IL-2). However, appreciable levels of reactivity to anti-CD3 MoAb were detected in the B220-CD4+ cells, although the responsiveness of this subset to such stimuli were reduced, compared with those of normal control. These results indicate that the B220-CD4+ cells in lpr mice are phenotypically and functionally distinct from normal B220-CD4+ cells.     

Adsorption of anti-dsDNA antibodies by immobilized polyanionic compounds.

Antibodies to dsDNA are characteristically present in serum from patients with systemic lupus erythematosus (SLE), and have been shown to have the capacity to react with various molecules bearing repeating negative charges. After a number of polymeric or monomeric molecules with differently charged groups and hydrophobic molecules had been coupled covalently as ligands on cellulose gel, the adsorption capacities of the ligands for anti-dsDNA antibodies were evaluated. It was found that gels coupled with polyanionic dextran sulphate (DXS) and polyacrylic acid (PA) and monoanionic sulphanilic acid (SA) absorbed anti-dsDNA antibodies effectively. DXS gel also adsorbed antibodies to ssDNA and heparan sulphate, antigens with repeating negatively charged moieties, while no ligand was able to adsorb anti-nRNP antibodies. The finding that DXS gels adsorbed anti-dsDNA antibody in proportion to their charge density, and that the interaction between anti-dsDNA and DXS gel is broken readily by an increase in ionic strength, indicated that the binding is ionic in nature. Moreover, virtually all F(ab')2 anti-dsDNA became adsorbed onto the DXS gels, suggesting that the binding occurred via specific antigen-binding sites on the antibody molecule. Binding of these polyanion-binding autoantibodies with anionic sites in the glomerular basement membrane may therefore cause the tissue damage observed in SLE.     

Autoantibodies to histone, DNA and nucleosome antigens in canine systemic lupus erythematosus.

Dogs can develop systemic lupus erythematosus syndromes that are clinically similar to those seen in humans. In contrast, previous observations suggest differences in their autoantibody reactivity patterns against histones and DNA which are components of the nucleosome in chromatin. The objective of this study was to assess comprehensively the levels of autoantibodies against histone, DNA and nucleosome antigens in a population of lupus dogs. The specificities of antibodies in lupus and control dog sera were determined using IgM- and IgG-specific reagents in an ELISA against a variety of chromatin antigens. When compared with control sera, IgG antibodies to individual histones H1, H2A, H3 and H4 were significantly higher in the lupus group. In contrast, we did not detect IgG antibodies specific for H2B, H2A-H2B, DNA, H2A-H2B-DNA or nucleosome in lupus dogs. There was no significant increase in any of the IgM specificities tested. Therefore, the reactivity pattern to nucleosome antigens in canine lupus is restricted to IgG antibodies against individual histones H1, H2A, H3 and H4. This stands in contrast with human and murine lupus, where autoantibodies are directed against a wide variety of nucleosomal determinants, suggesting that unique mechanisms lead to the expansion of anti-histone antibody clones in canine lupus. The high incidence of glomerulonephritis in dog lupus suggests that anti-DNA antibodies are not required for the development of this complication, whereas IgG anti-histone antibodies may be relevant to its pathogenesis.