Exposure to nuclear antigens contributes to the induction of humoral autoimmunity during tumour necrosis factor alpha blockade

OBJECTIVE

Type I interferons and apoptotic particles contribute to antinuclear autoimmunity in experimental models. This study assessed whether similar mechanisms contribute to break peripheral B-cell tolerance in humans by studying the induction of antinuclear antibodies by tumour necrosis factor blockade in spondyloarthritis.

METHODS

40 spondyloarthritis patients treated with infliximab or etanercept and 20 renal cell carcinoma patients treated with sorafenib were studied. Serum antinucleosome IgM and nucleosomes were measured by ELISA. Type I interferon serum activity was measured using a functional reporter cell assay. Synovial apoptosis was assessed by terminal transferase nick end-labelling (TUNEL) assay and anti-active caspase-3 immunostaining. Complement was measured by nephelometry.

RESULTS

Despite a similar clinical improvement and reduction of synovial inflammation, antinucleosome IgM were induced by infliximab but not etanercept. This induction did not correlate with type I interferon activity, which was transiently downmodulated by infliximab but persistently upregulated by etanercept. In contrast, antinucleosome IgM levels did correlate with serum nucleosome levels, which were significantly upregulated by infliximab but not by etanercept treatment. This increase in serum nucleosome levels was not directly related to massive cell death, but rather to a decrease of complement 3 and 4 serum levels during infliximab treatment.

CONCLUSION

Infliximab and etanercept have a differential effect on both type I interferon activity and nucleosome levels. Only elevated serum nucleosomes relate to the induction of antinucleosome antibodies after infliximab treatment.

Serological and molecular studies of Epstein-Barr virus infection in allogeneic marrow graft recipients

We have shown in two allogeneic bone marrow transplant recipients that Epstein-Barr virus can be eradicated by the BMT procedure or its complications, and that these patients are susceptible to infection with a new EBV strain. This conclusion was based on a combination of EBV serology and virus strain identification ("Ebnotyping," using the size variations of 5 EBV nuclear antigens). In the present study, we conducted a serological survey of EBV infection in 153 marrow graft recipients and their donors. Ten patients who were positive for IgG antibodies against EBV viral capsid antigens prior to BMT became completely seronegative at a median of 197 days post-BMT (range 106-320 days). Four of these patients, who had received seronegative marrow, remained seronegative during prolonged periods (222 to 2105 days). Six patients had received seropositive marrow. Two of them remained seronegative during their subsequent periods of follow-up (895 and 1437 days). An additional 10 patients showed a 100-fold or greater decrease in VCA IgG antibody titers. Their titers reached a nadir of 10 (the lower limit of positive) at a median of 134 days post BMT (range 83-386 days). The serological patterns of the above 20 patients were particularly frequent among patients with chronic graft-versus-host disease; 12 of 20 patients with decreasing VCA titers (60%) developed chronic GVHD versus only 22 of 73 patients with stable or increasing VCA titers (30%). These results suggest that GVHD may contribute to the elimination of residual EBV-carrying recipient cells. Establishment of EBV-carrying lymphoblastoid cell lines (LCL) was attempted in 60 donor-recipient pairs whose cryopreserved peripheral blood mononuclear cells were available. LCL were established from 18 of 51 EBV-seropositive marrow donors and 10 of 57 seropositive recipients prior to BMT. The same EBV strain was detected in 4 of the 6 cases in which LCL could be established from both the donor and the recipient prior to BMT. The persistence of the original EBV strain was demonstrated in a recipient of a T cell-depleted graft who showed only transient hematological recovery and no GVHD, and was associated with the persistence of B cells of recipient origin.

Deoxycytidine kinase and deoxycytidine deaminase values correspond closely to clinical response to cytosine arabinoside remission induction therapy in patients with acute myelogenous leukemia

In this study, it has been shown that in 21 patients with AML the dCyd kinase and dCyd deaminase activities correspond closely to the clinical response to ara-C remission induction therapy. Patients with primary disease were treated with a conventional-dose ara-C regimen whereas nonresponders and relapsed patients followed an ID ara-C regimen (1 g/m2 X 12). Of these 21 patients (11 with primary disease and ten relapsed), seven had ara-C resistant disease (three primary and four relapsed patients). Five of the seven patients had a very low dCyd kinase and normal dCyd deaminase activity, whereas the other two had a normal dCyd kinase and an increased dCyd deaminase activity.