Differential evolution of peripheral cytokine levels in symptomatic and asymptomatic responses to experimental influenza virus challenge.

Exposure to influenza virus triggers a complex cascade of events in the human host. In order to understand more clearly the evolution of this intricate response over time, human volunteers were inoculated with influenza A/Wisconsin/67/2005 (H3N2), and then had serial peripheral blood samples drawn and tested for the presence of 25 major human cytokines. Nine of 17 (53%) inoculated subjects developed symptomatic influenza infection. Individuals who will go on to become symptomatic demonstrate increased circulating levels of interleukin (IL)-6, IL-8, IL-15, monocyte chemotactic protein (MCP)-1 and interferon (IFN) gamma-induced protein (IP)-10 as early as 12-29 h post-inoculation (during the presymptomatic phase), whereas challenged patients who remain asymptomatic do not. Overall, the immunological pathways of leucocyte recruitment, Toll-like receptor (TLR)-signalling, innate anti-viral immunity and fever production are all over-represented in symptomatic individuals very early in disease, but are also dynamic and evolve continuously over time. Comparison with simultaneous peripheral blood genomics demonstrates that some inflammatory mediators (MCP-1, IP-10, IL-15) are being expressed actively in circulating cells, while others (IL-6, IL-8, IFN-α and IFN-γ) are probable effectors produced locally at the site of infection. Interestingly, asymptomatic exposed subjects are not quiescent either immunologically or genomically, but instead exhibit early and persistent down-regulation of important inflammatory mediators in the periphery. The host inflammatory response to influenza infection is variable but robust, and evolves over time. These results offer critical insight into pathways driving influenza-related symptomatology and offer the potential to contribute to early detection and differentiation of infected hosts.

Hydroxychloroquine sulfate treatment is associated with later onset of systemic lupus erythematosus.

Systemic lupus erythematosus (SLE) is a clinically diverse, complex autoimmune disease which may present with coincident onset of many criteria or slow, gradual symptom accrual. Early intervention has been postulated to delay or prevent the development of more serious sequelae. One option for treatment in this setting is hydroxychloroquine. Using 130 US military personnel who later met ACR SLE criteria, a retrospective study of onset, development and progression of SLE with and without pre-classification hydroxychloroquine (n = 26) use was performed. Patients treated with hydroxychloroquine prior to diagnosis had a longer (Wilcoxon signed rank test, P = 0.018) time between the onset of the first clinical symptom and SLE classification (median: 1.08 versus 0.29 years). Patients treated with prednisone before diagnosis also more slowly satisfied the classification criteria (Wilcoxon signed rank test, P = 0.011). The difference in median times between patients who received NSAIDs before diagnosis, as opposed to those who did not, was not different (P = 0.19). Patients treated with hydroxychloroquine also had a lower rate of autoantibody accumulation and a decreased number of autoantibody specificities at and after diagnosis. These findings are consistent with early hydroxychloroquine use being associated with delayed SLE onset. A prospective, blinded trial testing the capacity of hydroxychloroquine to delay or prevent SLE in high risk populations is warranted.

Rapid clinical progression to diagnosis among African-American men with systemic lupus erythematosus.

The initial clinical course of systemic lupus erythematosus (SLE) is variable, ranging from relatively minor manifestations progressing over years to rapid onset of fulminate disease. We sought to identify factors associated with the rapid manifestation of SLE. Chart review of military medical records was used to identify 130 patients who met the American College of Rheumatology classification criteria for SLE. Demographics, clinical criteria date of occurrence, and the date of SLE classification (at least four clinical criteria) met were documented. Prospectively stored serum samples prior to the diagnosis were evaluated for SLE autoantibodies. Median time from the first recorded criteria to diagnosis was significantly shorter in African-American (AA) males compared with AA females and European American (EA) females and males combined. AA males were more likely to have nephritis as their first clinical symptom. Also, less time transpired between the first clinical criterion and SLE diagnosis in AA males with nephritis than in other groups presenting with nephritis. Even when cases presenting with nephritis were excluded, a diagnosis of SLE was made more rapidly in AA males. African-American men progress from initial clinical manifestations to SLE diagnosis more rapidly than other ethnic or gender groups.

Selective small antigenic structures are capable of inducing widespread autoimmunity which closely mimics the humoral fine specificity of human SLE.

Recent data have suggested that autoantibodies in lupus can progress from simple immunity against a few antigenic structures to a complex response against multiple autoantigens. Our aim was to determine whether these diverse epitope patterns can indeed be generated by antigenic challenge with a single, small structure. Rabbits were immunized with either a 60 kDa Ro peptide commonly antigenic in human systemic lupus erythematosus (SLE) (Ro 274-289) or one which is rarely a humoral target (Ro 500-515). Rabbits immunized with the antigenic peptide (Ro 274-289) not only developed antibodies to multiple epitopes of 60 kDa Ro and La, as has been described, but also produced non-cross-reactive antibodies to the common spliceosomal proteins Sm B' and D1, and nRNP A and C. Rabbits immunized with the Ro 274-289 peptide also mount a progressive, diversified immune response to the sequential antigenic regions of these proteins (60 kDa Ro, Sm B' and D1, nRNP A and C), which is nearly identical to that seen in human SLE. Animals immunized with the nonantigenic peptide Ro 500-515 develop antibodies only to 60 kDa Ro. These results demonstrate that loss of tolerance to select single, small antigenic structures can begin a cascade which virtually recreates, at the epitope level, the humoral autoimmune specificity seen in human SLE.

The role of Epstein-Barr virus in systemic lupus erythematosus.

Systemic lupus erythematosus (SLE) is a devastating autoimmune disease with no known cure. Lupus patients suffer from a myriad of clinical symptoms which variably include arthritis, pleuritis, pericarditis, vasculitis, and nephritis. The underlying mechanisms behind these clinical findings and the etiologic events preceding and causing disease onset, however, remain largely unknown. For many years, investigators have suspected that Epstein-Barr virus might somehow be involved in the etiology and/or pathogenesis of systemic lupus. Numerous studies have examined this possibility from various angles and have arrived at different conclusions. This work reviews these historical papers in the context of new results and presents a hypothetical role for this virus as an etiological environmental trigger for SLE.

Lupus autoantibodies recognize the product of an alternative open reading frame of SmB/B'.

An unusual feature of the gene for the spliceosomal protein SmB/B' is the presence of an unusually long alternative open reading frame (aORF) which could encode 220 amino acids. We cloned and expressed this aORF protein and used immunological assays to determine its antigenicity in patients with systemic lupus. Sera from 10 of 22 (46%) anti-Sm positive lupus patients showed significant binding to the SmB' aORF protein by ELISA while neither the normal controls nor anti-Sm negative lupus patient controls showed significant reactivity. Antigenicity of the SmB' aORF protein was further localized to the C-terminus using a deletion construct. This is the first known example in which the product of an alternative open reading frame acts as an autoantigen in human disease. These results are consistent with the possibility that generation of anti-Sm autoantibodies in a subset of lupus patients is due to abnormal processing and expression of an aORF SmB/B' message, by an as yet unidentified mechanism.

Side-chain specificities and molecular modelling of peptide determinants for two anti-Sm B/B' autoantibodies.

Autoantibodies binding the Sm B and B' peptides (B/B') are commonly associated with systemic lupus erythematosus in man and in MRL lpr/lpr mice. The linear antigenic regions of two anti-Sm B/B' murine monoclonal auto-antibodies have been mapped using overlapping octapeptides. Unique epitopes are identified by each antibody. Monoclonal KSm-5 recognizes the peptide, PPPGMRPP, which is repeated three times in the Sm B polypeptide. KSm 3 preferably binds to two similar, almost neighboring octapeptides, PPPGIRGP and PGIRGPPP. The two monoclonal antibodies do not cross react. These regions of Sm B/B' are major areas of antigenicity in human sera. Amino acid deletion and substitution in antigenic octapeptides show that binding to the KSm-5 epitope is lost with most modifications. Molecular dynamic modelling suggests that when PPPGMRPP is substituted in the sixth position arginine, KSm/5 binding may be associated with a shared peptide backbone structure rather than charge or hydrophobicity of the substituted amino acid. In contrast, binding of KSm-3 to PPPGIRGP is abolished when the sixth position arginine is substituted by any other amino acid. Substitution at arginine and modelling experiments, therefore, suggest very different mech-anisms of binding. Autoantibodies may bind quite different features of similar peptide structures.