A Rare Case of Paxlovid-Induced Pancreatitis.

Acute pancreatitis can result secondary to an inflammatory cascade due to an insult to the pancreatic parenchyma, whether it be from infections, medications, etc. We present a case of a 37-year-old male with acute pancreatitis after being started on Paxlovid, a combination drug containing Nirmatrelvir and Ritonavir, for COVID-19 treatment. Multiple reports in the literature have documented such an association between acute pancreatitis and the protease inhibitor Ritonavir. We suspect that similar results may have taken place that link the initiation of this medication with pancreatic inflammation.

Affinity maturation generates pathogenic antibodies with dual reactivity to DNase1L3 and dsDNA in systemic lupus erythematosus.

Anti-dsDNA antibodies are pathogenically heterogeneous, implying distinct origins and antigenic properties. Unexpectedly, during the clinical and molecular characterization of autoantibodies to the endonuclease DNase1L3 in patients with systemic lupus erythematosus (SLE), we identified a subset of neutralizing anti-DNase1L3 antibodies previously catalogued as anti-dsDNA. Based on their variable heavy-chain (VH) gene usage, these antibodies can be divided in two groups. One group is encoded by the inherently autoreactive VH4-34 gene segment, derives from anti-DNase1L3 germline-encoded precursors, and gains cross-reactivity to dsDNA - and some additionally to cardiolipin - following somatic hypermutation. The second group, originally defined as nephritogenic anti-dsDNA antibodies, is encoded by diverse VH gene segments. Although affinity maturation results in dual reactivity to DNase1L3 and dsDNA, their binding efficiencies favor DNase1L3 as the primary antigen. Clinical, transcriptional and monoclonal antibody data support that cross-reactive anti-DNase1L3/dsDNA antibodies are more pathogenic than single reactive anti-dsDNA antibodies. These findings point to DNase1L3 as the primary target of a subset of antibodies classified as anti-dsDNA, shedding light on the origin and pathogenic heterogeneity of antibodies reactive to dsDNA in SLE.

Alternative exon usage in TRIM21 determines the antigenicity of Ro52/TRIM21 in systemic lupus erythematosus.

The origin and mechanisms of autoantigen generation in systemic lupus erythematosus (SLE) are poorly understood. Here, we identified SLE neutrophils activated in vivo by IFN as a prominent source of Ro52, also known as tripartite motif-containing protein 21 (TRIM21), a critical autoantigen historically thought to be primarily generated by keratinocytes in SLE. Different from mononuclear cells and keratinocytes, SLE neutrophils are enriched in several unique Ro52 species containing a core sequence encoded by exon 4 (Ro52Ex4) in TRIM21. Ro52Ex4 is the main target of anti-Ro52 antibodies and is found in 2 Ro52 variants (Ro52α and a potentially novel isoform termed Ro52γ) upregulated in SLE neutrophils. Further analysis of Ro52γ revealed a subset of autoantibodies against a unique C-terminal domain (Ro52γCT) generated from a frameshift due to the lack of exon 6 in Ro52γ. Antibodies to Ro52Ex4 and Ro52γCT distinguish SLE patient subsets characterized by distinct clinical, laboratory, treatment, and transcriptional profiles that are not discerned by the "classical" anti-Ro52 antibodies. These studies uncover IFN-activated neutrophils as a key source of unique immunogenic forms of Ro52 in SLE. Moreover, the finding of Ro52Ex4 and Ro52γCT as core targets of anti-Ro52 antibodies focus interest on Ro52γ as the potential isoform toward which immunological tolerance is initially lost in SLE.

Autoantibodies targeting LINE-1-encoded ORF1p are associated with systemic lupus erythematosus diagnosis but not disease activity.

OBJECTIVES: Long Interspersed Element 1 (LINE-1) is an endogenous retroelement that constitutes a significant portion of the human genome and has been implicated in the pathogenesis of systemic lupus erythematosus (SLE). The LINE-1 RNA chaperone protein ORF1p was recently identified as an SLE autoantigen. Here we analyse ORF1p for qualities underlying SLE autoantigen status, compared anti-ORF1p antibodies to markers of SLE disease activity, and performed screening for antibodies against LINE-1 reverse transcriptase ORF2p. METHODS: ORF1p was examined in epithelial cell lines treated with cytotoxic lymphocyte granules and UV irradiation. Anti-ORF1p and anti-ORF2p antibodies were assayed by ELISA and analysed in two SLE cohorts. RESULTS: We found that ORF1p localises to cytoplasmic RNA-containing blebs in apoptotic cells, and is a substrate of the cytotoxic protease granzyme B (GrB). Anti-ORF1p antibodies were present in 4.2% of healthy controls, compared to 15.8% (p=0.0157) and 15.5% (p=0.036) of subjects in the two SLE cohorts. Anti-ORF1p antibodies were not associated with SLE disease activity nor peripheral blood markers of interferon (IFN) activation. Anti-ORF1p titres demonstrated stability over serial time points. Anti-ORF1p antibodies were not associated with anti-DNA, anti-RNP, or other SLE autoantibodies. There was no difference in anti-ORF2p ELISA results in controls versus SLE patients. CONCLUSIONS: LINE-1 ORF1p is a component of apoptotic blebs and a substrate for GrB. Anti-ORF1p antibodies are enriched in SLE subjects but are not associated with dynamic markers of disease activity. These data support a potential role for LINE-1 dysregulation in SLE pathogenesis.

Exposure to Aggregatibacter actinomycetemcomitans before Symptom Onset and the Risk of Evolving to Rheumatoid Arthritis.

Periodontal disease has been implicated in the pathogenesis of rheumatoid arthritis (RA), an autoimmune disease characterized by immune-mediated synovial damage, and antibodies to citrullinated antigens. Here, we investigate the association between exposure to the periodontal pathogen Aggregatibacter actinomycetemcomitans (Aa) and the development of RA. IgM, IgG and IgA antibodies to Aa leukotoxin A (LtxA) were detected by ELISA in plasma from a cohort of Swedish adults at different stages of RA development, from before onset of symptoms to established disease. Patients with early and established RA had increased levels of anti-LtxA IgM compared with matched non-RA controls and periodontally healthy individuals. Logistic regression revealed that anti-LtxA IgM levels were associated with RA during early disease (OR 1.012, 95%CI 1.007, 1.017), which was maintained after adjustment for smoking, anti-CCP antibodies, rheumatoid factor, HLA-DRB1 shared epitope alleles and sex. We found no association between anti-LtxA IgG/IgA antibodies and RA at any stage of disease development. The data support a temporal association between anti-LtxA IgM antibodies and the development of RA, suggesting that a subset of RA patients may have been exposed to Aa around the time of transition from being asymptomatic to become a patient with RA.

HDL subclass proteomic analysis and functional implication of protein dynamic change during HDL maturation.

Recent clinical trials reported that increasing high-density lipoprotein-cholesterol (HDL-C) levels does not improve cardiovascular outcomes. We hypothesize that HDL proteome dynamics determine HDL cardioprotective functions. In this study, we characterized proteome profiles in HDL subclasses and established their functional connection. Mouse plasma was fractionized by fast protein liquid chromatography, examined for protein, cholesterial, phospholipid and trigliceride content. Small, medium and large (S/M/L)-HDL subclasseses were collected for proteomic analysis by mass spectrometry. Fifty-one HDL proteins (39 in S-HDL, 27 in M-HDL and 29 in L-HDL) were identified and grouped into 4 functional categories (lipid metabolism, immune response, coagulation, and others). Eleven HDL common proteins were identified in all HDL subclasses. Sixteen, 3 and 7 proteins were found only in S-HDL, M-HDL and L-HDL, respectively. We established HDL protein dynamic distribution in S/M/L-HDL and developed a model of protein composition change during HDL maturation. We found that cholesterol efflux and immune response are essential functions for all HDL particles, and amino acid metabolism is a special function of S-HDL, whereas anti-coagulation is special for M-HDL. Pon1 is recruited into M/L-HDL to provide its antioxidative function. ApoE is incorporated into L-HDL to optimize its cholesterial clearance function. Next, we acquired HDL proteome data from Pubmed and identified 12 replicated proteins in human and mouse HDL particle. Finally, we extracted 3 shared top moleccular pathways (LXR/RXR, FXR/RXR and acute phase response) for all HDL particles and 5 top disease/bio-functions differentially related to S/M/L-HDL subclasses, and presented one top net works for each HDL subclass. We conclude that beside their essencial functions of cholesterol efflux and immune response, HDL aquired antioxidative and cholesterol clearance functions by recruiting Pon1 and ApoE during HDL maturation.