Expression of the major rheumatoid factor cross-reactive idiotype in pediatric patients with systemic lupus erythematosus

Investigations of cellular immunity in juvenile idiopathic arthritis

The following was emphasised in an informative, educational issued on the American College of Rheumatology website in April 2017: “About one child in every 1000 develops some type of chronic arthritis. These disorders can affect children at any age, although rarely in the first six months of life. It is estimated that around 300,000 children in the United States have been diagnosed with the condition”. Therefore, knowledge of immunological investigations in patients with juvenile idiopathic arthritis is important for finding new treatment pathways. Our aim was to assess the immunological investigations and immune system implications in juvenile idiopathic arthritis. We will discuss: a) the specifically targeted proteins – the citrullinated peptide antibodies; b) non-specifically targeted proteins – heat-shock proteins (anti-HSP60, -65, and -70 antibodies), CLEC16A, inflammasomes, and phagocyte-derived S100; c) interleukins – IL-1, IL-6, IL-10, IL-17, and IL-18; d) innate immunity – macrophage activation syndrome, natural killer cells, complement activity, and immune complexes; and e) therapeutic targets – monoclonal antibodies, JAK inhibitors, and intravenous immune globulin.

VH usage and somatic hypermutation in peripheral blood B cells of patients with rheumatoid arthritis (RA)

The human antibody repertoire has been demonstrated to have a marked V-gene-dependent bias that is conserved between individuals. In RA patients, certain heavy chain V genes (VH) have been found to be preferentially used for encoding autoantibodies. To determine if such preferential use of VH genes in autoantibodies is associated with a general distortion of the V gene repertoire in RA patients, the VH composition of peripheral blood B cells was analysed among four RA patients and four age- and sex-matched healthy controls. Usage of individual VH genes (eight VH3 and three VH4 genes tested by hybridization with a set of gene-specific oligonucleotide probes) was highly biased among RA patients, but no evidence of a distortion in the bias was observed compared with healthy controls. However, the occurrence of somatic mutations in these VH genes (estimated by differential hybridization with motif-specific oligonucleotide probes targeted to CDR and FR of the tested genes, and by DNA sequence analysis) was strikingly different between patients and healthy subjects. The number of VH3 rearrangements that had accumulated somatic mutations and the number of mutations per rearrangement were significantly elevated in three of the four RA patients. A slight but not significant elevation in mutations among rearranged VH4 genes was also observed in these patients. These data suggest that although usage of individual VH genes among peripheral blood B cells is not affected by the disease, the autoimmune process may involve a significant fraction of the B cell compartment.

Expression of the rheumatoid factor cross-reactive idiotype in JRA: association with disease onset subtype, disease activity and disease severity

We previously reported that approximately one-third of patients with juvenile rheumatoid arthritis (JRA) express high concentrations of antibodies marked by the rheumatoid factor cross reactive idiotype (RCRI) in their sera (6). In order to determine if an expression of RCRI is associated with certain clinical features of the disease, we prospectively studied 49 patients with JRA over a six month period, and determined serum RCRI concentrations by inhibition ELISA. RCRI concentrations correlated significantly with the duration of morning stiffness (r = .3866, p less than .01), and the functional class (p less than .001), but not with the number of active joints. Expression of RCRI was higher in patients with systemic onset disease (p less than .03), compared to patients with pauciarticular or polyarticular disease. In patients studied on more than one occasion, the RCRI expression was relatively constant despite changes in disease activity. A subset of JRA patients with systemic onset disease, higher serum concentrations of the RCRI.