Serum immunoglobulin and beta 1C-beta 1A globulin concentrations in juvenile rheumatoid arthritis

α2-fraction and haptoglobin as biomarkers for disease activity in oligo- and polyarticular juvenile idiopathic arthritis

OBJECTIVES

Unlike in adult rheumatology, for most forms of juvenile idiopathic arthritis (JIA) no reliable biomarkers currently exist to assess joint and disease activity. However, electrophoresis is frequently found changed in active juvenile arthritis. The objective of this study was to evaluate the α2-fraction of serum electrophoresis and its main components as biomarkers for JIA, categories extended/persistent oligoarthritis and seronegative polyarthritis, in comparison with the conventionally used erythrocyte sedimentation rate and C-reactive protein.

METHODS

Serum samples and clinical data from 181 patients with JIA were collected. Serum electrophoresis and α2-fraction and its components were determined using standard methods. Relationship between calculated α2-fraction of serum electrophoresis (CA2F) and its components, acute-phase parameters and cJADAS27 was assessed using Pearson's correlation coefficient and linear regression modelling, adjusting for confounding effects. Results were confirmed in a second cohort with 223 serum samples from 37 patients, using a mixed model to account for repeated measures.

RESULTS

Compared to ESR and CRP, CA2F showed higher correlation to cJADAS27, in particular for persistent oligoarthritis. Of the three components of the α2-fraction, haptoglobin showed the highest correlation to cJADAS27. Regression analysis demonstrated higher ability to predict cJADAS27 for CA2F, and especially for haptoglobin as a component thereof, than for CRP and ESR.

CONCLUSION

Compared to conventional methods, α2-fraction of serum electrophoresis and specifically, haptoglobin show higher correlations with disease activity in common subtypes of JIA, representing excellent candidates as biomarkers for disease activity. Further studies are necessary to determine diagnostic value and correlations in other subtypes.

Hypogammaglobulinemic patient with polyarthritis mimicking rheumatoid arthritis finally diagnosed as septic arthritis caused by Mycoplasma hominis

Hypogammaglobulinemia is a reduction or absence of immunoglobulin, which may be congenital or associated with immunosuppressive therapy. In addition to infectious diseases, autoimmune diseases have also been reported in patients with hypogammaglobulinemia. A 26-year-old man with hypogammaglobulinemia had multiple joint pain and swelling with erosive changes in the proximal interphalangeal joint of the right middle finger on X-ray film, mimicking rheumatoid arthritis (RA). As polyarthritis remained after immunoglobulin replacement therapy and there was no finding indicating any infection at that time, a diagnosis of RA was made. Prednisolone and etanercept were started. However, his polyarthritis did not improve and he developed meningitis and massive brain ischemia. Finally, a diagnosis of disseminated Mycoplasma hominis infection was made. The differential diagnosis of polyarthritis in patients with hypogammaglobulinemia should strictly exclude Mycoplasma infection by culture with special media or longer anaerobic culture, and molecular methods for mycoplasma.

The clinical value of measuring immunoglobulins when assessing penicillamine therapy in rheumatoid arthritis

Immunoglobulins are often high in active rheumatoid arthritis and fall when treatment with a slow-acting anti-rheumatic drug is instituted. We assessed the value of monitoring immunoglobulins during penicillamine therapy; 145 patients were followed for up to 5 years, IgA, IgM and IgG levels were compared to 12 other clinical and laboratory variables on 903 occasions. Mean levels of IgA and IgG fell by 10-30%. These changes were less than with ESR or clinical measures such as articular index and duration of morning stiffness. Immunoglobulin levels showed weak correlations with other variables. Only a small number of patients had hypogammaglobulinemia. Initially, 5 cases had low IgA with subsequent falls in 3 more. Initially, 2 cases had low IgG with subsequent falls in 5 more. No patients had low IgM levels. These changes seemed clinically irrelevant. Radiological progression was related to IgA levels. Patients with persistently high rates of radiological progression had persistently higher serum IgA. We conclude that IgM gives the most "acute phase" pattern of response. IgA gives more theoretically interesting information, especially concerning radiological progression. There is only a limited amount of clinically valuable information gained from measuring immunoglobulins.

Overestimation of immunoglobulins in the presence of rheumatoid factor by kinetic immunonephelometry and rapid immunoturbidimetry

The United Kingdom External Quality Assessment Scheme for Specific Proteins has demonstrated that one method group, comprised of kinetic immunonephelometric assays, gives significantly higher results for immunoglobulins in certain pathological sera containing rheumatoid factor. Using IgM as a model, we have compared kinetic immunonephelometry and a rapid (5 min incubation) immunoturbidimetric assay with radial immunodiffusion (RID) on seven sera. Compared with RID significantly higher results were obtained by kinetic nephelometry on all five sera positive for rheumatoid factor, and by turbidimetry on three of the four of these studied. In a serum with IgM increased due to primary biliary cirrhosis lower results (P0.005) were obtained by nephelometry than by RID. The remaining serum was normal, and no significant intermethod differences were found. The possible causes for these discrepancies are discussed.

Primary hypogammaglobulinaemia and arthritis

Arthritis may be the first clinical manifestation of primary hypogammaglobulinaemia. In 16 years of 281 patients who had immunodeficiency, 30 had arthritis at presentation. It was more common in Bruton's disease (15 (22%) of 69 patients) than in other forms of immunodeficiency (15 (7%) of 212 patients). Non-septic arthritis was more prevalent than septic arthritis, particularly monoarticular arthritis in Bruton's disease and pauciarticular disease in common variable immunodeficiency. Boys in whom a diagnosis of Bruton's disease was delayed were likely to develop recurrent infections complicated by arthritis. The measurement of serum immunoglobulin concentrations readily differentiates immunodeficiency from conditions such as Still's disease and dictates subsequent management.

Serological abnormalities in juvenile chronic arthritis: a review of 46 cases

Data of 46 patients with juvenile chronic arthritis were evaluated. All of them were under the age of 16 at the time of study. Patients with juvenile ankylosing spondylitis, psoriatic arthritis, and arthritis associated with inflammatory bowel disease were excluded from this series. Twenty-six patients had pauciarticular, 9 had systemic, 8 had polyarticular, and 3 patients had seropositive 'adult type' JCA. In all patient groups IgG, IgM, IgA, and C3 levels were significantly higher than in the control group. None of the controls but 13 of 46 patients had high IgE levels. IgA and IgG values were significantly higher in the seropositive subgroup than in the pauciarticular subgroup. There was no other positive correlation between levels of immunoglobulins, C3, and clinical features of disease. Platelet counts were significantly higher in patients with active disease. In the control group 4 out of 10 children had 'hidden' rheumatoid factor. All these children with positive findings were young.

Plasma protein patterns in health and disease

The complex nature of protein metabolism has made interpretation of serum protein data a difficult task. Interpretive efforts can be facilitated by use of protein profiles which consist of quantitative immunochemical data combined with qualitative electrophoretic patterns. These profiles can be designed to clarify physiological relationships and emphasize pathological conditions through pattern recognition. This review will present protein profiles observed in acute, subacute, and chronic inflammation: liver diseases, protein losing disorders, plasma cell dyscrasias, humoral immune deficiencies, autoimmune diseases, genetic deficiency states, and other disorders. The value of consultative interaction and the use of combined profiles in the assessment of a patient's protein status will be covered. A discussion of protein patterns in normal individuals will include data on day-to-day, age- and sex-related variation. A section on management of protein data will present various approaches to profile reporting. Graphical report formats which minimize the time required for information transfer and simplify assimilation of results will be emphasized.

Intraarticular activation of the complement system in patients with juvenile rheumatoid arthritis

Analyses of CH50, complement components, properdin factors, and kininogen in synovial fluid of patients with juvenile rheumatoid arthritis revealed evidence of activation of the classic complement pathway in all clinical subgroups. Juveniles with the adult pattern of disease had the greatest incidence of complement abnormalities. Evaluation of individual components by both activity determination and protein measurement showed decreased synovial fluid specific functional activity (activity per microgram protein) to the more marked in synovial fluids with profound depressions of complement activity. These findings provide further evidence that nonfunctional, antigenically intact component protein may remain after complement activation. Radial immunodiffusion measurements of properdin factors and kininogen failed to support their involvement in joint inflammation. Serum complement component measurements by activity but not protein concentration correlated with other parameters or inflammation. Four patients had isolated depressions of serum C2 activity. Immunoglobulin levels, particularly IgA, correlated with some complement measurements and with the sedimentation rate.