Pathogenic implications of age of onset in juvenile rheumatoid arthritis

An analysis of age of onset in juvenile rheumatoid arthritis was performed in the last 300 children seen in our clinic. There was a peak age of onset in girls at 1 to 3 years. Distribution of age of onset in boys was bimodal with the first peak at 2 years of age and the second at 9 years. There was no accentuation of frequency in either sex in the 10- to 14-year age group. The distribution of age of onset was bimodal in both monarticular and polyarticular onset of disease, but no particular modal age of onset was seen with systemic onset of disease. It is possible that these data reflect that JRA is not a homogenous disease, or that there are age-sex related differences in host susceptibility or pathogenic agents.

Abnormalities in the distribution of serum immunoglobulin concentrations in juvenile rheumatoid arthritis

Concentrations of serum IgG. IgA, and IgM were determined in 200 patients with juvenile rheumatoid arthritis. The relative frequency distribution of IgG and IgM approached that of a log-normal curve; however, there was marked skewing of the distribution of the serum concentrations of IgA. The prevalence of selective IgA deficiency was 4%. In order to permit further intragroup comparisons, the serum immunoglobulin concentrations were standardized by comparison to a sex-age matched control group. By this process it was found that there was concordance of the serum levels of IgG with IgA, and IgG with IgM. The standardized concentrations of IgA and IgM were less in females than males. The aberration in distribution of serum IgA concentrations found in this study, and the relative inability of females to respond to their disease by increasing specific serum immunoglobulin levels, add further data supporting the concept of immunodeficiency in the pathogenesis of juvenile rheumatoid arthritis.

The antigen-binding characteristics of antibody pools of different relative affinity

The interstrain differences in relative affinity of mouse anti-HSA antibody previously shown by studies at equilibrium are also observed when rates of association and dissociation and avidity indices are measured. Marked differences are demonstrated in the binding characteristics of high and low relative affinity antibody to both protein and hapten antigens. These results are explained on the basis of heterogeneity of antibody-binding affinity.

Relative affinity of anti-protein antibodies in New Zealand mice

New Zealand mice—NZB, NZW and NZB/W F₁ hybrids—were immunized with human serum transferrin in saline. The number of responder animals, levels and relative affinity of the antibody produced to this antigen were determined. Distinct trends in those immunologic parameters were noted with strain, sex and age at immunization. The relative affinity of the antibodies produced by the strains was lower than that previously demonstrated for several other inbred mouse strains. These results are discussed with reference to the spontaneous soluble complex disease developed by the New Zealand mice.

The heterogeneity of antibody affinity in inbred mice and its possible immunopathologic significance

The range of relative affinity of antibody to HSA in mice from ten strains is presented. Previously reported high and low affinity strains are not exceptional.

Age, sex, dose and time after immunization have little effect on relative affinity of antibody to HSA and HST.

Antibodies, raised by injecting DNP-HSA or DNP-RSA, and tested by ³H-εDNP-L-lysine, show similar interstrain differences of affinity. This excludes recognition of only a limited proportion of the diverse antigenic sites on complex protein antigens as the sole explanation of this phenomenon.

The use of ammonium sulphate globulin precipitation for determination of affinity of anti-protein antibodies in mouse serum

The use of a modification of the ammonium sulphate globulin precipitation technique for the determination of antibody affinity is reported. This method is shown to provide reproducible and valid measurements for the comparison of affinity of unselected and unpurified antibody to human serum albumin and transferrin in different mouse strains.