STUDIES ON THE SERUM GAMMA 1A-GLOBULIN LEVEL. II. GAMMA 1A-DEFICIENCY IN A CASE OF SYSTEMIC LUPUS ERYTHEMATOSUS

Selective IgA deficiency in children and adults with systemic lupus erythematosus

The objective of this study was to determine the frequency and clinical characteristics of selective IgA deficiency (SIgAD) in children and adults with systemic lupus erythematosus (SLE), and evaluate potential differences in presentation and course of the SLE. IgA deficiency was defined as a serum IgA concentration < or =0.01 mg/mL determined on two sera by radial diffusion. SLE was classified by the 1982 criteria of the American College of Rheumatology. Seventy-seven children with SLE followed prospectively for > or =20 years and 152 adults surveyed during a one-year period were assayed for serum IgA levels. Disease characteristics were compared among the deficient patients and the IgA-normal patients. Twelve patients with SIgAD were identified: 1) Juvenile(J)-SLE: four children with juvenile onset (< or =18 years) and four others encountered as adults; and 2) Adult(A)-SLE: four patients with adult onset. No significant differences were found in clinical presentation or course except for a possible increase in recurrent infections and the observation that there were only two African-Americans. Five patients had received blood transfusions with no reactions; three of these patients had serum anti-IgA antibodies. One pediatric patient developed low levels of IgA (<or =1 mg/mL) during a follow-up of three years. Two adult patients died (septicemia, carcinoma); one was on dialysis. SIgAD was identified in 5.2% of children and 2.6% of adults with SLE for an estimated 35-fold increase in frequency. This small number of patients did not appear to have an altered clinical presentation or course from that expected in patients with SLE who did not have SIgAD.

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.

IgA deficiency in children. A clinical study with special reference to intestinal findings

Clinical, immunological, and intestinal studies on 26 children with IgA deficiency in the age range 2 to 16 years are reported. 9 of these children were suffering from autoimmune disease, namely thyroiditis (5), thyrotoxicosis (1), rheumatoid arthritis (2), and probable Sjögren's syndrome (1). The last-mentioned patient had defective cellular immunity. Altogether 11 patients were subject to recurrent respiratory tract infections. The symptomatology of the remaining patients was variable. In a boy with growth retardation, a chromosome anomaly was found, and endocrinological studies indicated total absence of growth hormone. In 21 patients IgA was undetectable, while 5 had trace amounts of IgA in their sera. IgG was raised in 11 patients, and one patient had low serum IgG. IgM levels were mostly normal. Precipitating antibodies to cow's milk proteins were present in all but one serum. Small intestinal biopsy was performed on all patients. In 3 cases total villous atrophy was detected and these probably had coeliac disease, though malabsorption symptoms were not always evident. Disaccharidase assay of biopsy specimens revealed 2 cases of isolated lactase deficiency among 8 tested. Results show that the increased incidence of autoimmune disease reported in IgA deficiency in adults also holds true in children; i.e. that there is a raised incidence of coeliac disease with or without symptoms in IgA deficiency.

Absent IgA and deletions of chromosome 18

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