Contribution of macromolecular IgA 1 to IgA abnormality in IgA nephropathy

Abstract

To evaluate the contribution of macromolecular IgA1 to IgA abnormality in childhood IgA nephropathy, serum samples from 29 healthy children and 26 patients with IgA nephropathy in different age-groups (7-9, 10-12, and 13-15 years) were each separated by sucrose density gradient ultracentrifugation and assayed for IgA1 using an enzyme-linked immunosorbent assay. IgA1 in fraction I (sedimentation coefficient >11.4s) was significantly greater in patients 7-15 years of age (median 36.3-57.0 mg/dl) than in the age-matched controls (median 8.8-10.4 mg/dl). IgA1 in fraction II (11.4-9.3s) was significantly greater in patients 10-15 years of age (median 46.7-52.6 mg/dl) than in the controls (median 27.8-35.5 mg/dl), and IgA1 in fraction III (<9.3s) was significantly greater in patients 13-15 years of age (median 156.9 mg/dl) than in the controls (median 120.7 mg/dl). The ratio of IgA1 in fractions I-III was higher in the patients of each age-group (median 0.233-0.314) than in the controls (median 0.067-0.082), while the ratio of IgA1 in fractions II-III was not significantly high in patients 7-12 years old (median 0.268 to 0.318) compared with the controls (median 0.182-0.264). Thus, IgA abnormality in childhood IgA nephropathy would be better represented by an increase in macromolecular IgA1 of >11.4s than by an increase in IgA1 in fractions of 11.4-9.3s or <9.3s.

Effect and therapeutic mechanisms of tonsillectomy for childhood IgA nephropathy

“…Using a combination of tonsillectomy and steroid therapy, Hotta 6 observed complete remission in 59.7% of 191 adult patients with IgAN, more often than in a group treated with steroids alone (35.4%). Previous data showed tonsillectomy to be effective for maintaining renal function and decrease urinary abnormalities even when the interval between initial diagnosis of IgAN and tonsillectomy was 5 years or more; 7 however, the effect was more prominent in patients with early surgery within 5 years from initial diagnosis.…”

“…5 Contribution from this macromolecular IgA1to-IgA abnormality also may be involved in the pathogenesis of IgAN. 6 Tonsillectomy, alone or in combination with pulse steroid therapy, has been studied as treatment for adult IgAN for about 10 years mainly in Japan; both clinical and histological improvements have been reported. 7 However, paediatric concerns such as possible impaired acquisition of normal immunity and increased frequency and severity of infections have limited consideration of tonsillectomy as treatment for paediatric chronic renal diseases.…”

“…IgA deposits in the kidney consist mainly of IgA1, which is a secretory IgA including a secretory piece; this also is true for tonsillar IgA 5 . Contribution from this macromolecular IgA1‐to‐IgA abnormality also may be involved in the pathogenesis of IgAN 6 …”