Decreased B cells and IgA-secreting B cells partially explain the high prevalence of IgA deficiency in dialysis patients.

AIMS: We previously reported 2 hemodialysis (HD) patients with recurrent infections and selective immunoglobulin A deficiency (IgAD). We further demonstrated that serum IgA levels were lower and the prevalence of IgAD was higher in uremic patients. The exact mechanisms of IgAD in uremic patients largely remained unclear. In some patients, it was caused by anti-IgA antibody neutralization and subsequent destruction. We performed the present study to survey if there is any defect in IgA production.

MATERIALS AND

METHODS

288 patients were initially included for examination of serum immunoglobulins. 16 normal persons, 16 dialysis patients without IgAD, and 12 dialysis patients with IgAD were enrolled after the initial examination. Blood was drawn into heparinized tubes. WBC counts and lymphocyte percentage were examined by a CBC counter. Lymphocytes were separated by the Ficoll-Paque method. Flow cytometry was utilized to isolate the B cell and IgA-secreting B cell after staining with CD 19 phycoerythrin and FITC-conjugated rabbit anti-human IgA antibody.

RESULTS

There is no significant difference between WBC counts or total lymphocyte counts of these 3 groups. However, we found a lower percentage of total lymphocyte counts in dialysis patients, either with or without IgAD. The total B cell numbers were lower in dialysis patients with IgAD. In addition, there were fewer IgA-secreting B cells in dialysis patients with IgAD.

CONCLUSION

Decreased B cell and IgA-secreting B cell counts are seen in uremic patients with IgAD. This, in turn, indicates that there might be a defect of IgA production in some patients, rather than IgA destruction by anti-IgA antibodies as seen in some other patients. Further study is needed to investigate the mechanisms of decreased B cells and IgA-secreting B cells.