IMMUNOGLOBULIN-M AND C1Q MESANGIAL LABELING IN IGA NEPHROPATHY

Colabeling with complement compont C1q or immunoglobulin M (IgM) is oc casionally reported in biopsy specimens from patients with IgA nephrop athy, The significance of this finding has been questioned. In 83 chil dren and young adults with otherwise typical IgA nephropathy, 15 patie nts had more than trace mesangial labeling for IgM or Clq, Of these, 1 4 patients (93%) had greater than 1+ proteinuria at the time of biopsy . This was in marked distinction to the patients with no mesangial lab eling for these reactants, only 15% of whom had greater than 1+ protei nuria. The children with IgM or Clq colabel did not differ from those lacking this finding in age at presentation, length of follow-up, or c urrent renal function. In childhood IgA nephropathy, colabeling with I gM or Clq is seen frequently, probably is a function of heavy proteinu ria at the time of biopsy, and does not contribute adversely to outcom e. (C) 1998 by the National Kidney Foundation, Inc.