LIGHT-CHAIN DEPOSITION DISEASE OF THE KIDNEY - MORPHOLOGICAL ASPECTS IN 24 PATIENTS

Renal biopsies and autopsy specimens of 23 patients with light chain deposition disease (LCDD) and one with only heavy chain deposits, were studied by light (LM) and electron microscopy (EM) as well as immunohistology (IH). Thirteen patients had multiple myeloma; 1 had lymphoma, and 1 chronic myeloid leukaemia with polycythaemia vera. In nine patients, no lymphoproliferative disease was identified. The LM lesions most suggestive of LCDD, nodular glomerulosclerosis (NS) and thickening and wrinkling of the tubular basement membranes (TBM), were present in only ten and 13 patients, respectively. In five of seven specimens without NS or TBM thickening by LM, EM was negative, indicating a limited value of EM in confirming the diagnosis. Renal amyloidosis was not identified, but in one patient amyloid in the heart and tongue was seen at autopsy. One patient had both granular and extensive glomerular non-amyloid fibrillary deposits. In two patients myeloma casts were identified. Twenty-one patients showed renal LC immune reactivity, 1 had both alpha heavy and lambda LC, 1 had only detectable gamma heavy chain. One biopsy was negative by IH, but had characteristic electron dense deposits. In six patients with immune reactivity to LC, no electron dense deposits could be identified by EM. This study emphasizes the spectrum of renal changes by LM and EM in LCDD, the frequent lack of consistency between deposits detected by IH and EM and the difficulty in coming to a definite diagnosis without LM, EM and IH. The results of this study and examination of the literature indicates that extensive morphological changes are more often present in kappa than in lambda LCDD.