Abstract
BackgroundChronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) is rare in Asians, and patients with CLL/SLL seldomly undergo kidney biopsy. The histopathological features and clinical relevance of tubulointerstitial injury in CLL/SLL have not been extensively characterized. Hence, we attempted to describe the clinical characteristics, renal pathology and clinical outcome of a well-characterized population of CLL/SLL patients with CLL cell infiltration in the renal interstitium from a large single center in China.MethodsBetween January 1st, 2010 and September 31st, 2020, 31946renal biopsies were performed at Peking University First Hospital, and 10 CLL/SLL patients with CLL cell infiltration in the renal interstitium were included. Complete clinical data were collected from these 10 patients, and renal specimens were examined by routine light microscopy, immunofluorescence and electron microscopy.ResultsThe extent of the infiltrating CLL cells in patients with CLL/SLL varied among different patients and ranged from 10 to 90% of kidney parenchyma. Six (60%) of 10 patients presented with an extent of infiltrating CLL cells ≥50%. Interestingly, we found that three patients (3/10, 30%) expressed monoclonal immunoglobulins in the infiltrating CLL cells, and special cytoplasmic crystalline structures were found in two of the three patients by electron microscopy for the first time. Severe renal insufficiency (Scr ≥200 μmol/L) was associated with ≥50% interstitial infiltration of CLL cells in the renal interstitium.ConclusionsThe current study confirmed that CLL cells infiltrating the renal interstitium can directly secrete monoclonal immunoglobulins, indicating that the interstitial infiltrating CLL cells possibly cause renal injury directly by secreting monoclonal immunoglobulins in situ. This finding may prove a new clue to elucidate the pathogenetic mechanism of renal injury involved with CLL/SLL.
Highlights
Chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/Small lymphocytic lymphoma (SLL)) is rare in Asians, and patients with CLL/SLL seldomly undergo kidney biopsy
We investigated the pathological features of infiltrating CLL cells in the renal interstitium in detail and tried to explore the possible pathogenesis of renal injury in association with CLL/SLL
CLL/ SLL was diagnosed before kidney biopsy in 5/10 cases, with a median interval of 18 months
Summary
Chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) is rare in Asians, and patients with CLL/SLL seldomly undergo kidney biopsy. A population-based study of predominately Han Chinese reported an even lower CLL/SLL incidence of 0.05/100,000 per year [5]. This disease is characterized by the clonal expansion of CD5 + CD23+ B cells in peripheral blood, bone marrow, and the secondary lymphoid tissues [6, 7]. A study from the Mayo Clinic found a 7.5% incidence of renal insufficiency at the time of CLL/SLL diagnosis in a cohort of over 2000 CLL/SLL patients. The presence of kidney disease was independently associated with adverse patient outcomes in CLL/SLL [10], which emphasizes the importance of a detailed exploration of the mechanism of renal insufficiency in CLL/SLL
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