PATHOMORPHOLOGICAL CHARACTERISTICS OF IMMUNOCOMPLEX RENAL DISEASE IN PATIENTS WITH IMMUNODEFICIENCY VIRUS AND HEPATITIS C VIRUS, RECEIVING ANTIRETROVIRAL THERAPY

The aim is to verify and describe the morphological substrate of renal impairment in HIV/HCV co-infection among patients receiving ART to assess and predict the morphogenesis of immunocomplex lesions. Materials and methods: To assess and predict the morphogenesis of immunocomplex renal disease, we examined retrospectively the kidney tissue samples of 15 patients, who died with HIV/HCV co-infection and received ART. Histological, histochemical and immunohistochemical research methods were used. Results: Segmental and diffuse mesangial proliferation with extracellular matrix expansion with glomerular damage ≥50% in 9 (60%) cases, and involving <50% of glomeruli in 5 (33%), with CD68 expression as single cells were detected. In 12 (80%) cases, there was uneven swelling and focal proliferation of endothelial cells with the involvement of 20-50% of the glomeruli, as well as the presence of cellular infiltrates in the lumen of capillary loops in 3 (20%) cases with monomorphic intensity in “+”. Sclerotic changes were present in various degrees of severity – from cases of complete glomerulosclerosis with obliteration of the Bowman’s lumen to focal and microfocal depressions 8 (55%), sclerosis 10 (66%), hyalinosis 1 (6%), uneven thickening, focal cleft 8 (55%) and perihilar focal sclerosis. These areas were positive for IgG and C1q complement fractions within the “+”, “++” intensity. Among the study group, no case of HIV-associated nephropathy was found that coincided with the predicted spectrum of kidney damage for patients in this sample. The described morphological changes were mainly verified as immuno-mediated by HCV. Conclusions: A comprehensive morphological study revealed the morphological substrate of kidney damage and its morphogenesis in patients with HIV/HCV co-infection, receiving ART.

Clinical and Radiographic Course of Bone Disease in Relapsed Multiple Myeloma in the Era of Novel Agents: Occurrence, Definition and Impact of Resclerosis Documented by Whole-Body Low-Dose Multidetector Computed Tomography

Abstract 3963 Despite the important progress obtained by the introduction of novel agents in the treatment of multiple myeloma (MM), osseous complications caused by the disease remain an important cause of morbidity impacting negatively on the patients′ quality of life. Although conventional radiographic assessments can detect the extent of bone disease, they are not able to assess the potential of new agents to induce resclerosis – as an indicator of bone remodelling - of bone lesions. Assessment by multidetector computed tomography (MDCT) not only offers the highest sensitivity for detection of osteolytic lesions while minimizing radiation exposure, but also allows precise estimation of instability and fracture risk. Most importantly, this technique documents the extent of treatment-induced resclerosis of MM bone disease. Increased stability of osseous lesions is of high impact for quality of life in the individual patient (pt). So far, there are no systematic data assessing the impact of novel agents on the pattern of resclerosis in MM. We therefore analysed 115 pt with newly diagnosed (n=25) and relapsed or refractory (rr) (n=90) MM disease who were treated at our institution between 2004 and 2011 with bortezomib (bort) and/or lenalidomide (len) (49 bort only, 30 bort and subsequent len, 36 len only). MDCT was employed for assessment of osseous lesions according to clinical symptoms or disease course following institutional guidelines. Also, bisphosphonates were applied according to institutional guidelines. Sclerosis was defined as increase in CT-attenuation of bone and was expressed in Hounsfield units (HU). Sclerotic changes detected by MDCT were documented according to localization, number, character (disseminated vs. focal) and site (inside medullary or extramedullary lesions) or described as sclerotic rim surrounding known osteolyses. Median pt age was 63 years, median number of treatment lines were 1 in the bort and 2 in the len group. Resclerosis was documented in 14 pts (17.7%) under bort and in 7 (10.6%) pts under len treatment. Sclerotic changes occurred as focal sclerosis of osteolyses (n=16), focal sclerosis of medullary lesions (n=4) or diffuse sclerosis of the bone (n=4) with combinations of various patterns being detected in individual pt. One pt responding to bort and, in subsequent relapse, also to len showed different patterns of resclerosis under each treatment. Pts experiencing sclerotic changes under bort, in 7 cases had a PR, 2 VGPRs, 1 CR and 4 had SD as best treatment response. All Pts with sclerotic changes under len showed at least a PR with 1 pt achieving CR. In 1 pt response was not evaluable due to oligosecretoric disease. Median numbers of pretreatments were 1 (range 0–5) in pts with sclerotic changes in the bort and 2 (range 0–2) in the len group. Sclerotic changes persisted indepently of the subsequent disease course. Individual pt courses will be demonstrated. Resclerosis of bone lesions is a new phenomenon in MM pts which occurs under bort and len treatment. To the best of our knowledge this is the first systematic evaluation of the pattern of resclerosis observed under the respective treatments. We provide first evidence that sclerotic changes occur in a small, but marked proportion of pts with a high variety regarding the observed pattern (diffuse versus focal) and localisation (osseous or medullary). Whereas under len treatment resclerosis was solely detected in pts with at least PR, sclerotic changes under bort treatment even occurred when myeloma response was suboptimal. This might be explained by different effects of both drugs on the bone marrow microenvironment. Prospective evaluation of this phenomenon and systematic correlation to genomic profile is warranted. Disclosures: Weisel: Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees.

Identification of membrane-bound CR1 (CD35) in human urine: evidence for its release by glomerular podocytes.

Complement receptor 1 (CR1) is present on erythrocytes (E-CR1), various leucocytes, and renal glomerular epithelial cells (podocytes). In addition, plasma contains a soluble form of CR1 (sCR1). By using a specific ELISA, CR1 was detected in the urine (uCR1) of normal individuals (excretion rate in 12 subjects, 3.12 +/- 1.15 micrograms/24 h). Contrary to sCR1, uCR1 was pelleted by centrifugation at 200,000 g for 60 min. Analysis by sucrose density gradient ultracentrifugation showed that uCR1 was sedimenting in fractions larger than 19 S, whereas sCR1 was found as expected in fractions smaller than 19 S. The addition of detergents reduced the apparent size of uCR1 to that of sCR1. After gel filtration on Sephacryl-300 of normal urine, the fractions containing uCR1 were found to be enriched in cholesterol and phospholipids. The membrane-association of uCR1 was demonstrated by analyzing immunoaffinity purified uCR1 by electron microscopy which revealed membrane-bound vesicles. The apparent molecular mass of uCR1 was 15 kD larger than E-CR1 and sCR1 when assessed by SDS-PAGE and immunoblotting. This difference in size could not be explained on the basis of glycosylation only, since pretreatment with N-glycosidase F reduced the size of all forms of CR1; however, the difference in regular molecular mass was not abrogated. The structural alleles described for E-CR1 were also found for uCR1. The urine of patients who had undergone renal transplantation contained alleles of uCR1 which were discordant with E-CR1 in 7 of 11 individuals, indicating that uCR1 originated from the kidney. uCR1 was shown to bind C3b-coated immune complexes, suggesting that the function of CR1 was not destroyed in urine. A decrease in uCR1 excretion was observed in 3 of 10 patients with systemic lupus erythematosus, corresponding to the three who had severe proliferative nephritis, and in three of three patients with focal sclerosis, but not in six other patients with proteinuria. Taken together, these data suggest that glomerular podocytes release CR1-coated vesicles into the urine. The function of this release remains to be defined, but it may be used as a marker for podocyte injury.