Umberto Basile

Overview of immune abnormalities in lysosomal storage disorders

The critical relevance of the lysosomal compartment for normal cellular function can be proved by numbering the clinical phenotypes that arise in lysosomal storage disorders (LSDs), a group of around 70 different monogenic autosomal or X-linked syndromes, caused by specific lysosomal enzyme deficiencies: all LSDs are characterized by progressive accumulation of heterogeneous biologic materials in the lysosomes of various parts of the body such as viscera, skeleton, skin, heart, and central nervous system. At least a fraction of LSDs has been associated with mixed abnormalities involving the immune system, while some patients with LSDs may result more prone to autoimmune phenomena. A large production of proinflammatory cytokines has been observed in Gaucher and Fabry diseases, and wide different autoantibody production has been also reported in both. Many immune-mediated reactions are crucial to the pathogenesis of different inflammatory signs in mucopolysaccharidoses, and subverted heparan sulphate catabolism might dysregulate cellular homeostasis in the brain of these patients. Furthermore, an inappropriate activation of microglia is implicated in the neurodegenerative foci of Niemann-Pick disease, in which abnormal signalling pathways are activated by impaired sphingolipid metabolism. In addition, not the simple impaired catabolism of gangliosides per se, but also the production of anti-ganglioside autoantibodies contributes to the neurological disease of gangliosidoses. Even if the exact relationship between the modification of lysosomal activities and modulation of the immune system remains obscure, there is emerging evidence of different impaired immunity responses in a variety of LSDs: in this review we investigate and summarize the immune abnormalities and/or clinical data about immune system irregularities which have been described in a subset of LSDs.

Progressive multifocal leukoencephalopathy in a patient with Franklin disease and hypogammaglobulinemia

We report an association between histologically confirmed progressive multifocal leukoencephalopathy (PML) and an extremely rare humoral immunodeficiency disease, Franklin disease. In our patient, clinical presentation has been typical and prompted us, together with radiological findings, to perform a brain biopsy to confirm the diagnosis even if there was no evidence of any other risk factor except hypogammaglobulinemia. We suggest that PML should be suspected in patients in whom immunosuppression is not obvious (i.e. not only in the setting of HIV infection or disseminated end-stage lymphomas) and involves defects in humoral immunity.

Vitamin D deficiency and supplementation in patients with aggressive B-cell lymphomas treated with immunochemotherapy

Vitamin D deficiency has been reported to be a negative prognostic factor in elderly patients with aggressive B‐cell lymphomas. In vitro data suggest that vitamin D supplementation may enhance rituximab‐mediated cytotoxicity. We prospectively assessed 25‐hydroxyvitamin D [25(OH)D] levels at diagnosis in a cohort of 155 patients with aggressive B‐cell lymphomas of whom 128 had diffuse large B‐cell lymphoma (DLBCL) not otherwise specified. 25(OH)D levels were deficient (<20 ng/mL) in 105 (67%), insufficient (20–29 ng/mL) in 32 (21%), and normal (≥30 ng/mL) in 18 (12%) patients with a seasonal variation. Patient characteristics associated with lower 25(OH)D levels were poor performance status, overweight, B‐symptoms, elevated LDH, lower albumin and hemoglobin levels. As a result of a change in practice pattern, 116 patients received vitamin D3 (cholecalciferol) supplementation that included a loading phase with daily replacement and subsequent maintenance phase with a weekly dose of 25,000 IU until end of treatment. This resulted in a significant increase in 25(OH)D levels, with normalization in 56% of patients. We analyzed the impact of 25(OH)D levels on event‐free survival in patients treated with Rituximab‐CHOP. 25(OH)D levels below 20 ng/mL at diagnosis and IPI were independently associated with inferior EFS. Moreover, patients with normalized 25(OH)D levels following supplementation showed better EFS than patients with persistently deficient/insufficient 25(OH)D levels. Our study provides the first evidence that achievement of normal 25(OH)D levels after vitamin D3 supplementation is associated with improved outcome in patients with DLBCL and deficient/insufficient 25(OH)D levels when receiving rituximab‐based treatment.

Autoimmunity and lymphoproliferation markers in naïve HCV-RNA positive patients without clinical evidences of autoimmune/lymphoproliferative disorders

BACKGROUND HCV can lead to both chronic liver disease and B-cell lymphoproliferative disorders. A strong association exists between HCV and mixed cryoglobulinaemia (MC). METHODS Anti-nuclear antibodies (ANA), rheumatoid factor Ig-G (RF-IgG), free light chain κ and λ (FLC-κ, FLC-λ) levels and κ/λ ratio were evaluated in 50/420 subjects unexpectedly resulted anti-HCV positive after routine screenings for non-hepathological procedures. RESULTS Three/fifty patients had HCV-RNA undetectable in the serum and were excluded from the analysis. Thirty-nine/fifty patients had laboratory evidence of circulating cryoglobulins without liver disease and MC-related symptoms. Among them, 17 resulted ANA-positive. The mean cryocrit was higher in ANA-positive patients, while no other demographic/clinical differences were observed between the groups. Significantly higher levels of RF-IgG were observed in ANA-positive vs ANA-negative patients. κ and λ FLC were higher in ANA-positive patients. A ROC analysis, based on ANA-positivity vs ANA-negativity, confirmed a high sensitivity and specificity of RF-IgG test. CONCLUSIONS Published data concerning MC come mostly from symptomatic vasculitis. We analyzed HCV-patients without MC symptoms, founding cryoglobulins in the majority of them. The increased levels of FR-IgG and FLC in CGs-ANA-positive patients, suggest these test could be used to identify a state of silent autoimmune and/or lymphoproliferative condition before the transition to a frank disease in naïve HCV-patients without symptoms of extrahepatic manifestations.

Assessment of free light chains in HCV-positive patients with mixed cryoglobulinaemia vasculitis undergoing rituximab treatment

Mixed cryoglobulinaemia (MC) is an HCV‐related lymphoproliferative disorder characterized by the presence of circulating immune complexes called cryoglobulins. Treatment with anti‐CD20 monoclonal antibody rituximab is proved to be very useful, especially in patients ineligible to interferon‐based antiviral therapy. Recently, free light chain (FLC) κ/λ ratio and FLC patterns were associated with MC. The aim of this study was to evaluate changes in FLC‐κ, FCL‐λ, FLC ratio following rituximab treatment in patients with HCV‐related MC and to correlate FLC‐κ, FCL‐λ and FLC ratio values with therapy response.

Free light chains: Eclectic multipurpose biomarker

The production of antibodies is accompanied by a slight excess of synthesis of κ and λ immunoglobulin light chains; small amounts of them are released in the peripheral blood and can also be found in various body fluids, such as synovial fluid, cerebrospinal fluid, urine and saliva. They are rapidly filtered by the glomerulus and >99% are reabsorbed from the cells of the proximal convoluted tubule, making them present in the urine in only trace amounts. The production of an excess of protein without a reason or a specific function in a biological system is rare. Free light chains, considered for years a waste product of Ig synthesis, are currently known to be very active molecules, able to bind antigens as well as whole immunoglobulin and helping to develop specific antibody affinity. The ability of free light chains to activate mast cells and then become an active part of the pathogenic mechanisms of chronic inflammatory diseases has increased interest in their clinical use, both as an attractive therapeutic target or as a biochemical marker of disease evolution or remission. This is an overview of relevant scientific interest that immunoglobulin light chains κ and λ have attracted over the years, a report on the progress in knowledge about their structure and function, with a special focus on their biological meaning and potential clinical utility in different diseases.

Pre-analytical phase in cryoglobulin (CRG) detection: an alternative method for sample transport.

aEleonora Torti and Maria Teresa Dell’Abate contributed equally to this work. *Corresponding author: Umberto Basile, Department of Laboratory Medicine, School of Medicine, Catholic University of the Sacred Heart, Largo A. Gemelli 8, 00168 Rome, Italy, Phone: +39 06 3015 4222, E-mail: umberto.basile@rm.unicatt.it Eleonora Torti and Maria Teresa Dell’Abate: Department of Laboratory Medicine, School of Medicine, Catholic University of the Sacred Heart, Rome, Italy Luigi Colacicco and Cecilia Zuppi: Institute of Biochemistry School of Medicine, Catholic University of the Sacred Heart, Rome, Italy Francesca Gulli and Gian Lodovico Rapaccini: Institute of Internal Medicine, School of Medicine, Catholic University of the Sacred Heart, Rome, Italy Letter to the Editor

Anti-nuclear antibody detection in cryoprecipitates: distinctive patterns in hepatitis C virus-infected patients.

BACKGROUND Anti-nuclear antibodies are immunoglobulins directed against nuclear antigens. They are associated with many autoimmune disorders, but are frequently found in patients infected with hepatitis C virus, possibly indicating an underlying common origin. Likewise, mixed cryoglobulinemia often accompanies autoimmune diseases and hepatitis C infection. AIM To compare anti-nuclear antibodies and immunoglobulin content of cryoprecipitates from hepatitis C virus-positive patients in order to assess their predictive value in the onset of hepatitis C virus-driven extrahepatic disorders. METHODS Serum from 40 hepatitis C virus-positive patients and 50 controls with rheumatoid arthritis was processed for cryoglobulin detection: all subjects presented with Type III mixed cryoglobulinemia. Immunoglobulin content and immunoglobulin subclasses of cryoprecipitates were assessed by immunofixation and tested by ELISA for rheumatoid factor. Cryoprecipitates were also analysed for anti-nuclear antibodies by indirect immuno-fluorescence to identify specific patterns typical of each condition. RESULTS Anti-nuclear antibody patterns differed significantly; 26 infected subjects (65%) were IgG3 positive: of these, 25 were also anti-nuclear antibody-positive (96.1%). CONCLUSIONS IgG3 are autoreactive clones unrelated to viral recognition and possibly involved in autoimmune disorders. Altogether, these results may represent useful diagnostic device for early detection of hepatitis C virus-induced autoimmune diseases.

Relationship between circulating syndecan-1 levels (CD138s) and serum free light chains in monoclonal gammopathies

BackgroundMonoclonal gammopathies encompass a wide range of diseases characterized by the monoclonal expansion of a B-cell clone. Despite emerging therapeutic strategies, chances of survival of patients who are affected are still scarce, which implies that new tools are necessary not only for the diagnosis but also for the follow-up of patients affected by such diseases. In this context, the use of free light chains (FLCs) has been incorporated into many guidelines.Likewise, tumor microenvironment is consistently gaining importance as role player in tumor pathogenesis. Specifically, Syndecan-1 (CD138), a heparan-sulfate proteoglycan is attracting interests as it is highly expressed and shed by myeloma plasma-cells.The aim of our study was to analyze CD138 levels in the serum of patients affected by multiple myeloma or light chain only disease, and to compare the values obtained with free light chain (FLC) kappa, lambda and FLC ratio in both groups of patients.Methods84 patients affected by Multiple Myeloma and Light Chain Myeloma were recruited for this study. Serum CD138 was assessed by ELISA (Diaclone Research, France) and FLC values were quantified by nephelometry (Freelite TM Human Kappa and Lambda Free Kits, The Binding Site, UK). Data was analyzed by GraphPad Prism software and Statgraph.ResultsWe observed higher CD138 mean values in myeloma patients compared to the light chain only myeloma group. A positive linear regression of CD138 and FLC was observed in the light chain only cohort as opposed to myeloma patients which show an inverse trend.ConclusionsThe study highlighted an existing relationship between FLCs and CD138 and wishes to seek also a correlation in order to rapidly and efficiently perform diagnosis and different diagnostic schemes.

Serum free light chain quantitative assays: Dilemma of a biomarker

Serum free light chains detection assays are consistently meeting greater interest for the diagnosis and monitoring of monoclonal gammopathies and plasma cell dyscrasias. Nowadays, there are neither standardized methods nor reference material for the determination of free light chains; for this reason, it is important to compare two different assays used in clinical laboratory.