T cell receptor variable ß gene repertoire in liver and peripheral blood lymphocytes of chronically hepatitis C virus-infected patients with and without mixed cryoglobulinaemia.

To characterize the repertoire of T lymphocytes in chronically hepatitis C virus (HCV)-infected patients with and without mixed cryoglobulinaemia (MC). T cell receptor (TCR) variable (V) ß clonalities in portal tracts isolated from liver biopsy sections with a laser capture microdissection technique in 30 HCV-positive MC patients were studied by size spectratyping. Complementarity-determining region 3 (CDR3) profiles of liver-infiltrating lymphocytes (LIL) were also compared with those circulating in the blood. The representative results of TCR Vß by CDR3 were also obtained from liver tissues and peripheral blood lymphocytes (PBL) of 21 chronically HCV-infected patients without MC. LIL were highly restricted, with evidence of TCR Vß clonotypic expansions in 23 of 30 (77%) and in 15 of 21 (71%) MC and non-MC patients, respectively. The blood compartment contained TCR Vß expanded clones in 19 (63%) MC and 12 (57%) non-MC patients. The occurrence of LIL clonalities was detected irrespective of the degree of liver damage or circulating viral load, whereas it correlated positively with higher levels of intrahepatic HCV RNA. These results support the notion that TCR Vß repertoire is clonally expanded in HCV-related MC with features comparable to those found in chronically HCV-infected patients without MC.

A new human leukocyte antigen class I allele: HLA-A*02:374.

HLA-A*02:374 differs from HLA-A*02:01:01 by one amino acid change at codon 112 where G is replaced by V.

Identification and sequence analysis of a novel human leukocyte antigen allele B*51:141.

The newly detected HLA-B*51:141 is distinguished from HLA-B*51:08 by a single-nucleotide exchange at codon 30 where D is replaced by Y.

Identification of a new Patr-B*01 variant, Patr-B*0102, by sequence-based typing in a chimpanzee (Pan troglodytes).

Description of a new non-human primate major histocompatibility complex (MHC)-B (Patr-B) allele.

HLA DR-DQ combination associated with the increased risk of developing human HCV positive non-Hodgkin's lymphoma is related to the type II mixed cryoglobulinemia.

This investigation was focused on the contribution of individual human leukocyte antigen (HLA)-DR and -DQ alleles to the human hepatitis C virus (HCV)(+) non-Hodgkin's lymphoma (NHL), with and without mixed cryoglobulinemia (MC), to study whether individual HLA class II alleles are expressed preferentially or equally in human HCV-specific NHL. For this purpose, peripheral blood mononuclear cells were obtained from two groups of patients with HCV(+) NHL and with or without MC (70 and 71 cases, respectively), and from 4575 blood donors. Eighty-three subjects with HCV infection only, and 118 patients with MC, only without lymphoma, were added as additional control groups. Individual HLA-DR and -DQ alleles were determined using high-resolution sequence-based typing and then data were collected by considering the HLA-DRB1 and DQB1 supertypes on the basis of common structural and functional features, proposed by in silico Bioinformatic studies. From the data, it is evidenced that the DR5-DQ3 HLA combination was strongly associated with the HCV (+) MC (+) NHL group of patients compared with bone marrow donor population (P

A new HLA-A*680106 allele identified in individuals with celiac disease from the Friuli area of northeast Italy.

A novel human leukocyte antigen (HLA)-A*680106 antigen was identified in two Italian individuals by polymerase chain reaction sequencing-based typing.

[Fibronectin gene polymorphisms and clinical manifestations of mixed cryoglobulinemic syndrome: increased risk of lymphoma associated to MspI DD and HaeIII AA genotypes]. / Polimorfismi del gene della fibronectina e manifestazioni cliniche della sindrome crioglobulinemica: aumentato rischio di linfoma legato ai genotipi MspI DD e HaeIII AA.

OBJECTIVE: To analyse FN gene polymorphisms in type II mixed cryoglobulinemic syndrome (MCsn), an immune-complex mediated systemic vasculitis linked to hepatitis C virus (HCV) infection and characterized by rheumatoid factor (RF) positive B-cell proliferation at high risk for the progression into non Hogkin's lymphoma (NHL). METHODS: Samples from eighty-one patients, with MCsn (type II serum cryoglobulins and clinical signs of vasculitis were studied. Sixty-five (65/81, 80.3%) patients were HCV-positive. Twenty-one (25.9%) patients had developed a B-cell NHL during the course of MCsn. Seventy-two patients with HCV-negative and MC-unrelated NHL and 110 healthy blood donors (HBDs) were taken as controls. HaeIIIb and MspI FN gene polymorphisms were analysed by ELISA, whenever possible. RESULTS: HaeIIIb and MspI allele and genotypic frequencies did not differ between MCsn patients and HBDs. Of note, the DD-MspI allele and genotype frequencies did not differ between MCsn patients and HBDs. Of note, the DD-MspI (OR = 5.56; DI = 1.67-18.51, p = 0.0046) and the AA-HaeIIIb (OR = 5.54, CI = 1.64- 18.76, p = 0.0066) homozygosis appeared significantly and independently associated with the development of B-cell NHL in MCsn patients, with the HaeIIIbA allele possibly conferring an increased risk of NHL in the general population (OR = 1.72, CI = 1.128-2.635, p = 0.0133). In contrast, the major vasculitic manifestations, such as peripheral neuropathy, skin ulcers and glomerulonephritis tended to be associated with the counterpart MspI C allele. No association between FN plasma levels and FN genotypes was found. CONCLUSION: Genotyping for MspI and HaeIIIb FN gene polymorphisms may be clinically relevant to define the predisposition to the major clinical manifestations in MCsn.

Identification of new major histocompatibility complex-A, -B, -C alleles in chimpanzees (Pan troglodytes).

Two new Patr-A, five new Patr-B and three new Patr-C alleles from Pan troglodytes are described.

Description of two new major histocompatibility complex (MHC) class II DRB1 [Pan troglodytes (Patr)-DRB1] alleles.

Sequence-based typing strategy is used to identify polymorphism of Patr-DRB1. Two new Patr-DRB1 are described.

Fibronectin gene polymorphisms are associated with the development of B-cell lymphoma in type II mixed cryoglobulinemia.

OBJECTIVE: To analyse fibronectin (FN) gene polymorphisms in type II mixed cryoglobulinemic syndrome (MCsn), an immune-complex mediated systemic vasculitis linked to hepatitis C virus (HCV) infection and characterised by rheumatoid factor (RF) positive B-cell proliferation at high risk for the progression into non-Hodgkin's lymphoma (NHL). METHODS: Samples from 74 patients with MCsn (type II serum cryoglobulins and clinical signs of vasculitis) were studied. In all, 58 (78.4%) patients were HCV-positive. In total, 21 (28.4%) patients developed a B-cell NHL during the course of MCsn. A total of 72 patients with HCV-negative and MC-unrelated NHL and 110 healthy blood donors (HBDs) were taken as controls. HaeIIIb and MspI FN gene polymorphisms were analysed by PCR and specific restriction enzyme digestions, following reported procedures. Plasma FN levels were analysed by ELISA, whenever possible. RESULTS: HaeIIIb and MspI allele and genotype frequencies did not differ between MCsn patients and HBDs. Of note, the DD-MspI (OR = 5.99; CI 1.77-20.261, p = 0.0039) and the AA-HaeIIIb (OR = 4.82, CI 1.42-16.39, p = 0.0176) homozygosis appeared significantly associated with the development of B-cell NHL in MCsn patients, with the HaeIIIb A allele possibly conferring an increased risk of NHL in the general population (OR = 1.72, CI 1.128-2.635, p = 0.0133). None of the other MCsn-related clinical manifestations were significantly associated with a particular genetic pattern. No association between FN plasma levels and FN genotypes was found. CONCLUSION: Genotyping for MspI and HaeIIIb FN gene polymorphisms may be clinically relevant to define the risk of lymphoma development in MCsn.

Genetic insights into the disease mechanisms of type II mixed cryoglobulinemia induced by hepatitis C virus.

The ability of the immune system to distinguish between self and non-self is critical to the functioning of the immune response. A breakdown in these mechanisms can lead to the onset of autoimmune disease. Clinical and molecular data suggest that shared immunogenetic mechanisms lead to the autoimmune process. The most studied part of the autoimmune process is the human leukocyte antigen (HLA) region. Recently, progress has been made in narrowing down HLA cluster classifications based on structural and functional features of HLA alleles. Using this approach we have investigated 175 patients with hepatitis C virus (HCV)-induced type II cryoglobulinemia (MC), and compared them to a control group of 14,923 bone marrow donors. Additionally, we investigated the frequency of HLA homozygosity in the same groups of subjects. Our results provide evidence of a role for DR5 and DQ3 HLA class II clusters and a higher frequency of HLA homozygous leading to the clinical outcome of type II mixed cryoglobulinemic autoimmune disease. The DR5 cluster is characterized by a Glu in beta 9 and its polymorphism is connected with preferred anchors at beta 9 of the binding peptide, while the DQ3 cluster is characterized by Glu B86 and Leu B87, which allows the binding of large hydrophobic amino acids at p1 of the binding peptide. The mechanisms by which variations in HLA lead to autoimmunity remain unknown, although they are likely to be mediated by continuous presentation of HCV epitopes to T cells and a genetic background that limits the effective clearance of HCV. The results presented in this paper have increased our knowledge of the mechanism of autoimmune disease and B-cell lymphoproliferation during HCV infection. The work was performed in accordance with the principles of the 1983 Declaration of Helsinki. There is no conflict of interest.

Bone marrow B-cell clonal expansion in type II mixed cryoglobulinaemia: association with nephritis.

OBJECTIVES: To investigate the relationship between the pattern of bone marrow (BM) B-cell expansion and the clinical features of mixed cryoglobulinaemia (MC) syndrome. METHODS: Fifty-five patients with type II MC syndrome were analysed. Their median age was 64 yrs (range 24-82), the median disease duration was 6 yrs (range 1-26) and the mean follow-up after BM analysis was 2.65 yrs (s.d. = 1.33). Peripheral neuropathy was present in 33 patients (60%), nephritis in 14 (25.4%), skin ulcers in 14 (25.4%) and lymphoma or atypical lymphoproliferative disorder (LPD) in 17/55 (30.9%). Anti-HCV antibodies were found in 43/55 patients (78.2%). BM B-cell expansion was evaluated by a semi-nested PCR amplification of the V-D-J region of the IgH genes. RESULTS: A clonal B-cell expansion in the BM was found in 33/55 (60%) patients, while a polyclonal pattern in 22/55 (40%). A BM pattern of clonal B-cell expansion increased the risk of nephritis of about 10 times [odds ratio (OR) = 10.11, CI95%1.52-67.31], if compared to a polyclonal pattern. In contrast, the risk of skin ulcers was decreased in BM clonal cases (OR = 0.09, CI95%0.02-0.49). Overt lymphomas did not emerge from patients with BM monoclonal expansion (without clinical or histopathological features of lymphoproliferation; or with LPD) in a short-term, consistent with the finding that monoclonality was associated with nephritis and not with an underlying, not recognized lymphoma. CONCLUSION: BM clonal B-cell expansion is associated with nephritis in MC syndrome. Particular B-cell clones may be preferentially expanded and may play a pathogenic role in MC nephritis.

Identification of four novel MHC-C alleles in chimpanzees.

Sequence-based typing strategy is used to identify polymorphism of Patr-C. Four new Patr-C alleles are described.

Proteins specifically hyperexpressed in a coeliac disease patient with aberrant T cells.

An aberrant T cell population is the basis for diagnosis of refractory coeliac disease and determines the risk of enteropathy-associated T cell lymphoma. This disease is serious with a poor survival. Pathogenetic mechanisms sustaining aberrant T cell proliferation remain unknown. Recently, alemtuzumab has been proposed as a promising new approach to treat these patients. Only few single cases have been tested at present; nevertheless, in all the cases a clinical improvement was observed. However, whether intraepithelial lymphocytes have been targeted effectively by alemtuzumab is still debated. This study reports, using two-dimensional difference gel electrophoresis (2D DIGE), hyperexpressed proteins associated specifically with aberrant T cells found in a patient with coeliac disease by comparison of the protein expression of this sample with that of patients with coeliac disease and polyclonal T cells or with control subjects. The data demonstrated a significantly higher expression of IgM, apolipoprotein C-III and Charcot-Leyden crystal proteins in a duodenal biopsy specimen of the patient with clonal T cells compared with that of other patients. These preliminary results allow hypothesizing different clinical effects of alemtuzumab in patients with coeliac disease and aberrant T cell proliferation, because as well as the probable effect on T cells, alemtuzumab could exert its effect by acting on inflammatory associated CD52(+) IgM(+) B cells and eosinophil cells, known to produce IgM and Charcot-Leyden crystal proteins, that we demonstrated to be altered in this patient. The results also emphasize the possible association of apolipoprotein with aberrant T cell proliferation.

Hepatitis C virus infection, cryoglobulinaemia, and beyond.

Hepatitis C virus (HCV) infection is the major cause of mixed cryoglobulinaemia (MC), an immune complex (IC)-mediated systemic vasculitis mainly involving the small blood vessels. The precise mechanism of cryoprotein production is currently unknown. HCV virions and non-enveloped core protein participate in the formation of cold-insoluble ICs. Cryoglobulinaemic patients represent a distinct HCV-infected population, in that significant HCV enrichment of lymphoid cells is accompanied by evidence of productive virus infection and increased frequency of B cells. Liver, the major target organ of HCV, is the site of accumulation of inflammatory infiltrates that shares many architectural features with lymphoid tissue and reflects a distorted homeostatic balance between factors that enhance cellular recruitment, proliferation and retention, and those that decrease cellularity (cell death and emigration). There is now overwhelming evidence of a direct contribution to B-cell growth and survival through production of a variety of cytokines and chemokines. Liver tissue over-expression and abnormal circulating levels of B-cell activating factor belonging to the TNF family can provide effective costimulatory mechanisms to sustain the B-cell clonal expansion, which constitutes molecular stigmata of MC. Indolent lymphoproliferation might act as the starting point of chronic, multistage lymphomagenesis. An innovative therapeutic strategy is directed to 'eradication of the virus' and deletion of B-cell clonalities.

Hepatitis C virus productive infection in mononuclear cells from patients with cryoglobulinaemia.

The relationship between the occurrence of cryoglobulins and hepatitis C virus (HCV) productive infection in peripheral blood and bone marrow-derived lymphocytes was explored. HCV minus strand RNA, the viral replicative intermediate, was searched for by a polyA(+) tract strand-specific Tth-based reverse transcriptase-polymerase chain reaction (RT-PCR) in lymphoid cells of 46 patients with acute and chronic infection. The HCV minus strand was demonstrated in RNA extracted from six (13%) and five (11%) peripheral blood and bone marrow-derived lymphocytes, respectively. The HCV replicating form in lymphoid cells was associated strictly with mixed cryoglobulinaemia (MCG), in that it was found in six of 13 (46%) MCG patients, including two with B cell non-Hodgkin's lymphoma (NHL). No traces of HCV-negative strand RNA were found in four patients with acute hepatitis C, in 15 with chronic active hepatitis without extrahepatic disorders, in seven with monoclonal gammopathy of undetermined significance, and in seven with B-NHL without MCG. These results emphasize the direct role of the virus in the pathogenesis of MCG and support the contention that HCV is not specifically lymphotropic, its entry and replication in lymphoid cells being determined largely by selective interactions.

HCV-NS3 and IgG-Fc crossreactive IgM in patients with type II mixed cryoglobulinemia and B-cell clonal proliferations.

We demonstrate that in three cases of MC (two with immunocytoma), the IgM-RF+ component of their cryoprecipitated represents the circulating counterpart of the B-cell receptor (BCR) of the monoclonal overexpanded B-cell population. These IgMs were isolated and used to demonstrate a crossreactivity against both hepatitis C virus (HCV) NS3 antigen and the Fc portion of IgG. Epitopes were identified in a fraction of exemplary samples by using epitope excision approach (NS(31250-1334) and IgG Fc(345-355)). The same phenomenon of crossreactivity has been shown to occur in vivo after immunization of a mouse with the NS3(1251-1270) peptide. To verify if the same reaction was also present in MC samples characterized by an oligo/polyclonal B-cell proliferation, IgM crossreactivity was tested in 14 additional samples. Five out of the 14 were reactive against HCV NS3 and 11 out of 14 were reactive against IgG-Fc peptide. The data support the role of HCV NS3 antigen in a subset of patients with MC, whereas the high frequency of the IgG-Fc epitope suggests that these B cells originate from precursors strongly selected for auto-IgG specificity. We suggest that engagement of specific BCRs by NS3 (or NS3-immunocomplex) antigen could explain the prevalence of IgM cryoglobulins in these patients.

Type II mixed cryoglobulinaemia as an oligo rather than a mono B-cell disorder: evidence from GeneScan and MALDI-TOF analyses.

OBJECTIVE: To identify and characterize rheumatoid factor (RF)-producing B-cells and cryoprecipitate immunoglobulin (Ig) M in hepatitis C virus (HCV)-positive patients. METHODS: We purified and characterized, by peptide mass fingerprinting integrated with an NCBI IgBlast data bank search, the IgM component of cryoprecipitate and analysed the VDJ pattern of bone marrow B-cells by gene scan analysis of 17 HCV-positive patients with type II mixed-cryoglobulinaemia. RESULTS: IgM purified from all of the patients presented an RF specificity. In three of these patients a high and predominant B-cell clone (>or=30%) was found in the bone marrow. B-cell-receptor sequences were determined and immunophenotyping of these clones was performed. Peptide masses originating after tryptic digestion of the B-cell-receptor combinatory regions and those originating by tryptic digestion of the cryoprecipitated IgM from the same patient were comparable. In the remaining patients an oligoclonal/polyclonality was found. However, in some of these patients we were able to find peptides that matched with the B-cell-receptor sequences of overexpanded B cells, indicating that, even in the absence of a clear monoclonal expansion, a fraction of total cryoprecipated IgM may derive from overexpanded B-cell clones found in patients' bone marrow. CONCLUSIONS: In the majority of mixed cryoglobulinaemia-HCV-positive patients, both in the serum and in B cells from the bone marrow, an oligoclonal pattern is the main molecular picture. When a monoclonal B-cell clone is found, its B-cell-receptor shows an antigen-binding fragment identical to that of cryoprecipitable RF-IgM. Phenotypically, B cells are CD20-positive but CD5-negative, suggesting that the B-1 B-cell subset is not likely to produce high-affinity IgM-RF molecules.