Differential transcriptomics in sarcoidosis lung and lymph node granulomas with comparisons to pathogen-specific granulomas.

RATIONALE: Despite the availability of multi-"omics" strategies, insights into the etiology and pathogenesis of sarcoidosis have been elusive. This is partly due to the lack of reliable preclinical models and a paucity of validated biomarkers. As granulomas are a key feature of sarcoidosis, we speculate that direct genomic interrogation of sarcoid tissues, may lead to identification of dysregulated gene pathways or biomarker signatures. OBJECTIVE: To facilitate the development sarcoidosis genomic biomarkers by gene expression profiling of sarcoidosis granulomas in lung and lymph node tissues (most commonly affected organs) and comparison to infectious granulomas (coccidiodomycosis and tuberculosis). METHODS: Transcriptomic profiles of immune-related gene from micro-dissected sarcoidosis granulomas within lung and mediastinal lymph node tissues and compared to infectious granulomas from paraffin-embedded blocks. Differentially-expressed genes (DEGs) were profiled, compared among the three granulomatous diseases and analyzed for functional enrichment pathways. RESULTS: Despite histologic similarities, DEGs and pathway enrichment markedly differed in sarcoidosis granulomas from lymph nodes and lung. Lymph nodes showed a clear immunological response, whereas a structural regenerative response was observed in lung. Sarcoidosis granuloma gene expression data corroborated previously reported genomic biomarkers (STAB1, HBEGF, and NOTCH4), excluded others and identified new genomic markers present in lung and lymph nodes, ADAMTS1, NPR1 and CXCL2. Comparisons between sarcoidosis and pathogen granulomas identified pathway divergences and commonalities at gene expression level. CONCLUSION: These findings suggest the importance of tissue and disease-specificity evaluation when exploring sarcoidosis genomic markers. This relevant translational information in sarcoidosis and other two histopathological similar infections provides meaningful specific genomic-derived biomarkers for sarcoidosis diagnosis and prognosis.

Nonproliferative and Proliferative Lesions of the Rat and Mouse Hematolymphoid System.

The INHAND Project (International Harmonization of Nomenclature and Diagnostic Criteria for Lesions in Rats and Mice) is a joint initiative of the Societies of Toxicologic Pathology from Europe (ESTP), Great Britain (BSTP), Japan (JSTP), and North America (STP) to develop an internationally accepted nomenclature for proliferative and nonproliferative changes in rats and mice. The purpose of this publication is to provide a standardized nomenclature for classifying changes observed in the hematolymphoid organs, including the bone marrow, thymus, spleen, lymph nodes, mucosa-associated lymphoid tissues, and other lymphoid tissues (serosa-associated lymphoid clusters and tertiary lymphoid structures) with color photomicrographs illustrating examples of the lesions. Sources of material included histopathology databases from government, academia, and industrial laboratories throughout the world. Content includes spontaneous lesions as well as lesions induced by exposure to test materials. The nomenclature for these organs is divided into 3 terminologies: descriptive, conventional, and enhanced. Three terms are listed for each diagnosis. The rationale for this approach and guidance for its application to toxicologic pathology are described in detail below.

Flow immunophenotyping of benign lymph nodes sampled by FNA: Representative with diagnostic pitfalls.

BACKGROUND: Fine-needle aspiration with flow cytometry (FNA-FC) is routinely used in the evaluation of lymph nodes suspicious for lymphoma, yet data comparing immunophenotype distributions and outliers in benign lymph nodes sampled by fine-needle aspiration (FNA) versus excision are lacking. METHODS: Flow cytometry data from 289 benign lymph node FNA cases were assessed for the overall antigen distribution, with a focus on outliers relevant to the diagnosis of lymphoma. Distributions and outlier proportions were compared with those of a separate cohort of 298 excisional biopsies. RESULTS: Compared with excisional biopsies, FNA specimens overrepresented CD3+ events (72% vs 63%), underrepresented CD19+ events (22% vs 29%), and had 25% fewer large cell-gated events. Normalized antigen distributions in FNA were equivalent to those in excisional biopsy. Twenty-three percent of FNA-FC cases exhibited an outlier, including a skewed kappa:lambda light-chain ratio, increased CD5+ or CD10+ B-cell events, a skewed CD4:CD8 ratio, and increased CD7 loss on T cells, with no significant differences in frequency or type in comparison with excisional specimens. Outliers for the light-chain ratio and T-cell antigens were enriched among older patients and included patients with a variety of autoimmune/rheumatologic conditions. CONCLUSIONS: Benign lymph node FNA yields flow immunophenotypes remarkably similar to those from excisional biopsies. Outlier flow immunophenotypes are identified in benign lymph nodes sampled by FNA at a frequency similar to that with excisional biopsies. Older patients, who have a higher baseline risk of lymphoma, are more likely to exhibit lymphoma-mimicking outliers such as a light-chain predominance on B cells and skewed CD4:CD8 ratios or increased CD7 loss on T cells, and they warrant additional diagnostic caution.

Possible relationship between fibrosis of IgG4-related thymitis and the profibrotic cytokines, transforming growth factor beta 1, interleukin 1 beta and interferon gamma: a case report.

BACKGROUND: IgG4-related disease often forms a mass and the affected lesion is clinically removed because the mass cannot be differentiated from a neoplasm. Affected lesions commonly occur in the pancreas, hepatobiliary tract, kidney, and retroperitoneum. However, the lesion rarely occurs in the thymus. A histological worldwide consensus of IgG4-related disease proposed that pathological diagnosis of IgG4-related disease should meet more than two of three major features: 1) dense lymphoplasmacytic infiltration with greater than 40% IgG4+/IgG+ plasma cells, 2) storiform fibrosis; and 3) obliterative phlebitis. Currently, fibrosis of IgG4-related disease is thought to be induced by profibrotic cytokines such as transforming growth factor beta 1 (TGFB1), interleukin 1 beta (IL1B) and interferon gamma (IFNG), which are secreted by regulatory T cells (Tregs) and CD4-positive cytotoxic T cells. However, it is unclear whether profibrotic cytokines are associated with the fibrosis seen in IgG4-related thymitis. Here we examined whether cytokines in the mass were increased compared with those in the surrounding thymus, and whether Tregs were present in the mass, using reverse transcription absolute quantitative polymerase chain reaction (RT-ab-qPCR) and immunohistochemistry. CASE PRESENTATION: A 70-year-old Japanese man contracted IgG4-letated thymitis. Histological and immunohistochemical analyses demonstrated his mass had massive fibrosis with a focally storiform pattern and lymphoplasmacytic infiltration with 40% IgG4+/IgG+ plasma cells, but not obliterative phlebitis. The mass was surrounded by atrophic thymus. We diagnosed the mass as IgG4-related thymitis. Immunohistochemically, Tregs were scattered throughout the mass. RT-ab-qPCR showed that messenger RNA expressions of TGFB1, IL1B and IFNG in the mass were 270-, 158- and 5.5- fold higher than in the surrounding thymus. His serum IgG4 level after surgery was within the normal range (83.4 mg/dl soon after surgery, 89.3 mg/dl 2 weeks after surgery). CONCLUSIONS: Our results suggested the profibrotic cytokines TGFB1, IL1B and IFNG induce fibrosis and that Tregs might produce some of these cytokines in IgG4-related thymitis as well as in the other affected lesions of IgG4-related disease.

Unsuspected human immunodeficiency virus infection presenting as immunoglobulin G4-related lymphadenopathy: a case report.

Immunoglobulin G4 (IgG4)-related disease (IgG4-RD) is an immune-mediated condition characterized by infiltration of the involved organs by IgG4-bearing plasma cells. The prevalence of autoimmune diseases, associated with or occurring in patients with human immunodeficiency virus (HIV) infection, has been increasing. We describe a 58-year-old man with an undiagnosed HIV infection, which presented as chronic cervical lymphadenopathy with an elevated serum IgG4 and a very high IgE. Histologically, lymph nodes showed expanded sinusoids and burnt-out germinal centers with increased plasmacytic infiltration and collagen fiber deposition. The absolute number of IgG4+ plasma cells and the IgG4+/IgG+ plasma cell ratio was increased. The lymph nodes were enlarged and clinically the patient improved after steroid treatment. Nine months later, he was diagnosed with acquired immune deficiency syndrome, following presentation with a cavitary left lung lesion. Immunohistochemical studies on the previously resected lymph node revealed complete absence of CD4+ T-lymphocytes and increased CD8+ T-lymphocytes. The pathologic findings met the criteria of both HIV infection and IgG4-related lymphadenopathy. Our case demonstrates that further investigations for underlying HIV infection in a case of IgG4-RD are critical, especially when extremely elevated IgE is concomitantly present.

Nodular lymphoid hyperplasia: A marker of low-grade inflammation in irritable bowel syndrome?

AIM: To evaluate the prevalence of nodular lymphoid hyperplasia (NLH) in adult patients undergoing colonoscopy and its association with known diseases. METHODS: We selected all cases showing NLH at colonoscopy in a three-year timeframe, and stratified them into symptomatic patients with irritable bowel syndrome (IBS)-type symptoms or suspected inflammatory bowel disease (IBD), and asymptomatic individuals undergoing endoscopy for colorectal cancer screening. Data collection included medical history and final diagnosis. As controls, we considered all colonoscopies performed for the aforementioned indications during the same period. RESULTS: One thousand and one hundred fifty colonoscopies were selected. NLH was rare in asymptomatic individuals (only 3%), while it was significantly more prevalent in symptomatic cases (32%). Among organic conditions associated with NLH, the most frequent was IBD, followed by infections and diverticular disease. Interestingly, 31% of IBS patients presented diffuse colonic NLH. NLH cases shared some distinctive clinical features among IBS patients: they were younger, more often female, and had a higher frequency of abdominal pain, bloating, diarrhoea, unspecific inflammation, self-reported lactose intolerance and metal contact dermatitis. CONCLUSION: About 1/3 of patients with IBS-type symptoms or suspected IBD presented diffuse colonic NLH, which could be a marker of low-grade inflammation in a conspicuous subset of IBS patients.

Clinical Associations of Biallelic and Monoallelic TNFRSF13B Variants in Italian Primary Antibody Deficiency Syndromes.

We assessed the prevalence of TNFRSF13B mutations and the clinical correlates in an Italian cohort of 189 CVID, 67 IgAD patients, and 330 healthy controls to substantiate the role of TACI genetic testing in diagnostic workup. We found that 11% of CVID and 13% of IgAD carried at least one mutated TNFRSF13B allele. Seven per cent of CVID had monoallelic-mutations and 4% had biallelic-mutations. The frequency of C104R monoallelic-mutations was not higher than that found in healthy controls. Biallelic-mutations were exclusively found in CVID. CVID patients carrying monoallelic-mutations had an increased prevalence of lymphadenopathy, granulomata, and autoimmune cytopenias. CVID carrying biallelic-mutations had a low prevalence of autoimmunity in comparison with TACI wild-type CVID. Moreover, biallelic-mutated CVID had higher frequency of switched memory B-cells and higher IgM and IgA antibodies to polysaccharide antigens than TACI wild-type and monoallelic-mutated CVID. TACI-mutated IgAD patients had only monoallelic-mutations and did not display clinical difference from IgAD wild-type patients. In conclusion, TNFRSF13B genetic screening of antibody deficiencies may allow the identification of mutational patterns. However, as with counseling for risk assessment, geneticists should be aware that the interpretation of genetic testing for TACI mutations is difficult and the potential impact on clinical management is still limited.

C9orf72 is required for proper macrophage and microglial function in mice.

Expansions of a hexanucleotide repeat (GGGGCC) in the noncoding region of the C9orf72 gene are the most common genetic cause of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia. Decreased expression of C9orf72 is seen in expansion carriers, suggesting that loss of function may play a role in disease. We found that two independent mouse lines lacking the C9orf72 ortholog (3110043O21Rik) in all tissues developed normally and aged without motor neuron disease. Instead, C9orf72 null mice developed progressive splenomegaly and lymphadenopathy with accumulation of engorged macrophage-like cells. C9orf72 expression was highest in myeloid cells, and the loss of C9orf72 led to lysosomal accumulation and altered immune responses in macrophages and microglia, with age-related neuroinflammation similar to C9orf72 ALS but not sporadic ALS human patient tissue. Thus, C9orf72 is required for the normal function of myeloid cells, and altered microglial function may contribute to neurodegeneration in C9orf72 expansion carriers.

Autoimmune lymphoproliferative syndrome due to somatic FAS mutation (ALPS-sFAS) combined with a germline caspase-10 (CASP10) variation.

Autoimmune lymphoproliferative syndrome (ALPS) is a primary immunodeficiency caused by impaired Fas/FasL-mediated apoptosis of lymphocytes and is characterized by chronic nonmalignant or benign lymphoproliferation, autoimmune manifestations and expansion of double negative (DN) T-cells (TCRαß+CD4-CD8-). Most cases of ALPS are associated with germline (ALPS-FAS) or somatic (ALPS-sFAS) heterozygous FAS mutations or a combination of both. Here we report three unrelated patients with ALPS-sFAS. Only one of them showed impaired Fas function in PHA-activated T-cells. In this patient, the genetic analysis of the caspase-10 gene (CASP10) identified a heterozygous germline change in exon 9 (c.1337A>G) causing Y446C substitution in the caspase-10 protein. In addition, this patient had a dysregulated T- and B-cell phenotype; circulating lymphocytes showed expansion of T effector memory CD45RA+ (TEMRA) CD4 T-cells, effector memory CD8 T-cells, CD21(low) B-cells and reduced memory switched B-cells. Additionally, this patient showed altered expression in T-cells of several molecules that change during differentiation from naïve to effector cells (CD27, CD95, CD57 and perforin). Molecular alterations in genes of the Fas pathway are necessary for the development of ALPS and this syndrome could be influenced by the concurrent effect of other mutations hitting different genes involved in Fas or related pathways.

Lymphocytosis, lymphadenopathy: benign or malignant?

The increasing use of immunophenotypic and molecular analysis in the routine evaluation of patients with lymphocytosis, lymphadenopathy, or other hematologic disorders has led to the identification of unexpected small clonal lymphoid populations. These clones, sometimes with disease-specific markers, such as the t(14;18), are especially challenging for the clinician because of their unknown biologic potential and uncertain clinical behavior. Study of these early lymphoid lesions is providing important clues to the process of lymphomagenesis, and may provide the rationale for preemptive therapy in the future. More and more, the hematologist/oncologist is consulted regarding otherwise healthy individuals with lymphadenopathy and/or lymphocytosis, and pathology reports that confound the referring internist or surgeon. The report does not name a malignant lymphoproliferative disorder, but is not completely "normal". Does the patient have a benign or malignant condition? How should they be evaluated? Is treatment indicated? These patients prove challenging for the consulting hematologist as well as the referring physician. In this review, we will focus on some of these scenarios and attempt to provide guidance for their management.

Hairy cell leukemia: Uncommon clinical features, unusual sites of involvement and some rare associations.

Unusual clinical manifestations and associations with auto-immunity or other systemic disorders are uncommon clinical features of hairy cell leukemia (HCL). The exact prevalence of these rare associations is difficult to determine as they are mostly published as anecdotal case reports and generally not included in larger published series. This chapter deals with uncommon clinical manifestations and rare sites of involvement in HCL. It also summarizes the association with systemic hemato-oncological disorders as well as second malignancies, based on review of the relevant literature and from personal experience.

Dasatinib-related Follicular Hyperplasia: An Underrecognized Entity With Characteristic Morphology.

Dasatinib, a second-generation tyrosine kinase inhibitor with activity against BCR-ABL1 and other Src family tyrosine kinases, is approved as a first-line treatment option for Philadelphia chromosome-positive chronic myelogenous leukemia (CML) in the chronic phase. Recently, lymphadenopathy with morphologic features of reactive follicular hyperplasia was described in a cohort of patients with CML on long-term dasatinib therapy. However, the complete morphologic and immunophenotypic features of this previously underappreciated adverse effect have not been fully described. Herein, we report 3 cases of unexplained lymphadenopathy resulting in multiple diagnostic procedures in patients with CML and a history of long-term dasatinib therapy. Morphologic examination demonstrated preserved nodal architecture showing hybrid features of progressive transformation of germinal centers and Castleman-type changes in a background of florid follicular hyperplasia. Large germinal centers were disrupted by complex infolding of IgD+ mantle zones arranged as cuffs surrounding perforating capillaries. Other abnormalities variably present included decreased CD20 expression among polytypic B cells and increased Epstein-Barr virus reactivity in scattered paracortical cells and/or individual germinal centers. B-cell clonality studies showed no predominant clonal rearrangements. Consideration of dasatinib-related lymphadenopathy may pre-empt unnecessary repeat diagnostic procedures in patients with CML or other dasatinib-susceptible malignancies and persistent lymphadenopathy.

Applied Protein and Molecular Techniques for Characterization of B Cell Neoplasms in Horses.

Mature B cell neoplasms cover a spectrum of diseases involving lymphoid tissues (lymphoma) or blood (leukemia), with an overlap between these two presentations. Previous studies describing equine lymphoid neoplasias have not included analyses of clonality using molecular techniques. The objective of this study was to use molecular techniques to advance the classification of B cell lymphoproliferative diseases in five adult equine patients with a rare condition of monoclonal gammopathy, B cell leukemia, and concurrent lymphadenopathy (lymphoma/leukemia). The B cell neoplasms were phenotypically characterized by gene and cell surface molecule expression, secreted immunoglobulin (Ig) isotype concentrations, Ig heavy-chain variable (IGHV) region domain sequencing, and spectratyping. All five patients had hyperglobulinemia due to IgG1 or IgG4/7 monoclonal gammopathy. Peripheral blood leukocyte immunophenotyping revealed high proportions of IgG1- or IgG4/7-positive cells and relative T cell lymphopenia. Most leukemic cells lacked the surface B cell markers CD19 and CD21. IGHG1 or IGHG4/7 gene expression was consistent with surface protein expression, and secreted isotype and Ig spectratyping revealed one dominant monoclonal peak. The mRNA expression of the B cell-associated developmental genes EBF1, PAX5, and CD19 was high compared to that of the plasma cell-associated marker CD38. Sequence analysis of the IGHV domain of leukemic cells revealed mutated Igs. In conclusion, the protein and molecular techniques used in this study identified neoplastic cells compatible with a developmental transition between B cell and plasma cell stages, and they can be used for the classification of equine B cell lymphoproliferative disease.

IgG4-Related Disease Presenting as a Solitary Neck Mass.

IgG4-related disease is a newly recognized entity associated with autoimmune conditions involving almost every organ system. It is characterized by elevated serum IgG4 as well as mass like tissue infiltration by IgG4-positive plasma cells. Imaging findings are nonspecific, vary depending on the site of disease, and include mass like enlargement of the salivary or lacrimal glands and enlarged lymph nodes. Radiographic findings often mimic malignancy, necessitating tissue sampling to confirm the diagnosis. Distinguishing IgG4-related disease from malignancy is important as IgG4 responds well to steroids and conservative management.

Interleukin-2 treatment reverses effects of cAMP-responsive element modulator α-over-expressing T cells in autoimmune-prone mice.

Systemic autoimmune diseases, such as systemic lupus erythematosus (SLE), are often characterized by a failure of self-tolerance and result in an uncontrolled activation of B cells and effector T cells. Interleukin (IL)-2 critically maintains homeostasis of regulatory T cells (T(reg)) and effector T cells in the periphery. Previously, we identified the cAMP-responsive element modulator α (CREMα) as a major factor responsible for decreased IL-2 production in T cells from SLE patients. Additionally, using a transgenic mouse that specifically over-expresses CREMα in T cells (CD2CREMαtg), we provided in-vivo evidence that CREMα indeed suppresses IL-2 production. To analyse the effects of CREMα in an autoimmune prone mouse model we introduced a Fas mutation in the CD2CREMαtg mice (FVB/Fas(-/-) CD2CREMαtg). Overexpression of CREMα strongly accelerated the lymphadenopathy and splenomegaly in the FVB/Fas(-/-) mice. This was accompanied by a massive expansion of double-negative (DN) T cells, enhanced numbers of interferon (IFN)-γ-producing T cells and reduced percentages of T(regs). Treatment of FVB/Fas(-/-) CD2CREMαtg mice with IL-2 restored the percentage of T(regs) and reversed increased IFN-γ production, but did not affect the number of DNTs. Our data indicate that CREMα contributes to the failure of tolerance in SLE by favouring effector T cells and decreasing regulatory T cells, partially mediated by repression of IL-2 in vivo.

Immunogenetics of Disease-Causing Inflammation in Sarcoidosis.

Sarcoidosis is a systemic inflammatory disorder characterised by tissue infiltration by mononuclear phagocytes and lymphocytes with associated non-caseating granuloma formation. Originally described as a disorder of the skin, sarcoidosis can involve any organ with wide-ranging clinical manifestations and disease course. Recent studies have provided new insights into the mechanisms involved in disease pathobiology, and we now know that sarcoidosis has a clear genetic basis largely involving human leukocyte antigen (HLA) genes. In contrast to Mendelian-monogenic disorders--which are generally due to specific and relatively rare mutations often leading to a single amino acid change in an encoded protein--sarcoidosis results from genetic variations relatively common in the general population and involving multiple genes, each contributing an effect of varying magnitude. However, an individual may have the necessary genetic profile and yet the disease will not develop unless an environmental or infectious factor is encountered. Genetics appears also to contribute to the huge variability in clinical phenotype and disease behaviour. Moreover, it has been established that sarcoidosis granulomatous inflammation is a highly polarized T helper 1 immune response that starts with an antigenic stimulus followed by T cell activation via a classic HLA class II-mediated pathway. A complex network of lymphocytes, macrophages, and cytokines is pivotal in the orchestration and evolution of the granulomatous process. Despite these advances, the aetiology of sarcoidosis remains elusive and its pathogenesis incompletely understood. As such, there is an urgent need for a better understanding of disease pathogenesis, which hopefully will translate into the development of truly effective therapies.

Paediatric nodal marginal zone B-cell lymphadenopathy of the neck: a Haemophilus influenzae-driven immune disorder?

Many hyperplasias and lymphomas of marginal zone B-cells are associated with infection. We identified six children and one adolescent with cervical lymphadenopathy showing prominent polyclonal nodal marginal zone hyperplasia (pNMZH) and four adolescents with monoclonal paediatric nodal marginal zone lymphoma (pNMZL). The clonality status was assessed using BIOMED-2-IG PCR analysis. Haemophilus influenzae was identified in all six cases of pNMZH that could be tested by direct culture (N = 3) or a very sensitive PCR for the H. influenzae gyrase gene in frozen materials (N = 5). H. influenzae was not detected in three pNMZLs and 28 non-specific reactive cervical lymph nodes of age-matched controls, except for a single control node that was obtained during oropharyngeal surgery for a cleft palate showing very low copy numbers of H. influenzae. pNMZH patients were younger than pNMZL patients (median age 12 versus 21 years). pNMZH showed a prominent nodular appearance with variable fibrosis without acute inflammation. Within the nodules, the expanded germinal centres and variably sized marginal zones were colonized by activated B-cells with weak expression of IgD and lack of CD10 and/or BCL6 expression. Some areas showed skewed light chain expression in plasma cells (4/5 cases lambda). In four cases tested, this was confirmed by flow cytometry for surface Ig (3/4 cases lambda). In contrast, pNMZL showed more extensive expansion of marginal zones by centrocytoid cells and often expression of BCL2 protein. Several H. influenzae strains are known to interact with the constant part of IgD on human B-cells, leading to their polyclonal proliferation and activation. We speculate that in vivo stimulation of IgD+ marginal zone B-cells by this bacterium may be implicated in this particular lymphadenopathy that should be distinguished from monoclonal pNMZL.

A case of progressively transformed germinal center-type IgG4-related lymphadenopathy.

Progressively transformed germinal centers (PTGC), a lymph node process unfamiliar to most otolaryngologists, is a morphological variant of reactive lymphofollicular hyperplasia of lymph nodes. Immunoglobulin (Ig)G4-related disease (IgG4-RD) is a newly identified condition, characterized by hyper-IgG4-γ-globulinemia and mass-forming or hypertrophic lesions associated with infiltration of IgG4(+) plasma cells in the affected organs. Recently, a case study of PTGC was reported that fulfilled the diagnostic criteria of IgG4-RD (IgG4(+) PTGC) [1]. A 68-year-old male was referred to our hospital with swelling in the left submandibular region. Palpation revealed swollen lymph nodes, the largest of which measured 5cm in diameter. (18)F-fluorodeoxyglucose (FDG)-positron emission tomography/computed tomography identified lymphadenopathy with high (18)F-FDG uptake in the left submandibular region. We strongly suspected malignant lymphoma, and excisional biopsy of the submandibular lymph node was performed under general anesthesia. Pathological findings were consistent with IgG4(+) PTGC, and serological examination demonstrated elevated levels of IgG4. These findings were consistent with IgG4-RD. The patient did not have systemic lesions; therefore, he has not undergone corticosteroid therapy. IgG4(+) PTGC should be considered as a differential diagnosis for cervical lymphadenopathy by otolaryngologists as well as pathologists.

High dietary intake of vitamin C suppresses age-related thymic atrophy and contributes to the maintenance of immune cells in vitamin C-deficient senescence marker protein-30 knockout mice.

Vitamin C (VC) is an essential nutrient for humans and certain other animals. It has antioxidant properties and has been reported to ameliorate oxidative damage to lipids, DNA and proteins. However, the effects of VC on immune function are poorly understood, especially the influence of long-term high-dose VC intake on the number and function of immune cells. In the present study, to evaluate the immune effects of VC, VC-deficient senescence marker protein-30 knockout (SMP30KO) mice were fed a diet containing the recommended level of VC (20 mg/kg per d; 0·02 % VC) or a high level of VC (200 mg/kg per d; 0·2 % VC) for 1 year. The plasma VC concentration of the 0·02 % group was the same as that of age-matched C57BL/6 mice after 1 year of feeding; however, plasma VC concentration and thymus weight were significantly higher in the 0·2 % VC group than in the 0·02 % VC group. The total counts of leucocytes, lymphocytes, granulocytes and monocytes in the peripheral blood, as well as the number of splenocytes and thymocytes, were all significantly higher in the 0·2 % VC group than in the 0·02 % VC group. In addition, the number of naive T cells in peripheral blood lymphocytes, the number of memory T-cell populations in splenocytes, and the number of cluster of differentiation (CD)4⁺CD8⁺ or CD4⁺CD8⁻ or CD4⁻CD8⁺ T cells in thymocytes were all markedly higher in the 0·2 % VC group than in the 0·02 % VC group after 1 year of dietary treatment. These results suggest that a long-term high-dose intake of VC is effective in the maintenance of immune cells, partly through the suppression of age-related thymic involution in VC-deficient SMP30KO mice.