Yasuhiro Shimojima

Regulatory T Cells and the Immune Aging Process: A Mini-Review

Constant exposure to new and persisting antigens and the need to replace cellular attrition with newly built cells lead to profound remodeling of the immune system after the age of 50 years. The impact of the immunosenescence process varies amongst the different cellular subsets represented within the immune system. Emerging data suggest that progressive aging significantly affects frequencies, subset distribution and functional competence of regulatory T cells (Tregs). Given the central role of Tregs in immune homeostasis, age-related loss of Treg function would be predicted to cause excessive immunity, encountered in elderly humans as a syndrome of chronic, smoldering inflammation as well as the age-related increase in the risk for autoimmunity. Conversely, age-dependent gain of Treg activity would result in failing immunity, such as the rising risk of malignancies and infections amongst the elderly. Emerging data suggest that some Treg populations, specifically naturally occurring Tregs, seem to accumulate with advancing age, whereas inducible Tregs appear to be less available in the older host. More studies are necessary to elucidate functional competence of old Tregs, with an emphasis on comparing the efficacy of young and old Tregs for defined functional domains. Mechanisms of declining Treg inducibility are not understood, but may provide an opportunity for targeted immunomodulation in the elderly. On the horizon is the potential to develop novel therapeutic interventions that target Tregs to make the elderly more efficient in fighting cancers and infections and dampen the risk for senescence-associated inflammation.

NADPH oxidase deficiency underlies dysfunction of aged CD8+ Tregs.

Immune aging results in progressive loss of both protective immunity and T cell-mediated suppression, thereby conferring susceptibility to a combination of immunodeficiency and chronic inflammatory disease. Here, we determined that older individuals fail to generate immunosuppressive CD8+CCR7+ Tregs, a defect that is even more pronounced in the age-related vasculitic syndrome giant cell arteritis. In young, healthy individuals, CD8+CCR7+ Tregs are localized in T cell zones of secondary lymphoid organs, suppress activation and expansion of CD4 T cells by inhibiting the phosphorylation of membrane-proximal signaling molecules, and effectively inhibit proliferative expansion of CD4 T cells in vitro and in vivo. We identified deficiency of NADPH oxidase 2 (NOX2) as the molecular underpinning of CD8 Treg failure in the older individuals and in patients with giant cell arteritis. CD8 Tregs suppress by releasing exosomes that carry preassembled NOX2 membrane clusters and are taken up by CD4 T cells. Overexpression of NOX2 in aged CD8 Tregs promptly restored suppressive function. Together, our data support NOX2 as a critical component of the suppressive machinery of CD8 Tregs and suggest that repairing NOX2 deficiency in these cells may protect older individuals from tissue-destructive inflammatory disease, such as large-vessel vasculitis.

VAD with or without subsequent high-dose melphalan followed by autologous stem cell support in AL amyloidosis: Japanese experience and criteria for patient selection.

Patients with AL amyloidosis were treated with VAD (vincristine, doxorubicin and dexamethasone) with or without high-dose melphalan followed by auto-PBSCT according to eligibility criteria based on disease severity, and prospectively investigated the therapeutic benefits and complications. Thirty-one patients were enrolled in this study. VAD and subsequent high-dose melphalan with auto-PBSCT were performed only in patients who met all of the eligibility criteria. Among patients ineligible for this treatment, VAD alone was performed in those with satisfactory general status. Eleven patients met the eligibility criteria, and of these, 7 were treated with VAD and subsequent high-dose melphalan with auto-PBSCT. Seven patients received VAD alone, and the remaining 17 were treated with the supportive therapy. Among the 14 patients treated with chemotherapy, 9 (5 of the 7 treated with VAD and high-dose melphalan, and 4 of the 7 treated with VAD alone) showed complete hematological response with apparent improvement of amyloidosis-related clinical symptoms. Serious complications of chemotherapy were cytomegalovirus infection and pneumocystis carinii pneumonia seen in 1 and 2 patients, respectively. These chemotherapies may be effective for reduction of M-protein and are also useful in improving of amyloidosis-induced organ dysfunction. In patients who cannot tolerate high-dose melphalan, VAD alone is a potent therapeutic option, although there are possible harmful effects on the heart and peripheral nerve.

Adult or late-onset triple A syndrome: case report and literature review.

Triple A syndrome is caused by mutations in the gene encoding ALADIN, leading to achalasia, alacrima and addisonism. Neurologic manifestations of the disease include motor neuron disease-like presentations, motor-sensory or autonomic neuropathy, optic atrophy, cerebellar ataxia, Parkinsonism, and mild dementia. We report a 60-year-old Japanese man with triple A syndrome. He was born to non-consanguineous parents. He underwent a surgical operation for achalasia at age 40, and thereafter, he developed a slowly progressive gait disturbance. Neurological examinations at age 60 revealed limb muscle wasting and weakness with pyramidal tract signs, distal-dominant sensory disturbance, optic atrophy, and autonomic dysfunction. Alacrima was detected using Schirmer test. All of these features were consistent with typical triple A syndrome. He lacked adrenal insufficiency that is frequently observed in patients with the classic phenotype of triple A syndrome. His sural nerve biopsy showed a moderate loss of myelinated fibers and hypomyelination. He was homozygous for a missense mutation, p.R155H, in the disease-causing gene, AAAS. Seven patients with genetically-confirmed, adult or late-onset triple A syndrome, including ours, have been reported to date. All the patients showed upper and lower motor neuron signs (100%), while sensory disturbance (29%) and autonomic dysfunction (57%) were less frequent. Careful assessment for alacrima followed by molecular genetic analysis of AAAS should be considered in patients who show a combined phenotype of motor neuron disease and sensory/autonomic disturbance, even in elderly patients.

Rituximab therapy in chronic inflammatory demyelinating polyradiculoneuropathy with anti-SGPG IgM antibody.

We report a patient with chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) who showed high titers of anti-sulfated glucuronyl paragloboside (SGPG) IgM antibody without M-protein in serum. The patient was resistant to corticosteroids and immunosuppressants, but after administration of rituximab, clinical symptoms improved and the patient remained in a stable state for approximately 10 months. Rituximab may be a potent therapeutic option for refractory cases of CIDP irrespective of detectable M-protein in either serum or urine.

Efficacy of tacrolimus in treatment of polymyositis associated with myasthenia gravis

We report a patient with polymyositis (PM) associated with myasthenia gravis (MG). Both disorders had been controlled for around 15 years by oral prednisolone and a cholinesterase inhibitor following surgical removal of invasive thymoma and radiotherapy, but muscular weakness due to myalgia and an increase in serum levels of myogenic enzymes, mainly ascribable to the recurrence of PM, reappeared immediately after cessation of these drugs, which was done because the patient had multiple bone fractures and severe osteoporosis due to the long-term corticosteroid therapy. Oral tacrolimus was therefore tried, and produced an improvement in muscular symptoms in association with normalization of myogenic enzymes. PM associated with MG as in this patient might be the best indication for tacrolimus, considering its efficacy in MG, but this drug should also be actively considered as a therapeutic option in refractory cases of PM alone, particularly when either corticosteroids or other immunosuppressive agents are not usable.

Phenotypic analysis of plasma cells in bone marrow using flow cytometry in AL amyloidosis

AL amyloidosis is an intractable disease resulting from a plasma cell dyscrasia which has a wide clinical spectrum. To investigate the phenotype of plasma cells in the bone marrow, a flow cytometric analysis was carried out in 10 patients with this disease (mean age, 57.8 ± 7.9 years) and controls with M-protein (positive controls, n=4) and without it (negative controls, n=8). All patients were shown to have either Aκ- or A

Lupus erythematosus profundus (lupus panniculitis) induced by interferon-β in a multiple sclerosis patient

LD-immunoreactive amyloid deposits on the biopsied tissues. On flow cytometry CD38++CD19+CD56-- cells (polyclonal plasma cells) showed no significant difference between patients (0.59 ± 0.37%) and either negative (2.25 ± 2.84%) or positive controls (0.38 ± 0.20%), while CD38++CD19-CD56+ cells (monoclonal plasma cells) showed a significantly higher level in the patients (1.34 ± 1.54%) than in either negative (0.041 ± 0.004%, p<0.005) or positive controls (0.11 ± 0.09%, p<0.05). With respect to maturation of plasma cells, five of the patients (50%), three of the positive controls (75%) and all of the negative controls showed a dominant proliferation of mature subtype (CD45+MPC-1+CD49e- or CD45+MPC-1+CD49e+). Immature (CD45+MPC-1- or CD45-MPC-1--) and intermediate (CD45-MPC-1+CD49e-) subtypes were dominantly present in the bone marrow in 2 and 3 patients, respectively. In AL amyloidosis monoclonal plasma cells producing M-protein can be easily and reliably detected in the bone marrow by flow cytometry. This analysis might provide plasma cell phenotypic markers useful for assessing the prognosis and for monitoring the response to treatment.

Coadministration of tacrolimus with corticosteroid accelerates recovery in refractory patients with polymyositis/ dermatomyositis: a retrospective study

We report a patient with multiple sclerosis (MS) who developed subcutaneous nodules on the face, shoulders and extremities while being treated with interferon (IFN)-beta-1b. These nodules fluctuated in parallel with myelopathy, and were diagnosed as lupus erythematosus profundus (LEP) based on histopathological findings. The patient showed no relapse of either neurological symptoms or subcutaneous nodules after cessation of IFN-beta-1b. This agent can cause induration and necrosis in the sites of injection but also systemic skin lesions such as LEP ascribable to its immunomodulatory effects.

Short communicationAdult or late-onset triple A syndrome: Case report and literature review

BackgroundTo investigate whether or not coadministration of tacrolimus (TAC) with prednisolone (PSL) can produce a beneficial effect in the treatment of polymyositis/ dermatomyositis (PM/DM).MethodsWe reviewed medical records of 32 PM/DM patients who had been admitted to our hospital, and abstracted those who had received TAC in addition to oral PSL for treatment. The clinical usefulness of TAC in PM/DM was objectively evaluated focusing upon the manual muscle strength test (MMT) score, serum creatine kinase (CK) and tapering of PSL.ResultsNine patients with PM and 6 with DM were enrolled in this study. TAC was added because of difficulty in reduction of PSL in 12 patients and recurrence with corticosteroid-induced complications in the remaining 3. Both PM and DM patients showed significant increases in the MMT score and significant decreases in serum CK 1 to 3 months after starting TAC compared with before. Skin symptoms in a clinically amyopathic DM patient also improved 1 month after starting TAC. The daily dosage of PSL could be significantly reduced in both PM and DM after starting TAC compared with before. No serious adverse events ascribable to TAC occurred in any patients.ConclusionAdditional use of TAC with PSL may safely promote improvement of PM/DM and also accelerate tapering of the latter.