Immunodeficiencies Associated with Abnormal Newborn Screening for T Cell and B Cell Lymphopenia

Newborn screening for SCID has revealed the association of low T cells with a number of unexpected syndromes associated with low T cells, some of which were not appreciated to have this feature. This review will discuss diagnostic approaches and the features of some of the syndromes likely to be encountered following newborn screening for immune deficiencies.     

Chipping away at a mountain: Genomic studies in common variable immunodeficiency

Common variable immunodeficiency (CVID) represents one of the most frequently diagnosed disorders of the immune system. Though several causative and associated genes have been identified, the origins of most cases remain unknown. Diagnostic delay is common due to the gradual evolution and wide spectrum of phenotypes, which can include autoimmune disease, enteropathy, and lung disease. A recent genome wide array identified novel gene associations with CVID, and also showed that identification of a genetic signature via a Support Vector Machine algorithm may be a powerful diagnostic tool. Studies utilizing whole genome or exome sequencings have also met with success in identifying new causes of CVID in subgroups of patients.     

Antitumor activity of astaxanthin and its mode of action

Astaxanthin, a carotenoid without vitamin A activity, may exert antitumor activity through the enhancement of immune responses. Here, we determined the effects of dietary astaxanthin on tumor growth and tumor immunity against transplantable methylcholanthrene-induced fibrosarcoma (Meth-A tumor) cells. These tumor cells express a tumor antigen that induces T cell-mediated immune responses in syngenic mice. BALB/c mice were fed astaxanthin (0.02%, 40 micrograms/kg body wt/day in a beadlet form) mixed in a chemically defined diet starting zero, one, and three weeks before subcutaneous inoculation with tumor cells (3 x 10(5) cells, 2 times the minimal tumorigenic dose). Three weeks after inoculation, tumor size and weight were determined. We also determined cytotoxic T lymphocyte (CTL) activity and interferon-gamma (IFN-gamma) production by tumor-draining lymph node (TDLN) and spleen cells by restimulating cells with Meth-A tumor cells in culture. The astaxanthin-fed mice had significantly lower tumor size and weight than controls when supplementation was started one and three weeks before tumor inoculation. This antitumor activity was paralleled with higher CTL activity and IFN-gamma production by TDLN and spleen cells in the astaxanthin-fed mice. CTL activity by TDLN cells was highest in mice fed astaxanthin for three weeks before inoculation. When the astaxanthin-supplemented diet was started at the same time as tumor inoculation, none of these parameters were altered by dietary astaxanthin, except IFN-gamma production by spleen cells. Total serum astaxanthin concentrations were approximately 1.2 mumol/l when mice were fed astaxanthin (0.02%) for four weeks and appeared to increase in correlation with the length of astaxanthin supplementation. Our results indicate that dietary astaxanthin suppressed Meth-A tumor cell growth and stimulated immunity against Meth-A tumor antigen.     

Innate immunity associated with inflammatory responses and cytokine production against common dietary proteins in patients with autism spectrum disorder

OBJECTIVES: Children with autism spectrum disorder (ASD) frequently reveal various gastrointestinal (GI) symptoms that may resolve with an elimination diet along with apparent improvement of some of the behavioral symptoms. Evidence suggests that ASD may be accompanied by aberrant (inflammatory) innate immune responses. This may predispose ASD children to sensitization to common dietary proteins (DP), leading to GI inflammation and aggravation of some behavioral symptoms. METHODS: We measured IFN-gamma, IL-5, and TNF-alpha production against representative DPs [gliadin, cow's milk protein (CMP), and soy] by peripheral blood mononuclear cells (PBMCs) from ASD and control children [those with DP intolerance (DPI), ASD siblings, and healthy unrelated children]. We evaluated the results in association with proinflammatory and counter-regulatory cytokine production with endotoxin (LPS), a microbial product of intestinal flora and a surrogate stimulant for innate immune responses. RESULTS: ASD PBMCs produced elevated IFN-gamma and TNF-alpha, but not IL-5 with common DPs at high frequency as observed in DPI PBMCs. ASD PBMCs revealed increased proinflammatory cytokine responses with LPS at high frequency with positive correlation between proinflammatory cytokine production with LPS and IFN-gamma and TNF-alpha production against DPs. Such correlation was less evident in DPI PBMCs. CONCLUSION: Immune reactivity to DPs may be associated with apparent DPI and GI inflammation in ASD children that may be partly associated with aberrant innate immune response against endotoxin, a product of the gut bacteria.     

Effect of tumor necrosis factor-alpha, interferon-gamma, and transforming growth factor-beta on adipogenesis and expression of thyrotropin receptor in human orbital preadipocyte fibroblasts

Graves' ophthalmopathy (GO) is an orbital autoimmune disease that is closely associated with Graves' hyperthyroidism. Examination of retroorbital tissues in GO reveals an accumulation of glycosaminoglycans, increased fat volume, lymphocytic infiltration, and the presence of several inflammatory cytokines. A subpopulation of human orbital fibroblasts can be differentiated in vitro into cells with the morphologic features of adipocytes. We demonstrated recently that these differentiated cultures show increased expression of functional TSH receptor (TSHr). To determine whether the presence of inflammatory cytokines might impact adipogenesis or TSHr expression in these cultures, we treated orbital fibroblasts from normal individuals or GO patients with tumor necrosis factor-alpha (TNF-alpha), interferon-gamma (IFN-gamma), or transforming growth factor-beta. We found that each of these cytokines inhibits TSH-dependent cAMP production and TSHr gene expression, and that TNF-alpha and IFN-gamma also inhibit morphological adipocyte differentiation. When cytokines were added after differentiation, the inhibition was less pronounced. Our results suggest that TNF-alpha, IFN-gamma, and transforming growth factor-beta may act within the orbit in GO to modulate expression of the putative orbital autoantigen, TSHr. In addition, the former two cytokines may play a role in determining the extent to which the volume of the orbital adipose tissue increases in this condition.     

Immunosuppression: Preliminary results of alternative maintenance therapy for familial hemophagocytic lymphohistiocytosis (FHL)

Hemophagocytic lymphohistiocytosis (HLH) describes a group of disorders with similar clinical features that are associated with a very high mortality rate. Patients with HLH, and particularly the infantile form referred to as familial hemophagocytic lymphohistiocytosis (FHL), are often treated with multiple courses of epipodophyllotoxins, such as etoposide, for prolonged periods of time. Because of the concern regarding the risk of epipodophyllotoxin-induced acute myelogenous leukemia (AML) we have explored the use of immunosuppression as maintenance therapy for patients with FHL while they await the only known definitive treatment, i.e., bone marrow transplantation (BMT). We report 2 infants with FHL who had significant central nervous system involvement at diagnosis. Both were initially treated with etoposide, methotrexate, and glucocorticosteroids. Once clinical improvement was achieved these patients were successfully maintained in clinical remission of FHL on daily cyclosporine A (CSA) and glucocorticosteroids along with intermittent intrathecal methotrexate for 5 months until appropriate unrelated donors could be identified for BMT.     

Cerebrospinal fluid and serum markers of inflammation in autism

Systemic immune abnormalities have no known relevance to brain dysfunction in autism. In order to find evidence for neuroinflammation, we compared levels of sensitive indicators of immune activation: quinolinic acid, neopterin, and biopterin, as well as multiple cytokines and cytokine receptors, in cerebrospinal fluid and serum from children with autism, to control subjects with other neurologic disorders. In cerebrospinal fluid from 12 children with autism, quinolinic acid (P = 0.037) and neopterin (P = 0.003) were decreased, and biopterin (P = 0.040) was elevated, compared with control subjects. In sera from 35 persons with autism, among cytokines, only tumor necrosis factor receptor II was elevated compared with controls (P < 0.02). Decreased quinolinic acid and neopterin in cerebrospinal fluid are paradoxical and suggest dysmaturation of metabolic pathways and absence of concurrent infection, respectively, in autism. Alternatively, they may be produced by microglia but remain localized and not expressed in cerebrospinal fluid.     

Dietary ribonucleotides modulate type 1 and type 2 T-helper cell responses against ovalbumin in young BALB/cJ mice

Dietary ribonucleotides have been shown to augment type 1 T-helper cell (Th1) responses to a protein antigen (Ag) in Th1-prone C57BL/6 mice, but their effects on type 2 Th (Th2)-prone mice are unknown. BALB/cJ mice have skewed Th2 responses against ovalbumin (OVA), characterized by augmented production of Th2 cytokines and immunoglobulin (Ig)G1/IgE antibodies (Ab); Th1 responses augment IgG2a Ab production, whereas Th2 responses augment IgG1/IgE Ab production. In this study, we determined the effects of dietary ribonucleotides obtained from yeast on the balance of Th1/Th2 responses against OVA in young BALB/cJ mice. Mice were fed a ribonucleotide-free (NF) or ribonucleotide-supplemented (NS) diet (4.74 g nucleotides/kg diet) and given OVA (10 microg/dose) with incomplete Freund's adjuvant (IFA) at 3 and 6 wk. We assessed T-cell responses in the regional draining lymph nodes (LN) by measuring production and expression of Th1/Th2 cytokines, interferon-gamma (IFN-gamma) and interleukin-5 (IL-5), respectively. Anti-OVA IgG subclass and IgE Ab levels were determined 3 wk after the first OVA challenge and 5 d and 2 wk after the second OVA challenge. Dietary ribonucleotides significantly augmented OVA-specific IFN-gamma production by the regional draining LN cells after the first and second OVA challenges. The NS diet increased anti-OVA IgG2a Ab levels after the first OVA challenge and both anti-OVA IgG2a and anti-OVA IgG2b after the second challenge. OVA-specific IgG1 and IgE Ab levels were lower (P < 0.05) after the second OVA challenge in mice fed the NS diet. Dietary ribonucleotides did not affect production or expression of IL-5. Our findings thus indicate that in Th2-prone BALB/c J mice, dietary ribonucleotides modulated skewed Th2 responses against OVA toward Th1 as measured by production of IFN-gamma, a Th1 cytokine, and changes in anti-OVA Ab isotype levels.     

Evidence of dysregulated cytokine production by sinus lavage and peripheral blood mononuclear cells in patients with treatment-resistant chronic rhinosinusitis.

BACKGROUND: Treatment-resistant chronic rhinosinusitis (CRS) imposes a clinical challenge. Its pathogenesis may be associated with dysregulated immune/inflammatory responses in the sinus. OBJECTIVE: To evaluate production of types 1 and 2 T cytokines (interferon gamma [IFN-gamma] and interleukin [IL] 5/IL-4, respectively) and regulatory/inflammatory cytokines (IL-10, IL-12, and IL-18) by sinus lavage (SL) cells and peripheral blood mononuclear cells (PBMCs) in patients with treatment-resistant CRS. METHODS: Sample SL cells and PBMCs obtained from 19 patients with treatment-resistant CRS were cultured with or without stimuli, and cytokine levels in the supernatant were measured using enzyme-linked immunosorbent assay. Control PBMC samples were obtained from 26 children. RESULTS: Chronic otitis media was found in 15 patients. Neutrophils and/or epithelial cells were dominant in SL cells. IFN-gamma, IL-12p40, and IL-10 (>100 pg/mL) were detected in SL cell cultures from 12, 9, and 8 patients, respectively. Production of IL-12p40 and IL-18 by SL cells correlated positively with phytohemagglutinin and IL-12p70 stimuli. In 12 patients, we detected IL-18 (>100 pg/mL) in SL cell cultures without stimuli, whereas PBMCs produced little IL-18, irrespective of stimuli. There was no correlation between cytokine levels produced by SL cells and PBMCs, except for IL-12p40 produced using IL-18. Decreased IFN-gamma production by PBMCs was observed in 6 patients with CRS compared with controls, but 4 of them had elevated IFN-gamma production by SL cells. Production of IL-12p40 by PBMCs was higher in 10 patients with CRS than in controls, and 7 of these patients had lower IL-10 production, resulting in an increased IL-12p40/IL-10 ratio. CONCLUSIONS: There is a role for locally produced regulatory cytokines in IFN-gamma production in the sinus in patients with treatment-resistant CRS. However, aberrant cytokine production patterns by PBMCs can be detected at high frequency in these patients, indicating that this can be used as a prognostic marker for patients with CRS.