2 Function ex vivo

S150 normal DHR oxidation and normal response to PHA, OKT3, PWM, Candidin, PPD, gp43 of Pb, Toxoplasmosis, Tetanus Toxoid and CMV. Her Immunoglobulins, ferritin and glycemia are normal. 97% of her Neutrophils have low peroxidase activity. Discussion and conclusions: The great number of neutrophils found in P. brasiliensis granulomas demonstrates the importance of these cells during this mycosis. Neutrophils from healthy human donors can ingest and kill the fungus. There are evidences of the importance of the oxidative burst of neutrophils and their ability to inhibit Pb growth in susceptible (B10.A) and resistant (A/J) mice. The combination of two intracellular infections in which granulomas are important for the resistance and clearance of the pathogens suggest that the deficient myeloperoxidase of our patient might explain her susceptibility to PCM and her peritoneal tuberculosis (uncommon form of tuberculosis). doi:10.1016/j.clim.2009.03.441

S.64. Severe Combined Immunodeficiency Associated with a Novel IL2RG Mutation Kent Robertson1, Robert Nelson1, W. Scott Goebel1, Darla Gowan1, Kathleen Boyd1, Michael Tsangaris1, Jennifer Puck2, Paul Haut1. 1Indiana University School of Medicine, Indianapolis, IN; 2University of California San Francisco, San Fracncisco, CA A full term 2nd male offspring of a healthy mother presented at 6 mos of age with weight loss and diarrhea. He developed tachypnea without fever, bilateral pulmonary infiltrates, Streptococcal pneumoniae bacteremia and Klebsiella bacteriuria. Physical examination at 9 mos revealed a weightb 5th percentile, wheezes and absence of palpable lymph tissue. Chest radiograph revealed bilateral perihilar interstitial markings and a normal mediastinum. Peripheral blood cells were: WBC, 6,100; Hb, 12.6; platelets, 310,000; 59% neutrophils, 24% lymphocytes, 16% monocytes, 1% eosinophils; 83% CD19, 6% CD2, b 1% each of CD3, CD4 and CD8; 10% CD16/CD56. Serum antibodies were: IgG-47 mg/dL, IgA- b 1 mg/dL, IgM-11 mg/dL; anti-tetanus, 2.81 IU/mL ( N 0.10); diphtheria 0.38 IU/mL ( N 0.10); Streptococcus pneumoniae titers, undetectable. DiGeorge probe was negative (normal karyotype). Lymphocyte proliferation to mitogens and antigens was essentially absent. Molecular analyses: IL2RG, hemizygous c.854+5G N A intronic mutation; unremarkable sequences for CD3e, JAK3, DCLREIC, IL7R, CD3D, RAG1,2 and ADA. BAL revealed Pneumocystis jiroveci, Mycobacterium avium-intracellular and RSV. He underwent allogeneic unrelated 4/6 A/Bmismatched cord transplantation following modified reducedintensity conditioning that included cyclophosphamide, fludarabine and melphalan. ANC was N 500/mm3 day+18. At 5 mos, peripheral counts were normal; chimerism analysis revealed 80% donor T and 12% donor myeloid cells. Opportunistic infections cleared and he is home clinically well 6 months post. The c.854+5GN A IL2RG mutation has not been reported, but a similar 854+5G N C is known to disrupt exon 6 splicing, suggesting that our patient has X-linked SCID. doi:10.1016/j.clim.2009.03.442

Abstracts

S.66. Repletion of Vitamin D in vivo Restores TLR1/2 Function ex vivo Carol Cady1, Melissa Boyne2, Ronald Harbeck2, Vijaya Nagabhushanam2. 1University of Colorado Denver, Aurora, CO; 2National Jewish Health, Denver, CO Vitamin D is known to be an important modulator of autoimmune disease and innate immunity. In murine models of autoimmune encephalitis, diabetes and lupus, administration of vitamin D delayed the progression and decreased the severity of disease. In humans, vitamin D deficiency was associated with more active lupus/SLE; ex vivo, vitamin D suppressed B cell proliferation and immunoglobulin production. Vitamin D has been shown to decrease T cell proliferation, increase T regulatory cells and decrease IL12 production by dendritic cells. However, controlled studies on the long term effects of vitamin D deficiency on the immune system are lacking. During the course of the workup of a patient referred to our clinic for evaluation of recurrent viral infections, we found that vitamin D deficiency (serum Vitamin D, 25OH level of 19 ng/ml) was associated with non-responsiveness of ex vivo peripheral blood mononuclear cells (PBMCS) to PamCSK4, a TLR1/2 agonist. Following oral repletion of Vitamin D, 25OH to a serum level of 59 ng/ml, TNF-α production by PBMCS in response to PamCSK4 was restored (1510 pg/ml; normal N 169 pg/ml). TNF-α production by PBMCS in response to zymosan, a TLR2/6 agonist, was increased following vitamin D supplementation (253 pg/ml to 1095 pg/ml). TNF-α secretion following stimulation by phytohemagglutinin was decreased following normalization of vitamin D levels ( N 2000 pg/ml to 889 pg/ml). We propose use of this newly developed assay to further delineate the mechanism by which Vitamin D modulates innate immunity. doi:10.1016/j.clim.2009.03.443

S.67. Detection of Myelin Reactive CD4+Cells in the Peripheral Blood of Patients with Multiple Sclerosis using MHC Class II Tetramers Khadir Raddassi1, Junbao Yang2, Sally Kent1, Elizabeth Bradshaw1, Kasia Bourcier3, Vicki Seyfert-Margolis3, William Kwok2, David Hafler1. 1Brigham and Women's Hospital/ Harvard Institutes of Medicine, Boston, MA; 2Benaroya Research Institute, Seattle, WA; 3University of California San Francisco, San Francisco, CA Multiple sclerosis (MS) is an autoimmune disease characterized by infiltration of pathogenic immune cells in the CNS resulting in the destruction of the myelin sheath surrounding axons. Detecting human myelin reactive T cells and monitoring their frequency in the peripheral blood is difficult. We investigated whether MOG-specific T cells could be detected using DRB1⁎0401/MOG tetramers in MS subjects with the DRB1⁎0401 haplotype. In initial experiments, we focused on defining the optimal culture conditions for expansion of MOG reactive T cells upon MOG peptide stimulation of PBMCs. Using these optimal conditions we were able to detect MOG97-109 reactive T cells