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Biomedical subjects

Mohamed A Hamidou

Publications and source records attributed to Mohamed A Hamidou.

8 recordsLinked to original sources

T cell repertoire and Epstein-Barr virus-specific T cell response in chronic active Epstein-Barr virus infection: a case study.

In a patient with chronic active Epstein-Barr virus infection associated with vasculitis and fulminant CD4+ T cell lymphoproliferative disorder, we probed the peripheral blood mononuclear cells (PBMC) for the presence of an EBV-specific T cell repertoire and tested the possible relationship between the lymphocytic infiltrate and the EBV-specific T cell response. Our results give credence to the presence of an apparently normal EBV-specific memory T cell response after in vitro reactivation of the patient's PBMC with autologous infected B lymphoblastoid cell lines. In keeping with the characterization of the vasculitis, certain T cell subsets were detected after expansion of skin lesion-infiltrating lymphocytes and were found to be infected with EBV. These particular T cell expansions were neither the effectors nor the targets of the in vitro reactivated EBV-specific T cells, thus excluding a simple relationship between EBV, the skin lesions, and the T cell expansions frequently observed in these patients.

Adult↗

Silent versus cranial giant cell arteritis. Initial presentation and outcome of 50 biopsy-proven cases.

BACKGROUND: The objective of the present study was to compare the silent form of giant cell arteritis (GCA) to the classic cephalic form of the disease. METHODS: We conducted a retrospective study based on a chart review of 50 consecutive, biopsy-proven GCA, recorded at a department of internal medicine. We sought to distinguish a silent form, defined by a prolonged inflammatory syndrome or fever of unknown origin with the absence of cephalic signs, polymyalgia rheumatica, or large artery involvement, from an overt "classic" cranial temporal arteritis. RESULTS: The prevalence of the silent form of GCA was 46% in our study. Abnormal temporal arteries were more frequent in the cephalic group. The silent GCA group had higher C-reactive protein levels (p<0.05), a higher platelet count (p<0.05), and lower serum albumin (p<0.05). There was no significant difference in temporal artery specimens in the two groups. Clinical relapses tended to be more frequent, and patients free of corticosteroids tended to be less frequent, in the cephalic group, though the difference was not statistically significant. CONCLUSIONS: The silent and cephalic forms of GCA could have distinct clinical and biological patterns and different outcomes. The limitation of our study was its retrospective design. Further studies are required to determine if this distinction is useful in treating GCA patients.

Journal Article↗

Comparison of different kits in the detection of autoantibodies to cardiolipin and beta2glycoprotein 1.

OBJECTIVE: To estimate the performance characteristics of 10 commercial kits and one in-house kit for the detection and quantification of anticardiolipin (aCL) (six kits) and anti-beta2glycoprotein 1 (anti-beta2GP1) (five kits) antibodies, and to evaluate the degree of variability between these different kits. METHODS: We determined the presence of aCL and anti-beta2GP1 IgG and IgM antibodies in 67 sera from 62 patients and reviewed the data separately. Each serum sample was tested with six commercial aCL determination kits and with four commercial and one in-house anti-beta2GP1 determination kit. We then analysed the operating characteristics of each kit (sensitivity, specificity, positive and negative predictive values) and we analysed the absolute and 2 x 2 agreements. RESULTS: The 62 patients included had primary antiphospholipid syndrome (APS) in 10 cases, secondary APS for eight, systemic lupus (SLE) for 23 and other diagnoses for the remaining 21. Operating characteristics differed from one kit to another. Good agreement was found using sensitive aCL determination kit and specific anti-beta2GP1 determination kit. Agreement between kits was medium for IgG aCL. 2 x 2 concordance studies showed a group of three aCL kits which were quite homogenous and showed that all anti-beta2GP1 kits formed quite a homogenous group. CONCLUSION: A high degree of variability still persists for aCL antibody determination posing the question of the qualification of commercial or in-house kits and the question of standardization of results. A better concordance is found for high positive results. Good agreement exists for anti-beta2GP1 kits. aCL determination is still needed and should be complemented by anti-beta2GP1 determination.

Antiphospholipid Syndrome↗

Temporal arteritis associated with systemic necrotizing vasculitis.

OBJECTIVE: To evaluate the clinical and laboratory characteristics of patients with systemic vasculitis associated with temporal artery involvement. METHODS: From a cohort of 120 patients fulfilling American College of Rheumatology criteria for temporal arteritis, we retrospectively identified 7 patients with systemic necrotizing vasculitis associated with histological temporal arteritis. RESULTS: Among the 7 patients, 2 had classic polyarteritis nodosa, one had unclassified systemic vasculitis, one had Wegener's granulomatosis (WG), and 3 had microscopic polyangiitis. The mean age of the patients was 70.2 years, and cranial symptoms revealed the disease in all but one patient. Temporal arteritis was generally associated with extracephalic manifestations suggestive of systemic vasculitis. Antineutrophilic cytoplasmic antibodies were positive in 3 of the 4 patients with small vessel vasculitis. Pathologically, the main temporal artery was involved in all but one patient, with inflammatory infiltrate of vasa vasorum and adventitia associated in 5 with small tributary involvement. Fibrinoid necrosis was rare, observed in 2 specimens; 2 patients with unclassified systemic vasculitis and WG had a classic giant cell arteritis (GCA) histologic pattern. Only one patient had exclusive involvement of small vessels, surrounding the spared main temporal artery. Muscle biopsies showed histopathological evidence of vasculitis in 2 patients, skin biopsy in one, and vein biopsy in the other. CONCLUSION: Temporal artery involvement in systemic necrotizing vasculitis was generally associated with extracranial clinical features suggestive of systemic vasculitis. Temporal artery biopsy is a simple tool for diagnosis of vasculitis, but the histopathological findings do not always discriminate between necrotizing vasculitis and classic GCA.

Aged↗

Systemic vasculitis with lymphocytic temporal arteritis and Toxocara canis infection.

Vasculitis associated with helminthic infection is rare. We report a case of systemic negative antineutrophil cytoplasmic antibodies vasculitis associated with Toxocara canis infection documented by enzyme-linked immunosorbent assay and Western blot analysis. This case report is unusual because of lymphocytic temporal arteritis and renal involvement. The spontaneous remission of systemic vasculitis without use of steroids or immunosuppressive agents favors a close relationship between vasculitis and the parasite that is more than a coincidental association. To our knowledge, this is the first observation of temporal vasculitis associated with helminthic infection, extending the clinical spectrum of visceral larva migrans.

Aged↗