14 research outputs found
Benign monoclonal expansion of CD8+ lymphocytes in HIV infection
Background—A transient expansion of the CD8+ T cell pool normally occurs in the early phase of HIV infection. Persistent expansion of this pool is observed in two related settings: diffuse infiltrative lymphocytosis syndrome (DILS) and HIV associated CD8+ lymphocytosis syndrome. Aim—To investigate a group of HIV infected patients with CD8+ lymphocytosis syndrome with particular emphasis on whether monoclonality was present. Methods—A group of 18 patients with HIV-1 infection and persistent circulating CD8+ lymphocytosis was compared with 21 HIV positive controls. Serum samples were tested for antinuclear antibodies, antibodies to extractable nuclear antigens, immunoglobulin levels, paraproteins, human T lymphotropic virus type 1 (HTLV-1), Epstein-Barr virus, and cytomegalovirus serology. Lymphocyte phenotyping and HLA-DR typing was performed, and T cell receptor (TCR) gene rearrangement studies used to identify monoclonal populations of T cells. CD4+ and CD8+ subsets of peripheral blood lymphocytes were purified to determine whether CD8+ populations inhibited HIV replication in autologous CD4+ cells. Results—A subgroup of patients with HIV-1 infection was found to have expanded populations of CD8+ T cell large granular lymphocytes persisting for 6 to 30 months. The consensus immunophenotype was CD4- CD8+ DR(high) CD11a+ CD11c+ CD16- CD28± CD56- CD57+, consistent with typical T cell large granular lymphocytes expressing cellular activation markers. Despite the finding of monoclonal TCR gene usage in five of 18 patients, there is evidence that the CD8+ expansions are reactive populations capable of mediating non-cytotoxic inhibition of HIV replication. Conclusions—A subgroup of HIV positive patients has CD8+ lymphocytosis, but despite the frequent occurrence of monoclonal TCR gene usage there is evidence that this represents an immune response to viral infection rather than a malignant disorder. Key Words: HIV infection • CD8+ lymphocytosis • clonalit
Toxicidade diferencial de agrotĂłxicos utilizados em citros para Neoseiulus californicus, Euseius concordis e Brevipalpus phoenicis
Brevipalpus phoenicis (Geijskes) (Acari: Tenuipalpidae) Ă© considerada uma das principais pragas em citros no Brasil, devido Ă transmissĂŁo do vĂrus da leprose dos citros e Ă necessidade de frequentes aplicações de acaricidas para seu controle. Assim, objetivou-se comparar a toxicidade dos principais agrotĂłxicos utilizados em citros no Brasil, sobre populações de B. phoenicis e de ácaros predadores das espĂ©cies Neoseiuluscalifornicus (McGregor) e Euseius concordis (Chant) (Acari: Phytoseiidae). Foram avaliadas duas populações de E. concordis: uma procedente de Jaboticabal (SP) e outra de Descalvado (SP). Arenas de folhas (para fitoseĂdeos) ou frutos (para B. phoenicis) de Citrus sinensis Osbeck (L.) cv. Pera, contendo 25 fĂŞmeas adultas de cada espĂ©cie foram pulverizadas em torre de Potter. As avaliações de mortalidade foram realizadas 72 horas apĂłs a aplicação. Foram utilizadas 4 a 6 concentrações de cada produto (abamectina, acefato, azociclotina, bifentrina, clorfenapir, dicofol, dinocape, Ăłxido de fembutatina, propargito e piridabem) para a obtenção das curvas de concentração-resposta. Abamectina, azociclotina, clorfenapir, dicofol, dinocape, Ăłxido de fembutatin, propargito e piridabem foram altamente tĂłxicos a B. phoenicis, com valores de CL90 iguais ou inferiores aos das concentrações recomendadas desses produtos. N. californicus foi mais tolerante a bifentrina, propargito, Ăłxido de fembutatina e dinocape que B. phoenicis e E. concordis (ambas as populações). Esses acaricidas tiveram baixa toxicidade aos adultos de N. californicus, para o qual as CL50 foram pelo menos seis vezes maiores que suas concentrações recomendadas. Acefato foi extremamente tĂłxico a E. concordis, mas inĂłcuo a adultos de N. californicus. A população de E. concordis de Jaboticabal foi mais resistente que a de Descalvado a azociclotina, bifentrina, clorfenapir, dicofol e propargito