Porque usamos imunoglobulina anti-D em excesso no abortamento precoce? / Why do we waste anti-D immunoglobulin in early miscarriage?

OBJETIVO: avaliação da hemorragia feto-materna (HFM) nas pacientes que receberiam profilaxia da aloimunização Rh com emprego de imunoglobulina anti-D (300 mig), pós-aborto precoce. MÉTODO: foram admitidas no estudo pacientes do grupo sanguíneo Rh negativo, com parceiro Rh positivo ou ignorado, com quadro de aborto até 12 semanas de gestação internadas para curetagem uterina. Uma amostra de 5 ml de sangue venoso destas pacientes foi obtida após o procedimento, na qual realizamos o teste qualitativo de roseta para detectar quais casos necessitariam determinação quantitativa do volume de sangue fetal transferido para circulação materna, que foi então apurado pelo teste de Kleihauer-Betke (K-B). RESULTADOS: das 26 pacientes avaliadas, em uma o teste de roseta foi positivo, e o teste de K-B apontou HFM de 1,5 ml. CONCLUSÕES: a dose de imunoglobulina anti-D nos casos de abortamento até a 12ª semana de gestação deveria ser substancialmente reduzida, parecendo-nos oportuna a disponibilização no mercado nacional de apresentação com 50 mig, que representaria além da economia, maior racionalidade.

Importance of antibody isotype in monoclonal anti-idiotype therapy of a murine B cell lymphoma. A study of hybridoma class switch variants.

An initial panel of four syngeneic monoclonal antibodies directed against the idiotype of a murine B cell lymphoma was used to treat this tumor in vivo. The antibody in the panel of the IgG2a isotype was more effective in treatment than the other antibodies, which were of the IgG1 and IgG2b isotypes. To independently assess the role of antibody isotype in mediating antitumor effects, switch variant hybridoma families were isolated from the hybridomas secreting the less effective IgG1 and IgG2b antibodies. A family isolated from an IgG1-secreting parent consisted of IgG1-, IgG2b-, and IgG2a-secreting members, and an IgG2a variant was isolated from an IgG2b-secreting parent for another family. Antibody members of each family differed only in heavy chain composition and were the same with respect to their light chains and their affinity and specificity for idiotype. The IgG2a members of both families were superior to the other members in inhibiting tumor growth with an order of effectiveness of IgG2a greater than IgG1 greater than IgG2b. These in vivo results paralleled the abilities of these different isotype antibodies to mediate antibody-dependent cellular cytolysis in vitro. For the IgG2b----IgG2a family, in vivo treatment with the IgG2a member given i.p. after i.p. tumor challenge at one-tenth the dose of the IgG2b member was still superior to the latter. At one-hundredth the dose of the IgG2b, the IgG2a was still superior to the latter when the antibodies were given i.p. and tumors subcutaneously. These data and those showing that the clearance of these antibodies from the serum differed in only a relatively minor way indicate that the IgG2a antibodies in this system had greater antitumor effects primarily by virtue of their greater capacity for host effector interaction.