IFNγ production in peripheral blood of early Lyme disease patients to hLFAα<Subscript>L</Subscript> (aa326-345)

Background  

It has been proposed that outer surface protein A (OspA) of Borrelia burgdorferi sensu stricto contains a T helper 1 (Th1) cell epitope that could play a role in an autoimmune response to hLFA1.     

Acute infection by hepatitis B virus

The clinical spectrum of acute hepatitis B virus infection is very broad, with clinical manifestations that range from anicteric and sub-clinical hepatitis to severe acute icteric hepatitis and even, in some cases, to fulminant hepatitis. Diagnosis depends to a large extent on the degree of clinical suspicion of hepatitis, establishing the aetiological origin of the B virus through the study of serological markers and/or DNA in the blood. Although in the majority of cases there is a favourable evolution of acute hepatitis B virus infection, with spontaneous resolution of the clinical manifestations in 4-8 weeks, progression to chronic hepatitis is not unusual in certain cases, above all in infancy. No specific treatment exists for acute hepatitis B virus infection that would reduce its severity or prevent its evolution into chronic hepatitis. However, relative rest and the administration of an hypercaloric diet are recommended. In cases of severe acute hepatitis hospital admission should be recommended; in cases of fulminant hepatitis, admission to the intensive care unit for intensive monitoring and evaluation of a liver transplantation is recommended if spontaneous improvement does not occur. This paper reviews briefly the clinical manifestations, diagnosis, prognosis and treatment of acute hepatitis B virus infection.     

Risk factors for acute graft-versus-host disease in patients undergoing transplantation with CD34+ selected blood cells from HLA-identical siblings

A study on 315 patients undergoing transplantation with CD34+ selected blood cells from HLA-identical siblings was performed to determine risk factors for acute GVHD (aGVHD). Recipients of a dose of CD34+ cells (x 10(6)/kg) of 2 or less, more than 2 to 4, and more than 4 had a cumulative incidence of aGVHD grades I-IV of 21%, 35%, and 43%, respectively (log-rank P =.01); similarly, recipients of a dose of CD3+ cells (x 10(6)/kg) of 0.05 or less, more than 0.05 to 0.1, and more than 0.1 had a cumulative incidence of aGVHD grades I-IV of 18%, 35%, and 44%, respectively (log-rank P =.007). Using a Cox regression model, 4 independent factors for aGVHD I-IV were identified: increased CD34+ cell dose (P =.02), increased CD3+ cell dose (P =.02), female patients (P =.01), and higher patient age (> 42 years) (P =.007). This study shows, for the first time in T-cell-depleted transplantations, a positive correlation between the number of CD34+ cells and aGVHD and, also, that the number of CD3+ cells necessary to initiate aGVHD is lower than previously reported.     

Autoregulation of an antibody response via network-induced auto-anti-idiotype

The antibody response of a single outbred rabbit was studied throughout three rounds of injections with Micrococcus lysodeikticus vaccine over a 31-mo period. The first-round response was characterized by a vigorous anti- micrococcus response and a strong anti-IgG rheumatoid factor response. The second-round response consisted of a triad of interacting molecules: anti- micrococcal antibodies, autoanti-idiotypic antibodies specific for distinct clonotypes of the first-round anti-micrococcal antibodies, and Fc-specific anti-IgG rheumatoid factor. The interacting triple complex was detected because of the formation of an immune complex that became insoluble upon dilution of the serum. Complex formation was inhibited in the presence of saccharide compounds known to be major immunodominant determinants of the micrococcal cell-wall carbohydrate polymer. The same saccharides did not affect the reaction of rheumatoid factor with IgG. Direct-binding radioimmunoassays ruled out mediation of the dilution-precipitation reaction by soluble micrococcal antigens. Specific absorption of rheumatoid factor inhibited the dilution-precipitation reaction. Auto-anti-idiotypic antibodies were specifically purified from second-round sera, directly confirming the presence of these antibodies. Suppressive effects of auto-anti-idiotypic antibodies on distinct antibody clonotypes were shown by gel isoelectric focusing of first-, second-, and third-round sera. Clonotypes expressed in the first round of immunizations were reduced in quantity or absent when auto-anti-idiotypic antibodies were detectable. Greatly enhanced levels or initial synthesis of new clonotypes of anti-micrococcal antibodies were detected during the period of auto-anti-idiotype synthesis. The third-round sera, devoid of detectable auto-anti-idiotype, contained clonotypes characteristic of both first- and second-round antisera. Thus, auto-anti- idiotypic-mediated suppression appeared to be reversible. The data are interpreted as lending strong support for concepts of autoregulation of immune processes in normal outbred animals via an idiotypic network.