1/5. Acute nephritis and pulmonary alveolitis following pneumococcal pneumonia.Acute glomerulonephritis developed in a man with pneumococcal pneumonia. serum complement studies revealed decreased levels of C4, properdin, and C3. Renal immunofluorescence studies demonstrated pneumococcal antigen, C1q, C4, C3 proactivator, properdin, C3, IgG, and IgM. Circulating cryoglobulin contained pneumococcal antigen and antibody, C3, and immunoglobulins. Serial pneumococcal antigen and antibody levels did not display patterns that were characteristic of classical immune elimination, but the patterns may have been influenced by the reentry of antigen. A diffuse, pulmonary alveolitis also developed in the patient. lung immunofluorescence studies revealed pneumococcal antigen, IgG, and C3 in alveolar walls and capillary basement membranes. The glomerulonephritis and alveolitis resolved after a prolonged course. These findings provide presumptive evidence for pneumococcal, immune complex glomerulonephritis with complement activation via both classical and alternative pathways and suggest an immunologic pathogenesis for the pulmonary alveolitis.- - - - - - - - - - ranking = 1keywords = antigen (Clic here for more details about this article) |
2/5. Haemolytic uraemic syndrome and the Thomsen Friedenreich antigen.In three children with haemolytic uraemic syndrome (HUS), evidence of red cell polyagglutinability due to Thomsen Friedenreich antigen (T-antigen) exposure was demonstrated. This was suspected after difficulties in ABO typing and was confirmed using specific antisera. Further supportive evidence included elevation of plasma sialic acid, alteration in red cell surface charge and evidence of T-antigen exposure in the renal biopsy specimen of one patient. Although involvement of this antigen in the pathogenesis of HUS has been associated with a high mortality, all three children have made a complete recovery. With early recognition and subsequent avoidance of plasma products, prognosis of this condition may be improved.- - - - - - - - - - ranking = 1.6keywords = antigen (Clic here for more details about this article) |
3/5. Clinically significant cross-reactions with counterimmunoelectrophoresis between pneumococcus type 6 and haemophilus influenzae type b.Biologically and clinically significant cross-reactions may occur between the immunochemically similar capsule antigens of haemophilus influenzae type b and streptococcus pneumoniae type 6 by using counterimmunoelectrophoresis (CIE). In three cases of culture-proven S. pneumoniae type 6 disease, a false-positive H. influenzae type b CIE result was detected in a body fluid. Two of three cases were also positive when tested by CIE with pneumococcal omnisera. However, in one of the culture-proven cases of pneumococcal type 6 disease, the omniserum was negative and only the burro 132 H. influenzae type b antiserum demonstrated a positive precipitant reaction. In addition to the three case isolates, we evaluated nine blood or cerebrospinal fluid isolates of pneumococcus type 6, using a variety of both species- and type-specific antisera, by CIE. Two burro antisera detected 12 of 12 (100%) of the S. pneumoniae type 6 strains. A rabbit H. influenzae type b antiserum did not detect any (0 of 12; 0%) of the S. pneumoniae type 6 strains evaluated. All (12 of 12; 100%) of the S. pneumoniae type 6 strains were detected with both rabbit omniserum (S. pneumoniae) and rabbit type 6 antiserum. Our data illustrate the importance of being aware of the immunologic cross-reactivity of the H. influenzae type b capsule with the pneumococcus type 6 capsule and the possibility of false-positive results with CIE when patient specimens are interpreted.- - - - - - - - - - ranking = 0.2keywords = antigen (Clic here for more details about this article) |
4/5. hemolytic-uremic syndrome and T-cryptantigen exposure by neuraminidase-producing pneumococci: an emerging problem?Hemolytic anemia, thrombocytopenia, and renal failure form a constellation of complications observed in patients infected with neuraminidase-producing pneumococci. The circulating enzyme causes exposure of the T-cryptantigen on cell surfaces to which most people possess a naturally occurring antibody. Antigen-antibody interaction activates effector systems that lead to the clinical manifestations. The syndrome is most frequently seen in infants, in whom it carries more than a 50% mortality rate. T-cryptantigen activation can be detected by demonstrating red cell agglutination by the peanut lectin Arachis hypogea. plasma exchange and avoidance of blood products containing immunoglobins are of value in the management of this devastating complication of pneumococcal infection.- - - - - - - - - - ranking = 1.2keywords = antigen (Clic here for more details about this article) |
5/5. streptococcus pneumoniae-induced hemolytic uremic syndrome: a case for early diagnosis.Hemolytic uremic syndrome associated with infection by neuraminidase-producing streptococcus pneumoniae usually presents with fulminant pneumonia and has a high mortality rate. Post-pneumococcal hemolytic uremic syndrome may occur earlier in life than classical hemolytic uremic syndrome. We describe an 18-month-old male with hemolytic uremic syndrome, S. pneumoniae pneumonia, and T-antigen activation characteristic of neuraminidase activity. We have summarized the features of this case and 11 previously reported children. As the use of blood products containing IgM may aggravate this disorder, early recognition of hemolytic uremic syndrome associated with S. pneumoniae neuraminidase production may lead to improved patient outcome through the judicious use of blood products.- - - - - - - - - - ranking = 0.2keywords = antigen (Clic here for more details about this article) |