Biomedical subjects

J Estreicher

Publications and source records attributed to J Estreicher.

9 recordsLinked to original sources

PubMed1992

Abnormal immune adherence and elimination of hepatitis B surface antigen/antibody complexes in patients with AIDS.

C3b-coated immune complexes (IC) adhere to complement receptor 1 (CR1) on human E in the circulation. E from AIDS patients have an acquired low CR1 number. To study immune adherence and IC elimination in AIDS, radiolabeled hepatitis B surface Ag/antibody complexes were injected i.v. in six AIDS patients and in 14 healthy controls. The binding of IC to E was reduced in AIDS patients (mean binding 2 min after injection: 24.9 +/- 13.3%) compared with healthy individuals (63 +/- 3.7%) (p = 0.0005). The low binding correlated directly with the number of CR1/E and to the capacity of these E to bind IC in vitro. During the first 15 min disappearance of IC was faster in AIDS patients than in normal subjects and correlated with CR1 number. Thereafter, elimination was very slow in AIDS patients, which suggested that a fraction of IC might be released back into the circulation similarly to what has been observed for C3b-coated E. When the data were analyzed with a mathematical model allowing for such release to occur, five of six AIDS patients had a high release rate compared with little or no release in normal individuals (p less than 0.001). Thus, low CR1 on E is responsible for defective immune adherence, and might determine abnormal disappearance of IC from the circulation as well.

Acquired Immunodeficiency Syndrome↗

PubMed1991

Defective immune adherence and elimination of hepatitis B surface antigen/antibody complexes in patients with mixed essential cryoglobulinemia type II.

Mixed essential cryoglobulinemia type II (monoclonal Ig/polyclonal IgG) is characterized by systemic vasculitis caused by the deposition of circulating immune reactants that include the monoclonal component. Such reactants may include immune complexes (IC) formed from exogenous Ag. IC binding to E C receptor type 1 appears to play a role in transport and buffering of such IC (immune adherence: IA). To define the mechanisms responsible for immune deposition, 7 patients with cryoglobulinemia type II (IgM kappa/polyclonal IgG) and 14 normal volunteers were injected i.v. with hepatitis B surface Ag/antibody complexes. Two minutes after injection, only 19.4% (mean) of the circulating complexes were bound to E in patients as compared with 63.1% in normal subjects. This IA correlated directly with C4 and inversely with the IgM rheumatoid factor (RF) titer. Disappearance of IC was faster in patients (mean elimination rate: 15.7%/min) than in normal subjects (9.3%). In vitro experiments demonstrated that C depletion, interference with IC opsonization by monoclonal IgM RF, and decreased binding of opsonized IC in the presence of monoclonal RF are each associated with decreased IA. These observations suggest that, in patients with cryoglobulinemia type II, monoclonal IgM RF and low C contribute to reducing IA of circulating IC that might be rapidly trapped in tissues, resulting in injury.

Adult↗

PubMed1991

Immune adherence and clearance of hepatitis B surface Ag/Ab complexes is abnormal in patients with systemic lupus erythematosus (SLE).

Complement levels and complement receptor 1 (CR1) on erythrocytes (E) are reduced in systemic lupus erythematosus (SLE). To see whether these abnormalities are responsible for defective transport and elimination of immune complexes (IC) from the circulation, patients with active SLE (14) and normal volunteers (14) were injected with preformed IC (hepatitis B surface Ag/Ab). Two minutes after injection only 25.9 +/- 19.1% (mean +/- 1 s.d.) of the circulating IC were bound to E in the SLE patients as compared to 63 +/- 3.7% in the normal subjects (P = 0.0001). For SLE patients, the reduced immune adherence was best explained by a combination of complement depletion and low CR1 binding capacity (tau = 0.80, P = 0.0001). The disappearance of IC as estimated from the area under the elimination curve was faster in SLE than in controls (P = 0.02), and correlated with CR1 (tau = 0.54, P = 0.0001) and immune adherence observed in vivo (tau = 0.33, P = 0.013). Finally, immune adherence was absent and IC disappeared very rapidly in a patient with C2 deficiency and an SLE-like disease. These observations suggest that in SLE the defective immune adherence reaction might be responsible for the accelerated disappearance of IC from the circulation.

Adolescent↗

PubMed1979