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PubMed1986

Circulating immune complexes in sickle cell anaemia.

Circulating immune complexes were investigated in sera of 100 patients with sickle cell anaemia (SCA) in different clinical stages, using inhibition of complement-dependent rosette formation (EAC rosette inhibition), anticomplementary activity, polyethylene glycol 6000 precipitation, immunoconglutinin titre, total haemolytic complement, C4 and C3d. A high positivity was observed in patients with hepatic crisis (75%) and cases with leg ulcers (43%) compared with painful crisis (12%) and asymptomatic (7%) patients. These results provide evidence for the presence of circulating immune complexes during leg ulcers and hepatic crisis in SCA.

Adolescent↗
PubMed1987

Influence of operations with cardiopulmonary bypass on polymorphonuclear leukocyte function in infants.

To determine the effect of operations with cardiopulmonary bypass on the immunologic function of polymorphonuclear leukocytes in infants, we studied polymorphonuclear leukocyte function and immunologic profile in 16 infants undergoing repair of congenital heart lesions. An oxygen/air/high-dose fentanyl anesthetic was used for all patients. Absolute neutrophil count increased significantly (p less than 0.05) after bypass and remained increased 48 hours afterward. Chemotaxis, random migration of polymorphonuclear leukocytes, and phagocytic index were unaffected, but bactericidal capacity decreased significantly immediately after cardiopulmonary bypass and remained decreased 48 hours later. Serum opsonizing capacity to bacterial and fungal antigens was variably altered, and complement factors 3 and 4 decreased significantly after cardiopulmonary bypass. Total hemolytic complement decreased significantly immediately after cardiopulmonary bypass and returned to normal by 48 hours. These data suggest that operations with cardiopulmonary bypass in infants significantly affect the immunologic function of polymorphonuclear leukocytes and result in consumption of complement.

Blood Bactericidal Activity↗
PubMed1979

Interactions of complement with the red-cell membrane.

Interactions of the complement components with the red-cell membrane are, as delineated, many and complex. Much is known about the nature of the complement components that take part in these interactions, but relatively little is known about the membrane or the components of the membrane with which they interact. Such understanding will be essential if we are to be able to explain the great resistance to complement lysis shown by normal red cells or the abnormalities that result in increased or decreased interacition of complement with abnormal red cells.

Antibodies↗
PubMedDate not supplied

Complement activation in the adult respiratory distress syndrome following cardiopulmonary bypass.

We investigated complement fractions in patients after extracorporeal circulation for coronary bypass operations or cardiac valve replacement, and in two cases developing an adult respiratory distress syndrome (ARDS) after this type of intervention. The patients presenting an ARDS had significantly increased levels of C3d (p less than 0.001), the small molecular breakdown product of C3, associated with decreased levels of total classic haemolytic activity (p less than 0.05) and of the complement component C1q (p less than 0.001) when compared to a group of 10 patients who had uneventful evolution after bypass. However, all patients undergoing cardiopulmonary bypass had significantly increased levels of C3d (p less than 0.005 or less) associated with significant decrease of various complement components within 24 h after bypass, when compared to a control group of 5 patients investigated after aorto-iliac bypass graft surgery. We conclude that significant complement activation can persist in patients 24 h after bypass and--at higher levels--be a pathogenic and biological marker of ARDS after extracorporeal circulation.

Adult↗
PubMed1985

Evidence for complement activation by protamine-heparin interaction after cardiopulmonary bypass.

Complement activation by the alternate pathway has been implicated in the pathophysiology of cardiopulmonary bypass (CPB), and laboratory studies suggest that the complement cascade may be activated by the protamine-heparin complex. To determine if the administration of protamine to patients receiving heparin activates complement, we studied 100 patients undergoing CPB by assaying levels of C3a and C4a (classic pathway) at regular intervals before and after protamine administration. In group I (90 patients), protamine was given at the usual interval (median 5 minutes) after CPB. In group II (10 patients), protamine was withheld until skin closure (median 45 minutes) after CPB. Results demonstrated that C4a was not activated during CPB in either group. After CPB, the C4a level in group I was 459 ng/dl and increased to 1047 ng/dl 10 minutes after protamine administration (p less than 0.001). In group II, the C4a level was 484 ng/dl at the end of CPB and 354 ng/dl 15 minutes later, which corresponds to the value immediately after protamine administration in group I. The delayed administration of protamine in group II caused a significant increase in C4a at the time of skin closure (1090 ng/dl; p less than 0.001). Corresponding results from C3a analysis before and after protamine administration confirmed the activation of complement cascade. Our study provides the first clinical evidence that the protamine-heparin complex activates complement via the classic (C4a) pathway. The hemodynamic effects of protamine after CPB may be related to complement activation.

Aged↗
PubMed1985

[Current diagnostic possibilities in hereditary angioedema and acquired angioedema].

Amidolytic assays for the determination of C1 esterase inhibitor have been proposed some years ago; however, the substrates employed lacked sensitivity. The recent development of a C1 esterase-sensitive substrate (N-alpha-methoxycarbonyl-l-lysyl(epsilon-CBO)-glycyl-arginyl-4-nit roanilide) provides a method that can be routinely used. Any interferences with other plasma proteases could not be observed. Normal range was ascertained to be 1.48 +/- 0.23 kU/l; within-run precision revealed C.V.'s of 1.74% (for the normal range) and 7.3% (for the pathological range). This method can be considered most suitable for functional determination of C1 esterase inhibitor and is superior to the determination of antikallikrein activity. To point out to the diagnostic relevance of a functional C1 esterase inhibitor assay some examples are illustrated.

Angioedema↗
PubMed1986

Unusual complement activation properties of serum immunoglobulins of the pigeon Columba livia.

Complement-mediated lysis of mouse erythrocytes (MRBC) by whole pigeon antisera was found to occur in the presence of magnesium ions alone. The underlying basis for this observation was demonstrated to be the ability of IgM antibodies to activate the alternative pathway of pigeon complement, whereas IgG activates a calcium-dependent pathway possessing an unusually low lytic capacity. In addition to differing from the alternative pathway by requiring both calcium and magnesium ions, the calcium-dependent pathway exhibited higher activity at low temperature and more rapid kinetics of haemolysis. The presence of early acting C1 in pigeon serum was inferred by the selective depletion of calcium-dependent activity which occurred as a result of incubating serum containing only calcium ions with MRBC sensitized with IgG. Under the same conditions, MRBC sensitized with IgM failed to deplete complement activity, indicating that C1 does not participate in complement activation by this isotype. Interestingly, the calcium-dependent pathway detected in pigeon serum appears to more closely resemble the C1-bypass pathway rather than the classical pathway of mammalian complement.

Animals↗
PubMed1985

Activation of the alternative complement pathway by intraocular lenses.

To determine if posterior chamber polymethylmethacrylate lenses with polypropylene loops activate complement, the authors measured levels of C3a, C4a and C5a by radioimmunoassay in human sera incubated with and without these lenses. Human sera incubated with intraocular lenses showed elevated levels of C3a and C5a but no change in C4a. There were no statistically significant differences in the generation of activated complement by polypropylene loops vs polymethylmethacrylate optics. The authors also compared the ability of intraocular lenses to activate complement with that of zymosan and endotoxin, known activators of the alternative pathway. Our results suggest that polymethylmethacrylate lenses with polypropylene loops generate C3a and C5a by activation of the alternative complement pathway.

Adult↗