Surgical operations have been shown to cause a variety of immunological disturbances in man both in vivo and in vitro. With few exceptions the overall picture is one of a generalized state of immunodepression in the postoperative period. The implications of these observations are that host defences may be compromised by surgical procedures, thus providing a 'fertile soil' for bacterial invasion and tumour cell metastasis at the very time when risks from invading pathogens and viable tumour cells are maximal. We have studied the effects of surgical operations on the immune system in 35 patients with benign disease. Surgical procedures were classified as either minor (n = 15) or major (n = 20). A panel of monoclonal antibodies was used to identify peripheral blood lymphocyte subpopulations and analysis was performed using flow cytometry. Simultaneous estimations of plasma alpha-1 proteinase inhibitor (alpha-1-PI), alpha-2-macroglobulin (alpha-2-M), alpha-2-pregnancy-associated glycoprotein (alpha-2-PAG) and plasma suppressive activity (PSA) on stimulated allogeneic lymphocytes were performed before operation and on postoperative days 1, 3, 7, 17 and 21. Circulating numbers of all lymphocyte subpopulations fell significantly following surgery, except for B lymphocytes which did not change. The magnitude, and duration of the reduction in cell numbers and the subpopulation affected was significantly related to the degree of surgical trauma, and returned to pre-operative values by postoperative day 7. Changes in alpha-1-PI, alpha-2-M, alpha-2-PAG and PSA were also significantly related to the degree of surgical trauma, and these plasma changes persisted longer than the cellular disturbances. Surgical operations induce a reversible depression of cellular immunity which precedes plasma suppressive activity in its return to pre-operative levels. Immunostimulating agents such as interferon and the interleukins deserve evaluation as prophylactic agents pre-operatively.

Purification of C4a from heat-activated bovine plasma by elution from CM-Sephadex C-50 at pH 7.4 and gel filtration on Sephadex G-50 gives a 20% yield of pure C4a. The complete amino acid sequence of bovine C4a has been determined by automatic sequencer degradation of CNBr and enzymic fragments, and by carboxypeptidase digestion. The 77-residue bovine sequence shows 12 differences from the human sequence with five of these differences occurring in the C-terminal 11 residues. The sequence of C4a confirms earlier suggestions of homology with C3a and C5a: the three sequences show an almost equal number of identities with each other. The six cysteine residues of the 'disulphide knot' are conserved as well as seven other residues including the C-terminal arginine.

No abstract

PAPP-A, SP1, hCG and alpha 2-PAG were determined in the serum of 17 patients at weekly intervals between 3 and 12 weeks from the last menstrual period; progesterone and 17 beta-oestradiol concentrations were also measured in the same samples. SP1 and hCG concentrations were consistently found to rise steeply from the first time the proteins were detected. PAPP-A, though detectable in early samples from 9 of the patients, started to rise sharply in all cases between 6 and 10 weeks after LMP. Alpha 2-PAG, which was detected in all serum samples, showed no consistent behaviour with advancing pregnancy. In 3 patients, alpha 2-PAG was elevated as early as 3 weeks after LMP, while in others it remained at low levels during the entire interval observed. The correlation between these proteins (except between SP1 and hCG) is therefore poor; and their synthesis or secretion seems to be independently controlled.