The effect of obesity on neutrophil Fc receptors and adhesion molecules (CD16, CD11b, CD62L)

BACKGROUND

There is a large body of epidemiological data associating obesity with a wide variety of clinical disease processes, including cancer and wound infections. However, defining the specific defects of neutrophils has proved difficult and often contradictory.

METHODS

27 patients having gastric bypass surgery for obesity (BMI > 40) were compared with 10 normal controls (BMI < 26). Relative neutrophil frequencies and expression of the activation antigens CD11b (integrin adhesion molecule), CD16 (Fc receptor), and CD62L (L-selectin), were evaluated by flow cytometry.

RESULTS

The study control group had a mean age of 37 +/- 7.6 yrs (range 30 to 57) with no significant health problems. Their mean BMI was 23 +/- 2.5 kg/m2 (range 21-26). The mean age of the sample group was 40.36 +/- 13.7 yrs (range 18 to 60) with a mean BMI of 52 +/- 8.2 kg/m2 (range 41 to 72). These patients had a large spectrum of diseases that afflict the morbidly obese, including hypertension (14), arthritis (10), exertional dyspnea (13), venous stasis (7), hypothyroidism (2), NIDDM (3), heart murmur (1), along with 8 smokers. The neutrophil frequency in the obese patients was comparable to the controls (control 49% vs obese 51%). Additionally, there was no apparent difference between obese and controls regarding CD11b or CD16 expression (424 vs 498 gmf) (267 vs 262 gmf). However, there was a significant reduction of CD62L (L-selectin) expression noted in the morbidly obese with respect to controls (102 vs 303 gmf, p < 0.001). An increased percentage of eosinophils when compared to controls (6.7% vs 1.73%, p < 0.001) was also observed.

CONCLUSION

Discordant CD11b/CD62L levels, depressed levels of CD62L, and elevated eosinophil percentages support the hypothesis that a chronic inflammatory state exists in morbid obesity. Decreased levels of CD62L in the morbidly obese neutrophil pool possibly affect the neutrophil's ability to activate and migrate to sites of inflammation. This may play a role in the higher incidence of infectious complications seen in morbidly obese individuals.

Serum prolactin and oestradiol levels at different stages of puberty

Serum prolactin and oestradiol levels were measured in 183 children who were staged for pubertal development. Mean serum prolactin levels are higher in girls than in boys at stage 3 of pubertal development. In girls prolactin levels rise at stage 2, and are higher after menarche; in boys there is no change in prolactin levels. In this study serum oestradiol correlates with prolactin in the girls, but not in the boys.

Some observations on the determination of cortisol in human plasma by radioimmunoassay using antisera against cortisol-3-BSA

Antisera were obtained from rabbits immunised against cortisol-3-BSA with a view to examining their application in a radioimmunoassay of the steroid. One such antiserum was studied in detail; cross-reactivity with other C21 steroids normally present in human plasma was negligible and it proved possible to establish a radioimmunoassay which satisfied all criteria of reliability. The specificity of the cortisol determination achieved in human plasma was examined by performing measurements with and without including an initial Sephadex LH-20 column chromatographic purification step; the values obtained were in excellent agreement both for normal plasma and for that obtained following adrenal stimulation with ACTH.

Specific determination of testosterone in female plasma by radioimmunoassay: a rapid and reliable procedure for the routine clinical laboratory

A rapid and reliable procedure for the specific determination of testosterone in female plasma is described. The assay entails a simple biphasic solvent partitioning of plasma extracts in order to remove cross-reacting steroids before quantitation of testosterone by radioimmunoassay using an antiserum raised against testosterone-11alpha-hemisuccinyl-bovine serum albumin. "Testosterone' values obtained in this way are in excellent agreeement with those obtained following thin-layer chromatographic purification of plasma extracts. However, the present procedure is easier, faster and cheaper to perform, and enables a single technician to assay 32 females plasma samples (in duplicate) in one working day.

Bubble stability test compared with lecithin assay in prediction of respiratory distress syndrome

A simple test for surfactant, utilizing bubble stability in ethanol, was performed in 106 samples of amniotic fluid obtained from 94 patients. Of these patients 80 delivered within 48 hours of the collection of the sample. The results were compared with the lecithin concentration in the same amniotic fluid samples and with the quality of respiration in the neonate. The test was "positive," indicating fetal pulmonary maturity, in 37 cases and none of these infants developed respiratory distress syndrome (R.D.S.). In only one of these cases, however, was gestation less than 37 weeks. The test was "intermediate" or "negative" in 43 cases but in 35 of these infants respiration at birth was perfectly normal.Performed by the method described by its originators, this simple test gives too many false negative results to be of value in routine clinical practice, although a positive result is helpful. The concept of the test is ingenious, however, and further developments may be expected.