Analysis of expression of the PD-1/PD-L1 immune checkpoint system and its prognostic impact in gastroenteropancreatic neuroendocrine tumors

The immune checkpoint based therapy targeting the programmed death-1 (PD-1) receptor and its PD-L1 ligand has recently been approved for the therapy of different malignant conditions, but not yet for gastroenteropancreatic neuroendocrine tumors (GEP-NETs). In this context, we evaluated the expression of PD-1 and PD-L1 in GEP-NETs and its potential correlations with clinical outcomes. Expression of PD-1/PD-L1 was analyzed by immunohistochemistry in 116 GEP-NETs and 48 samples of peritumoral tissue. In addition, the expression of these molecules was assessed by flow cytometry in peripheral blood mononuclear cells (PBMC) from patients with GEP-NETs (n = 32) and healthy controls (n = 32) and in intratumoral mononuclear cells (TMCs) (n = 3). Expression of PD-L1 and PD-1 was detected by immunohistochemistry in 6% and 1% of tumor tissue samples, respectively, and in 8% of peritumoral tissue samples, for both markers. We also observed that PD-1 expression by TMCs was associated with metastatic disease at diagnosis, and the levels of circulating PD-1+ PBMCs were associated with progressive disease upon follow-ups. In addition, circulating PD-1+ PBMCs were significantly correlated with PD-L1 expression by tumor cells. Our data suggest that PD-1/PD-L1 is expressed in 1 to 8% of GEP-NETs, and that this feature is significantly associated with disease evolution (p < 0.01).

[Capillary beta-hydroxybutyrate determination for monitoring diabetic ketoacidosis]

BACKGROUND AND OBJECTIVE

Diabetic ketoacidosis (DKA) is the most severe acute metabolic complication of type 1 diabetes mellitus. Insulin treatment is commonly guided by plasma glucose levels and changes in venous blood gases, while β-hydroxibutyrate (BHB) levels are rarely measured. The study objective was to evaluate the value of capillary BHB monitoring in the course and resolution of DKA.

PATIENTS AND METHODS

Thirty patients with type 1 diabetes admitted for DKA were enrolled. A standard protocol including monitoring of blood glucose, venous blood gases, semiquantitative ketonuria, and capillary BHB was used. Patients were divided into three groups by time to DKA resolution (group 1:<24 h, group 2: 24-48 h, group 3: >48 h), and BHB results were compared to all other biochemical measurements.

RESULTS

Mean laboratory results upon admission were: blood glucose 415 (standard deviation [SD] 106) mg/dL; bicarbonate 9.6 (SD 1.5) mmol/L; pH 7.13 (SD 0.04); BHB 4.33 (SD 0.48) mmol/L, and ketonuria 3+ in 22 patients and 4+ in 6. BHB correlated well with bicarbonate (r=-0.24139; P=0.0161) and pH (r=-0.56419; P<0.0001). BHB normalized earlier than ketonuria in all cases (group 1: 15.5 vs 18.8 hours P<0.05; group 2: 18.2 vs 23.5 hours P<0.01; group 3: 37.3 vs 41.7 hours P<0.01). Ten percent of patients still had ketonuria when blood ketone levels were already normal (<0.5 mmol/L).

CONCLUSION

BHB measurement is an easy, practical, and reliable monitoring method in DKA and may be used as a parameter to adjust insulin treatment.

L-hydroxytryptophan amplifies pulsatile secretion of LH in the follicular phase of normal women

OBJECTIVES

The hypothalamus possesses serotoninergic fibres which arise from neuronal cell bodies located in the raphe nuclei and have synapse on GnRH-secreting neurones. Hitherto, no firm evidence has been produced to support a role for serotoninergic control of LH in humans. Our first objective was to investigate whether pulsatile administration of L-5-hydroxytryptophan--the immediate precursor of serotonin--affects pulsatile LH secretion in the medium-late follicular phase of normal women. Since the results of the first experiment suggest that L-5-hydroxytryptophan amplifies LH release, our second objective was to investigate whether, in the absence of GnRH, L-5-hydroxytryptophan can release LH. This was done by studying LH response in patients with hypogonadotrophic hypogonadism of hypothalamic origin.

PATIENTS

Twenty-two normal women (18-25 years old) and 8 patients with hypogonadotrophic hypogonadism (2 men with Kallmann's syndrome and 6 women with anorexia nervosa).

DESIGN

Serum LH levels in the 22 subjects (reference population) were monitored at 10-minute intervals over an 8-hour period (1000-1800h) during medium-late follicular phase. In 7 of these subjects, serum LH levels were monitored in their next medium-late follicular phase while L-5-hydroxytryptophan was administered at hourly intervals from 1000 to 1800 h; the peripheral conversion of L-5-hydroxytryptophan to serotonin was inhibited by 150 mg of benserazide at 0930 and 1430h. To investigate whether, in the absence of GnRH, L-5-hydroxytryptophan can release LH, two patients with Kallmann's syndrome were monitored over a 7-hour period and 6 patients with anorexia nervosa over a 9-hour period. After a 2-5 hour control period the subjects received 150 mg of benserazide, and pulsatile L-5-hydroxytryptophan (every 30 minutes in the Kallmann's patients and every 45 minutes in the subjects with anorexia nervosa).

MEASUREMENTS

LH pulses were identified and analysed according to number, amplitude, interpulse interval and pulse duration.

RESULTS

In the normal women, L-5-hydroxytryptophan increased pulse amplitude (mean +/- SD; 3.02 +/- 1.42 IU/l vs. 1.75 +/- 0.98 IU/l before L-5-hydroxytryptophan and 1.90 +/- 1.04 IU/l in the reference population; P < 0.01 in both cases), but had no significant effects on pulse duration, interpulse interval or number of pulses. L-5-hydroxytryptophan had no effect on LH in patients with Kallmann's syndrome. In the anorexia nervosa group, the mean serum LH level increased significantly after L-5-hydroxytryptophan (3.90 +/- 2.46 IU/l vs. 3.06 +/- 1.23 IU/l, P < 0.001) but, as in Kallmann's patients, the three women in this group without residual LH pulsatility did not respond to L-5-hydroxytryptophan.

CONCLUSION

Pulsatile administration of L-5-hydroxytryptophan increases LH pulse amplitude in the follicular phase of normal women. In the absence of GnRH, L-5-hydroxytryptophan does not stimulate pituitary LH secretion.