Chronobiology in hematology and immunology

When should the immune clock be reset? From circadian pharmacodynamics to temporally optimized drug delivery

Immune defenses are organized along both 24-h and yearly time scales. Two circadian systems have been isolated in man, which can be desynchronized: (1) the circulation of T, B, or NK lymphocyte subsets in peripheral blood and (2) the density of epitope molecules (CD3, CD4, ...) at their surface, which may relate to cell reactivity to antigen exposure. The in vitro response of murine splenocytes to interleukin 2, interferon (IFN), or cyclosporin A strongly depended upon circadian time of exposure. Temporally optimized delivery of biologic response modifiers (BRM) may be guided by immunologic marker rhythms. An alternative yet complementary strategy was sought with IFN: since high doses were shown as more effective than low doses against several malignancies, this drug was given at the presumed less toxic time, so that its dose could be increased. Continuous drug delivery was circadian modulated in 8 cancer patients. Dose intensities twice to fourfold higher than those usually recommended were safely infused to ambulatory patients. Chronotherapy with BRM may represent a necessary step for optimizing the immunologic control of malignancies.

Pineal influence on the diurnal rhythm of nonspecific immunity indices in chickens

The effect of pinealectomy and melatonin injections on the diurnal rhythms of serum lysozyme and blood granulocytes was examined in White Leghorn cockerels kept from time of hatching for 5 weeks in L:D 12:12 conditions and immunized twice with sheep red blood cells (SRBC). Pinealectomy or sham-operation was made during first week of life. Pinealectomized chickens were injected daily with a melatonin dosage increased over 4 consecutive weeks (the dosage was 10, 13, 16, and 20 ng per bird daily during the 4 weeks, respectively; MEL I) at the beginning of darkness. The same treatment was performed on chickens with an intact pineal gland using additional melatonin doses increased 10 times (MEL II) and 500 times (MEL III). Intact chickens were also injected with MEL II and MEL III 4 hr before the end of light. Control birds received equivalent injections of vehicle. Five-week-old chickens were sacrificed during a 24-hr period every 4 hr. The existence of diurnal rhythm was evaluated by cosinor analysis. Pinealectomy shifted the acrophase of the diurnal rhythm of granulocytes and abolished that of serum lysozyme. Both rhythms were restored in pinealectomized chickens by MEL I but not by vehicle injections. The same melatonin dose was unable to change the granulocyte rhythm but delayed the acrophase of that of serum lysozyme in chickens with an intact pineal gland. Two higher melatonin doses influenced the diurnal rhythm of granulocytes as a function of dose and time of administration. The rhythm of serum lysozyme was dependent only on the time of injection. The pineal gland seems to control, via its hormone melatonin, the diurnal rhythm of nonspecific immunity in chickens.

Circadian analysis of mononuclear cells in the rat following pinealectomy and superior cervical ganglionectomy

The role of the pineal gland and adrenocorticosteroids in circadian rhythmicity of immune function was investigated in Sprague-Dawley rats that either had been pinealectomized (PX) or had undergone superior cervical ganglionectomy (SCGX), which functionally denervates the pineal. For both experiments, conducted between August and October, rats were entrained to a 10-h light:14-h dark cycle and fed ad libitum. The circadian rhythm in monocytes (ANOVA, p less than .01 for Control + Sham + PX samples) tended to parallel that of plasma corticosteroid levels (ANOVA, p less than .01) with the peak during early dark and the nadir at early light. In comparison, suppressor/cytotoxic T cells and B cells tended to be more frequent during early light with minimum levels during early dark (ANOVA, p less than .05 and .01, respectively, for Control + Sham + PX samples). Natural killer (NK) activity in control animals varied significantly (ANOVA, p less than .05) over the light:dark cycle with peak activity during early dark in the SCGX experiment, but was only slightly elevated during late dark in the PX experiment. PX animals exhibited increased frequency of NK cells, but only in samples collected during the day (t test, p less than .05). This effect was not observed in sham-operated PX controls and in SCGX animals. Neither PX nor SCGX had a significant (ANOVA) effect on plasma corticosterone levels. These observations in the rat are consistent with findings in mice and humans that corticosteroids play an important general role in circadian rhythmicity of immune functions. In contrast, the present study suggests that pineal gland influence of immune function(s) is more specific and that pineal gland interaction with NK cells has a circadian component.

Time-variations of pretreatment peripheral blood S + G2/M-phase size determined by flow cytometry in adult acute myeloid leukaemia

The circadian and seasonal variations of pretreatment proliferative activity of peripheral blood (PB) as PB S + G2/M-phase size was determined by flow cytometry in 61 adult patients with acute myeloid leukaemia (AML). Pretreatment PB S-phase (p less than 0.002), G2 + M-phase (p less than 0.008) and S + G2/M-phase size are statistically correlated to the time of sampling, with the highest phase size at the end of the day. Time-variations of the blast cell count are slightly significant (p = 0.049). Cytological diagnosis-related differences in S + G2/M-phase (p less than 0.003) and white blood cell count (p less than 0.04) time-variations are observed. For all patients, no seasonal variations can be drawn, but in AML 1 (p less than 0.029) and AML 4-5 patients (p less than 0.003), the circadian variations of S + G2/M are affected by the seasons. The present results suggest that time may be taken into account in the monitoring of chemotherapy in acute leukaemia.

Prognostic significance of peripheral blood S + G2/M phase size in adult acute non-lymphoblastic leukaemia

Flow cytometric analysis of peripheral blood (PB) S + G2/M phase size was performed in 73 adult patients with untreated acute non-lymphoblastic leukaemia, to assess whether the results may correlate to response rate and patient prognosis. All patients were treated with the same induction chemotherapy regimen: ARA-C alone or in combination with an anthracycline antibiotic. Pretreatment PB S + G2/M phase size is significantly correlated to induction response rate (p less than 0.02), duration of response (p less than 0.02) and duration of survival. Patients with low PB S + G2/M phase size experience a longer survival, in patients over and below 50 yr (p less than 0.001). Lastly, early deaths tend to be more frequent in the high median age and high PB S + G2/M phase size group. Our study suggests that PB S + G2/M phase size has prognostic significance in obtaining response and duration of survival.

Interactions of aging and annual rhythms on the recovery of cryopreserved murine splenic lymphocytes

The physiological status of donor organisms is an often overlooked factor in cryopreservation experiments. Murine splenic lymphocytes exhibit systematic changes in function which are endogenous and influence recoveries of viable and functional frozen-thawed cells over the life span of mice. One of these changes is the decline in the performance of unfrozen cells as organisms age. Superimposed on the age-related decline in lymphocyte functions are circannual rhythms in T- and B-cell mitogenesis, and the properties of these rhythms also change with age. Splenocytes from young, 15-month-old and 23- to 27-month-old C57BL/6 mice were cryopreserved and tested for recovery of mitogenic responses to activation by the T-cell mitogens, phytohemagglutinin and concanavalin A, and the B-cell mitogen, lipopolysaccharide. Tritiated thymidine incorporation by activated, dividing cells was determined after 72 hr of in vitro culture. Seasonal patterns in recovery of viable and functional cryopreserved cells from young mice resembled those of their unfrozen controls (6). By 15 months of age, the responses after freeze-thaw stress decreased to the levels observed for cells obtained from senescent mice, and seasonal patterns were no longer observed. In these middle-aged mice, intracellular changes in lymphocytes that are equivalent to those in senescent animals resulted in irreparable structural-functional injury during cryopreservation.

Circadian time dependence of murine tolerance for carboplatin

A large amplitude circadian rhythm in murine tolerance for the anticancer agent, carboplatin (cyclobutane dicarboxylatoplatinum II, CBDCA) was demonstrated. Two studies were performed in a total of 266 male B6D2F1 mice standardized by LD 12:12. In the first experiment CBDCA (80 mg/kg/day) was administered intravenously (iv) daily for three consecutive days at all six circadian stages (3, 7, 11, 15, 19, or 23 hr after light onset, HALO). CBDCA dosing at 15 HALO resulted in 58% long-term survivors as compared to 0% after treatment at 3 or 23 HALO (chi 2 = 28; p less than 0.001). In the second experiment, CBDCA (72 or 80 mg/kg/day X 3 days, iv) was administered at any of three circadian stages (0, 8, or 16 HALO). Mice were killed, blood was collected, and seven tissues were obtained 5 and 10 days after the first dose, in order to determine serum urea and creatinine concentrations, leukocyte and red blood cell counts, and to evaluate histologic lesions. No renal toxicity was encountered. Bone marrow and colon mucosa were the major target tissues of CBDCA in these dosages and schedules. CBDCA dosing at 16 HALO was least toxic to the bone marrow as assessed by peripheral leukocyte count and histologic score (p from ANOVA less than 0.05). Histologically assessed lesions of the colon mucosa were less severe after CBDCA dosing at 16 HALO as compared to those at 8 HALO, and significantly so for the lowest dosage tested (p approximately 0.05). Uptake of CBDCA 24 hr after the third dose ranged from 23 micrograms/g of dry tissue in the colon to 7 micrograms/g in the duodenum. Mean tissue concentrations increased between Day 4 and Day 10 for the liver and spleen, and remained similar for the kidney. No consistent circadian dependence was found with regard to Day 4 mean Pt uptake in different tissues, whereas the lowest Day 10 Pt concentrations corresponded to CBDCA dosing at 16 HALO for all tissues investigated. Toxicity did not appear to be directly related to the total platinum concentration in these tissues.

Multipotent stem cell (CFU-S) numbers and circadian variations in aging mice

The multipotent stem cell (CFU-S) numbers were studied in aging female C3H mice (16, 21 and 26 months old, respectively) versus young controls (3 months old). Using the spleen colony technique, the d-8 CFU-S numbers were measured every 3 h during the 24-h period at three different times of the year. Prominent circadian variations were found in young mice. The peak and trough values were significantly different also in aging mice, although the peak-trough differences were declining. When comparing young and old mice at different times of the 24-h period, the CFU-S numbers were sometimes significantly different, but often not. The 24-h mean values were consistently declining during aging. Young mice had different circadian variation patterns and 24-h mean values when examined at different times of the year. It is concluded that the d-8 CFU-S numbers decline in aging mice. Conflicting reports may partly be due to neglect of physiological variations.

Variation in spontaneous chromosomal damage as a function of biologic rhythms in women

An unequivocal observation of a higher rate of cellular genetic damage in terms of increased frequencies of sister chromatid exchanges (SCEs) and chromosome aberrations during "ovulatory" and "estrogenic" stages as compared with those of "progestogenic" stage of the menstrual cycle in women and the reported fluctuations in SCEs as a function of time in men indicate that chronobiologic considerations are essential in the design of studies of humans and animals experiments. It seems that female subjects are more influenced by biologic rhythms because of specific hormonal cycles and are sensitive to genetic damage during ovulatory/estrogenic stages of the menstrual cycle.

Seasonal modulation of the circadian time structure of circulating T and natural killer lymphocyte subsets from healthy subjects

A seasonal modulation of the circadian time structure of circulating T and natural killer (NK) lymphocyte subtypes was documented in five healthy men aged 24-36 yr. Venous blood was obtained every 4 h for 24 h from each subject in January, March, June, August, and November 1984. Three subjects were also studied in April and/or August and/or November 1983 for the T subsets only. Mononuclear cells were isolated on Ficoll-Paque gradient and aliquots were incubated with OKT3, OKT4, OKT8, or HNK-1 monoclonal antibodies for characterizing all, T, T helper, T suppressor-cytotoxic, and NK lymphocytes, respectively, under an epifluorescence microscope. An effect of both sampling time and study month was statistically validated (P less than 0.01) with both two-way analysis of variance and cosinor for the peripheral counts in total, pan-T, T helper, and NK lymphocytes (cells per cubic millimeter). Seasonal changes affected both the circadian patterns and the 24-h mean values. Thus the double amplitude (total extent of variation) of the circadian rhythm in circulating total, T and T helper lymphocytes varied between 0 in March (P greater than 0.30; no rhythm) and up to 46-68% of the 24-h-mean (M) in November, with acrophases (times of maximum, 0) localized in the first half of the night (P less than 0.001). Maximal values were found at 8:30 h for both T suppressor-cytotoxic and NK lymphocytes; a smaller second peak was also found at 20:30 h, and a 12-h rhythm was validated by cosinor (P less than 0.0001), with no patient change in waveform along the year scale. A circannual rhythm was statistically validated by cosinor for total (0 in November), pan-T (0 in March), T suppressor-cytotoxic (0 in December), and NK lymphocytes (0 in October). A rhythm with a period equal to 6 mo was found for circulating T helper cells with 0 occurring both in April and October. Seasonal variations in the incidence of several immunologically related diseases may correspond to an endogenous circannual time structure.

Age-related differences and circadian and seasonal variations of myelopoietic progenitor cell (CFU-GM) numbers in mice

The effect of aging on the myelopoietic progenitor cell (CFU-GM) numbers in mice was studied with special emphasis on biological rhythms in hemopoiesis. Female C3H mice, 16-, 21- and 26-month-old, were investigated versus 3-month-old controls every 3 hours during the 24-h period at three different times of the year. Strong circadian rhythms were observed in both CFU-GM concentration and content in the femur of all age-groups. The amplitudes and the 24-h mean values were declining in mice aged 21 and 26 months. From 16 months of age, a significant advance of circadian peak phases was observed. The overlapping was variable during the 24-h period. The present results may explain previous inconsistencies regarding myelopoietic progenitor cell numbers in aging mice. Some seasonal differences in rhythmicity patterns were also observed. Fitting of original data to single sinus functions was highly significant, although important details sometimes were obscured.

Factors that influence formation of sister chromatid exchanges in human blood lymphocytes

Sister chromatid exchange (SCE) reflects an interchange of DNA sequences between helices in a replicating chromosome. This was initially accomplished by Taylor and colleagues (1957) using tritiated thymidine incorporation followed by autoradiography. The development of an elegant technique for differential staining of sister chromatids by incorporating a thymidine analog, 5-bromodeoxyuridine (BrdU) has greatly simplified the detection of SCEs in metaphase chromosomes. In recent years, the analysis of SCE has been considered to be a highly sensitive and additional (i.e., with chromosome aberrations) end point for measuring mutagenic/carcinogenic potential of various environmental agents and is increasingly being used to detect and differentiate among chromosome fragility human diseases that predispose to neoplasia. Attention has been focused to see if the induction of SCEs in lymphocyte cultures can be used as a reliable "biological dosimeter" for genetic risk assessment and to monitor the exposed populations. Several physical or preparatory as well as biological factors that modify the response and formation of SCEs make the monitoring difficult. The purpose of this article is to review and analyze these factors to facilitate an effective development of a standard protocol for SCE testing and for appropriate evaluation of test results. This may also provide clues to understand the yet unknown molecular mechanism(s) and biological significance of SCE formation.

Ten-year-replicated circadian profiles for 36 physiological, serological and urinary variables in healthy men

At 3-hr intervals over a 24-hr span, 36 systemic, serologic and urinary variables were examined in 7 men in their mid 20's in the Spring of 1969, and again in the same 7 men in the Spring of 1979 under a similar chronobiologic protocol, using the same chemical and numerical analytical procedures. The variables examined for rhythms by cosinor were: vital signs--blood pressure (systolic, diastolic, pulse pressure and mean arterial pressure), heart rate, intraocular pressure (left and right), oral temperature; serum components--albumin, albumin/globulin ratio, total bilirubin, calcium, carbon dioxide, chlorides, bilirubin, cholesterol, globulin, glucose, potassium, sodium, sodium/potassium ratio, transaminase, triglycerides, total protein, urea nitrogen; and urine components--calcium, calcium/magnesium ratio, creatinine, magnesium, pH, potassium, sodium, sodium/potassium ratio, urea clearance, urea nitrogen, volume and zinc. Although all subjects appeared clinically healthy in 1969 and in 1979, certain inter-study differences were observed in a number of rhythm parameters of different variables. Statistically significant increases in mesor for the group as a whole were observed for serum Ca, cholesterol, Cl, CO2, K, Na, and while statistically significant mesor decreases for a group as a whole were noted in serum glucose and transaminase. Statistically significant increases in amplitude for the group as a whole were observed in serum chloride and urinary Na/K ratio, while statistically significant decreases were observed in amplitude for blood pressure, heart rate, serum albumin, A/G ratio, globulin, glucose, protein, sodium and transaminase.(ABSTRACT TRUNCATED AT 250 WORDS)

Circadian and circannual variations of cell cycle distribution in the mouse bone marrow

The cell cycle distribution of bone marrow cells from the femurs of female C3H mice has been investigated by flow cytometry according to the time of the day and month of the year. Both circadian and seasonal variations were found for the different cell cycle phases as well as the total cell numbers per femur. Both the mesor, the acrophase and the amplitude of the S, G2 and (G1 + G0) phases varied significantly in some months, while in other months only insignificant rhythms were found. The relative cell cycle distribution only partly reflected variations in the total numbers of proliferating cells, since the total cell number per femur was also variable. The total numbers of cells in DNA synthesis seem to be higher in the first part of the year, indicating increased cell proliferation during winter and spring. In this period the acrophases of DNA synthesis and G2 were in the morning, while the second half of the year showed the peak later in the day. In general, hemopoietic cell proliferation seems to constitute a labile equilibrium with rapidly changing activities.

Diurnal rhythms in performance tests of school children with and without language disorders

Time-of-day related changes on four tests used by speech therapists and four other performance tests, in addition to oral temperature, were documented in 16 school children (7-9 years of age). Six of them had language disorders and were receiving speech therapy. Children were synchronized with diurnal activity from around 0730 to around 2100 and nocturnal rest. For each child, at each test time point (e.g. 0900, 1100, 1530 and 1930) tests were performed three times, with two different speech therapists, in a random order, with only one session per day. Conventional methods (t-tested mean differences; ANOVA; correlation tests) were used for statistical analyses. Among 29 parameters (items) which were analyzed, only nine exhibited time-of-day related changes, mainly in speed to-perform measures. In most detected rhythms best performance occurred either at 1100 or at 1530 with no difference in subgroups except for the fastest performance of the sentence repetition test. With regard to the daily mean M, controls performed better than children with language disorders for the word (syllabic) repetition test (P less than 0.0004) but this was reversed for both computing and colouring skill tests (P less than 0.04 and less than 0.002). A difference related to sex (but not to language disorders) was observed in the Ms of speed in sign reproduction (P less than 0.0000) and sorting cards (P less than 0.01), with boys being faster than girls. In children, as in adults, time-of-day effects should be considered when the quantification of performance is desired.

Rhythmic variations of different hemopoietic cell lines and maturation stages in aging mice

Non-proliferative and proliferative myeloid, and lymphoid and erythroid bone marrow cells were studied in aging female C3H mice. A chronobiological approach was used and mice aged 16, 21 and 26 months were examined vs. 3 month-old mice every 3 h during the 24-h period in three different experiments. Significant circadian fluctuations were observed in most of the cell populations, even in the oldest mice. The rhythmicity patterns might be different at different times of the year, and in young mice seasonal fluctuations in the 24-h mean values were observed. The absolute numbers of the 24-h means seemed to be highest at 21 months of age in all cell lines and maturation stages. Sinus function fitting indicated a decline of the amplitudes in aging mice. Minor age-related phase-differences were indicated in some populations. However, the fitting of original data to single sinus functions was variable and often obscured important features in the cell number variations. The present investigation illustrates the importance of performing time-sequence studies in hematology.

Alterations of cell cycle distribution in the bone marrow of aging mice measured by flow cytometry

The effect of aging on the cell cycle distribution in bone marrow cells was measured by flow cytometry with special reference to the lability in bone marrow physiology. Female C3H mice were examined every 3 h during a 24-h period at the age of 16, 21 and 26 months, vs 3-month-old control mice. Considerable circadian fluctuations were found in the different cell cycle phases in young mice. The rhythmicity patterns were different when comparing different months. In aging mice the variations were dampened, while consistent age-related phase shifts were not seen. The maximal 24-h mean numbers of cells in all three cell phases, but especially the S and G2 phases were reached at 21 months. The relative number of S and G2 phases were significantly reduced in 26-month-old mice, indicating an age-related shift of the proliferative capacity. The present findings are discussed in relation to age-related changes in granulopoiesis and the increase of myelotoxic effects during cancer chemotherapy in aging individuals.

Circannual rhythm in natural killer activity and mitogen responsiveness of murine splenocytes

Seasonal variations were observed in murine splenic natural killer (NK) cell activity and also in murine lymphocyte responsiveness to mitogens, namely, concanavalin A, phytohemagglutinin, and lipopolysaccharide. The maximum and minimum splenic NK cell activities were observed in January-February and July-August, respectively. Conversely, maxima and minima of lymphoproliferative responses to all the three mitogens occurred in April-June and January-February, respectively. Such variations, when inferential statistics are used, appeared to be accounted for by circannual and other low-frequency (infradian) bioperiodicities. More specifically, the circannual rhythm in murine NK cell activity was demonstrated in data from a total of 356 mice collected over a period of 5 years. The various components of the immune system are characterized by a multifrequency time structure. The understanding of the organization of the immune system along the yearly scale may have bearings on that of the seasonal incidence of numerous infectious diseases and on the success/failure of immunotherapy.

Circadian rhythms of peripheral blood leukocytes in aging mice

The effect of aging on white blood cell numbers was studied with special reference to the lability in blood cell physiology. Thus, the total numbers of leukocytes, polymorphonuclear granulocytes (PMNs) and lymphocytes were investigated in C3H mice, 3-month-old mice vs. mice aged 16, 21 and 26 months. Strong circadian rhythms were observed in the different cell classes, while there were insignificant seasonal changes. Even the oldest mice had significant variations, especially in the total leukocyte numbers and the PMNs. Subtle age-related shifts in the rhythmicity patterns were indicated. When comparing the 24-h means, there was a shift between the different white blood cell classes. A permanent reduction of the lymphocyte number was observed from the age of 16 months, while the number of PMNs steadily increased in the aging mice. The present results may explain inconsistencies among previous studies, demonstrating the significance of a chronobiological approach.

Circadian time dependence of murine tolerance for the alkylating agent peptichemio

Since the extent of host toxicity of cytostatics is considerably affected by dosing time, a chronopharmacologic approach was undertaken for optimizing the therapeutic index of the alkylating agent, peptichemio (PTC). In 4 studies involving a total of 463 male B6D2F1 mice, a highly statistically significant circadian rhythm characterized murine tolerance for PTC (8 or 10 mg/kg/day i.v. X 3 days). Six circadian stages were explored (3, 7, 11, 15, 19 and 23 Hours After Light Onset--HALO). Day-40 survival rate varied between 20% (PTC at 3 HALO) and 55% (PTC at 15 HALO) (chi 2 = 16.7; P less than 0.01). In each study, body weight loss was maximal in mice injected with PTC at 3 HALO and minimal in those treated at 15 HALO (P less than 0.01). In a further study involving 96 male B6D2F1 mice, the toxicity of PTC on several target tissues (bone marrow, spleen, small bowel, colon, liver, kidney and lungs) was investigated by histology and leukocyte count as a function of drug dosing time. A circadian rhythm in the susceptibility of the bone marrow, the spleen and the intestinal tract was demonstrated. Optimal murine tolerance for PTC resulted from dosing it at 15 HALO, e.g. in the first half of the activity span.

The influence on survival of season of onset of childhood acute lymphoblastic leukemia (ALL)

Rhythmicity has been found to be an important characteristic of leukocytes. We tested, therefore, whether rhythmicity could be found to be reflected in one or more of the developmental stages of childhood acute lymphoblastic leukemia. The patient material comprised 205 children 96 girls and 106 boys) whose disease was diagnosed in Israel during the years 1976-1981. Their mean age was 5.9 years +/- 3.94. No seasonal onset of disease was found, either in the whole group or in subgroups divided by sex or lymphocyte surface markers. Survival analyses however, revealed that the season of diagnosis influenced survival. Excluded from the study were 9 cases (4.4%) due to lack of some items. The follow-up period was between 1 and 72 months (median 26 months). It appeared that the life table curves were running in their temporal order, each following curve representing a consecutive 3-month period. The difference between the curves was statistically significant (p = 0.025/0.009). The survival percentages at the end of the follow-up increased steadily, from a trough during November-January (56.5%) to a peak in August-October (80.0%). Analysis by sex and white blood cell (WBC) count showed that the difference between the life table curves was primarily due to girls presenting less than 50,000 cells per cumm (n = 73, p = 0.005/0.0028). The survival percentages in the same order as mentioned earlier were: 47.1%, 68.4%, 89.5% and 94.4%. The steady rise in the different female time series suggests a circannual pattern.(ABSTRACT TRUNCATED AT 250 WORDS)

Role of the pineal gland in immunity. Circadian synthesis and release of melatonin modulates the antibody response and antagonizes the immunosuppressive effect of corticosterone

Inhibition of synthesis of the pineal neurohormone melatonin (MEL) in mice, by administration of propranolol (PRO) in the evening, and daily injections of p-chlorophenylalanine (PCPA), resulted in a significant depression of the primary antibody response to sheep red blood cells (SRBC). Spleen cells from these mice showed a reduced reactivity against antigens in the autologous mixed lymphocyte reaction (AMLR). In contrast, alloreactivity remained normal. Reconstitution of the night-time peak of plasma MEL by evening injections to the mice completely reversed the suppression of the humoral response and the AMLR. MEL administration was able to antagonize the depression of antibody production induced by corticosterone in vivo. These results suggest that the pineal gland has important immunomodulatory functions through its cyclic, circadian release of MEL.

Modulation of the immune response in fish

This is a brief overview of the field of immune modulation in fish. Special attention is given to the effects of biological rhythms on the immune responses of animals. Biological rhythms in fish appear to be poorly studied and the effects of such rhythms on fish immune responses needs to be evaluated. Implications for research on the modulation of fish immune responses are discussed.

Interindividual differences in the circadian hematologic time structure of cancer patients

The complete hematologic blood cell count of 11 patients with advanced cancer were determined on 14 occasions, every 4 hr over 36-48 hr. Oral temperature was also measured at the same times as blood sampling. Five patients had breast cancer, five had ovarian cancer and one a leiomyosarcoma. Circadian rhythms were detected by the cosinor method for seven hematologic variables (red blood cells, hemoglobin, hematocrit, white blood cells, neutrophils, lymphocytes, platelets) and for oral temperature in the whole group of patients. All acrophases were located between 1300 and 1700 hr, except for lymphocytes (2100 hr). A rhythm with a period of 8 hr was validated for lymphocytes and monocytes. Validated or estimated amplitudes and acrophases were closely similar in both breast and ovarian cancer subgroups. Individual cosinor analyses documented large differences from patient to patient, which were accounted for by differences in performance status. Thus, subjects with poor performance status and rapidly progressive disease had very few validated rhythms as compared to those patients with good performance status. As a result a statistically significant correlation was found between the number of validated hematologic circadian rhythms and the performance status (r = -0.88; P less than 0.01).

Influence of BCG administration time on the in-vivo migration of leukocytes

The temporal variation in the migration of polymorphonuclear leukocytes (PMN) induced by live BCG was studied in the mouse. Ten microliter of a 5 X 10(6) live BCG/ml suspension or sterile saline were placed on a cell trap immediately before its subcutaneous implantation at different clock times: 0100, 0500, 0900, 1300, 1700 and 2100 in animals synchronized with L(0700-1900): D(1900-0700). Eight hours later, the cell trap was removed, prepared for histological identification and counted. PMN counts in the cell trap were maximal 480 min after implantation. Non-specific migration was thought to occur and the peak value of leukocytes of 22.8 +/- 6.1 cells/10,000 micron 2 was obtained when the saline cell-trap was implanted at 0500. In the BCG-treated mice, a circadian rhythm was observed in the migration of leukocytes. The acrophase was at 1700. The results support the hypothesis that the circadian stage of antigen encounter influences the magnitude of the immune response.

Temporal order vs. variability in activation of lymphocytes from aging mice

Changes in patterns of circannual rhythms in the in vitro activation of splenic lymphocytes from aging C57BL/6 mice may account both for reports of conflicting results in tests of immune function and for the assumed increase in variability in data obtained using cells from older mice. Single cell suspensions from 4-6, 15 and 24-28-month-old mice living in presumably constant environments were cultured in vitro with mitogens, and the incorporation of tritiated thymidine by dividing cells was determined. Free-running periods of T and B lymphocyte rhythms of blastogenic responses increased in cells from both older groups; amplitudes of the T but not B cell rhythms were reduced in senescent mice. This results in continuously changing phase relationships of both T and B cell rhythms, without consistently higher levels of activation of cells from young animals, thus obscuring at intervals the age-related declines in function. Because data were collected for several years, it was clear from the patterns of the rhythms and also the combined data that the greatest ranges in levels of activation ("variability") characterized T and B cells from the youngest mice rather than older animals.

Maintenance chemotherapy for childhood acute lymphoblastic leukaemia: better in the evening

The course of 118 children with acute lymphoblastic leukaemia who had achieved complete remission with a standard induction protocol and had also received meningeal prophylaxis with intrathecal methotrexate (MTX) and cranial irradiation was reviewed. Maintenance chemotherapy consisted of daily 6-mercaptopurine (6-MP), weekly MTX, and monthly vincristine and prednisone. 82 children took 6-MP and MTX in the morning and 36 in the evening. Disease-free survival as determined by Kaplan-Meier analysis was better for children on evening chemotherapy. Regression analysis (Cox proportional hazards model, with evening vs morning schedule as exposure variable, and age at diagnosis, leucocytosis at diagnosis, and sex as covariates) showed that, for those surviving free of disease for longer than 78 weeks, the risk of relapsing was 4.6 times greater for the morning schedule than for the evening one.

Circadian rhythm in tolerance of mice for the new anthracycline analog 4'-O-tetrahydropyranyl-adriamycin (THP)

A statistically significant circadian rhythm in tolerance of 226 male B6D2F1 mice synchronized with LD 12:12 for 4'-O-tetrahydropyranyl-adriamycin (THP) was demonstrated. Four intravenous dosages (18, 25, 32 and 40 mg/kg) and six different dosing times (3, 7, 10, 14, 19 and 23 hr after light onset-HALO) were compared. Survival rate, body weight loss and leukopenia depended on both the dose and time of injection. The overall survival rate varied between 83% (light-rest span) and 56% (dark-activity span) (chi2 = 17; d.f. = 2; P less than 0.001). Maximal body weight loss occurred 4-5 days after drug injection. Total leukocyte counts were determined on these days. Both body weight loss and leukopenia were reduced by approximately 100% in those mice injected in their late rest span (7-10 HALO) as compared to those treated in the middle of their activity span (19 HALO). Circadian rhythms in day-60 survival rate, body weight loss and leukopenia were statistically validated by cosinor analysis, with estimated peak times (acrophases) occurring respectively at 7:30, 9:20 and 8:40 HALO. Minor cardiac lesions consisting of diffuse vacuolization and loss of muscular striation were observed in histologic sections from 3/32 hearts (16 controls, 16 treated). All three corresponded to THP given at 19 (2/2 mice) or 23 HALO (1/4 mice). Thus lethal, hematologic and possibly cardiac tolerance for THP were largely optimized by administering the drug to mice in their late span (7-10 HALO).

Sex differences in circadian rhythms of several variables in lymphoreticular organs, liver, kidney, and corneal epithelium in adult CD2F1 mice

In this paper data resulting from an investigation into the influence of sex on selected circadian rhythms in lymphoreticular organs, liver, kidney, and corneal epithelium of adult CD2F1 mice are reported. Increased organ weight, total DNA and RNA in the spleen, total DNA and [3H thymidine [( 3H]TdR) incorporation into DNA in the thymus, and [3H]TdR incorporation into DNA in the liver and bone marrow in female mice compared to male littermates is demonstrated. In contrast, kidney weight and [3H]TdR incorporation into DNA as well as the corneal epithelium mitotic index are greater in male mice. Except for the corneal epithelium mitotic index and total splenic RNA and DNA, circadian rhythmicity in the variables studied is validated using the cosinor method of rhythmometric analysis in male but not in female mice. The lack of sinusoidal rhythmicity in female mice is presumed to be due to asynchrony of estrous cycling between mice within this group. Moreover, a differential organ response to exogenous testosterone enthanate is reported. The administration of this hormone suppresses [3H]TdR incorporation into DNA in the thymus and liver but not in the spleen or bone marrow at 18, 42, or 72 hr after injection.

Effect of beta-adrenergic stimulation on the circulatory lymphocyte count: studies in normals and in patients with chronic airflow obstruction

In eight non-allergic patients with chronic airflow obstruction (CAO) and eight age and sex matched, healthy control subjects the circadian variation in circulatory lymphocyte count was studied in relation to serum cortisol and urinary epinephrine levels. In addition, we investigated the effect of the beta-adrenergic agent terbutaline on the lymphocyte count in two ways: as a long-term effect after 8 days of oral slow-release terbutaline with constant diurnal and nocturnal serum levels in patients, and as a short-term effect by a constant rate infusion of 0.2 micrograms/min over 4 hr in normals. Both patients and controls showed similar circadian patterns of urinary epinephrine excretion and lymphocyte counts. Patients with CAO, however, had significantly lower epinephrine levels and significantly higher lymphocyte counts at all hours of observation (every 4 hr from 0800 to 0800 hr the next day), as compared with normal controls. After 8 days of slow-release terbutaline the lymphocyte count in the patient group decreased to levels not significantly different from that of normals. The circadian rhythm of the lymphocytes, however, persisted under terbutaline therapy. No correlation existed between the lymphocyte count modulating factor, serum cortisol and the lymphocyte count over 24 hr. On placebo infusion in the control persons an increase of lymphocytes over 4 hr occurred, as a consequence of circadian rhythmicity. On terbutaline infusion a significant increase of lymphocytes after 1 hr was followed by a decrease to levels significantly below those on the placebo day. The same pattern was found in the leucocyte count. From this study it is concluded that beta-adrenergic stimulation corrects the relative lymphocytosis to counts comparable with normals. Other coinciding factors must regulate, however, the circadian rhythmicity.

Peripheral blood leukocyte alterations in mice induced by a hemoregulatory pentapeptide (HP 5b)

The effects of different doses of a synthetic hemoregulatory pentapeptide, analoguous to an inhibitory factor associated with human granulocytes, on the numbers of peripheral blood leukocytes have been investigated in female C3H mice. Following single injections as well as continuous infusion for 6 days, the numbers of granulocytes in peripheral blood were reduced to about one half of the normal. Maximal effect with single injection was seen with 120 micrograms (10(-5) M), while 1.2 mg (10(-4) M) as one dose only had a slight, temporary effect on the granulocyte numbers in peripheral blood. Upon continuous infusion of 14 micrograms/h (less than 10(-5) M) for 19 days, a stimulation with doubling of the granulocyte numbers was seen instead. The substance also decreased the monocyte numbers in peripheral blood. With prolonged exposure, a relative monocytosis was seen instead. After both single injection and continuous infusion, the pentapeptide increased the lymphocyte numbers in peripheral blood. The thrombocyte numbers were not altered. The decreased granulocyte numbers seemed to be due to a dual mechanism, one reducing proliferation in the maturing compartment which gives a rapid cell reduction, and one mediated through inhibition of the committed stem cells for myelopoiesis, giving a long-lasting reduction in the granulocyte numbers. It is postulated that the pentapeptide has a complex regulatory effect in vivo.

Circulating CALLA-positive lymphocytes exhibit circadian rhythms in man

Common acute lymphoblastic leukemia antigen (CALLA) is a polypeptide with a molecular weight of 100,000 daltons (P100). It has been mainly found on the membrane of leukemic lymphoblasts, but not on that of normal circulating lymphocytes. Circadian rhythmicity in circulating CALLA-positive (CALLA+) lymphocytes was investigated in five healthy male subjects. Blood was sampled every 4 h for 24 h in each subject. Seven times series were obtained (three for the same subject). Leukocyte and differential counts were determined, and mononucular cells (greater than 95% lymphocytes) were isolated in Ficoll-Paque gradient. CALLA+ cells were characterized with both J5 and VILA1 monoclonal antibodies. Other T- and B-cell subpopulations were also determined in the same samples. Up to 1160 +/- 498 (mean +/- 1 S.E.M) J5-labelled CALLA+ lymphocytes per mm3 were found in peripheral blood at night. At this time, circulating VILA1-labelled CALLA+ lymphocytes also reached their peak although with a much lower number (66 +/- 14 cells/mm3). A circadian rhythm (with a period identical to 24h) was statistically validated with several methods for the number of J5-labelled cells, that of VILA1-labelled cells and the J5: VILA1 ratio. The count of J5-labelled CALLA+ cells was correlated with that of total lymphocytes, total T (OKT3+) and inducer T (OKT4+) cells (p less than 0.01), but neither with suppressor/cytotoxic cells (OKT8+) nor with B cells (SIg+, B1+, B2+, or HLA-Dr+). No correlation was found between any of these lymphocyte subpopulation and the count of VILA1-labelled CALLA+ cells. Such results further support the hypothesis that VILA1 and J5 monoclonal antibodies do not bind to the same epitope of the CALLA molecule. The large nocturnal increase in circulating J5-labelled CALLA+ lymphocytes may be accounted for by a release of immature presumably T lymphocytes in the peripheral blood.