Herpes simplex virus shedding in genital secretions

Nine women and eight men with a history of genital herpes had cultures taken for 60 consecutive days to assess the frequency and duration of viral shedding in the absence of symptoms. Daily self-obtained specimens (cervical-vaginal swabs from women and urethral swabs from men) were submitted for viral isolation. Five of 972 samples were found to contain infectious virus; two of the positive specimens correlated with overt disease. The other three positive cultures, two from the same individual, were not clearly associated with a genital infection. Thus, the overall frequency of asymptomatic viral shedding was 0.31% and occurred in two of 17 individuals. It is concluded that prolonged continuous sampling may be necessary to assess the risk of asymptomatic shedding. Infectious virus was not present in the genital secretions of most individuals (15 of 17) in the absence of a lesion, even when cultured on a daily basis for 60 days.

Elevated mononuclear leukocyte phosphodiesterase in allergic dogs with and without airway hyperresponsiveness

To investigate if mononuclear leukocyte beta-adrenergic hyporesponsiveness of Basenji greyhound (BG) dogs is associated with atopy or nonspecific airway hyperresponsiveness, we examined the relationship between mononuclear leukocyte cAMP phosphodiesterase levels, airway responsiveness to methacholine, and intradermal allergen responses in 17 BG dogs, five unrelated purebred Basenjis, and five greyhounds. BG dogs were hyperresponsive to aerosols of methacholine compared to Basenjis and greyhounds. Both BG dogs and Basenjis were allergic and had increased leukocyte cAMP phosphodiesterase activity compared to greyhounds. We concluded that the leukocyte abnormality is not associated with airway hyperresponsiveness. The leukocyte abnormality is either associated with the allergic state, with some hereditary trait that BG dogs acquired from the Basenji ancestry, or the leukocyte abnormality is necessary but not sufficient for the development of airway hyperresponsiveness.

Monocyte localization of elevated cAMP phosphodiesterase activity in atopic dermatitis

Patients with atopic dermatitis (AD) manifest a number of immune abnormalities which correlate with in vitro defects including lymphocyte transformation, chemotaxis, and cytotoxicity. Past studies have shown reduced leukocyte cyclic 3',5'-adenosine monophosphate (cAMP) levels after exposure to adenylate cyclase-active agonists, and we have demonstrated that this results from increased catabolism due to elevated cAMP-phosphodiesterase activity. These results were obtained in preparations containing mixtures of lymphocytes and monocytes. In order to determine more precisely the cellular site of the defect we have separated the leukocytes into lymphocyte- and monocyte-enriched preparations using either Percoll-gradient centrifugation or adherence isolation. Both techniques yielded over 93% pure lymphocytes, whereas the former yielded 64% monocytes compared with the latter method which generated 94% pure monocytes. Atopic monocytes, obtained by either technique, consistently showed elevated phosphodiesterase activity compared with those of the nonatopic monocytes. Such differences were not evident in lymphocyte preparations from normal and atopic subjects. In spite of the increased rate of cAMP degradation in atopic leukocytes, the resting cAMP levels do not differ from those of normal subjects. We questioned whether this is caused by increased cAMP synthesis and evaluated cellular adenylate cyclase activity. We found no evidence in AD cells for an increased rate of adenylate cyclase catalysis, either basal activity or after stimulation by forskolin. Therefore, the resting cAMP levels must have been compensated by other mechanisms. Impaired cyclic nucleotide metabolism in atopic monocytes may affect a number of immunologic and inflammatory reactions and could account for many of the clinical abnormalities in atopic diseases.

Functional differences between human cutaneous mast cells and basophils: a comparison of morphine-induced histamine release

Intravenous administration of morphine sulfate often produces urticarial and hypotensive reactions associated with elevations in plasma histamine. The source of this histamine and mechanisms controlling its release are poorly understood. Previous studies of morphine-induced histamine release compared human leukocytes to rat peritoneal mast cells. The effects of morphine on human cutaneous mast cells has not been examined. We studied in vitro histamine release from human basophils and human skin preparations containing cutaneous mast cells to evaluate their relative contribution to the pharmacologic effects of morphine. Human skin mast cell preparations showed dose-dependent histamine release over a morphine concentration range of 1.5 X 10(-5) to 4.5 X 10(-3) M, with peak release occurring at 5 X 10(-4) M, with peak release occurring at 5 X 10(-4) M. Clinically, morphine sulfate is usually injected as a 1.5 X 10(-2) M solution. Histamine release was calcium dependent and equivalent to that obtained with 3 and 10 mM strontium. Morphologic examination revealed degranulation and exocytosis occurring in morphine-stimulated tissue but not in specimens exposed to buffer alone. Lactate dehydrogenase levels did not increase following morphine incubation, thus supporting a noncytolytic mechanism of histamine release. Basophils, in contrast, showed no significant histamine release from exposure to morphine up to 10(-2) M. Concanavalin A, as a positive control in these same preparations, produced a mean histamine release of 21.0%.(ABSTRACT TRUNCATED AT 250 WORDS)

Abnormal retinal function associated with isotretinoin therapy for acne

Three of 50 patients treated with isotretinoin (1 mg/kg/day) for cystic acne complained of poor night vision and/or excessive glare sensitivity. While still receiving the drug or shortly thereafter, two patients were found to have abnormal dark-adaptation curves, with elevations of either cone or rod thresholds, or both. Two patients had abnormal electroretinograms (ERGs). One had a mildly abnormal electro-oculogram. The dark-adaptation curves were normal for one patient several months after isotretinoin therapy was discontinued. Two patients had elevated cone thresholds at least one year later. Six months following cessation of therapy, the ERG was still abnormal for one patient, but continued improvement was evident at 25 months; for the second patient, the ERG was normal at one year. Analysis of Naka-Rushton parameters for the ERG scotopic b-wave stimulus-response curves indicated response compression for two patients, as evidenced by a reduction in the maximum response. For one patient, the half-saturation constant was elevated 0.7 log units, suggesting reduction of retinal sensitivity, perhaps from decrease in retinal photopigment concentration. We suspect that isotretinoin may complete for normal retinol binding sites on cell surfaces or transport molecules. A prospective study is currently underway to determine if a clinically measurable adverse effect on retinal function is seen with greater frequency.

Increased metachromatic cells and lymphocytes in bronchoalveolar lavage fluid of dogs with airway hyperreactivity

Bronchoalveolar lavage (BAL) was performed in 11 basenji greyhound (BG) dogs, which showed persistent airway hyperreactivity to methacholine and citric acid aerosols, and in 15 non-BG dogs, which were significantly less reactive to these challenges. Five of the BG dogs had never received any aerosols prior to BAL, and 3 of the non-BG dogs were allergic to Ascaris suum. No dog received aerosols for 2 wk prior to BAL. Fluid recovered was centrifuged, and aliquots were taken for histamine content and cell identification. Total cell numbers were similar in BG and non-BG dogs. The BG dogs had increased percentages of lymphocytes and metachromatic cells in BAL fluid compared with those in non-BG dogs. Lymphocytes averaged 35.5 +/- 2.3% (mean +/- SEM) and 17.2 +/- 1.2% (p less than 0.005) in BG and non-BG dogs, respectively. The BG dogs that had received previous aerosol challenge and the BG dogs never challenged had 6.2 +/- 0.4% (mean +/- SEM) and 4.6 +/- 0.6% metachromatic cells in BAL. Nonallergic non-BG dogs had 0.91 +/- 0.2% and allergic non-BG dogs had 2.6 +/- 0.5% metachromatic cells in BAL (p less than 0.05 from BG). Total histamine closely correlated with numbers of metachromatic cells in BAL (r = 0.86). Forty-nine percent fewer mast cells were detected in cell preparations fixed in formalin than in cell preparations fixed in basic lead acetate. Electron micrographs revealed 2 mast cell types on the basis of structural characteristics of the granules.(ABSTRACT TRUNCATED AT 250 WORDS)

Pharmacophysiology of atopic dermatitis

Atopic dermatitis is clearly characterized by altered cutaneous physiologic responses. There is a tendency to acral vasoconstriction. Rubbing causes skin pallor and white dermographism. Vascular instability is demonstrated by responses to cholinergic agents, histamine, and nicotinates. Psychophysiologic studies demonstrate exaggerated vasodilator responses to emotional stress with consequent pruritus and scratching. The itch threshold is low, duration is prolonged, and nighttime scratching movements may be frequent or almost continuous. Regardless of the inciting trigger factors, the scratching causes the damage and the severe dermatitis. Thermal as well as emotional stimuli to sweating cause severe itching in AD, yet the concept of a miliaria-type, poral occlusion mechanism remains unproven. Some studies suggest actually increased sweating along with erythema and pruritus during acute flares of AD. The concept of sweat-borne allergens causing skin reactions during sweating is interesting but has never been proven. Studies of sweat responses to pharmacologic agents have produced conflicting data, and attempts to link these responses to Szentivanyi's beta-adrenergic blockade theory are not convincing. The numerous variables of climate, season, sex, age, and habitus affect sweating greatly. Future studies must carefully control for each of these factors before pharmacologically induced sweat responses can be interpreted clearly. A number of lines of evidence suggest involvement of histamine and other mediators in the evolution of erythema, pruritus, and scratching in AD. Flares of the condition have been reproducibly evoked by only two incitants: experimental emotional stress interviews and specific food challenge in selected sensitive individuals. In the latter, increased plasma histamine has been demonstrated, presumably generated by antigen/IgE stimulated degranulation of mast cells in the gut and/or skin. The demonstrated increased histamine releasability of basophils from atopic individuals may be the result of defective cellular regulatory mechanisms. Recent studies have demonstrated increased cyclic AMP-phosphodiesterase activity in leukocytes from atopic individuals. The resultant decreased intracellular cyclic AMP removes an inhibitory factor, which in turn causes net cellular hyperresponsiveness. This effect has been shown to account, at least in part, for increased histamine release from leukocytes of patients with AD. These and other studies focused upon cell functional regulation are providing better understanding of basic biochemical abnormalities and may lead to improved diagnostic and therapeutic approaches in managing atopic disease.

Anaphylactic reaction during anaesthesia associated with positive intradermal skin test to fentanyl

A 29 year-old female patient suffered vascular collapse which became apparent immediately after general anaesthesia. Resuscitation was prolonged and difficult, and complicated by the need for reoperation. Based on the time history, fentanyl was suspected as the causative agent. Fentanyl allergy was confirmed by skin testing one month later. The case is discussed, and the possible reasons for the delay in appearance of symptoms and signs are considered.

Elevated leukocyte phosphodiesterase as a basis for depressed cyclic adenosine monophosphate responses in the Basenji greyhound dog model of asthma

The BG dog manifests various characteristics of human asthma, including airway hyperreactivity to low concentrations of methacholine. Studies have suggested that airway hyperreactivity in asthma is related to inadequate intracellular cAMP responses. We studied cAMP characteristics in MNL from 19 BG and 14 mongrel dogs. beta-Adrenergic receptors were assessed by 125I CYP in the presence and absence of propranolol. The responses of cAMP to ISO were measured by radioimmunoassay. Adenylate cyclase activity was determined in homogenized MNL preparations by cAMP generation. PDE activity was quantitated by radioenzyme assay. Mongrel dog leukocyte ISO-stimulated cAMP levels doubled, whereas there were negligible increases in MNL from BG dogs. Basal PDE levels were higher in BG dogs than in mongrel dogs. The PDE inhibitor Ro 20-1724 restored ISO-stimulated cAMP responses in MNL of BG dogs. Adenylate cyclase activity was not lower in MNL homogenates from BG dogs than in mongrel dogs. Cells from both BG and mongrel dogs demonstrated similar receptor numbers and affinities of saturable, specific beta-adrenergic binding over a 10 pM to 400 pM range. Our results suggest that depressed cAMP responses in BG dogs are due to high PDE activity rather than to a defect in the beta-adrenergic receptor adenylate cyclase system.

Immunopharmacology of the atopic diseases

The atopic conditions, atopic dermatitis, asthma, and allergic rhinitis, may arise as a result of infiltrating bone marrow-derived cells into skin or respiratory mucosae. Release of inflammatory factors from these cells could account for cutaneous vascular instability and pruritus in atopic dermatitis. Erythema and itch have been induced by experimental stress interviews and by blind food challenges. In the latter, increased plasma histamine was detected and correlated with cutaneous reactions. Basophils from patients with atopic dermatitis have increased histamine release after exposure to immunologic or nonimmunologic lectin stimuli. This increased releasability may relate to inadequate cyclic AMP regulation of cell function. We have found that leukocytes of patients with atopic dermatitis have elevated phosphodiesterase activity and consequently reduced intracellular cyclic AMP. Exposure of the cells to a phosphodiesterase inhibitor caused considerable reduction in histamine release. Similarly, exposure of atopic B lymphocytes to a phosphodiesterase inhibitor greatly reduced the high spontaneous IgE synthesis in mononuclear leukocyte cultures. Elevated leukocyte phosphodiesterase activity may also serve as a marker for the atopic diathesis. We have found elevated enzyme activity in umbilical cord blood from newborns with atopic parents, suggesting that this defect may relate to a genetically determined defect. These studies have provided insight into basic abnormalities associated with atopic dermatitis and the atopic diathesis. Defects of regulatory mechanisms in immune and inflammatory cells may help explain the seemingly disparate disorders of physiologic, pharmacologic, and immunologic systems in atopy.

Phosphodiesterase inhibition by Ro 20-1724 reduces hyper-IgE synthesis by atopic dermatitis cells in vitro

Peripheral blood mononuclear leukocytes (MNL) from patients with atopic dermatitis spontaneously produce large amounts of IgE in vitro. These cells also show markedly elevated levels of cAMP phosphodiesterase (PDE) which may be responsible for the observed abnormal cAMP responsiveness. Treatment of atopic dermatitis MNL with varying concentrations of the cAMP PDE inhibitor Ro 20-1724 resulted in progressively decreasing amounts of IgE synthesis, statistically significant at the 10(-4) M and 10(-5) M concentrations. There was a close correlation between PDE inhibition and inhibition of IgE synthesis, r = 0.93, p less than 0.05. To define the cellular target of the drug, we used monoclonal antibodies directed toward MNL subsets (Lyt 3, OKT8, OKT4, monocyte-myeloid) in a modified "panning" method to perform experiments with purified subsets. With untreated subsets, removal of OKT4-positive cells significantly reduced IgE synthesis; readdition of OKT4-positive cells enhanced IgE synthesis. OKT8 cells and monocytes did not affect IgE synthesis. Pretreatment of T cell-depleted MNL with Ro 20-1724 resulted in significantly more inhibition of IgE synthesis than did pretreatment of T enriched cells prior to recombination with the reciprocal untreated subset and subsequent culture. Similarly, pretreatment of monocyte-depleted cells resulted in significantly more inhibition of IgE synthesis than pretreatment of monocyte-enriched cells prior to recombination and culture. The majority of the effect appeared to be mediated by a direct effect on the B cells. However, some inhibition of IgE synthesis was also achieved through pretreatment of T enriched cells. Since pretreatment of isolated suppressor/cytotoxic or helper/inducer T-cell subsets did not give the same degree of inhibition as with unfractionated T cells, a T-T interaction may be involved in this aspect. The imidazolidinone derivative, Ro 20-1724, significantly and consistently inhibited both the elevated cAMP phosphodiesterase activity and the elevated spontaneous IgE synthesis of MNL from patients with atopic dermatitis. These findings demonstrate a previously undescribed link between cAMP PDE levels and in vitro IgE synthesis.

Enrichment of dog leukocyte subpopulations using density gradients

Density gradient methods have been used for the enrichment of leukocyte subpopulations from human blood. We have adapted a three step method utilizing centrifugation on Hypaque-Ficoll (HF), double density HF (ddHF) and Percoll density gradients to separate lymphocytes, monocytes and basophils from dog blood. After HF separation, both Basenji-Greyhound (BG) and mongrel dogs had similar percentages of lymphocytes and monocytes, but BG dogs had significantly greater (p greater than 0.025) numbers of granulocytes. When cells from HF gradients were spun directly on Percoll, the presence of granulocytes decreased the purification of leukocyte subpopulations. An intervening separation on a ddHF gradient removed granulocytes without a selective loss of lymphocytes or monocytes. When cells from ddHF gradients were further separated on Percoll, 2 distinct cell layers resulted. Layer 1 was monocyte rich with 72.4 +/- 6.5% monocytes, 26.6 +/- 6.2% lymphocytes, and 0.8 +/- 1.8% granulocytes. Layer 2 was lymphocyte rich with 74.3 +/- 11.1% lymphocytes, 21.4 +/- 7.8% monocytes and 3.9 +/- 4.2% granulocytes. Viability as determined by Trypan blue exclusion was above 90%. Using cAMP-Phosphodiesterase (PDE) as a marker, higher PDE activity was present in the monocyte rich layer. This was similar to that reported in humans. Basophil numbers were enhanced by the use of a 1-step separation on a ddHF gradient. The percentage of basophils was increased 10-fold over baseline levels, with a viability of 90%. These techniques can be used to purify various canine leukocyte subpopulations and provide cells for biochemical analysis.

Comparison of histamine release in human skin mast cells induced by morphine, fentanyl, and oxymorphone

Human leukocyte and skin mast cell preparations were incubated with morphine sulfate in concentrations ranging from 1.5 X 10(-5) M to 4.5 X 10(-3) M. Skin mast cells also were incubated with oxymorphone and fentanyl in the same concentrations. Human leukocytes did not release histamine in response to any concentration of morphine. In skin mast cells, histamine release by morphine first was detected at 1.5 X 10(-4) M. Histamine release further increased at 5.0 X 10(-4) M with no incremental increase at higher concentrations. Oxymorphone and fentanyl failed to release histamine at any concentration. Histamine release by morphine required calcium but was not influenced by changes in the 1-4 mM range. Skin mast cell preparations were pretreated for 30 min in naloxone 5 X 10(-4) M and then morphine 5 X 10(-4) M was added for 30 min without removing naloxone. Naloxone neither released histamine nor inhibited morphine-induced histamine release. The release of histamine by morphine but not equimolar concentrations of fentanyl and oxymorphone indicates that histamine release by narcotics is not a nonspecific effect of high drug concentration. The failure of naloxone to inhibit morphine-induced histamine release suggests that histamine release by morphine is not dependent on opiate receptor binding or activation. These results indicate that this human mast cell preparation will be useful in further understanding the mechanism of histamine release induced by morphine and other agents.

Increased leukocyte sensitivity to phosphodiesterase inhibitors in atopic dermatitis: tachyphylaxis after theophylline therapy

Previous studies have demonstrated elevated cyclic 3',5'-adenosine monophosphate specific phosphodiesterase (PDE) activity in mononuclear leukocytes (MNL) from patients with atopic dermatitis (AD) and with allergic respiratory disease. We have studied the effect of PDE inhibitors on MNL from normal subjects and from patients with AD. We measured PDE activity in MNL after in vitro exposure to Ro20-1724, theophylline, and isobutylmethylxanthine. The effect of PDE inhibitors was also measured in MNL of patients during and after oral theophylline therapy. There was a dose-response effect of Ro20-1724 on PDE activity of AD cells. This activity was significantly more inhibited than that in MNL of normal subjects or in MNL of theophylline-treated patients with AD. The inhibition pattern of PDE in MNL of treated patients with AD did not vary significantly from the pattern observed in MNL from normal patients. Two weeks after oral theophylline was stopped, the PDE activity in MNL was once again susceptible to in vitro inhibition. The relative resistance of MNL to PDE activity in normal subjects to in vitro PDE inhibitors may be due to the existence of different PDE enzyme forms or the presence of endogenous inhibitors. The clinical importance of the tachyphylaxis observed is uncertain, but our results suggest that intermittent dosing with PDE inhibitors may provide a therapeutic advantage in treatment of AD and other atopic diseases.

Elevated umbilical cord blood leukocyte cyclic adenosine monophosphate-phosphodiesterase activity in children with atopic parents

We found cyclic adenosine monophosphate-phosphodiesterase (cAMP-PDE) activity to be significantly elevated in the umbilical cord blood mononuclear leukocytes of forty-two children with one atopic parent (3.2 +/- 0.3) and in eighteen children with two atopic parents (4.2 +/- 0.7) as compared to twenty-two children with two nonatopic parents (1.9 +/- 0.2) (p less than 0.005). Among those newborns with one atopic parent, mean PDE activities were significantly elevated in cord blood cells regardless of whether only the father was atopic, thus eliminating the possibility of transplacental enzyme passage. Follow-up evaluations of twenty-four children, age 6 months or older, suggest that infants with elevated PDE activity at birth have an increased likelihood of developing dermatitis and/or "atopic features." Further long-term studies will determine the predictive value of newborn mononuclear leukocyte PDE activity.

Inhalational anesthesia and histamine release during bronchospasm

The influence of inhalational anesthetics on histamine released during bronchospasm induced by Ascaris antigen aerosol was studied in Basenji-Greyhound (BG) dogs. Five BG dogs were anesthetized with thiopental and halothane on separate occasions and challenged with Ascaris antigen aerosol for five minutes. Pulmonary resistance (RL), dynamic compliance (Cdyn), and arterial plasma histamine levels were measured over 30 min following antigen exposure. Prior to antigen challenge, RL, Cdyn, and histamine levels were similar in thiopental- and halothane-anesthetized dogs. The peak change in RL and Cdyn occurred 10 min after the start of antigen challenge. RL increased 3.0 +/- 0.4-fold (mean +/- SEM) in thiopental-anesthetized dogs as compared with 1.6 +/- 0.2-fold in halothane-anesthetized dogs (P less than 0.05). Cdyn decreased to a similar extent in both groups, with maximal decreases of 0.53 +/- 0.08 and 0.53 +/- 0.09 times the prechallenge value for thiopental- and halothane-anesthetized dogs, respectively. Plasma histamine levels peaked at 5 min. Plasma histamine increased to 8.0 +/- 5.0 ng/ml in thiopental-anesthetized dogs compared with 10.7 +/- 4.7 ng/ml in halothane-anesthetized dogs. Histamine levels were not significantly different during or after antigen challenge between thiopental- and halothane-anesthetized dogs. Halothane, but not thiopental, significantly attenuated the increase in RL provoked by antigen challenge. However, arterial plasma histamine levels were similar during both anesthetics. Therefore, the authors conclude that the protective effect of halothane on airways was not due to an inhibition of release of histamine from mast cells.

Basic and clinical aspects of atopic dermatitis

The history of atopic dermatitis is replete with many disparate theories. The most enduring is the allergic causation theory but definitive, convincing evidence remains elusive. Elevated IgE synthesis is well established and reflects abnormal immune regulation. The basic mechanism for the regulatory defect remains conjectural. Cellular immune functions, including delayed cutaneous hypersensitivity, in vitro lymphocyte transformation and chemotaxis are reduced in atopic dermatitis. However, these abnormalities fluctuate with the clinical condition and may be secondary phenomena. A number of physiologic and pharmacologic abnormalities in atopic dermatitis are not clearly understood. Recent studies of patients leukocytes have shown that the diminished cyclic AMP responses are a consequence of increased catabolism by elevated cyclic AMP-specific phosphodiesterase. This high enzyme activity correlates well with elevated IgE synthesis and histamine release by cultured leukocytes. Both of these functions can be reduced by phosphodiesterase inhibitors in vitro. These new investigations provide fresh insight into the pathogenesis of atopic dermatitis and offer possible new therapeutic approaches. Basic studies of biochemical abnormalities may help define the defective molecular site that accounts for the many immune and physiologic abnormalities that have been described in atopic dermatitis and the other atopic conditions.

"Recurrent herpes zoster": an unproved entity?

Physicians sometimes misdiagnose recurrent zosteriform herpes simplex virus (HSV) skin infections as "zoster" or "recurrent zoster." Misdiagnosis can lead to inappropriate therapy with potentially harmful consequences, particularly in patients with ophthalmitis or immunosuppression, in which early institution of the correct antiviral therapy may be crucial. We report three patients who were originally misdiagnosed to have recurrent herpes zoster skin infections before we cultured HSV from their vesicles. We suggest: (1) that most recurrent zosteriform eruptions are caused by HSV; (2) that "recurrent zoster" has yet to be documented; and (3) that the diagnosis of "recurrent zoster" be reserved for those patients who have laboratory confirmation of recurrent varicella zoster (VZ). Viral culture or examination of vesicle contents by indirect immunofluorescent technic can provide definitive diagnosis of the etiology of a zosteriform eruption.

Direct depletion and purification of monoclonal antibody defined cells from unfractionated human mononuclear leukocytes using antibody coated polystyrene Petri dishes

Human peripheral blood mononuclear leukocytes were depleted or enriched in various monoclonal antibody-defined subsets using a simplification of the indirect " panning " technique. Unfractionated mononuclear leukocytes (MNL) were sensitized with appropriate dilutions of monoclonal antibodies to human Lyt3 , OKT4 and OKT8 antigens, and to a monocyte-myeloid line antigen. The sensitized cells were then placed on polystyrene Petri dishes coated with goat antimouse IgG to obtain a population of cells depleted and a population of cells enriched in each cell type. Direct separation of surface immunoglobulin-bearing cells was similarly achieved by coating the Petri dish with goat antihuman immunoglobulins. Results showed that MNL could be depleted to greater than 95% purity with these methods and that positively selected adherent cells could be enriched to at least 85% purity. The relative proportions of MNL subpopulations in various sorted cell populations is reported. Cells obtained by panning are functionally intact. As compared to complement lysis both marker positive and marker negative cells can be obtained and the technique requires less technical expertise than using fluorescence activated cell sorting. The modification reported here is simpler and less time consuming for human T cell subpopulation separations than previously reported panning methods since an initial sheep erythrocyte rosetting step was not used.