Comparative effects of azathioprine, cyclophosphamide and frentizole on humoral immunity in mice

Data is presented comparing the activities of three immunosuppressive agents, cyclosphosphamide, frentizole and azathioprine in models of humoral immunity in mice. Cyclophosphamide and frentizole suppressed the primary and secondary plaque forming cell responses to sheep erythrocytes at lower doses than did azathioprine. Prolonged suppression of serum antibody titers occurred following short-term therapy with cyclophosphamide or frentizole, but not azathioprine. Azathioprine was also the least effective agent in suppressing a primary response to the T-independent antigen, trinitrophenylated lipopolysaccharide. All three agents were found to inhibit the induction and activity of suppressor cells at immunosuppressive doses.

IgE production in five inbred rat strains following immunization with alum-precipitated egg albumin

Five inbred rat strains were assessed for their ability to mount IgE responses to alum-precipitated egg albumin (alum EA). Fischer (FI) and Lewis (LE) rats which possess the B1 at the major histocompatibility (Ag-G) locus exhibited weak IgE responses to this antigen. High titer IgE responses were obtained in rats possessing the B3 allele at the Ag-B locus. In some instances the anti-EA IgE response was enhanced following an infection with Nippostrongylus brasiliensis. An effort was also made in these studies to determine whether or not there is some correlation between high IgE production and a depressed capacity for cellular immunity. The basis of these experiments was twofold: (a) recent reports have shown elevated serum levels of IgE in some clinical diseases where cellular immunity is depressed, and (b) in the studies reported here, high titers of IgE were obtained in one rat strain known to be somewhat deficient in its capacity for cellular immunity, whereas very low titers were produced by a strain which is much stronger in this respect. From the results obtained, there appears to be no correlation between IgE production and an inherently weaker capacity for cellular immunity.

Reciprocal changes in serum concentrations of 3,3',5-triiodothyronine (T3) in systemic illnesses

Serum concentrations of 3,3',5'-triiodothyronine (reverse T3, rT3) were measured in adult patients with several systemic illnesses whose serum total and/or free T3 were low, serum total T4 was low or normal, and free T4 was either normal or elevated. The mean serum rT3 was 76, 46, and 77 ng per 100 ml in patients with hepatic cirrhosis, chronic renal failure, and acute febrile illnesses, respectively; the values in patients with hepatic cirrhosis and acute febrile illness were significantly higher than, and values in patients with renal failure did not differ significantly from, the mean serum rT3 (41 ng per 100 ml) in normal subjects. The mean serum rT3 in another group of patients from Calcutta, India, who had severe protein calorie malnutrition (PCM), was 53 ng per 100 ml; it was significantly higher than the corresponding value, 22 ng per 100 ml, in the same patients after feeding treatment. Mean serum rT3 in patients with systemic illnesses was not so high as that (151 ng per 100 ml) in the normal newborn, who also has low serum T3 and normal or high T4. High serum rT3 in patients with systemic illness could not be attributed to increased serum protein binding of rT3; whenever studied, the dialyzable fraction of rT3 was not decreased but actually increased. The mean serum-free rT3 was 450,207, and 366 pg per 100 per 100 ml in patients with hepatic cirrhosis, chronic renal failure, and acute febrile illnesses, respectively; each of these values was significantly higher than the corresponding value, 98 pg per 100 ml, in normal subjects. The mean serum free rT3, 516 pg per 100 ml, in newborn cord sera was similar to that in patients with hepatic cirrhosis but was higher than that observed in patients with chronic renal failure and acute febrile illnesses. High serum rT3 and low serum T3 in patients with PCM improved to normal or towards normal after feeding treatment. Since the peripheral metabolism of T4 is normally the predominant source of T3 as well as rT3 in man, our data, demonstrating reciprocal changes in serum rT3 and T3 and no consistent change in serum T4, suggest that body metabolism of T4 may be so altered in systemic illness that the conversion of T4 to rT3 may be increased while that to T3 is decreased. The mechanism or the biological significance of such a diversion of T4, from the normally occurring conversion to highly potent T3, to the generation of poorly calorigenic rT3 in systemic illness, is not clear at this time. The data in patients with PCM demonstrate, however, that such a change in the metabolism of T4 can be reversible.

Association of amyloidosis with erythema nodosum leprosum reactions and recurrent neutrophil leucocytosis in leprosy

Rectal biopsy in 190 inpatients at a leprosy hospital in the Highlands of Papua New Guinea disclosed 16 patients with secondary amyloidosis. This represented 20% of the patients who had had polar lepromatous leprosy (L.L.) for more than 2 years. Patients with amyloidosis characteristically had either a history of recurrent attacks of erythema nodosum leprosum (E.NH) reactions or chronic trophic ulcers. Levels of the serum component (protein SAA) antigenically related to the amyloid fibril protein AA were monitored, at varying intervals for three months, in lepromatous patients with E.N.L. reaction. The SAA levels rose during E.N.L. reactions in parallel with the neutrophil count. SAA occurred with greatest frequency among patients with LH, while most non-lepromatous patients with detectable SAA had chronic trophic ulcers. The correlation between raised neutrophil count and elevated SAA concentration, observed in this and other studies, suggests that neutrophils are associated with the production of SAA.

Insulin secretion and glucose tolerance in adults with protein-calorie malnutrition

Glucose tolerance, insulin secretion, and responses to arginine infusion were studied in 17 adults with severe protein-calorie malnutrition (PCM) in Calcutta, India. Patients were selected for the severity of their malnutrition and for absence of other diseases. After 2-4 mo of refeeding there was complete clinical recovery, and control studies were performed. Glucose tolerance, as assessed by intravenous glucose-tolerance test (IVGTT), was reduced in PCM. Insulin response, both to glucose and to arginine infusion, was clearly reduced. The K value of the IVGTT correlated well with the ratio of mean to basal serum insulin during the first 40 min of the test. Basal serum insulin was nearly unchanged in PCM as compared with after recovery, although one patient studied serially showed a temporary drop in basal insulin during the first week of refeeding. In PCM, plasma amino acid levels failed to fall in response to arginine-induced insulin secretion as they did in the control studies. It appears that insulin secretory response is severely reduced in PCM and that a degree of insulin resistance in relation to body weight is present. These changes result in diminished glucose tolerance and probably in a reduced rate of tissue utilization of amino acids. Such alterations may be of adaptive significance in chronic PCM.

The pituitary-gonadal axis in men with protein-calorie malnutrition

The pituitary-gonadal axis was studied in 28 men with severe protein-calorie malnutrition in a Calcutta hospital. The men were selected for the severity of their malnutrition and for absence of other diseases. They had clinical findings of hypogonadism and low total and unbound plasma testosterone. During 2-5 months of refeeding there was clinical recovery and increase of plasma testosterone to normal. Plasma LH was high in malnutrition, decreased during refeeding, and remained above normal after refeeding. Some patients failed to show LH elevation in malnutrition despite low plasma tesosterone. Plasma FSH was high in malnutrition, decreased during refeeding, and was near the level of normal Indian men after refeeding. HCG 4000 IU im per day for 3 days produced subnormal increments in plasma testosterone both in malnutrition and after refeeding; corresponding decreases in FSH occurred. It is concluded that the hypogonadism of protein-calorie malnutrition is primarily on the basis of diminished Leydig cell function. Appropriate pituitary LH response is intact in some patients, but is either absent or inadequate in others. Subclinical Leydig cell insufficiency, indicated by LH elevation and subnormal response to HCG, persists after refeeding has produced recovery from malnutrition and clinical hypogonadism. FSH elevation in malnutrition may be secondary to the reduced Leydig cell function.

Circulating thyroid hormones and thyrotropin in adult patients with protein-calorie malnutrition

We studied plasma concentrations of thyroxine (T4), triiodothyronine (T3), free T4, free T3, thyrotropin (TSH), albumin and thyroxine-binding globulin (TBG) before and following 56 to 145 days (mean, 85) of refeeding in ten Indian patients who had severe protein-calorie malnutrition (PCM). The mean baseline plasma T4 concentration of 8.2 mug per 100 ml in these patients was comparable to the corresponding post-treatment value of 7.7 mug per 100 ml. However, since the dialyzable fraction of T4 (DFT4) was considerably higher (0.048 vs 0.029%), the mean baseline plasma free T4 concentration, 3.8 ng per 100 ml, was significantly greater than the mean post-treatment value of 2.2 ng per 100 ml. The mean baseline plasma concentration of T3, 21 ng per 100 ml, was markedly lower than the corresponding value of 96 ng per 100 ml after treatment. The mean plasma concentration of free T3, 94 pg per 100 ml, was also significantly lower than the post-treatment value of 303 pg per 100 ml. This was the case even when the mean DFT3 prior to treatment was significantly higher than that following treatment (0.46 vs 0.32%). The mean baseline ratio of plasma concentrations of total T3 and T4 (T3/T4 X 100) of 0.25 was significantly lower than the corresponding normal value of 1.3 after treatment. The mean plasma TSH concentration of 6.0 muU per ml in patients prior to treatment was comparable to the mean value of 5.5 muU per ml following treatment. The mean baseline plasma concentration of TBG of 3.3 mg per 100 ml was also comparable to the mean post-treatment value of 3.6 mg per 100 ml. The data on thyroid hormone levels in PCM can be explained if there were i) a selective increase in metabolic clearance rate of T3 without a change or a decrease in that of T4 and ii) a reversible defect in extrathyroidal conversion of T4 to T3. The latter possibility appears more likely.

Further studies with the potentiated reagin response to egg albumin

High titers of reagins were obtained in rats by initial immunization with egg albumin and <i>B. pertussis </i>and subsequent infection with larvae of <i>N. brasiliensis. </i>These antibodies have physicochemical properties and biological activities identical to those of rat immunoglobulin E (IgE). IgE type antibodies against <i>N. brasiliensis </i>are also produced in these same animals but not until the titers of IgE against egg albumin have decreased.