The effect of hydrocortisone on immunoglobulin metabolism

Corticosteroid-induced low immunoglobulin levels in multiple sclerosis - A confounding factor

BACKGROUND

Changes in immunoglobulin (Ig) levels may occur in association with various drugs targeting immunity, including those used to treat multiple sclerosis (MS). However, influence of high-dose corticosteroids (CS) is poorly described.

OBJECTIVE

To describe influence of disease-modifying drugs (DMD) and CS on the Ig levels.

METHODS

Monocentric retrospective study examining changes in Ig levels in relation with CS intake in a series of 304 consecutive MS patients (and 1204 samples) followed or hospitalized for 7 years in a single centre. Ig levels are routinely collected in MS patients followed in our centre.

RESULTS

IgG levels were significantly lower in MS patients exposed to CS infusion during the last 24 months. IgG levels were also lower in DMD-treated patients exposed to CS. DMD-specific decrease of IgM levels was confirmed in interaction with CS.

CONCLUSION

Stratification by CS exposure suggested that a decrease in Ig levels occurring during DMD treatment was strongly associated with CS infusion. The strong and persistent effect of CS on Ig levels could be a hidden variable and should be considered in further studies targeting Ig levels.

Steroid-induced secondary immune deficiency

Despite their widespread clinical use, oral corticosteroids (OCSs) are well known to be associated with a myriad of adverse effects, including immunosuppression. By inhibiting transcription factors and affecting leukocyte function, prolonged OCS use leads to significant CD4 lymphopenia and often a decrease in serum immunoglobulin (Ig)G. Conversely, OCS use has minimal impact on circulating B cell, serum IgM, or serum IgA levels. Although there is a paucity of literature, individuals treated with prolonged OCS seem to typically maintain humoral response to various vaccinations despite hypogammaglobinemia, but this area warrants additional research, especially in the setting of the coronavirus disease 2019 pandemic. Individuals treated with prolonged OCS use are most at risk for opportunistic infections, especially those with underlying malignancy and history of bone marrow transplant. Risk mitigation strategies to decrease infectious complication with OCS use include limiting the dose and duration of therapy, appropriately completing a full vaccination series, consideration for passive immunization, and prophylaxis against opportunistic infections.

Tuftsin-phosphorylcholine (TPC) equally effective to methylprednisolone in ameliorating lupus nephritis in a mice model

The role of helminth treatment in autoimmune diseases is growing constantly. Systemic lupus erythematosus (SLE) is a multi-system autoimmune disease with challenging treatment options. Tuftsin-phosphorylcholine (TPC) is a novel helminth-based compound that modulates the host immune network. This study was conducted to evaluate the potential value of TPC in ameliorating lupus nephritis in a murine model and specifically to compare the efficacy of TPC to the existing first-line therapy for SLE: corticosteroids (methylprednisolone). Lupus-prone NZBxW/F₁ mice were treated with TPC (5 µg/mouse), methylprednisolone (MP; 5 mg/body weight) or phosphate-buffered saline (PBS) (control) three times per week once glomerulonephritis, defined as proteinuria of grade > 100 mg/dl, was established. Levels of anti-dsDNA autoantibodies were evaluated by enzyme-linked immunosorbent assay (ELISA), splenic cytokines were measured in vitro and the kidney microscopy was analysed following staining. TPC and MP treatments improved lupus nephritis significantly and prolonged survival in NZBxW/F₁ mice. TPC-treated mice showed a significantly decreased level of proteinuria (P < 0·001) and anti-dsDNA antibodies (P < 0·001) compared to PBS-treated mice. Moreover, TPC and MP inhibited the production of the proinflammatory cytokines interferon IFN-γ, interleukin IL-1β and IL-6 (P < 0·001) and enhanced expression of the anti-inflammatory cytokine IL-10 (P < 0·001). Finally, microscopy analysis of the kidneys demonstrated that TPC-treated mice maintained normal structure equally to MP-treated mice. These data indicate that the small molecule named TPC hinders lupus development in genetically lupus-prone mice equally to methylprednisolone in most of the cases. Hence, TCP may be employed as a therapeutic potential for lupus nephritis.

Secondary Antibody Deficiency in Glucocorticoid Therapy Clearly Differs from Primary Antibody Deficiency

PURPOSE

The aim of this study was to identify characteristics of hypogammaglobulinemia secondary to glucocorticoid therapy and their value in the differential diagnosis to primary forms of antibody deficiency.

METHODS

We investigated prevalence and character of hypogammaglobulinemia in a cohort of 36 patients with giant cell arteritis (GCA) and polymyalgia rheumatica (PMR) on glucocorticoid therapy in comparison to a gender- and age-matched cohort of hospital controls. We therefore determined serum immunoglobulin levels as well as B- and T cell-subsets in the peripheral blood of all participants. In addition, prior serum immunoglobulin levels and clinical data of the GCA and PMR patients were extracted from the electronic patient data-base.

RESULTS

21/36 GCA/PMR patients on glucocorticoid treatment developed antibody deficiency. In 19 patients this included IgG and in 13 patients IgG was the only affected isotype. The reduction of IgG was persistent in nearly 50 % of these patients during the observed period. GCA/PMR patients had reduced circulating naive and transitional B cells (p = 0.0043 and p = 0.0002 respectively) while IgM, IgG and IgA memory B cells were preserved. Amongst T-cell subsets, we found a reduction of CD4 memory T cells (p < 0.0001), CD4 regulatory T cells (p = 0.0002) and few CD8 memory T-cell subtypes.

CONCLUSION

Persistent humoral immunodeficiency occurs in about a quarter of GCA/PMR patients under glucocorticoid therapy. Because most patients have isolated IgG deficiency, preserved IgA production and class-switched memory B cells, by these markers this form of secondary hypogammaglobulinemia can be clearly distinguished from common variable immunodeficiency (CVID).

Development of orally active inhibitors of protein and cellular fucosylation

The key role played by fucose in glycoprotein and cellular function has prompted significant research toward identifying recombinant and biochemical strategies for blocking its incorporation into proteins and membrane structures. Technologies surrounding engineered cell lines have evolved for the inhibition of in vitro fucosylation, but they are not applicable for in vivo use and drug development. To address this, we screened a panel of fucose analogues and identified 2-fluorofucose and 5-alkynylfucose derivatives that depleted cells of GDP-fucose, the substrate used by fucosyltransferases to incorporate fucose into protein and cellular glycans. The inhibitors were used in vitro to generate fucose-deficient antibodies with enhanced antibody-dependent cellular cytotoxicity activities. When given orally to mice, 2-fluorofucose inhibited fucosylation of endogenously produced antibodies, tumor xenograft membranes, and neutrophil adhesion glycans. We show that oral 2-fluorofucose treatment afforded complete protection from tumor engraftment in a syngeneic tumor vaccine model, inhibited neutrophil extravasation, and delayed the outgrowth of tumor xenografts in immune-deficient mice. The results point to several potential therapeutic applications for molecules that selectively block the endogenous generation of fucosylated glycan structures.

Vaccination of adults with asthma and COPD

Vaccines play a major role in preventing potentially life-threatening diseases. More attention is now focused on the adult population, particularly as they age, as a reservoir for vaccine-preventable diseases. Adults with comorbid conditions such as asthma and chronic obstructive pulmonary disease (COPD) are considered to be at higher risk for invasive diseases, many of which are preventable through routine vaccination. This article reviews the pertinent literature for the use of vaccines in the management of adult patients with asthma and COPD.

Diagnostic strategy for patients with hypogammaglobulinemia in rheumatology

The discovery of hypogammaglobulinemia, which is defined as a plasmatic level of immunoglobulin (Ig) under 5 g/L is rare in clinical practice. However, the management of immunodepressed patients in rheumatology, sometimes due to the use of immunosuppressive treatments such as anti-CD20 in chronic inflammatory rheumatisms, increases the risk of being confronted to this situation. The discovery of hypogammaglobulinemia in clinical practice, sometimes by chance, must never be neglected and requires a rigorous diagnosis approach. First of all, in adults, secondary causes, in particular lymphoid hemopathies or drug-related causes (immunosuppressors, antiepileptics) must be eliminated. A renal (nephrotic syndrome) or digestive (protein-losing enteropathy) leakage of Ig is also possible. More rarely, it is due to an authentic primary immunodeficiency (PID) discovered in adulthood: common variable immunodeficiency (CVID) which is the most frequent form of PID, affects young adults between 20 and 30 years and can sometimes trigger joint symptoms similar to those in rheumatoid arthritis; or Good syndrome, which associates hypogammaglobulinemia, thymoma and recurrent infections around the age of 40 years. In most cases, after confirming hypogammaglobulinemia on a second test, biological examinations and thoracic-abdominal-pelvic CT scan will guide the diagnosis, after which the opinion of a specialist can be sought depending on the findings of the above examinations. At the end of this review, we provide a decision tree to guide the clinician confronted to an adult-onset hypogammaglobulinemia.

Radioimaging of light chain amyloid with a fibril-reactive monoclonal antibody

Currently, there are no available means in the United States to document objectively the location and extent of amyloid deposits in patients with systemic forms of amyloidosis. To address this limitation, we have developed a novel diagnostic strategy, namely, the use of a radiolabeled fibril-reactive murine monoclonal antibody (mAb) as an amyloid-specific imaging agent. The goal of this study was to determine the pharmacokinetics, biodistribution, and ability of this reagent to target the type of amyloid that is formed from immunoglobulin light chains, that is, AL.

METHODS

Subcutaneous tumors (amyloidomas) were induced in BALB/c mice by injection of human AL fibrils. The IgG1 mAb designated 11-1F4 and an isotype-matched control antibody were radioiodinated, and the pharmacokinetics and localization of these reagents were determined from blood and tissue samples. Amyloidoma-bearing animals that received (125)I- or (124)I-labeled antibodies were imaged by whole-body small-animal SPECT/CT or small-animal PET/CT technology, respectively.

RESULTS

Radioiodinated mAb 11-1F4 retained immunoreactivity, as evidenced by its subnanomolar affinity for light chains immobilized on 96-well microtiter plates and for beads conjugated with a light chain-related peptide. Additionally, after intravenous administration, the labeled reagents had the expected biologic half-life of murine IgG1, with monoexponential whole-body clearance kinetics. In the amyloidoma mouse model, (125)I-11-1F4 was predominately localized in the tumors, as demonstrated in biodistribution and autoradiographic analyses. The mean uptake of this reagent, that is, the percentage injected dose per gram of tissue, 72 h after injection was significantly higher for amyloid than for skeletal muscle, spleen, kidney, heart, liver, or other tissue samples. Notably, the accumulation within the amyloidomas of (125)I- or (124)I-11-1F4 was readily visible in the fused small-animal SPECT/CT or small-animal PET/CT images, respectively.

CONCLUSION

Our studies demonstrate the amyloid-imaging capability of a radiolabeled fibril-reactive mAb and provide the basis for a clinical trial designed to determine its diagnostic potential in patients with AL amyloidosis and other systemic amyloidoses.

Effects of long-term low-dose corticosteroid therapy on humoral immunity

BACKGROUND

Corticosteroids are agents that suppress the immune system. Their suppressive activity is predominantly restricted to cell-mediated immunity, with a marginal inhibitory effect on humoral immunity.

OBJECTIVE

To describe an acquired reversible B-cell deficiency in a patient treated with low-dose corticosteroids for 36 years.

METHODS

A broad range of T- and B-cell parameters were studied over time, during and after discontinuation of corticosteroid therapy. Published works on this topic in animal and human models are reviewed. The findings unique to this patient are highlighted.

RESULTS

While undergoing long-term corticosteroid therapy, a patient developed a clinical and immunologic picture suggestive of common variable immunodeficiency, with predominantly qualitative and quantitative B-cell abnormalities. These abnormalities resolved within 2 years after tapering of corticosteroid therapy.

CONCLUSIONS

Long-term low-dose corticosteroid use may reversibly decrease B-cell counts and specific antibody responses.

Salivary and serum immunoglobulin levels in cats with chronic gingivostomatitis

The salivary and serum concentrations of immunoglobulins G, M and A (IgG, IgM and IgA), and the salivary concentrations of albumin were measured by ELISA in 30 cats with chronic gingivostomatitis and 32 healthy cats. The cats with chronic gingivostomatitis had significantly higher salivary concentrations of IgG, IgM and albumin, and higher serum concentrations of IgG, IgM and IgA, but significantly lower salivary concentrations of IgA than the healthy cats. The cats with chronic gingivostomatitis were treated with either methylprednisolone, sodium aurothiomalate, metronidazole and spiramycin, or oral hygiene products. After three months of treatment, the cats receiving methylprednisolone had a significant reduction in serum IgG levels compared to the cats treated with sodium aurothiomalate or metronidazole and spiramycin, but after six months of treatment there were no significant differences between the groups. Before the treatments, the levels of oral inflammation were not correlated significantly with any of the serum or salivary immunoglobulin levels. However, the changes in oral inflammation were correlated significantly with the changes in the salivary IgM concentration after three and six months of treatment, and with the change in the salivary IgA concentration after six months of treatment.

Multiple roles for the major histocompatibility complex class I- related receptor FcRn

Multiple functions have recently been identified for the neonatal Fc receptor FcRn. In addition, a human homolog of the rodent forms of FcRn has been identified and characterized. This major histocompatibility complex class I-related receptor plays a role in the passive delivery of immunoglobulin (Ig)Gs from mother to young and the regulation of serum IgG levels. In addition, FcRn expression in tissues such as liver, mammary gland, and adult intestine suggests that it may modulate IgG transport at these sites. These diverse functions are apparently brought about by the ability of FcRn to bind IgGs and transport them within and across cells. However, the molecular details as to how FcRn traffics within cells have yet to be fully understood, although in vitro systems have been developed for this purpose. The molecular nature of the FcRn-IgG interaction has been studied extensively and encompasses residues located at the CH2-CH3 domain interface of the Fc region of IgG. These Fc amino acids are highly conserved in rodents and man and interact with residues primarily located on the alpha2 domain of FcRn. Thus, it is now possible to engineer IgGs with altered affinities for FcRn, and this has relevance to the modulation of IgG serum half-life and maternofetal IgG transport for therapeutic applications.

Humoral immunity in steroid-dependent children with asthma and hypogammaglobulinemia

OBJECTIVE

To determine primary and secondary antibody responses in children with hypogammaglobulinemia attributed to corticosteroid use.

RESULTS

In seven patients with steroid-dependent asthma and significant hypogammaglobulinemia (IgG concentration, 275 to 443 mg/dl), antibody responses to protein and polysaccharide antigens were shown to be normal, as were primary and secondary responses to a neoantigen, bacteriophage phi X174.

CONCLUSIONS

Patients with asthma, and with hypogammaglobulinemia resulting from steroid therapy, have normal humoral immunity, and immunoglobulin replacement therapy is not indicated.

Familial hypercatabolic hypoproteinemia. A disorder of endogenous catabolism of albumin and immunoglobulin

The metabolism of albumin and IgG was investigated in two siblings, products of a first-cousin marriage, a female aged 34 yr and a male aged 17, who had a marked reduction in their respective serum concentrations of IgG (1.3 and 3.1 mg/ml) and albumin (19 and 21 mg/ml). The metabolism of radioiodinated IgG and albumin was studied in the two patients. The total circulating and body pools of IgG were less than 28% of normal. The IgG synthetic rates were within the normal range. However, the IgG survival was short, with their respective fractional catabolic rates increased fivefold to 31% and 36% of the intravenous pool per day (normal, 6.7 +/- 2%/d). Furthermore, the patients had reduced total body pools, normal synthetic rates, and increased fractional catabolic rates for albumin. There was no proteinuria or abnormality of renal or liver function. In addition, the patients did not have circulating antibodies directed toward IgG, IgA, or albumin. Furthermore, both patients had normal fecal 51Cr-labeled albumin tests, thus excluding excessive gastrointestinal protein loss. We propose that these siblings have a previously unrecognized familial disorder characterized by reduced serum concentrations of IgG and albumin caused by a defect in endogenous catabolism, leading to a short survival of these proteins that is associated in this family with chemical diabetes and a skeletal deformity.

Changes in nonspecific immunity factor in some Equidae, Camelidae and Capridae species

Plasma lysozyme activity changed during the 2 years of the investigation period. In some species (e.g. ponies and goats) there are only seasonal fluctuations with the highest levels during summer and autumn in ponies and during winter in goats. In two Camelidae species, guanacos and llamas, only, downward trends were found, whereas in donkeys, both types of changes: seasonal variations with the maximal level during autumn and an upward long-term trend were found.

Twenty-four hour changes in lysozyme levels, total plasma protein concentration, gamma-globulin concentration, white blood cell count and numbers of lymphocytes and granulocytes in the peripheral blood of chinchillas Chinchilla laniger M. and rabbits Oryctolagus cuniculus L

Twenty-four hour changes in lysozyme level, total plasma protein concentration, gamma-globulin concentration, leucocyte number and different forms of leucocyte in the peripheral blood of male chinchillas and rabbits were investigated. All investigated parameters in both species showed statistically significant 24-hr changes, but only total plasma protein concentration in rabbits and gamma-globulin concentration and leucocyte number in chinchillas have a circadian rhythm character. The cosine curve characteristics for these rhythms are as follows; acrophases 0.45 + 2.18 hr, 10.02 + 4.29 hr, 2.14 + 3.20 hr; amplitudes 0.48 + 0.32 g%, 0.34 + 0.41 g%, 1.12 + 0.88 X 10(3)/min3; mesors 6.10 + 0.22 g%, 2.23 + 0.21 g%, 8.78 + 0.65 X 10(3)/mm3, respectively.

Corticosteroids for rheumatic disease. 1. Physiology, pharmacology, and therapeutic strategies

Of the corticosteroid preparations available, the intermediate-acting agents are the preparations most commonly used in the rheumatic diseases. Careful tailoring of dosage is important to avoid adrenal atrophy and signs of adrenocortical hypofunction. The best regimen in a given patient depends on the amount of antiinflammatory and immunosuppressive activity required. The therapeutic strategies in use include pulse therapy, daily high-dose therapy, daily low-dose therapy, and alternate-day dosing. The latter two methods are preferable because of the decreased likelihood of adverse reactions, yet are not sufficient in cases of fulminant systemic inflammatory processes.

Polyvalent immunoglobulins for prophylaxis of bacterial infections in patients following multiple trauma. A randomized, placebo-controlled study

One hundred and fifty severely injured patients requiring long-term artificial ventilation were evaluated in a prospective, randomized, double blind study comparing the prophylactic effect of an intravenous immunoglobulin (Sandoglobulin; IGIV) against nosocomial infections with a placebo preparation. The groups were comparable in age, sex, injury pattern, and severity of the trauma. Seventy-six patients received 12 g of Sandoglobulin as a 3% solution on day 0, day 5 and day 12, i.e. a total of 36 g. Sandoglobulin significantly reduced the incidence of pneumonia (28 cases in the IGIV group, 43 cases in the placebo group, p = 0.0111). This resulted in a reduced therapeutic use of antibiotics. For the occurrence of sepsis (IGIV: 14 cases; placebo 19 cases) and other infections (IGIV: 11 cases; placebo: 10 cases) no significant differences were found. No side effects of the administration of IGIV were observed. IGIV prophylaxis neither reduced the overall death rate nor those deaths caused by infection. On day 5 after administration of the first 12 g of IGIV, the IgG serum concentrations were significantly higher in the Sandoglobulin group (8.41 +/- 1.96 mg/ml and 7.42 +/- 2.25 mg/ml respectively, p less than 0.001) whereas later serum samples showed no significant differences.

The effect of corticosteroids upon the number and organ distribution of "background" immunoglobulin-secreting cells in mice

The influence of the synthetic corticosteroid dexamethasone sodium phosphate (DEXA) upon the immunoglobulin (Ig)-secreting cells was studied in not intentionally immunized BALB/c mice. This was done for IgM-, IgG-, and IgA-secreting cells in spleen, mesenteric lymph nodes (MLN), and bone marrow (BM). A single injection of DEXA (16 to 144 mg/kg body wt) markedly reduced the number of Ig-secreting cells in spleen and MLN within 1 day, but hardly affected their number in the BM. The decrease was immediately followed by a recovery and, at the highest doses and especially in MLN, by an overshoot. Two weeks after the initial decrease a second decrease was found. When mice were subjected to daily treatment with DEXA during 1 week, initially a recovery pattern was found in spleen and MLN similar to that found after a single injection of a high dose. In this case, however, the effects were less dose dependent, and the overshoot reaction was followed by a period of subnormal numbers of Ig-secreting cells which lasted at least 1 week. This late effect of DEXA not only occurred in spleen and MLN, but also in the BM. The most prominent effect of daily treatment with DEXA was the long-lasting decrease of the number of IgG-secreting cells starting 1 week after withdrawal of treatment. This decrease was associated with a severely decreased serum IgG level.

Metabolism of IgG in type II mixed essential cryoglobulinaemia--autologous cryoprecipitated and normal homologous IgG are incorporated into complexes and metabolized in vivo at similar rates

The metabolism of autologous cryoprecipitated and normal homologous IgG was studied in four patients with type II mixed essential cryoglobulinaemia. 131I-autologous IgG purified from each patient's cryoglobulin (Cryo-IgG), and 125I-pooled normal homologous IgG (N-IgG) were studied simultaneously to compare the extent of their incorporation into complexes with IgM in vitro and in vivo, and their turnover in vivo. A proportion of each preparation of IgG was incorporated into macromolecular complexes in vitro and in vivo in all patients, the Cryo-IgG only slightly more so than N-IgG. Results of the turnover studies were heterogeneous, but the common finding was the absence of any significant difference in the metabolism of Cryo-IgG and N-IgG. In two patients the fractional catabolic rates (FCR) of Cryo-IgG and N-IgG were increased and in one they were normal. The fourth patient was also hypogammaglobulinaemic (IgG 0.52 mg/ml) and it was shown that in vivo virtually all his IgG was combined with IgM; despite this the FCR of both types of IgG was reduced. These results suggest (1) that the IgG component of the cryoglobulins in these patients is unlikely to differ significantly from normal IgG and (2) that, contrary to expectation, complexed IgG is not necessarily rapidly eliminated from the circulation.

Effects of dexamethasone therapy on serum immunoglobulin levels and peripheral cell counts in women undergoing conservative benign gynecologic surgery

Twenty women undergoing conservative gynecologic surgery were treated perioperatively with high-dose dexamethasone (DEX) for 72 hours. Serum immunoglobulin levels (IgG, IgM, IgA) and peripheral cell counts, including lymphocyte subpopulations, were measured in each patient during the immediate preoperative and postoperative periods as well as 5 to 8 weeks later. These results were compared with the levels of a control population of 16 women undergoing conservative, non-pregnancy-related gynecologic surgery for benign conditions. There was a decrease in the level of all serum immunoglobulins measured in the immediate postoperative period in both groups, with a greater statistical decrease in the control group (P less than 0.001). statistically significant transient alterations in the peripheral cell counts occurred in the DEX group, as compared with the control group (P less than 0.001). The use of DEX was not associated with any postoperative infectious morbidity.

Corticosteroid treatment increases parasite numbers in murine giardiasis

Corticosteroid therapy is known to be hazardous in patients with occult infection but the mechanism by which the host parasite relationship is altered by steroids is not known. We have used an intestinal protozoal parasite, Giardia muris, to examine the effects of corticosteroids on the number of parasites in the intestine in the course of a primary infection. A single injection of cortisone acetate, subcutaneously, one day before oral inoculation of CBA mice with 1000 cysts of Giardia muris, resulted in significantly higher trophozoite counts in animals studied at one, two, three, four, and eight weeks post-infection, when they were compared with saline injected controls. Recrudescence of occult infection was also achieved by cortisone acetate treatment of mice which had been infected with Giardia muris eight months previously. Clinical studies are required to establish if recrudescence of occult protozoal infection is an important cause of morbidity when immunosuppressive therapy is given to patients in areas where giardiasis is endemic.

[The variation of 16 serum protein fractions following renal transplantation (author's transl)]

We have investigated 16 serum proteins in 20 patients with stable renal function after renal transplantation. Our investigations have shown the following substantial findings: a regular increase of prealbumin, alpha1-glycoprotein, haptoglobin, hemopexin and beta2-glycoprotein, as well as a rather frequent increase of alpha 2-macroglobulin. As far as variations of the serum protein levels are concerned there was no correlation with kidney disease, accompanying illnesses, therapy or interval since transplantation.

Influence of methylprednisolone on complement activity in germfree rats and on antibody activity to Escherichia coli in monocontaminated rats

By means of radio-isotope technique, the influence of methylprednisolone treatment on opsonic and bactericidal serum activities against E. coli was studied on germfree and monocontaminated rats. Based on the present results it seems unlikely that methylprednisolone impairs the production of complement components. A slight suppression of antibody activity was only found in markedly wasted monocontaminated rats treated with very high doses of methylprednisolone from the day before contamination.

Effects of corticosteroids on immunity in man. I. Decreased serum IgG concentration caused by 3 or 5 days of high doses of methylprednisolone

To study the effects of methylprednisolone on immune mechanisms in the absence of other immunosuppressive agents or immunologically mediated diseases, we gave 17 normal adult male volunteers 96 mg of methylprednisolone daily for 3-5 days and compared results with 12 untreated controls who were studied simultaneously, 86% of treated volunteers had significant decreases in the concentrations of serum IgG. 2-4 wk after methylprednisolone, the treated volunteers had a mean decrease in IgG of 22% compared with a decrease of only 1% in untreated controls. Likewise, significant decreases in IgA concentration occurred in 43% of treated volunteers, whereas significant decreases in IgM occurred in only 14%. The lowest immunoglobulin levels occurred during the 2nd wk after a 3 day course of methylprednisolone and during the 3rd wk after a 5 day course of drug. Slightly decreased plasma concentration of [(125)I]IgG was seen in six of seven volunteers who received a 5 day course but in only one of four who received a 3 day course of drug. However, an increase in the rate of plasma clearance of IgG occurred only during the treatment period itself. During the period when the serum concentration of IgG was falling, the specific activity of IgG in the serum was relatively higher in treated men than in controls indicating decreased entry of newly synthesized IgG into the circulation. These findings suggest that a short course of methylprednisolone treatment causes a pronounced and sustained decrease in serum IgG due to increased catabolism during drug administration and to decreased synthesis during and for a variable time after drug administration.

The relationship between L-chain synthesis and gamma-globulin production

The simultaneous administration of labeled human gammaG globulin and L-chains to subjects has allowed examination of the metabolic relationship between a component part and the whole immunoglobulin molecule. Studies were carried out in a series of control subjects and in a group of patients where substandard production of gamma-globulin was anticipated, i.e., patients with the nephrotic syndrome on chronic Imuran therapy and patients with uremia. Full expression of the plasma decay curve was obtained for both substances, that for L-chain requiring only 4-5 days except in uremic subjects and that for gamma-globulin requiring up to 30-40 days. Urinary excretion of inorganic iodide was also quantitated for 20-30 days. Equilibrium of the extravascular, vascular, and urinary radioactivity from the labeled gammaG globulin was usually not seen during this time interval suggesting more than one site of catabolism of the protein. Excess L-chain poduction was about 45% of the total L-chain production and probably in no instance could account for the low gamma-globulin production seen in certain patients with renal disease.

Hypercatabolism of IgG, IgA, IgM, and albumin in the Wiskott-Aldrich syndrome. A unique disorder of serum protein metabolism

The Wiskott-Aldrich syndrome is an immune deficiency disorder with an impairment of both humoral and cellular immune responses. Metabolic turnover studies of IgG, IgA, IgM, and albumin were conducted in seven patients with the Wiskott-Aldrich syndrome using purified radioiodinated proteins. The survival of each of the proteins studied was significantly shortened with a half-time of 7.5 days for IgG (normal 22.9 +/-4 SD), 3.0 days for IgA (normal 5.8 +/-1), 5.0 days for IgM (normal 10.1 +/-2.1), and 8.6 days for albumin (normal 17, range 13-20); the fractional catabolic rates were correspondingly elevated and the distribution of protein among the body compartments was normal. For three of the four proteins. IgG, IgA, and albumin, the steady-state synthetic rates were generally elevated leading to normal or even elevated serum proteins levels. Thus, in the case of IgA, the synthetic rate averaged five times normal while the fractional degradative rate was twice normal. The resulting serum concentration was, therefore, significantly elevated, IgM represented an exception to this pattern in that the increased rate of degradation was not counterbalanced by an increased synthetic rate and, therefore, the serum levels were low. Albumin clearance studies using albumin-(51)Cr showed gastrointestinal protein loss in these patients to be slightly greater than normal, but this could account for only a small fraction of the hypercatabolism observed. There was no proteinuria or abnormalities of thyroid, adrenal, renal, or liver function. Thus, none of the previously recognized causes of increased serum protein catabolism were present. Patients with the Wiskott-Aldrich syndrome, therefore, have a unique disorder of serum protein metabolism characterized by endogenous hypercatabolism of at least four major serum proteins. This phenomenon may be related to reticuloendothelial hyperfunction since the Wiskott-Aldrich syndrome is associated with reticuloendothelial hyperplasia and accelerated clearance of colloidal materials from the plasma.