Circulating T follicular helper cell and regulatory T cell frequencies are influenced by B cell depletion in patients with granulomatosis with polyangiitis

OBJECTIVE

Granulomatosis with polyangiitis (GPA) is a rare and sometimes fatal systemic autoimmune disease. ANCAs specific for PR3 are associated with GPA. Remission in GPA can be achieved through B cell depletion (BCD) therapy. Our aim was to understand whether the frequencies of T cell subsets are influenced by BCD.

METHODS

The frequencies of circulating T follicular helper cells (cTFHs) and regulatory T cells (Tregs) from 36 GPA patients including 11 rituximab-treated patients and 10 healthy controls were studied by flow cytometry. The functional capacity of Tregs was assessed by in vitro co-culture assays.

RESULTS

We observed an increased frequency of cTFHs and a reduced frequency of antigen-experienced Tregs in peripheral blood from GPA patients on conventional therapies but not in those treated with rituximab compared with healthy controls. Furthermore, the ratio of cTFHs to Tregs was significantly higher in GPA patients on conventional therapies than in GPA patients treated with rituximab who were clinically improved or controls. Whereas Tregs were numerically reduced in GPA patients on conventional therapy, the suppressive capacity of Tregs on a per cell basis was not significantly altered in these individuals.

CONCLUSION

Our study illustrated increased cTFHs with decreased antigen-experienced Tregs in GPA patients on conventional therapies, but in B cell-depleted patients the levels of cTFHs and Tregs were similar to healthy controls. The negative correlation between cTFHs and Tregs implies the balance between T cell subsets and its B cell dependence impact on disease activity in GPA.

Type 1 diabetes-associated IL2RA variation lowers IL-2 signaling and contributes to diminished CD4+CD25+ regulatory T cell function

Numerous reports have demonstrated that CD4(+)CD25(+) regulatory T cells (Tregs) from individuals with a range of human autoimmune diseases, including type 1 diabetes, are deficient in their ability to control autologous proinflammatory responses when compared with nondiseased, control individuals. Treg dysfunction could be a primary, causal event or may result from perturbations in the immune system during disease development. Polymorphisms in genes associated with Treg function, such as IL2RA, confer a higher risk of autoimmune disease. Although this suggests a primary role for defective Tregs in autoimmunity, a link between IL2RA gene polymorphisms and Treg function has not been examined. We addressed this by examining the impact of an IL2RA haplotype associated with type 1 diabetes on Treg fitness and suppressive function. Studies were conducted using healthy human subjects to avoid any confounding effects of disease. We demonstrated that the presence of an autoimmune disease-associated IL2RA haplotype correlates with diminished IL-2 responsiveness in Ag-experienced CD4(+) T cells, as measured by phosphorylation of STAT5a, and is associated with lower levels of FOXP3 expression by Tregs and a reduction in their ability to suppress proliferation of autologous effector T cells. These data offer a rationale that contributes to the molecular and cellular mechanisms through which polymorphisms in the IL-2RA gene affect immune regulation, and consequently upon susceptibility to autoimmune and inflammatory diseases.

STUDIES ON THE ETIOLOGY OF SPONTANEOUS CONJUNCTIVAL FOLLICULOSIS OF MONKEYS : II. BACTERIOLOGICAL EXPERIMENTS

In the bacteriological study here reported, we undertook an investigation of the flora associated with spontaneous conjunctival folliculosis. Following the plan of Noguchi (2), monkeys and chimpanzees were inoculated with the different organisms recovered from affected tissues. By this means, we disclosed among the bacteria a new species, Bacterium simiae, which was found to be specifically active, in that it induced follicular reactions in the conjunctiva apparently indistinguishable from the disease as it occurs in nature. The specific action of the bacterium in animals is the more striking when it is compared with the innocuousness of other organisms isolated from cases of folliculosis, and also when considered in relation to the behavior of quarantined animals. While the disease arises spontaneously in stock animals, of some 300 normal rhesus monkeys— these being isolated in lots of ten to twenty and quarantined from 6 to 14 weeks—not one has as yet shown folliculosis. With the insignificant exception already mentioned (1), the experimental disease was produced only when the inoculum contained either folliculosis tissue or cultures of the simian organism. Apart from these findings, the experimental results indicate that (a) the bacterium has thus far been recovered only from folliculosis cases and not from other forms of conjunctivitis nor from normal tissues; (b) the microorganism has been isolated not only from affected conjunctivae of stock monkeys but also from the tissue of animals— macaques and apes—experimentally infected with the bacterium, and (c) such recovered cultures have, in turn, been found to be specifically pathogenic in normal rhesus monkeys and chimpanzees. We may therefore postulate from this experimental study that an intimate relation exists between Bacterium simiae and spontaneous conjunctival folliculosis of simians.

ETIOLOGY OF OROYA FEVER : XVI. VERRUGA IN THE DOG AND THE DONKEY

In the experiments here reported, definite verruga lesions, in which the presence of Bartonella bacilliformis was established by culture or by passage to rhesus monkeys, were produced in a dog and in a donkey by inoculation of cultures or monkey passage strains. The reaction induced in these animals was entirely local, however; blood cultures were sterile. Histologically, the lesions produced were similar to those obtained in monkeys by inoculation of Bartonella bacilliformis, except for the presence of a marked polynuclear leucocytic exudate. In another donkey a lesion histologically suggestive of verruga was produced, while in one donkey and a horse the results of inoculation were negative or indefinite. The intravenous injection of a filtrate or of heat-killed cultures of Bartonella bacilliformis into two donkeys was followed by the appearance of large, soft, subcutaneous swellings, on various parts of the body, not resembling in any way verruga lesions.

THE EFFECT OF SECONDARY INFECTIONS ON EXPERIMENTAL TRACHOMA

The possibility suggested itself, in view of the theories already advanced with regard to the rô1e of secondary infections in the later manifestations of trachoma (1), that the implantation of common bacteria on the conjunctivae of monkeys already having well marked characteristic granulosis lesions might give rise to a condition showing less predominance of the follicular reaction and more of the hyperemic granulopapillary effect. We believe we have succeeded, by a suitable technique, in doing this and in producing thereby in the experimental animals a condition closely resembling the florid type of human trachoma (Type IIb and c of MacCallan). The organisms used were some of those which are found in the conjunctival sac of monkey and man with different types of granular conjunctivitis. Of themselves, they produced only a transient reaction or none, as Noguchi had already shown and as we ourselves had observed in control animals. When inoculated together with material containing Bacterium granulosis, they did not affect the usual action of this organism, but when introduced into a conjunctiva in which granulosis lesions were already well developed, they induced more of the characteristics of the florid stage of trachoma than have been hitherto observed in animals, notably increased hyperemia, edema and thickening, papillary hypertrophy, obscurity of blood vessels, and masking of the follicles. Microscopically these changes were accompanied by increased scar tissue formation, lymphoid infiltration, and papillary hyperplasia.

BACTERIUM GRANULOSIS IN RELATION TO TRACHOMA: ITS RECOVERY FROM EXPERIMENTALLY INFECTED MONKEYS AND FROM HUMAN TRACHOMA

One of the strains of Bacterium granulosis isolated by Noguchi in 1926 has been maintained in culture and in monkeys and continues to be capable, after 3 years, of inducing a chronic granular conjunctivitis in monkeys. Cultures of this strain have been recovered from the monkey lesions as late as 3 years after inoculation and have been shown to reproduce the granular disease in monkeys. Six additional strains of Bacterium granulosis have been isolated from cases of trachoma occurring in the Indian schools of Arizona. The cultures thus obtained are identical morphologically and culturally with those isolated by Noguchi and have induced the same chronic granular conjunctivitis in monkeys. Advanced untreated cases are more favorable for cultural study than treated cases. Cultures of Bacterium granulosis kept on semisolid medium containing 10 per cent rabbit serum ("leptospira medium") remain viable for many months at room temperature, and sealed ampoules of such cultures have been found to retain their pathogenicity for the monkey conjunctiva for at least 69 days at room temperature and at least 284 days at 4° to 6°C. Several additional cultural and biological characteristics of Bacterium granulosis have been described. Of outstanding importance is the fact that cocaine, in contradistinction to novocain, has a bactericidal effect on the organism. This fact, in view of the common use of cocaine for anesthesia, may explain the negative results of cultivation experiments reported by some workers.

ETIOLOGY OF OROYA FEVER : XIV. THE INSECT VECTORS OF CARRION'S DISEASE

With a view to determining the mode of infection in Carrion's disease, a study of the blood-sucking insects found in the districts of Peru where the disease prevails has been carried out, through the cooperation of The Rockefeller Institute and the Rockefeller Foundation. The material studied included ticks, mites, midges, lice, fleas, bedbugs, mosquitoes, buffalo gnats, horse-flies, "sheep ticks," 3 species of Streblidae, and 3 species of Phlebotomus, including Phlebotomus verrucarum Townsend and two new species which have been named Phlebotomus noguchii and Phlebotomus peruensis. The insects were collected without the use of chemicals, were prepared for transportation in such a manner as to prevent drying, and were shipped under conditions of refrigeration to New York, where they were inoculated into monkeys. The plan followed was to inject saline suspensions of the crushed insects intradermally into rhesus monkeys and to make cultures of the blood of the animals at intervals of 1 to 6 weeks after inoculation. The only class of insects in which the presence of Bartonella bacilliformis could be detected were phlebotomi. No cutaneous lesions were induced in monkeys injected with the crushed insects, but in the case of four different lots of phlebotomi the blood of the animals so injected yielded cultures of Bartonella bacilliformis which produced typical verrucous lesions on inoculation into other monkeys. The morphology and cultural characteristics of the Bartonella strains obtained from phlebotomi proved identical with those of strains isolated from human blood and skin lesions. Monkeys which had recovered from infection with the phlebotomus strains resisted inoculation with a human strain of Bartonella bacilliformis, and, conversely, monkeys which had passed through an infection induced by the human strain resisted inoculation with the strains obtained from phlebotomi. The experimental observations described in this paper lead us to conclude that certain phlebotomi act as insect vectors of Oroya fever and verruga peruana. The phlebotomi which have been shown quite certainly to carry the Bartonella bacilliformis are those of the species Phlebotomus noguchii. Phlebotomus verrucarum is also probably a vector, while Phlebotomus peruensis remains doubtful in this respect.

STUDIES ON THE FILTRABILITY OF BACTERIUM GRANULOSIS

The evidence hitherto reported concerning the filtration of trachomatous material, and inoculation of man and monkeys with the filtrates points to the conclusion that the incitant of trachoma is not, as a rule, filtrable. Our findings confirm this view and indicate further that no virus causing the disease is adsorbed to Bacterium granulosis. On the other hand, Bacterium granulosis itself in heavy suspensions is irregularly filtrable through Berkefeld V candles, like some other bacteria (14), but it is present in the filtrates in only small numbers. When suspensions were used of trachomatous human and monkey tissues, which contain much fewer organisms than do actual cultures, Bacterium granulosis was never recovered from the filtrates. The conception that trachoma is a disease caused by an ultramicroscopic virus is based on (a) the positive results of filtration in two animals, as reported by Nicolle and his coworkers, and (b) the presence of so called "inclusion bodies" in some of the cells of the lesions. One can state definitely that the evidence is now greatly against the filtrability of the etiological agent of trachoma. Furthermore, filtrability does not in itself suffice for the classification of an agent as an ultramicroscopic virus. Concerning (b), a vast literature has accumulated which indicates that the "inclusion bodies" of trachoma are not specific for the disease and that the bodies themselves may be bacterial in origin (15). We have not as yet found bodies of the kind characteristic of many filtrable viruses in the tissues of man or of monkeys with the experimental disease.

TRANSMISSION AND CULTIVATION EXPERIMENTS WITH HUMAN TRACHOMA AND THE EXPERIMENTAL DISEASE IN MONKEYS

1. Conjunctival tissue derived from alien and native American white persons in New York City, having trachoma in an advanced stage, has been used successfully to induce in Macacus rhesus monkeys characteristic granular conjunctivitis. The transfer of infection was effected either by a single subconjunctival injection, or by repeated swabbing with conjunctival secretions. 2. Pathogenic strains of Bacterium granulosis have been recovered from the trachomatous tissues of six out of eleven patients. In addition, the organisms have been isolated from the monkeys infected with human material. 3. Repeated swabbing with secretions obtained from monkeys having experimental trachoma has given rise to characteristic granular conjunctivitis in normal animals. In addition, repeated instillations of suspensions of conjunctival tissue fragments derived from affected monkeys have led to characteristic infection of the conjunctivae of normal monkeys. 4. Contact infection occurs in monkeys, as it has long been known to occur in human beings; animals with smooth conjunctivae developing the experimental disease when merely caged with infected monkeys. 5. Repeated instillation of cultures followed by rubbing the eyelids will lead to the disease in monkeys, a method of transfer which indicates one manner in which the affection may be transmitted from man to man. Yet another manner of producing the experimental condition is by repeated swabbing with cultures of Bacterium granulosis. Noguchi has already reported the successful outcome of the subconjunctival inoculation of cultures and the spread of the disease from an infected conjunctiva to the other eye of the same animal. 6. Tissues derived from cases of human trachoma or from monkeys having the experimental disease induce, on conjunctival inoculation of Macacus rhesus monkeys, the same clinical and pathological effects as do cultures of Bacterium granulosis. The conjunctival lesions closely resemble, in clinical appearance and in microscopic changes, those of the follicular stages of trachoma in man.

Therapy with nonglycosaminoglycan-binding mutant CCL7: a novel strategy to limit allograft inflammation

Chemokines are immobilized by binding to glycosaminoglycans (GAGs). A non-GAG-binding mutant CCL7 (mtCCL7) was developed that retained its affinity for chemokine receptors. This mtCCL7 induced leukocyte chemotaxis in diffusion gradients but did not stimulate trans-endothelial migration (p<0.01). Unlike wild-type CCL7, mtCCL7 persisted in the circulation of BALB/c mice for more than 6 h and prevented leukocyte infiltration of skin isografts (p<0.05). Treatment with mtCCL7 marginally increased the survival of C57BL/6 to BALB/c skin allografts and reduced graft infiltration by CD3+ cells (p<0.05). Importantly, mtCCL7 promoted long-term (>40 day) graft survival following minor histocompatibility (HY) antigen mismatched C57BL/6 skin transplantation; control grafts were rejected by day 24. Treatment with mtCCL7 produced a significant decrease in the frequency of IFN-gamma producing donor-reactive splenic T cells, reduced CCR2 expression by circulating leukocytes for 6 h (p<0.01) and blocked the normal increase in affinity of alpha4beta1 integrins for VCAM-1 following transient chemokine stimulation. These data suggest that mtCCL7 persists in the circulation and reduces both specific T-cell priming and the capacity of circulating immune cells to respond to GAG-bound chemokine at sites of developing inflammation.

Chronic allograft nephropathy: intraepithelial signals generated by transforming growth factor-beta and bone morphogenetic protein-7

It has been suggested that TGFbeta can cause chronic allograft nephropathy by inducing epithelial to mesenchymal transition (EMT); some studies show a reverse transition can be produced by bone morphogenetic protein-7 (BMP7). The current study assessed the relative contribution of signals generated within tubular epithelial cells by TGFbeta and BMP7 in normal kidney and after transplantation. Epithelial cells in normal human kidneys expressed phosphorylated forms of both Smad2/3 and Smad1/5/8 within their nuclei; cell culture experiments showed that these signaling molecules were generated in response to TGFbeta and BMP7, respectively. Phospho(p)-Smad2/3 was expressed at increased levels by tubular epithelial cells during acute renal allograft rejection and chronic allograft nephropathy but pSmad1/5/8 was expressed at very low levels; this staining profile was associated with induction of the EMT marker, S100A4. Further in vitro experiments demonstrated that this pattern of Smad signaling was a consequence of the stimulation of tubular epithelial cells with TGFbeta in the absence of BMP7. Importantly, addition of BMP7 to TGFbeta-stimulated cells enhanced the expression of pSmad1/5/8 and reduced expression of S100A4. These results suggest that exogenous BMP7 could restore the homeostatic balance of pSmad signaling found in normal kidneys, thereby preventing or reversing the development of chronic allograft nephropathy.

Tracking family practice graduates

Lancaster General Hospital in 1991 surveyed graduates of its 21-year-old Family Practice Residency on a number of medical and non-medical issues. The results, overviewed in this article, may lay the groundwork for future efforts to obtain a national consensus regarding family practice education in its current format.

Production of pregnancy-associated plasma protein-A (PAPP-A) by cultured tumour granulosa cells

Ten ovarian and 2 cervical tumour cell lines were analysed for the production of pregnancy-associated proteins. Pregnancy-associated plasma protein-A (PAPP-A) was detected by radioimmunoassay in culture media of 2 out of 4 (50%) tumour granulosa cell lines (mean = 104 microIU/10(5) cells/24 h) but not in any ovarian (n = 6) or cervical (n = 2) tumour cell lines. By contrast, human chorionic gonadotrophin (hCG), pregnancy specific beta 1-glycoprotein and alpha-fetoprotein (AFP) were not detected in any of the PAPP-A positive media. Only two cell lines produced hCG (58.5 and 25.5 mIU/10(5) cells/24 h). No AFP was produced by any of these 12 cell lines, whereas placental protein 5 was positive in 7. None of these proteins were detected in the culture media of 4 cell lines. In vitro derived PAPP-A was immunologically indistinguishable from either pregnancy or ovarian follicular PAPP-A. All PAPP-A species interacted reversibly with immobilised heparin and were determined by molecular sieve chromatography to have an apparent molecular weight of 820,000 daltons. Cultured tumour granulosa cells specifically synthesised and secreted a large protein which was immunologically and physicochemically indistinguishable from in vivo (pregnancy and ovarian follicular) derived PAPP-A.

STUDIES ON THE ETIOLOGY OF SPONTANEOUS CONJUNCTIVAL FOLLICULOSIS OF RABBITS : I. TRANSMISSION AND FILTRATION EXPERIMENTS

Spontaneous conjunctival folliculosis is widespread among various species of rabbits. It exists in two forms: Type I, in which the lesions are localized and the disease is relatively inactive, and Type II, in which the follicles are closely distributed over the entire surface of the conjunctivae and the affection is more active and characterized by extensive inflammatory reactions. One type can be converted into the other either by experimental methods or by natural processes. The disease can be transmitted from rabbit to rabbit by means of subconjunctival inoculation of suspensions of the affected tissues or by instillation of such material into the conjunctival sac, or even by mere contact of folliculosis animals with rabbits having smooth conjunctivae. It is plain that the disease is an infection. The causal agent of the infection is not filtrable through Seitz discs that retain Serratia marcescens nor through Berkefeld V candles that permit the passage of this organism. Furthermore, the lesions of the spontaneous or of the experimental disease do not exhibit the cytotropic effects or the inclusion bodies suggestive of the action of an ultramicroscopic virus. They are characterized, on the other hand, by a persistent and progressive chronicity and show certain resemblances to the granulomata. The evidence suggests that the spontaneous conjunctival folliculosis of rabbits is due to a microorganism-one having a low grade pathogenic action. In a paper shortly to be published, a bacterium capable of reproducing folliculosis in normal rabbits will be described.

STUDIES ON THE ETIOLOGY OF SPONTANEOUS CONJUNCTIVAL FOLLICULOSIS OF MONKEYS : I. TRANSMISSION AND FILTRATION EXPERIMENTS

Spontaneous folliculosis of Macacus rhesus monkeys-a type of follicular conjunctivitis associated with marked, local, inflammatory reactions-is apparently a disease sui generis, due to a specific infectious agent. It can be transmitted from monkey to monkey by means of subconjunctival injection of suspensions, and by conjunctival swabbing of the secretions, of affected tissues, or by contact of normal animals with folliculosis monkeys. The agent causing folliculosis has failed in our hands to pass through Berkefeld and Seitz filters, even those of an unusual degree of permeability; and the lesions that it causes show no cellular inclusions suggestive of the action of a virus. The condition is due apparently to an organism of low grade pathogenicity. The essential histopathological structure corresponds to that of a folliculoma (16) which, while not identical with a granuloma, bears certain resemblances to the latter. The studies here reported concern only one species of monkey, Macacus rhesus. Further investigations will be carried out on different species of Anthropoidea and other animals.

CORNEAL REACTIONS TO BACTERIUM GRANULOSIS AND OTHER MICROORGANISMS

The conclusions which may be drawn from the results of the experiments here presented are: 1. The cornea of the rabbit is highly sensitive to the action of various injected bacteria. The lesions vary from insignificant, transient changes to severe, destructive panophthalmitis, with fine gradations from the mildest to the violent form of inflammation. Moreover, animals that receive the same organisms show like changes. 2. The varying degree of inflammatory reaction is related to the pathogenicity of the special culture employed; as, for example, is shown by the reactions to Type I pneumococci and to Bacterium granulosis. It is evident that when a microorganism having a certain degree of virulence is used, a lesion of localized vasculonebulous keratitis resembling pannus tenuis or vasculosus of human trachoma can be induced. Thus Bacterium granulosis, Bacillus xerosis, Hemophilus influenzae, Pneumococcus Type II, Streptococcus viridans, and gonococcus can cause the pannus-like corneal changes in the rabbit. Of these organisms, however, only Bacterium granulosis induces early, uncomplicated and enduring keratitic lesions; the others cause first, diffuse keratitis with suppurative lesions; then, as a residual effect, transient, localized, vasculonebulous changes in the cornea. These changes, in contradistinction to the granulosis lesions, are, therefore delayed, complicated, and transient. When, on the other hand, the invasiveness and infecting power of the organisms are low, as is the case with the filtrable, Gram-negative bacillus and the small, Gram-negative bacilli ultimately derived from cases of folliculosis, no marked effect is produced by their intracorneal inoculation. If the pathogenicity of bacteria is high (as shown by Pneumococcus Type I, hemolytic streptococcus, and the remaining bacteria), intracorneal inoculation of the microorganisms leads to serious suppurative or destructive changes. 3. The results of experiments with monkeys indicate that while pannus is not a sequel of experimental trachomatous conjunctivitis, a lesion resembling it follows intracorneal inoculation of Bacterium granulosis. 4. One can infer from these results, therefore, that the stimulus necessary to produce corneal changes in animals, similar to those of trachomatous pannus, is an agent having a definite but extremely low power of invasiveness and infectivity.

THE EFFECT OF THE X-RAY ON THE NODULES OF VERRUGA PERUANA

The supposition that X-ray would affect the developing and the developed verruga nodules experimentally induced in the monkey, has proved correct. The experiments show that the early verruga nodules when exposed to a single, properly graduated dose of X-ray producing merely erythema of the skin, are inhibited in their evolution. Moreover, the skin of Macacus rhesus monkeys is modified by a single erythema dose of X-ray in such a way that infection of it with Bartonella bacilliformis is rendered more difficult. These results are sufficiently striking to warrant the trial of X-ray in suitably guarded doses in the treatment of verruga nodules in man. Should the employment of convalescent serum influence the course of Carrion's disease favorably and the use of X-ray bring about a more certain and rapid devolution of verruga nodules in man, two practically applicable therapeutic measures will have been provided for the treatment of the two forms of the human disease.

ETIOLOGY OF OROYA FEVER : XV. EFFECT OF IMMUNE SERUM ON THE COURSE OF BARTONELLA BACILLIFORMIS INFECTION IN MACACUS RHESUS

Experiments are reported on the effect upon the course of experimental verruga peruana in Macacus rhesus of the injection of (1) small quantities of rabbit immune serum simultaneously with living cultures, (2) one large dose of convalescent monkey serum 24 hours prior to inoculation, (3) a similar preliminary dose followed by three subsequent injections of the serum, (4) three large doses of convalescent serum, following the inoculation. The convalescent serum was found (1) to prevent the multiplication of Bartonella bacilliformis in the blood in most instances, and (2) to delay the development of the skin lesions for considerable periods, when given before inoculation. When the serum treatment was not begun until after the appearance of the skin lesions, it had no effect on the progress of the nodules, although the blood became free from Bartonella bacilliformis. Since the severe effects of verruga peruana (Carrion's disease) are believed to be due to the multiplication of Bartonella bacilliformis within the blood, the injection of convalescent serum in cases of Carrion's disease in man would appear to offer promise.