Current therapies for systemic vasculitis

Diffusion-weighted MR imaging: pediatric clinical applications

We have summarized the diffusion-weighed imaging (DWI) findings in a number of different cerebral disorders. In many cases, DWI with the accompanying apparent diffusion coefficient (ADC) map provides additional useful information to the standard imaging sequences. Pathophysiologic mechanisms resulting in baseline normal ADC values and changes with disease processes are not well understood; therefore, caution should be used when prognosticating the outcome of regions with abnormal ADCs. DWI should be used as an adjunct to routine imaging and interpreted in the context of the routine imaging findings and clinical scenario. As our understanding of ADC mechanisms increases and we begin to incorporate information about tissue organization from diffusion tensor imaging or diffusion spectrum imaging, the role of these methods in clinical diagnosis should continue to increase.

Treatment of Wegener's granulomatosis

The two principal aims in the treatment of Wegener's granulomatosis (WG) are to limit the extent and severity of permanent organ damage by controlling the disease promptly and to minimize the short- and long-term morbidity that often results from therapy. Remission is considered to be the absence of disease activity in any organ system. Once the disease has been controlled by the initial treatment regimen, which is dictated by the degree of disease severity, the focus of therapy shifts to maintaining disease remission, often with medications less toxic than those used to induce remission. The description of WG treatments in terms analogous to cancer chemotherapy (i.e., those designed to induce remissions and those intended to maintain them) is useful in the formulation of current disease management strategies and in the investigation of new therapies for WG.

Novel therapies in vasculitis

The vasculitides comprise various clinical and pathological entities which pose a therapeutic challenge in terms of disease control versus drug toxicity. Glucocorticoids are important in most regimens; duration of exposure and dosages can be minimised by the use of cytotoxic drugs and transplant immunosuppressives such as cyclosporin, tacrolimus and mycophenolate mofetil. Among alkylating agents, cyclophosphamide has proven to be highly effective; switching to less toxic antimetabolites, typically methotrexate, for maintenance after achieving disease control is an effective strategy. Plasmapheresis may be considered when pharmacological options are maximised. IVIG infusions are of proven benefit in Kawasaki disease and possible benefit in other vasculitides. Targeting infective aetiologies is the basis of therapies such as lamivudine and vidarabine for hepatitis B associated polyarteritis nodosa as well as ribavarin and IFN-alpha for hepatitis C associated cryoglobinaemic vasculitis. IFN-alpha also has immunomodulatory effect even in non-hepatitis C-associated vasculitis. Trimethoprim-sulphamethoxazole has been used in limited Wegener's granulomatosis. Thalidomide, colchicine and dapsone are miscellaneous agents that have been used in Behcet's disease and cutaneous vasculitis. Anti-lymphocytic monoclonal antibodies have been employed for induction therapy in Wegener's granulomatosis. The tumour necrosis factor inhibitor etanercept is just being explored as a therapeutic agent. Bone marrow and stem cell transplantation may find a role in refractory disease.

High-dose cyclophosphamide in severe aplastic anaemia: a randomised trial

BACKGROUND

High-dose cyclophosphamide has been proposed as an alternative immunosuppressive agent for treatment of severe aplastic anaemia, with a response rate similar to that with regimens containing antithymocyte globulin (ATG) but neither relapse nor clonal haematological complications. We undertook a phase III, prospective, randomised trial to compare response rates to immunosuppression with either high-dose cyclophosphamide plus cyclosporin or conventional immunosuppression with ATG plus cyclosporin in previously untreated patients.

METHODS

Between June, 1997, and March, 2000, 31 patients were enrolled. 15 were assigned cyclophosphamide (1 h intravenous infusion of 50 mg/kg daily for 4 days) and 16 were assigned ATG (40 mg/kg daily for 4 days); both groups received cyclosporin, initially at 12 mg/kg daily with adjustment to maintain concentrations at 200-400 microg/L, for 6 months. The primary endpoint was haematological response (no longer meeting criteria for severe aplastic anaemia). The trial was terminated prematurely after three early deaths in the cyclophosphamide group. Analyses were by intention to treat.

FINDINGS

Median follow-up was 21.9 months (range 1-33). There was excess morbidity in the cyclophosphamide group (invasive fungal infections, four cyclophosphamide vs no ATG patients; p=0.043) as well as excess early mortality (three deaths within the first 3 months cyclophosphamide vs no ATG patients; p=0.101). There was no significant difference at 6 months after treatment in the overall response rates among evaluable patients (six of 13 [46%] cyclophosphamide vs nine of 12 [75%] ATG).

INTERPRETATION

A longer period of observation will be necessary to assess the secondary endpoints of relapse and late clonal complications as well as disease-free and overall survival. However, cyclophosphamide seems a dangerous choice for treatment of this disorder, given the good results achievable with standard therapy.

A century of the synthesis of dapsone: its anti-infective capacity now and then

BACKGROUND

Although dapsone was first synthesized in 1908, a quarter of a century was to pass before it was used in the treatment of bacterial infections. Dapsone was, however, too toxic for humans (because of the excess dosage which was administered at that time) and was thus considered to be of no value in the treatment of common bacterial infections. Since the early 1950s, dapsone has been recognized as being uniquely effective against a number of noninfectious, inflammatory diseases and, today, this is its main indication. Thus, the reason why dapsone was first introduced into medicine, namely the treatment of bacterial infections, has been set aside and its main current applications are the treatment of noninfectious, inflammatory, autoimmune, and bullous diseases.

OBJECTIVE

To study the anti-infective capacity of dapsone against common bacterial infections. As many patients who receive dapsone for the treatment of noninfectious, inflammatory diseases have a concomitant bacterial infection or a superinfection of their skin disease, we thought that, if dapsone proved to be effective against common bacterial infections, it may obviate the need for an additional antimicrobial drug in these patients.

METHODS

Three bacterial ATCC> strains (Streptococcus pyogenes, Staphylococcus aureus, and Escherichia coli) were tested by a macrodilution minimal inhibitory concentration (MIC) test for dapsone. Dapsone concentrations were between 0.06 and 1125 microg/mL.

RESULTS

Even the highest concentration of dapsone of 1125 microg/mL did not inhibit bacterial growth.

CONCLUSIONS

Our results indicate that dapsone has no antibacterial effects whatsoever. Even at very high concentrations, it does not suppress the growth of most susceptible strains of bacteria. The story of dapsone (i.e. the long time that elapsed between its synthesis to its use for the chemotherapy of infectious diseases) will not repeat itself this time.

[Intravenous therapy with methylprednisolone and cyclophosphamide in vasculitis of peripheral nervous system. Evaluation of 8 patients]

The peripheral nervous system is frequently involved in systemic vasculitis and it may be helpful in the disease diagnosis. We report on eight patients: seven women and one man; five white, two black and one yellow; age mean 55.9 years; four had polyarteritis nodosa, one had systemic lupus erythematosus, one had isolated peripheral nerve vasculitis and one had livedoid vasculitis. All of them received endovenous therapy with "pulse" of methylprednisolone (1 g/day/3 days) and cyclophosphamide (1 g/1 day). Five patients improved, two remained unchanged and one died. The neurological improvement occurred after the third or fourth pulse and in the patients who have had a shorter time of disease.

Therapy of systemic vasculitis

The systemic vasculitides represent a highly heterogeneous and complex set of disorders primarily mediated via immunologic mechanisms. Standard therapy of these diseases includes the use of glucocorticoids without the use of additional cytotoxic agents. Recent long term follow-up investigations of patients treated with combined therapy has revealed an alarming incidence of treatment-related toxicity. Currently recommended therapeutic regimens are designed to minimize such toxicity while maintaining disease control. New therapeutic agents with greater disease specificity and lower toxicity are now being examined.