Treatments and supportive therapies for oral manifestations of chronic graft-versus-host disease

The aim of this study was to conduct a systematic review of treatments and therapies for oral manifestations of chronic graft-versus-host disease, aiming at improving patients’ quality of life and mainly the reduction of mortality caused by graft-versus-host disease. A systematic review was carried out by two evaluators, a Dentistry professor and an undergraduate student. A selection of open-access full-text online articles, carried out on PubMed, GoPubmed, NLM Gateway, LILACS, BIREME, SciELO, IBECS, and Web of Science. The survey was completed in July 2012. Of the 1147 studies found, 52 fit the selection criteria. Patients (n = 2130) received different treatment regimens, either systemic or topical. Drugs for systemic therapy were divided into those with action on the inhibition of proliferation and/or release of T and B cells, with action on inflammatory disorders, and of immunomodulatory effect. Topical drugs were divided into their pattern of mucosal absorption and their ability to act on tissue growth factors. The analysis of articles concluded that the most used systemic drugs were Methylprednisolone and corticosteroids, and Tacrolimus and topical Cyclosporine for topical and local therapy.


Introduction
Within all organ transplants, bone marrow transplantation (BMT) has increased worldwide in the past 40 years (Silva, Bouzas, & Filgueira, 2005).According to the Brazilian National Institute of Cancer, about 2000 transplants are done in the country, a number that may increase 30% every year.
However, some complications can occur after the procedure, such as chronic graft-versus-host disease (GVHD), common in 50-80% of all BMT.GVHD is the main responsible transplant-related morbidity and mortality, accounting for nearly a quarter of all deaths (Chao, 1998).
Oral manifestations of GVHD may occur in 30-80% of the cases (García;Molina;González, 2006), and can be classified as (a) mild, when the oral mucosa presents leukoedema, white streaks, burning sensation of the mouth and xerostomia; (b) moderate, with the mucosa showing maculopapular rash, microstomia, painful ulcerations and mucoceles, and (c) severe, with bullous lesions (Chao, 1998).Oral signs of the disease can be one of the earliest manifestations of systemic GVHD, reason why dentists should be members of the multiprofessional approach to treatment of the disease.They should be able to diagnose such signs and refer patients to oncologists as soon as possible, so that patients receive an early medical and dental treatment and may have a better prognosis.
Aiming at performing an analysis of existing therapies treatments and supportive treatments for oral manifestations of GVHD, this paper presents a systematic literature review of treatments and therapies on the disease.

Material and methods
The systematic review was carried out by two evaluators, a Dentistry professor and an undergraduate student, who run two independent web-based searches on the following online database: Pubmed, GoPubmed, NLM Gateway, LILACS, BIREME, SciELO, IBECS, and Web of Science.The articles should be in English and have abstracts.The first search combined the Medical Subject Headings (MeSH) terms 'Graft versus host disease' and 'Oral cavity'.The second search used the terms 'Cyclosporine' or 'Clofazimine' or 'Steroids' or 'Hydroxychloroquine' or 'Methotrexate' or 'Mycophenolate mofetil' or 'Eicosapentaenoic acid' or 'Pentostatin' or 'Rituximab' or 'Sirolimus' or 'Tacrolimus' or 'Thalidomide' or 'Budesonide' or 'Extracorporeal' or 'Platelet' or 'Azathioprine' and 'Graft versus host disease' and 'Oral cavity'.The descriptor was 'graft versus host disease'.The survey was completed in July 2012.
The online searches resulted in 1147 articles, but during the screening process these texts revealed additional articles, which integrated the sample.The screening process started using the title and the abstracts and was based on (a) inclusion criteria: articles that described different treatments and therapies for chronic GVHD with oral manifestation; open-access full-text online articles, and no age restriction, and (b) exclusion criteria: review articles, case studies, letters to editors, and general news.Once the duplicated and not relevant articles were discarded, the texts were fully analyzed and the eligibility criteria applied: articles with minimal size sample of 5 patients; randomized controlled trials and openlabel trials; studies in humans, both adults and children; patients with chronic GVHD; cases of primary outcomes (i.e., no analysis of recurrent GVHD); studies on treatments and supportive therapies for GVHD with systemic, topic, or extracorporeal application, and patients with chronic GVHD with oral manifestation (Figure 1).Within the 52 selected articles, the information tabulated was: therapeutic agent, study design, number of patients, oral response to treatment, and the drugs' major complications.The 'data were' imported into 'Microsoft Excel spreadsheet' by one of the reviewers, whereas the second double-checked them.

Results
The review showed several systemic therapies for the treatment of chronic GVHD.As the effectiveness of the drugs may vary depending on the targeted organ (Couriel et al., 2006), the review analyzed only those of global action that can influence the oral mucosa.
Three out of the 52 articles were open-label randomized double blind designed, whereas the remaining 49 were open-label single-arm.Response to treatment is reported as complete, when treatment led to the cure of the disease, or partial, when signs and symptoms in an organ or part of the body disappeared due to treatment.

Systemic Therapy
The drugs were divided into three types: (a) Those with action on the inhibition of proliferation and/or release of T and B cells: Cyclosporine, Hydroxychloroquine, Sirolimus, Tacrolimus, Pentostatin, Rituximab; (b) Those with action on inflammatory disorders: Clofazimine, Methotrexate, Methylprednisolone, Thalidomide; (c) Drugs of immunomodulatory effect: Mycophenolate mofetil, Extracorporeal photopheresis.
Drugs with action on the inhibition of proliferation and/or release of T and B cells These were the most examined systemic drugs among the 52 studies, found in 15 articles (Table 1).

Drugs with action on inflammatory disorders
The effect of drugs on inflammatory disorders in the treatment of GVHD was investigated by seven studies (Table 2).

Drugs of immunomodulatory effect
Mycophenolate mofetil was the most recently examined drug among those of immunomodulatory effect (Parker et al., 1995;Akpek, Lee, Anders, & Vogelsang, 2001;Dall'Amico & Messina, 2002) (Table 3).It is rapidly absorbed when administered orally and is used for prevention of transplant rejection (Furlong et al., 2009).A study carried out in 2000 (Busca et al., 2000) showed good overall response to treatment (60%), whereas the results of a more recent study, 2009, were not as promising: 59% of patients required additional treatment, and 17% developed gastric toxicity (Furlong et al., 2009).
Table 1.Systemic therapy using drugs with action on the inhibition of proliferation and/or release of T and B cells.OA = Oral administration; IVA = Intravenous administration; n = number of patients.Exp.= Experimental Group.
Agent (dosage) [study]  Study design n Systemic results

Topical and local therapy
Treatment of GVHD requires systemic treatment, but oral manifestations that do not subside with the systemic approach may benefit from topical and local therapy (Arora, 2008).Topical treatments may enhance healing of a particular body area, alleviating patients' systemic immunosuppression (Imanguli, Pavletic, Guadagnini, Brahim, & Atkinson, 2006).Several topical agents are currently used for the treatment of oral manifestations of GVHD, such as mouthwashes and topical immunosuppressants (Steroids, Cyclosporine, Azathioprine).Unquestionably, adequate oral hygiene is important to prevent oral infections, as well as the use of some agents that act on prevention and management of complications related to xerostomia, such as topical fluoride, saliva substitutes, and sialogogue pilocarpine (Elad, Or, Garfunkel, & Shapira, 2003a;Elad, Or, Resnick, & Shapira, 2003b).

Discussion
A growing body of research has focused on finding ways to improve both the quality of life and the survival rate of patients with GVHD (Lee, Dörken, & Schmitt, 2004).The difficulty in choosing the appropriate treatment for GVHD lies in the diversity of organs involved, the acute or chronic nature of the disease, and the hematologic and immunologic disorders associated with the syndrome (Ratanatharathorn, Ayash, Lazarus, & Uberti, 2001).
Systemic treatment is needed for more severe manifestations of the disease, especially when multiple organs are involved (Socie, Ritz, & Martin, 2012).Among the therapeutic currently available, systemic therapies are the most used due to the general nature of the disease, whether chronic or acute.However, long-term systemic treatment increases the risk of infections, recurrence of cancer, and risk of squamous cell carcinoma of oral mucosa (Wang et al., 2009).
Corticosteroids are still the first-line drugs used for GVHD, such as Methylprednisolone associated or not with Cyclosporine (Bisaccia et al., 2003).They are inflammatory mediators and useful as prophylactic treatment (Akpek et al., 2001), they act by preventing healthy tissues from responding to inflammatory processes, and inhibiting the release of inflammatory chemical mediators, making patients less susceptible to manifestations of GVHD.
Immunosuppressants are also front-line drugs to treat GVHD, as they inhibit T and B lymphocytes proliferation, thereby reduce the response of the body against the grafted tissue and improve the chances of successful transplantation (Wolff et al., 2004).Cyclosporine, Pentostatin, Rituximab and Sirolimus are among the most commonly used immunosuppressants.
Tacrolimus, also an immunosuppressant, has few side effects and, for this reason, is especially recommended for patients with liver failure as salvage therapy (Carnevale-Schianca et al., 2000).
Immunomodulatory drugs, such as Hydroxychloroquine, Mycophenolate mofetil, Thalidomide, and Methotrexate, may be associated to systemic therapy in order to improve the treatment.They are alternatives for patients who do not respond well to treatment (Moreira, De Medeiris, Bonfim, Pasquini, & De Medeiros, 1998).
Extracorporeal phototherapy is another immunomodulatory effective therapy on skin and oral injuries (Enk et al., 1998).It can prevent longterm complications when associated with steroids, and reduces the response-time to treatment (Bisaccia et al., 2003).
GVHD can affect specific sites with great intensity, cases that require supplementary topical drugs in order to reduce the risks involved in systemic therapy (Arora, 2008).Due to their low bioavailability, one of the main advantages of topical drugs, such as Budesonide and Cyclosporine, is their reduced systemic side effects when absorbed through mucous membranes (Elad, Or, Garfunkel, & Shapira, 2003a).
Mouth ulcers as an oral manifestation of GVHD impact patients' quality of life.Treatment can be done with topical Azathioprine, which reduces the pain caused by ulcerations (Epstein, Gorsky, Epstein, & Nantel, 2001).Platelet gel is also used to treat mouth ulcers, given that it releases growth factors that stimulate re-epithelialization, which, in turn, lead to tissue regeneration (Fante, Scudeller, Viarengo, Bernasconi, & Perotti, 2012).
However, the articles reviewed lack enough evidence about the effectiveness of topical therapies.All patients were receiving concomitant systemic treatment of different types, and often the dosages of the topical drug were not specified, which hinder definite conclusions.
Further research on oral manifestations of GVHD is needed, as the articles reviewed showed that topical treatment only showed positive results on oral lesions, whereas few studies analyzed the impact of systemic therapy in the mouth.
A deeper knowledge of the disease's pathophysiology is also needed, since it is the functional changes caused by GVHD that determine where the drugs can work.Therefore, studies on the mechanisms of GVHD in the oral cavity, as well as well-designed clinical trials are urgently needed, as they might provide means for better management of the disease and for improving patients' quality of life.

Conclusion
The articles reviewed showed that systemic therapy, despite its high risks of side effects, is still the most used for the treatment of chronic GVHD.Methylprednisolone and corticosteroids were the first choice for systemic treatment of the disease.As for topical and local therapy, Tacrolimus and topical Cyclosporine showed positive results on oral manifestations.

Figure 1 .
Figure 1.Flowchart with online search and the screening criteria to select the appropriate articles on chronic GVHD with oral manifestation (as adapted from Nabil & Samman, 2012).

Table 2 .
Systemic therapy using drugs with action on inflammatory disorders.OA = Oral administration; IVA = Intravenous administration; n = number of patients.

Table 3 .
Systemic therapy using drugs of immunomodulatory effect.

Table 4 .
Topical treatment using drugs of low absorption by the oral mucosa.

Table 5 .
Topical treatment using drugs with action on tissue growth factors.