Clinicopathologic characteristics and treatment of marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma).

Extranodal marginal zone lymphoma of the mucosa-associated lymphoid tissue (MALT lymphoma) accounts for 7% to 8% of newly diagnosed lymphomas. Because of its association with infectious causes, such as Helicobacter pylori (HP) or Chlamydophila psittaci (CP), and autoimmune diseases, it has become the paradigm of an antigen-driven malignancy. MALT lymphoma usually displays an indolent course, and watch-and-wait strategies are justified initially in a certain percentage of patients. In patients with gastric MALT lymphoma or ocular adnexal MALT lymphoma, antibiotic therapy against HP or CP, respectively, is the first-line management of choice, resulting in lymphoma response rates from 75% to 80% after HP eradication and from 33% to 65% after antibiotic therapy for CP. In patients who have localized disease that is refractory to antibiotics, radiation is widely applied in various centers with excellent local control, whereas systemic therapies are increasingly being applied, at least in Europe, because of the potentially systemic nature of the disease. Therefore, the objective of this review is to briefly summarize the clinicopathologic characteristics of this distinct type of lymphoma along with current data on management strategies.

The role of infectious agents, antibiotics, and antiviral therapy in the treatment of extranodal marginal zone lymphoma and other low-grade lymphomas.

OPINION STATEMENT: There is strong evidence to corroborate the association with Helicobacter pylori (Hp) to gastric extranodal marginal zone lymphoma (ENMZL) and hepatitis C virus (HCV) to splenic/nodal marginal zone lymphoma. Koch's postulates generally hold for these two associations and eradication of the infectious agent is well supported. Hp eradication (HPE) is recommended as front-line therapy for early stage gastric ENMZL regardless of Hp status. Complete response (CR) rate for Hp-negative patients is not as high as for Hp-positive patients; however, the benign nature of HPE and high rates of salvage allow this strategy to be safe while sparing some Hp-negative patients from systemic therapy or radiation. Similarly for HCV-seropositive patients, treatment with antivirals should be strongly considered as first-line for those who do not require immediate cytoreductive therapy or at some point even after completing chemoimmunotherapy. The controversy regarding the role for antibiotics is greatest for primary ocular adnexal lymphoma (POAL). Considering the low incidence of Chlamydia psittaci (Cp) infection with OAL and the challenges to reliably identifying Cp, we typically do not consider doxycycline in POAL treatment. Involved-field radiotherapy (IFRT) remains the treatment of choice for most with unilateral POAL. However, if reliable detection of Cp is available and Cp is identified, patients with unilateral low tumor stage POAL who do not require immediate radiotherapy could be considered for doxycycline as front-line treatment. Other infectious associations to indolent lymphomas have been made, including Borrelia borgdorferi (Bb) in cutaneous lymphoma and Campylobacter in immunoproliferative small intestinal disease (IPSID), but these associations are not as strong and primary treatment targeting the infectious agents is not recommended.

Chlamydophila psittaci subclinical infection in chronic polyarthritis.

OBJECTIVES: Recent evidence indicates that Chlamydophila psittaci (Cp) may establish chronic infections, which may promote autoimmunity and/or B cell lymphoproliferation. METHODS: The presence of a subclinical Cp infection was investigated in 293 patients with chronic inflammatory polyarthritis, including 175 patients with rheumatoid factor (RF)-positive and/or anti-CCP-positive rheumatoid arthritis (RA) and 118 with seronegative polyarthritis (46 RF-negative/anti-CCP-negative RA, 36 psoriatic arthritis and 36 undifferentiated spondyloarthritis). One hundred and eighty-five healthy controls were also investigated. The presence of Cp infection was assessed in peripheral blood mononuclear cells using several PCR protocols targeting different regions of the Cp genome (16S-23S spacer rRNA, OMP-A, and Gro-EL). The DNA of other Chlamydia species (C. Pneumoniae and C. Trachomatis) was also investigated. Amplicons were sequenced to confirm the specificity of PCR products. RESULTS: The presence of a subclinical chronic Cp infection was observed in a significantly higher percentage of patients with chronic polyarthritis (38/293; 13%) compared to healthy controls (1/185, 0.5%; OR=27.4, 95%CI:3.73-201.6, p<0.0001). Furthermore, the prevalence of Cp was higher in seronegative polyarthritis (23/118; 19.5%) than in seropositive RA patients (15/175; 7.4%; OR=2.58, 95%CI: 1.28-5.19, p=0.0078). The highest prevalence of Cp infection was found in RF/anti-CCP double-negative RA patients (13/46, 28.3%), followed by patients with psoriatic arthritis (6/36; 16.7%). No differences in age, sex, disease duration and undergoing therapies were noticed between Cp-positive and Cp-negative patients; nor between seropositive and seronegative patients. CONCLUSIONS: Cp may be an infectious trigger possibly involved in the pathogenesis of a fraction of inflammatory polyarthritis, particularly in seronegative patients.

Selenium and vitamin E effect on antibody production of sheep vaccinated against enzootic abortion (Chlamydia psittaci).

The effect of selenium (Se) and vitamin E (vit E) on antibody production of sheep vaccinated against Chlamydia psittaci (ovis) was investigated. Thirty-two sheep, one year old, seronegative to Chlamydia infection, vaccinated against enterotoxemia and dewormed were used. Injectable sodium selenite (0.1 mg/kg b.w.) was given twice to animals of the first group (gSe), with a three week interval. The sheep of the second group (gE) received 1 g vit E each orally, six times at weekly intervals. The animals of the third group (gSeE) were given Se and vit E in doses and routes of administration as in gSe and gE. The animals of the fourth group served as controls (gC) and injected normal saline. The first vaccination was made at the time that the second Se injection was given. Revaccination was made two weeks later. The experiment lasted 29 weeks. The results indicated that Se alone led to a significant increase of Chlamydia antibody response (P < 0.05), but not when it was given in combination with vit E. Animals that received vit E (gE) had much lower titres, just above of those of the controls.