Marginal zone lymphoma with severe rashes: A case report

BACKGROUND Marginal zone lymphoma(MZL)is an indolent subtype of non-Hodgkin lymphoma(NHL),which is rare clinically with severe rashes as the initial symptom.CASE SUMMARY This study reports a case of MZL with generalized skin rashes accompanied by pruritus and purulent discharge.First-line treatment with rituximab combined with zanubrutinib had poor effects.However,after switching to obinutuzumab combined with zanubrutinib,the case was alleviated,and the rashes disappeared.CONCLUSION For patients with advanced stage MZL not benefiting from type I anti-CD20 monoclonal antibody(mAb)combination therapy,switching to a type II anti-CD20 mAb combination regimen may be considered.This approach may provide a new perspective in the treatment of MZL.

Near-surface wind field characteristics of the desert-oasis transition zone in Dunhuang,China

The desert-oasis transition zone(DOTZ)serves as a buffer area between the desert and oasis.Understanding its wind field characteristics is of great significance for the prevention and control of aeolian disasters in the oasis.In this study,we used meteorological data during 2013–2019 from the portable meteorological stations at five sites(site A on the edge of the oasis,sites B,C,and D in the DOTZ,and site O in the desert)in Dunhuang,China to analyze the near-surface wind field characteristics and their causes,as well as to reveal the key role of the DOTZ in oasis protection.The results showed that the mean wind speed,frequency of sand-driving wind,and directional variability of wind decreased from west to east within the DOTZ,and wind speed was significantly affected by air temperature.The terrain influenced the prevailing winds in the region,mainly from northeast and southwest.Only some areas adjacent to the oasis were controlled by southeasterly wind.This indicated that the near-surface wind field characteristics of the DOTZ were caused by the combined effects of local terrain and surface hydrothermal difference.At site D,the annual drift potential(DP)was 24.95 vector units(VU),indicating a low wind energy environment,and the resultant drift direction(RDD)showed obvious seasonal differences.Additionally,the DOTZ played an important buffering role between the desert and oasis.Compared with the desert,the mean wind speed in the oasis decreased by 64.98%,and the prevailing wind direction was more concentrated.The results of this study will be useful in interpreting the aeolian activity of the DOTZ in Dunhuang.

Bendamustine and rituximab as frontline therapy in extranodal marginal zone lymphoma:a single-institution experience

Extranodal marginal zone lymphoma(EMZL)encompasses 70%of cases of marginal zone lymphoma.Frontline bendamustine and rituximab(BR)were derived from trials involving other indolent non-Hodgkin’s lymphomas.Only one trial has evaluated frontline BR prospectively in EMZL.This retrospective study reports outcomes among EMZL patients receiving frontline BR.Twenty-five patients were included with a median age of 69 years(40–81).Five(20.0%)patients had stage Ⅰ/Ⅱ disease,and 20(80.0%)had stage Ⅲ/Ⅳ disease.The median number of cycles was 6.0(3.0–6.0).Maintenance rituximab was administered to 10(41.7%)individuals.Overall response rate(ORR)was 100.0%(60.0%complete response,40.0%partial response).Medians of overall survival and progression-free survival were not reached.The estimated 2-year progression-free survival was 85.2%and overall survival was 100.0%.Four(16.6%)patients had infections related to treatment;3(12.0%)transformed to diffuse large B-cell lymphoma;5(20.8%)had a relapse or progression of EMZL;and 3(12.0%)died unrelated to BR.BR is an efficacious and well-tolerated front-line regimen for EMZL with response data consistent with existing literature.

Transformation of marginal zone lymphoma into high-grade B-cell lymphoma expressing terminal deoxynucleotidyl transferase:A case report

BACKGROUND High-grade B-cell lymphoma(HGBL)is an unusual malignancy that includes myelocytomatosis viral oncogene(MYC),B-cell lymphoma-2(BCL-2),and/or BCL-6 rearrangements,termed double-hit or triple-hit lymphomas,and HGBL-not otherwise specific(HGBL-NOS),which are morphologically characteristic of HGBL but lack MYC,BCL-2,or BCL-6 rearrangements.HGBL is partially transformed by follicular lymphoma and other indolent lymphoma,with few cases of marginal zone lymphoma(MZL)transformation.HGBL often has a poor prognosis and intensive therapy is currently mainly advocated,but there is no good treatment for these patients who cannot tolerate chemotherapy.CASE SUMMARY We reported a case of MZL transformed into HGBL-NOS with TP53 mutation and terminal deoxynucleotidyl transferase expression.Gene analysis revealed the gene expression profile was identical in the pre-and post-transformed tissues,suggesting that the two diseases are homologous,not secondary tumors.The chemotherapy was ineffective and the side effect was severe,so we tried combination therapy including venetoclax and obinutuzumab.The patient tolerated treatment well,and reached partial response.The patient had recurrence of hepatocellular carcinoma and died of multifunctional organ failure.He survived for 12 months after diagnosis.CONCLUSION Venetoclax combined with obinutuzumab might improve the survival in some HGBL patients,who are unsuitable for chemotherapy.

Sclerotic marginal zone lymphoma:A case report

BACKGROUND Marginal zone lymphoma(MZL)is an indolent non-Hodgkin B cell lymphoma with various architectural pattern including perifollicular,follicular colonization,nodular,micronodular,and diffuse patterns.A sclerotic variant has not been previously reported and represents a diagnostic pitfall.CASE SUMMARY A 66-year-old male developed left upper extremity swelling.Chest computed tomography(CT)in September 2020 showed 14 cm mass in left axilla.Needle core biopsy of axillary lymph node showed sclerotic tissue with atypical B lymphoid infiltrate but was non-diagnostic.Excisional biopsy was performed for diagnosis and showed extensive fibrosis and minor component of infiltrating B cells.Flow cytometry showed a small population of CD5-,CD10-,kappa restricted B cells.Monoclonal immunoglobulin heavy chain and light chain gene rearrangement were identified.Upon being diagnosed with MZL,patient was treated with rituximab,cyclophosphamide,doxorubicin,vincristine,and prednisone and achieved complete remission by positron emission tomography/CT.CONCLUSION This is an important case report because by morphology this case could have easily been overlooked as non-specific fibrosis with chronic inflammation representing a significant diagnostic pitfall.Moreover,this constitutes a new architectural pattern.While sclerotic lymphomas have rarely been described(often misdiagnosed as retroperitoneal fibrosis),we do not know of any cases describing this architectural presentation of MZL.

Laparoscopic splenectomy for treatment of splenic marginal zone lymphoma

AIM: To investigate the short-term and long-term ef-ficacy and safety of laparoscopic splenectomy (LS) for treatment of splenic marginal zone lymphoma (SMZL). METHODS: A total of 18 continuous patients who were diagnosed with SMZL and underwent LS in our department from 2008 to 2012 were reviewed. The perioperative variables and long-term follow-up were evaluated. To evaluate the efficacy and safety of this procedure better, we also included 34 patients with liver cirrhosis who underwent LS, 49 patients with immune thrombocytopenia (ITP) who underwent LS, and 20 patients with SMZL who underwent open splenectomy (OS). The results observed in the different groups were compared.RESULTS: No differences were found in the sex and Child-Pugh class of the patients in SMZL-LS, SMZL-OS, ITP, and liver cirrhosis groups. The splenic length of the patients in the SMZL-LS group was similar to that in the SMZL-OS and liver cirrhosis groups but significantly longer than in the ITP group. The SMZL-LS group had a significantly longer operating time compared with the SMZL-OS, ITP, and liver cirrhosis groups, and the SMZL-LS group exhibited significantly less blood loss compared with the SMZL-OS group. No difference was found in the length of the postoperative hospital stay between the SMZL-LS, SMZL-OS, ITP, and liver cirrhosis-LS groups. After surgery, 6 (33.3%) SMZL-LS patients suffered slight complications. During mean fol-low-up periods of 13.6 and 12.8 mo, one patient from the SMZL-LS group and two from the SMZL-OS group died as a result of metastasis after surgery. None of the ITP and liver cirrhosis patients died. CONCLUSION: LS should be considered a feasible and safe procedure for treatment of SMZL in an effort to improve the treatment options and survival of patients.

Revisiting mesoscale eddy genesis mechanism of nonlinear advection in a marginal ice zone

A three-dimensional（3-D） ocean model is coupled with a two-dimensional（2-D） sea ice model, to revisit a nonlinear advection mechanism, one of the most important mesoscale eddy genesis mechanisms in the marginal ice zone. Two-dimensional ocean model simulations suggest nonlinear advection mechanism is more important when the water gets shallower. Instead of considering the ocean as barotropic fluid in the 2-D ocean model, the 3-D ocean model allows the sea ice to affect the current directly in the surface layer via ocean-ice interaction. It is found that both mesoscale eddy and sea surface elevation are sensitive to changes in a water depth in the 3-D simulations. The vertical profile of a current velocity in 3-D experiments suggests that when the water depth gets shallower, the current move faster in each layer, which makes the sea surface elevation be nearly inverse proportional to the water depth with the same wind forcing during the same time. It is also found that because of the vertical motion, the magnitude of variations in the sea surface elevation in the 3-D simulations is very small,being only 1% of the change in the 2-D simulations. And it seems the vertical motion to be the essential reason for the differences between the 3-D and 2-D experiments.

Fluid-rock interaction in retrograde granulites of the Southern Marginal Zone,Limpopo high grade terrain,South Africa

Fluid infiltration into retrograde granulites of the Southern Marginal Zone （Limpopo high grade terrain） is exemplified by hydration reactions, shear zone hosted metasomatism, and lode gold mineralisation. Hydration reactions include the breakdown of cordierite and orthopyroxene to gedrite ＋ kyanite, and anthophyllite, respectively. Metamorphic petrology, fluid inclusions, and field data indicate that a low H2O-activity carbon-saturated CO2-rich and a saline aqueous fluid infiltrated the Southern Marginal Zone during exhumation. The formation of anthophyllite after orthopyroxene established a regional retrograde anthophyllite-in isograd and occurred at P-Tconditions of -6 kbar and 610 ℃, which fixes the minimum mole fraction of H20 in the CO2-rich fluid phase at ~ 0.1. The maximum H20 mole fraction is fixed by the lower temperature limit （~800 ℃） for partial melting at -0.3. C-O-H fluid calculations show that the CO2-rich fluid had an oxygen fugacity that was 0.6 log10 units higher than that of the fayalite-magnetite- quartz buffer and that the CO2/（CO2＋CH4） mole ratio of this fluid was 1. The presence of dominantly relatively low density CO2-rich fluid inclusions in the hydrated granulites indicates that the fluid pressure was less than the lithostatic pressure. This can be explained by strike slip faulting and/or an increase of the rock permeability caused by hydration reactions.

Functions of follicular and marginal zone B cells in pregnancy

Dear Editor, Pregnancy is a physiological condition when immune cells face a dual crisis, as on one hand, the body needs to essentially tolerate semi-allogenic fetus possessing antigens from maternal and paternal sides, while on the other hand the maternal as well as the fetal body must not be adversely affected by infections. This delicate balance between immune tolerance and responses is regulated by an orchestra of immune cells. Various immune regulations by B cells are lately being explored. These include the production of asymmetric antibodies, induced by pregnancy factors, providing protection against maternally derived antipaternal symmetric antibodies at the feto-maternal interface[1] to protect the fetus from immune attack by destructive maternal natural killer cells as well as cytotoxic lymphocytes(2)Moreover, the regulatory B cells can inhibit pro-inflammatory responses triggered by T cells and pro inflammatory mediators during pregnancy, by secreting interleukin-10, a potent anti-inflammatory cytokine(3)Interleukin-10, secreted by B cells, also suppresses activities of the dendritic cells and keeps them in an immature state as mature dendritic cells would induce T cells which are detrimental to pregnancy sustenance[4].

Characteristics of sea ice kinematics from the marginal ice zone to the packed ice zone observed by buoys deployed during the 9th Chinese Arctic Expedition

Sea ice growth and consolidation play a significant role in heat and momentum exchange between the atmosphere and the ocean.However,few in situ observations of sea ice kinematics have been reported owing to difficulties of deployment of buoys in the marginal ice zone(MIZ).To investigate the characteristics of sea ice kinematics from MIZ to packed ice zone(PIZ),eight drifting buoys designed by Taiyuan University of Technology were deployed in the open water at the ice edge of the Canadian Basin.Sea ice near the buoy constantly increased as the buoy drifted,and the kinematics of the buoy changed as the buoy was frozen into the ice.This process can be determined using sea ice concentration,sea skin temperature,and drift speed of buoy together.Sea ice concentration data showed that buoys entered the PIZ in mid-October as the ice grew and consolidated around the buoys,with high amplitude,high frequency buoy motions almost ceasing.Our results confirmed that good correlation coefficient in monthly scale between buoy drift and the wind only happened in the ice zone.The correlation coefficient between buoys and wind was below 0.3 while the buoys were in open water.As buoys entered the ice zone,the buoy speed was normally distributed at wind speeds above 6 m/s.The buoy drifted mainly to the right of the wind within 45°at wind speeds above 8 m/s.During further consolidation of the ice in MIZ,the direct forcing on the ice through winds will be lessened.The correlation coefficient value increased to 0.9 in November,and gradually decreased to 0.7 in April.

Variation of Antarctic marginal ice zone extent (1989-2019)

The Antarctic marginal ice zone(MIZ)is the transition region between open water and consolidated pack ice,which is defined as an area with 15%-80%sea ice concentration.The MIZ represents the outer circle of Antarctic sea ice and the biological activity circle of Antarctic organisms,which provides a direct indication of the extent of Antarctic sea ice.In this study,the joint total variation and nonnegative constrained least square algorithm are applied to retrieve the Antarctic MIZ extent based on passive microwave data sets from 1989 to 2019.The spatial and temporal variations of the Antarctic MIZ extent and five regions are analyzed.The results show that the Antarctic MIZ extent follows a strong monthly variation pattern,decreasing from November to February and increasing from March to October.The annual MIZ extent is largest in the Weddell Sea and smallest in the Western Pacific Ocean.The edge of the sea ice begins to form a closed ring in May,which eventually closes near the Antarctic Peninsula.The ring width variation is large in summer,but generally stabilizes between 350 and 370 km in winter.The average latitude of the Antarctic MIZ is relatively stable in summer,but changes substantially in winter with a difference of approximately 3°.In October,the lowest mean latitude of the MIZ can reach 64.35°S.The sea surface pressure,2-m temperature,and 10-m wind speed are negatively correlated with the MIZ extent variation,among which the second-order partial correlation coefficient of the sea surface pressure and MIZ extent is−0.8773 in the Western Pacific Ocean.

Primary mucosal-associated lymphoid tissue extranodal marginal zone lymphoma of the bladder from an imaging perspective: A case report

BACKGROUND Mucosal-associated lymphoid tissue extranodal marginal zone(MALT)lymphoma is a low-grade tumor that rarely occurs in the urinary bladder.There is currently no consensus on the common imaging findings or most appropriate treatment in MALT lymphoma in the urinary bladder due to the limited number of reports.CASE SUMMARY A 48-year-old woman was admitted to the hospital with a 1-year history of macroscopic hematuria.Imaging showed a large homogeneous mass with an unclear boundary and an irregular morphology in the bladder.The mass had an abundant blood supply.For further diagnosis,transurethral cystoscopic biopsy and bone marrow biopsy was performed,and the patient was finally diagnosed with primary MALT lymphoma of the bladder.R-CHOP chemotherapy was carried out.After three cycles of chemotherapy,the mass disappeared and the bladder wall thickness was only 4 mm,which indicated excellent therapeutic response to the chemotherapy.To date,the patient remains asymptomatic and she visits our hospital regularly for the completion of the remaining chemotherapy cycles.CONCLUSION Primary MALT lymphoma of the bladder is rare,and there are certain characteristics in the ultrasonographic findings.Imaging findings play an important role in evaluating the therapeutic efficacy and are critical during long-term follow-up after therapy.

Splenectomy with chemotherapy vs surgery alone as initial treatment for splenic marginal zone lymphoma

AIM:To evaluate the clinical characteristics of splenic marginal-zone lymphoma (SMZL) following antigen expression and the influence of therapeutic approaches on clinical outcome and overall survival (OS).METHODS: A total of 30 patients with typical histological and immunohistochemical SMZL patterns were examined. Splenectomy plus chemotherapy was applied in 20 patients, while splenectomy as a single treatment-option was performed in 10 patients. Prognostic factor and overall survival rate were analyzed.RESULTS: Complete remission (CR) was achieved in 20 (66.7%), partial remission (PR) in seven (23.3%), and lethal outcome due to disease progression occurred in three (10.0%) patients. Median survival of patients with a splenectomy was 93.0 mo and for patients with splenectomy plus chemotherapy it was 107.5 mo (Log rank=0.056, P>0.05). Time from onset of first symptoms to the beginning of the treatment (mean 9.4 mo) was influenced by spleen dimensions, as measured by computerized tomography and ultra-sound (t=2.558, P=0.018). Strong positivity (+++) of CD20 antigen expression in splenic tissue had a positive influence on OS (Log rank=5.244, P<0.05). The analysis of factors interfering with survival (by the Kaplan-Meier method) revealed that gender, general symptoms, clinical stage, and spleen infiltration type (nodular vs diffuse) had no significant (P>0.05) effects on the OS. The expression of other antigens (immunohistochemistry) also had no effect on survival-rate, as measured by a χ2 test (P>0.05).CONCLUSION: Initial splenectomy combined with chemotherapy has been shown to be beneficial due to its advanced remission rate/duration; however, a larger controlled clinical study is required to conf irm our findings.

Structural Architecture for Development of Marginal Extensional Sub-Basins in the Red Sea Active Rift Zone

This paper presents a robust kinematic model that describes northern Red Sea and Gulf of Suez rifting and the development of marginal extensional half-graben sub-basins (ESB). A combination of Landsat Enhanced Thematic Mapper Plus (ETM+) and structural data was used to provide model constraints on the development of rift segments and ESB in the active rift zones. Structural analysis shows rotation and change in strike of rift-bounding faults. The model describes the northern Red Sea region as a poly-phase rift system initiated by late Oligocene (30 - 24 Ma) orthogonal rifting and the development of marginal ESB (now inland ESB), followed by oblique rifting and flank uplift during the early Miocene (24 - 18 Ma). The oblique rifting fragmented the rift depression into segments separated by oblique-slip accommodation within reactivated Pan-African (ca. 600 Ma) fracture zones, resulting in the development of antithetic faults and an en-echelon distribution of inland ESB. The current phase of rifting was instigated by the development of the Dead Sea Transform in response to increased northeasterly extension during the middle Miocene (ca. 18 Ma). The model explains the widening of the Red Sea rift during the last phase more than the Gulf of Suez rift by developing more antithetic faults and formation of offshore ESB, and deepening the rift depression.

Follicular lymphoma presenting like marginal zone lymphoma:A case report

BACKGROUND Follicular lymphoma(FL),a common type of indolent lymphoma,carries markers of the germinal center,and the rearrangement of the BCL-2 gene is regarded as an initiating event and a hallmark of the neoplasm.When FL has marginal zone differentiation,some marginal zone features are carried by the neoplasm.CASE SUMMARY A 54-year-old male with lymphadenopathy,splenomegaly and hyperlymphocytosis was diagnosed with FL with marginal zone differentiation.The tumor demonstrated different features in the bone marrow(BM)compared with the follicle of the lymph node(LN).Some component of the neoplasm mimicked marginal zone lymphoma,such as infiltrating the marginal zone of the LN,displaying a monocytoid shape and lacking the expression of CD10 in the BM.The diagnosis of FL was made due to the concurrent detection of BCL-2 rearrangement in the LN and BM.CONCLUSION Discordant pathological features in LN and BM could mislead diagnosis.When clinical and pathological manifestations are confusing in diagnosis,typical genetic abnormalities are decisive.

Splenic Marginal Zone Lymphoma in a Patient with Positive Hepatitis B Virus Serology

We present a case in which an elderly woman diagnosed with a splenic marginal zone lymphoma (MZL) was found to have positive Hepatitis B serology. Link with Hepatitis C virus is well documented but reports of association of Hepatitis B virus (HBV) with splenic marginal zone lymphoma are still emerging. A 69-year-old lady presented with weight loss, pancytopenia and marked splenomegaly. Prior to commencing treatment, Hepatitis B serology confirmed Hepatitis B infection. She was treated with Chlorambucil along with anti-hepatitis B prophylaxis and HBV PCR monitoring. She had an excellent response to treatment with resolution of symptoms and splenomegaly. This case highlights the importance of testing for hepatitis B serology in patients diagnosed with splenic MZLs as causative agent. Although the association between HCV is well documented in the literature, a relationship between HBV may also be important. Also, chemotherapy +/- Rituximab for splenic MZL is associated with the reactivation of latent infections;hence providing prophylactic cover for pre-existing latent HBV infection may be required to prevent reactivation as in this case.

Secondary light chain amyloidosis with Waldenstr?m’s macroglobulinemia and intermodal marginal zone lymphoma:A case report

BACKGROUND The co-existence of Waldenstr?m’s macroglobulinemia(WM) with internodal marginal zone lymphoma(INMZL) is rare and often associated with poor prognosis.CASE SUMMARY We present a Chinese female patient who developed secondary light chain amyloidosis due to WM and INMZL and provides opinions on its systemic treatment.A 65-year-old woman was diagnosed with WM 6 years ago and received Bruton tyrosine kinase inhibitor monotherapy for two years.Her INMZL was confirmed due to left cervical lymphadenopathy.The patient presented with oedema in both lower limbs one year ago,and was diagnosed with secondary light chain amyloidosis.Treatment with the BC regimen(rituximab 375 mg/m~2 monthly for 6-8 courses,and bendamustine 90 mg/m~2 per day × 2,monthly for six courses) was initiated,but not tolerated due to toxic side effects.Bortezomibbased therapy was given for two months,including bortezomib,dexamethasone,and zanubrutinb.Oedema in both lower limbs was relieved and treatment efficacy was evaluated as partial remission.CONCLUSION A detailed clinical evaluation and active identification of the aetiology are recommended to avoid missed diagnosis and misdiagnosis.

The Ternary Marginal Extension of China's Free Trade Zone Development

This paper attempts to establish a framework of upgrading mechanism in China's foreign economic opening strate莒y in order to conclude the new connotation of upgrade for China's foreign economic opening,with the basic starting point of ternary marginal extension on extensive growth,in the perspective of corporate heterogeneity theory.It also involves the new path of the transformation from"quantity1'to"quality"regarding the amounts,models and locations of China's foreign trade and investment.At last,this theoretical frame is complemented upon a case study of free trade zone and regional cooperation of Guangdong,Hong Kong and Macao.

Tectonic Phase Separation Applied to the Sudetic Marginal Fault Zone(NE part of the Czech Republic)

This study emphasizes the advantage of tectonic phase separation in determination of a tectonic evolution of complicated fault zones. The research focused on the Sudetic Marginal Fault Zone(SMFZ) –a 250 km long active fault zone with documented intraplate seismicity situated on the NE margin of the Bohemian Massif(the Czech Republic). The tectonic history of the SMFZ as well as its kinematic development has been rather complicated and not quite understood. A field structural investigation was carried out in extensive surroundings of the fault zone. The fault-slip data were collected in a number of natural outcrops and quarries with the aim at establishing a robust and field-constrained model for local brittle structural evolution of the studied area. A paleostress analysis was calculated using the collected fault-slip data inversion. The T-Tecto software was utilized for semiautomatic separation of the paleostress phases. Simultaneously three methods of data separation were employed:(1) the Gauss inverse method,(2) the Visualization of Gauss object Function, and(3) the frequency analysis. Within the fault zone multiphase movements were observed on various types of faults as well as wide range of the kinematic indicators orientations. The frequency analysis confirmed the multiphase history of the SMFZ. The calculated tectonic phases were divided according to their relative age as constrained by cross cutting relationships and, where observed, multiple striations on a single fault plane and classified from the oldest to the younger. Data separation and inversion usingT-Tecto software with the Gauss inverse method revealed four different stress phases which are 3 strike-slip stress regimes and one compressional regime. The strike-slip regimes are characterized by σ1 trending NW-SE(43), NNE-SSW(18), ENE-WSW(76) and the compressional one by σ1 trending W-E(26). First, compression occurred parallel to the SMFZ supposedly during the Variscan period. Second, compression at an angle of 60° to general direction of the SMFZ yielded right-lateral movement along the fault zone. This is considered to have occurred during the late-Variscan and post-Variscan period. Third, compression in the W-E direction with almost vertical extension led to reverse movement along the fault zone. This is considered to have occurred during Cenozoic. Fourth, compression almost perpendicular to the SMFZ led to left-lateral transpression along the SMFZ. This is considered to have occurred during Quaternary.

Two distinct subpopulations of marginal zone B cells exhibit differential antibody-producing capacities and radioresistance

Marginal zone(MZ)B cells,which are splenic innate-like B cells that rapidly secrete antibodies(Abs)against blood-borne pathogens,are composed of heterogeneous subpopulations.Here,we showed that MZ B cells can be divided into two distinct subpopulations according to their CD80 expression levels.CD80^(high)MZ B cells exhibited greater Ab-producing,proliferative,and IL-10-secreting capacities than did CD80^(low)MZ B cells.Notably,CD80^(high)MZ B cells survived 2-Gy whole-body irradiation,whereas CD80^(low)MZ B cells were depleted by irradiation and then repleted with one month after irradiation.Depletion of CD80^(low)MZ B cells led to accelerated development of type II collagen(CII)-induced arthritis upon immunization with bovine CII.CD80^(high)MZ B cells exhibited higher expression of genes involved in proliferation,plasma cell differentiation,and the antioxidant response.CD80^(high)MZ B cells expressed more autoreactive B cell receptors(BCRs)that recognized double-stranded DNA or CII,expressed more immunoglobulin heavy chain sequences with shorter complementarity-determining region 3 sequences,and included more clonotypes with no N-nucleotides or with B-1a BCR sequences than CD80^(low)MZ B cells.Adoptive transfer experiments showed that CD21^(+)CD23^(+)transitional 2 MZ precursors preferentially generated CD80^(low)MZ B cells and that a proportion of CD80^(low)MZ B cells were converted into CD80^(high)MZ B cells;in contrast,CD80^(high)MZ B cells stably remained CD80^(high)MZ B cells.In summary,MZ B cells can be divided into two subpopulations according to their CD80 expression levels,Ab-producing capacity,radioresistance,and autoreactivity,and these findings may suggest a hierarchical composition of MZ B cells with differential stability and BCR specificity.