BACKGROUND:Upper lumbar spinal stenosis is a multifactorial degenerative disorder of the spine.For narrowing of the spinal canal in the upper lumbar region(L1-L4),surgical decision-making is particularly complex.Existing minimally invasive surgeries each have their own advantages and limitations.Currently,there are few reports on biomechanical comparison and finite element analysis of different surgical methods for the treatment of high lumbar spinal stenosis.OBJECTIVE:To analyze the biomechanical impact of endoscopic unilateral laminotomy for bilateral decompression,transforaminal endoscopic lumbar decompression,and cross-overtop decompression in the treatment of upper lumbar spinal stenosis using endoscopy,and to verify the reliability and effectiveness of these three surgical techniques in treating upper lumbar spinal stenosis,providing a biomechanical basis for clinical decision-making.METHODS:The CT images of the lumbar spine of a healthy volunteer were selected,and the finite element model M0 of the normal lumbar L1-L5 segments was established using Mimics,Geomagic,Solid works,and Ansys software.The L2-L3 segment,representing upper lumbar characteristics,was chosen.Based on this model,the surgical models for endoscopic unilateral laminotomy for bilateral decompression(M1),transforaminal endoscopic lumbar decompression(M2),and cross-overtop decompression(M3)were established.Using software,the changes in the range of motion of the entire lumbar segment and the maximum Von Mises stress of the intervertebral discs were simulated and evaluated for each group of models under six loading conditions:flexion,extension,left lateral bending,right lateral bending,left rotation,and right rotation.RESULTS AND CONCLUSION:(1)Compared with model MO,the range of motion in M1,M2,and M3 increased under all six conditions,with M1 showing a greater increase.(2)M1 and M2 demonstrated significant increases in range of motion under forward bending,extension,and right rotation,while the increase under other conditions remained below 7％.(3)Compared with model M3,model M1 exhibited slightly increased overall joint range of motion during extension and left bending,while no significant changes were observed in other aspects,and the L1-L5 lumbar segments did not reach an unstable state.(4)In model M1,the maximum Von Mises stress of the intervertebral discs increased most significantly under flexion and extension loading conditions.However,under left lateral bending,right lateral bending,left rotation,and right rotation loading conditions,the increase did not exceed 5％.(5)These findings suggest that due to the sagittal anatomical characteristics of the facet joints,the unilateral laminotomy for bilateral decompression technique,while decompressing,involves resection of more facet joints,which impacts overall segmental stability.The transforaminal endoscopic lumbar decompression technique is suitable for patients with foraminal stenosis but cannot achieve complete decompression for those with severe ventral central stenosis.The Cross-Overtop technique effectively enlarges the volume of the central canal and lateral recess,optimizing decompression,and shows unique advantages in treating upper lumbar spinal stenosis.

BACKGROUND:Upper lumbar spinal stenosis is a multifactorial degenerative disorder of the spine.For narrowing of the spinal canal in the upper lumbar region(L1-L4),surgical decision-making is particularly complex.Existing minimally invasive surgeries each have their own advantages and limitations.Currently,there are few reports on biomechanical comparison and finite element analysis of different surgical methods for the treatment of high lumbar spinal stenosis.OBJECTIVE:To analyze the biomechanical impact of endoscopic unilateral laminotomy for bilateral decompression,transforaminal endoscopic lumbar decompression,and cross-overtop decompression in the treatment of upper lumbar spinal stenosis using endoscopy,and to verify the reliability and effectiveness of these three surgical techniques in treating upper lumbar spinal stenosis,providing a biomechanical basis for clinical decision-making.METHODS:The CT images of the lumbar spine of a healthy volunteer were selected,and the finite element model M0 of the normal lumbar L1-L5 segments was established using Mimics,Geomagic,Solid works,and Ansys software.The L2-L3 segment,representing upper lumbar characteristics,was chosen.Based on this model,the surgical models for endoscopic unilateral laminotomy for bilateral decompression(M1),transforaminal endoscopic lumbar decompression(M2),and cross-overtop decompression(M3)were established.Using software,the changes in the range of motion of the entire lumbar segment and the maximum Von Mises stress of the intervertebral discs were simulated and evaluated for each group of models under six loading conditions:flexion,extension,left lateral bending,right lateral bending,left rotation,and right rotation.RESULTS AND CONCLUSION:(1)Compared with model MO,the range of motion in M1,M2,and M3 increased under all six conditions,with M1 showing a greater increase.(2)M1 and M2 demonstrated significant increases in range of motion under forward bending,extension,and right rotation,while the increase under other conditions remained below 7％.(3)Compared with model M3,model M1 exhibited slightly increased overall joint range of motion during extension and left bending,while no significant changes were observed in other aspects,and the L1-L5 lumbar segments did not reach an unstable state.(4)In model M1,the maximum Von Mises stress of the intervertebral discs increased most significantly under flexion and extension loading conditions.However,under left lateral bending,right lateral bending,left rotation,and right rotation loading conditions,the increase did not exceed 5％.(5)These findings suggest that due to the sagittal anatomical characteristics of the facet joints,the unilateral laminotomy for bilateral decompression technique,while decompressing,involves resection of more facet joints,which impacts overall segmental stability.The transforaminal endoscopic lumbar decompression technique is suitable for patients with foraminal stenosis but cannot achieve complete decompression for those with severe ventral central stenosis.The Cross-Overtop technique effectively enlarges the volume of the central canal and lateral recess,optimizing decompression,and shows unique advantages in treating upper lumbar spinal stenosis.

ObjectiveTo investigate the therapeutic mechanism of Xuefu Zhuyutang （XFZYT） for metabolic-associated fatty liver disease （MAFLD） through integrated network pharmacology and animal experiments. MethodsNetwork pharmacology was utilized to predict the core components， key therapeutic targets， and signaling pathways of XFZYT in the treatment of MAFLD. For animal experiments， a rat model of MAFLD was established by feeding a high-cholesterol diet for 4 weeks. Intervention was then administered with low-dose （2 g·kg^-1） and high-dose （4 g·kg^-1） XFZYT for 2 weeks. Biochemical assays were performed to measure the serum levels of aspartate aminotransferase （AST）， alanine aminotransferase （ALT）， total cholesterol （TC）， triglycerides （TG）， high-density lipoprotein （HDL）， and low-density lipoprotein （LDL）. In addition， the activities of superoxide dismutase （SOD） and catalase （CAT） and levels of malondialdehyde （MDA） and glutathione （GSH） in the serum were measured. The same way was adopted to measure the levels of TC and TG in the liver tissue. Enzyme-linked immunosorbent assay （ELISA） was employed to quantify the serum levels of interleukin （IL）-6， IL-1β， and tumor necrosis factor-alpha （TNF-α）. Histopathological evaluations included hematoxylin and eosin （HE） staining for liver tissue morphology， Oil Red O staining for lipid deposition， and dihydroethidium （DHE） probe staining for reactive oxygen species （ROS） levels. Western blot analysis was conducted to assess the protein levels of AMP-activated protein kinase （AMPK）， phosphorylated （p）-AMPK， nuclear factor erythroid 2-related factor 2 （Nrf2）， heme oxygenase-1 （HO-1）， nuclear factor-kappa B （NF-κB）， and p-NF-κB in the liver tissue. Untargeted metabolomics analysis of the serum was performed by liquid chromatography-tandem mass spectrometry （LC-MS/MS）. ResultsNetwork pharmacology analysis predicted 155 potential targets of XFZYT for MAFLD treatment， with core targets including signal transducer and activator of transcription 3 （STAT3）， protein kinase B1 （Akt1）， TNF， and IL-6. Kyoto Encyclopedia of Genes and Genomes （KEGG） pathway enrichment primarily implicated the AMPK signaling pathway. Animal experiments demonstrated that compared with the normal group， the model group exhibited dyslipidemia， hepatic function impairment， pronounced hepatic lipid deposition， and inflammatory manifestations， with elevated serum levels of AST， ALT， TC， TG， LDL， and MDA （P<0.05）， reduced HDL and GSH levels plus decreased SOD and CAT activities （P<0.05）， downregulated protein levels of Nrf2， HO-1， and p-AMPK （P<0.05）， and upregulated protein level of p-NF-κB （P<0.05） in the liver tissue. Compared with the model group， XFZYT intervention groups showed significant amelioration of dyslipidemia and hepatic function impairment， markedly reduced hepatic lipid deposition and inflammatory cell infiltration， decreased serum levels of AST， ALT， TC， TG， LDL， and MDA （P<0.05）， increased HDL and GSH levels plus enhanced SOD and CAT activities （P<0.05）， upregulated protein levels of Nrf2， HO-1， and p-AMPK （P<0.05）， and downregulated protein level of p-NF-κB （P<0.05）. Serum metabolomics revealed 511 differentially expressed metabolites （231 upregulated and 280 downregulated） between normal and model groups， while XFZYT groups versus model group showed 94 differential metabolites （51 upregulated and 43 downregulated）. Among them， 11 metabolites displayed the most significant alterations， with enriched pathways including glycerolipid metabolism， cholesterol metabolism， and insulin resistance， multiple of which demonstrated AMPK association. ConclusionXFZYT alleviates MAFLD by regulating the AMPK signaling pathway and associated metabolic networks.

ObjectiveTo investigate whether Huanglian Jiedutang （HLJD） and its major active constituents （geniposide， baicalin， and berberine） can inhibit the inflammatory response of BV2 cells under lipopolysaccharide （LPS） stimulation via the high-mobility group protein B1 （HMGB1）/Toll-like receptor 4 （TLR4）/nuclear factor-κB （NF-κB） signaling pathway， and to explore differences in therapeutic efficacy among the three monomers， their combined formula， and HLJD under equal content ratios. MethodsBV2 microglial cells were used as the primary experimental model. Cell viability was assessed using the cell counting kit-8 （CCK-8） method to examine the effects of different concentrations of dimethyl sulfoxide （DMSO， 0.8%， 0.4%， 0.2%， 0.1%， and 0.05%） on cell viability. IncuCyte was employed to monitor the growth of cells under different concentrations of HLJD （200， 100， 50， 25， 12.5， 6.25 mg·L^-1）. Nitric oxide （NO） assay was used to screen the optimal HLJD concentration. High-performance liquid chromatography （HPLC） determined the content of geniposide， baicalin， and berberine in HLJD， and experimental groups were subsequently established according to the relative proportions of these constituents. CCK-8 assay evaluated cell viability under different treatments. Enzyme-linked immunosorbent assay （ELISA） measured levels of inflammatory factors （TNF-α， IL-1β， IL-6， IL-10） in the supernatant. Flow cytometry assessed the effects of treatments on M1-type polarization of BV2 cells. Western blot determined the expression levels of HMGB1， TLR4， and NF-κB-related proteins. ResultsCompared with the blank group， DMSO at concentrations ≤0.2% did not affect cell viability within 48 h. BV2 cell growth plateaued at 24 h after treatment with 200 mg·L^-1 HLJD. Under stimulation with 2 mg·L^-1 LPS， this concentration of HLJD effectively reduced NO release， and 6 h pre-treatment had a stronger inhibitory effect on NO than direct administration. HPLC results showed that 1 mg of HLJD freeze-dried powder contained approximately 24 μg of geniposide， 15 μg of baicalin， and 30 μg of berberine. Based on these ratios， experimental groups were blank， LPS （2 mg·L^-1）， HLJD （200 mg·L^-1）， monomer combination， geniposide （4.8 mg·L^-1）， baicalin （3 mg·L^-1）， and berberine （6 mg·L^-1）. The monomer combination group consisted of all three active constituents dissolved together. LPS and HLJD or its active constituents did not affect cell viability compared with the blank group. LPS significantly increased TNF-α， IL-1β， IL-6， and IL-10 in the supernatant （P<0.01）. HLJD and its active constituents significantly reduced pro-inflammatory factors TNF-α， IL-1β， and IL-6 （P<0.05， P<0.01） while upregulating anti-inflammatory IL-10 （P<0.01）， with the monomer combination showing the strongest effect （P<0.05， P<0.01）. Compared with the blank group， LPS significantly increased the proportion of CD80⁺CD86⁺ （M1-type） BV2 cells （P<0.01）. HLJD and its constituents partially inhibited M1 polarization （P<0.05， P<0.01）， with the monomer combination exhibiting the most pronounced effect （P<0.05， P<0.01）. Compared with the blank group， LPS upregulated HMGB1， TLR4， and NF-κB-related proteins （P<0.01）， whereas HLJD and its active constituents significantly reduced their expression （P<0.05， P<0.01）， with the monomer combination having the strongest regulatory effect （P<0.05， P<0.01）. ConclusionHLJD and its major active constituents （geniposide， baicalin， berberine） can inhibit LPS-induced inflammatory responses in BV2 cells. The combination of the three active constituents demonstrates the most potent anti-inflammatory effect， significantly attenuating M1-type polarization of BV2 cells via the HMGB1/TLR4/NF-κB signaling pathway.

Objective: To evaluate the efficacy and safety of ruxolitinib combined with low-dose hormone for patients with acute graft-versus-host disease (aGVHD) after allogeneic hematopoietic stem cell transplantation (allo-HSCT). Methods: Thirty patients with aGVHD after allo-HSCT admitted to the Department of Hematology of the General Hospital of Western Theater Command from November 2021 to November 2024 were retrospectively analyzed. All patients were treated with low-dose hormone (methylprednisolone 0.3-1 mg kg -d ) combined with ruxolitinib 5-10 mg d . The efficacy and adverse reactions were observed during the follow-up period to analyze the survival outcomes of the patients. Results: A total of 30 patients with aGVHD after allo-HSCT were included in this study, consisting of 15 (50%) males and 15 (50%) females with a median age of 34 year-old (ranging from 14 to 62). Classification by disease type: there were 18 cases of acute myeloid leukemia, 4 cases of acute lymphoblastic leukemia, 4 cases of aplastic anemia, and 4 cases of myelodysplastic syndrome. Classification by aGVHD severity: there were 27 cases (90%) of Ⅱ-Ⅳ degree aGVHD and 11 cases (36.7%) of Ⅲ-Ⅳ degree aGVHD. Ruxolitinib in combination with low-dose glucocorticoid treatment yield responses in 28 (93.3%) patients, of which 27 (90%) achieved complete remission (CR), while 1 (3.3%) showed partial remission (PR). One patient (3.3%) had no response (NR), and 1 patient (3.3%) exhibited progressed disease (PD). Overall survival (OS) at 1 year of transplantation was 73.9% (95%CI 49.5% to 87.7%), progression-free survival (PFS) was 93.3% (95%CI 75.9% to 98.3%), non-relapse mortality (NRM) was 20.6% (95%CI 7.9% to 47.4%), and median survival time was 27.6 months. Conclusion: Ruxolitinib combined with low-dose hormones is safe and effective in the treatment of aGVHD after allo-HSCT.

Objective To investigate the impact of two different surgical methods, orthotopic kidney transplantation and abdominal heterotopic kidney transplantation, on the surgical outcomes of pig-to-pig kidney transplantation and the short-term survival of recipient pigs after surgery. Methods Twenty-four Bama miniature pigs were divided into two groups, with 12 pigs in each group, and underwent orthotopic kidney transplantation and abdominal heterotopic kidney transplantation, respectively. The perioperative indicators of the recipient pigs, renal blood perfusion, the overall incidence rate of complications and survival rate were compared between the two surgical methods. Results The total surgical time, renal artery anastomosis time, renal vein anastomosis time, cold ischemia time and total ischemia time were all shorter in the abdominal heterotopic kidney transplantation group than in the orthotopic kidney transplantation group, with statistically significant differences (all P<0.05). The number of satisfactory renal perfusion cases was higher in the abdominal heterotopic kidney transplantation group than in the orthotopic kidney transplantation group (83% vs. 75%), but the difference was not statistically significant (P>0.05). The total incidence of postoperative complications was 33% in the heterotopic kidney transplantation group, with a survival rate of 92%, and the cause of death was rupture of the vascular anastomosis. The total incidence of postoperative complications was 50% in the orthotopic kidney transplantation group, with a survival rate of 83%, and the causes of death were renal vein thrombosis and renal artery thrombosis. There were no statistically significant differences in the total incidence of postoperative complications and survival rates between the two groups (all P>0.05). Conclusions Compared with orthotopic kidney transplantation, abdominal heterotopic kidney transplantation showes better surgical outcomes in pig-to-pig kidney transplantation and is more beneficial for the short-term survival of recipient pigs after surgery. This provides experience for improving the stability of pig-to-non-human primate kidney xenotransplantation models in the future.

Objective To clarify the risk factors of diaphragmatic dysfunction (DD) after cardiac surgery with extracorporeal circulation. Methods A retrospective analysis was conducted on the data of patients who underwent cardiac surgery with extracorporeal circulation in the Department of Cardiovascular Surgery of Peking University People's Hospital from January 2023 to March 2024. Patients were divided into two groups according to the results of bedside diaphragm ultrasound: a DD group and a control group. The preoperative, intraoperative, and postoperative indicators of the patients were compared and analyzed, and independent risk factors for DD were screened using multivariate logistic regression analysis. Results A total of 281 patients were included, with 32 patients in the DD group, including 23 males and 9 females, with an average age of (64.0±13.5) years. There were 249 patients in the control group, including 189 males and 60 females, with an average age of (58.0±11.2) years. The body mass index of the DD group was lower than that of the control group [(18.4±1.5) kg/m2 vs. (21.9±1.8) kg/m2, P=0.004], and the prevalence of hypertension, chronic obstructive pulmonary disease, heart failure, and renal insufficiency was higher in the DD group (P<0.05). There was no statistical difference in intraoperative indicators (operation method, extracorporeal circulation time, aortic clamping time, and intraoperative nasopharyngeal temperature) between the two groups (P>0.05). In terms of postoperative aspects, the peak postoperative blood glucose in the DD group was significantly higher than that in the control group (P=0.001), and the proportion of patients requiring continuous renal replacement therapy was significantly higher than that in the control group (P=0.001). The postoperative reintubation rate, tracheotomy rate, mechanical ventilation time, and intensive care unit stay time in the DD group were higher or longer than those in the control group (P<0.05). Multivariate logistic regression analysis showed that low body mass index [OR=0.72, 95%CI (0.41, 0.88), P=0.011], preoperative dialysis [OR=2.51, 95%CI (1.89, 4.14), P=0.027], low left ventricular ejection fraction [OR=0.88, 95%CI (0.71, 0.93), P=0.046], and postoperative hyperglycemia [OR=3.27, 95%CI (2.58, 5.32), P=0.009] were independent risk factors for DD. Conclusion The incidence of DD is relatively high after cardiac surgery, and low body mass index, preoperative renal insufficiency requiring dialysis, low left ventricular ejection fraction, and postoperative hyperglycemia are risk factors for DD.

Objective To establish a rat model of acute antibody-mediated rejection (AMR) in kidney transplantation and investigate the preventive effect of dihydroartemisinin (DHA) on acute AMR. Methods BN rats were used as donors and Lewis rats as recipients. Kidney transplantation was performed 2 weeks after skin transplantation for sensitization. After establishing the acute AMR model in rat kidney transplantation, the recipients of experimental groups included the syngeneic kidney transplantation group (6 rats), the allogeneic kidney transplantation group (6 rats), the syngeneic skin transplantation followed by kidney transplantation group (12 rats), and the allogeneic skin transplantation followed by kidney transplantation group (24 rats). The groups for investigating the preventive effect of DHA on acute AMR included the control group (allogeneic skin transplantation followed by kidney transplantation) and the DHA group (allogeneic skin transplantation followed by kidney transplantation + DHA), with 12 rats in each group. The survival time of recipient rats, serum donor-specific antibody (DSA) levels and graft pathological changes were used to identify the acute AMR model. On this basis, DSA levels, pathological changes in the transplant kidneys and peripheral blood B-cell levels were detected to assess the preventive effect of DHA on acute AMR. Results Compared with the allogeneic kidney transplantation group, skin transplantation sensitization significantly shortened the survival time of recipient rats (P<0.01). Compared with the syngeneic skin transplantation followed by kidney transplantation group, the allogeneic skin transplantation followed by kidney transplantation group showed significantly elevated serum DSA-IgG levels from 7 days after skin transplantation to 5 days after kidney transplantation (P<0.01), and significantly elevated DSA-IgM levels at 7 and 14 days after skin transplantation(all P<0.01). The transplant kidneys in the allogeneic skin transplantation followed by kidney transplantation group showed a small number of inflammatory cell infiltrations, tubular necrosis, capillaritis, and C4d deposition starting from 1 day after kidney transplantation, with these pathological changes worsening as the post-transplantation days increased. The kidney damage became significant starting from 3 days after transplantation. The above pathology manifestations were consistent with the characteristics of acute AMR. On the basis of establishing the acute AMR model, DHA treatment significantly prolonged the survival time of recipient rats (P<0.01) , and reduced serum DSA-IgG and DSA-IgM levels. DHA treatment significantly alleviated the pathological manifestations of acute AMR, including kidney damage, inflammatory cell infiltration, capillaritis and tubular necrosis, and also reduced C4d deposition in the transplant kidneys, inflammatory cell infiltration and peripheral blood CD19⁺ B-cell levels. Conclusions An acute AMR model is established by performing kidney transplantation 2 weeks after allogeneic skin transplantation in rats. It is discovered that DHA has immunosuppressive effects and may effectively prevent acute AMR, which provides a new strategy for the management of clinical AMR.

Objective:To investigate the clinical characteristics and prognosis of patients with locally advanced or metastatic pulmonary neuroendocrine tumors(NETs).Methods:The clinical records of patients with locally advanced or metastatic pulmonary NETs in Peking Uni-versity Cancer Hospital&Institute were selected from January 2014 to June 2024.The clinical characteristics,treatment,and survival pro-gnosis were then analyzed.Results:There were 32 patients,of which 18 were male and 14 female.The median age was 56 years.Nine pa-tients had typical carcinoid and 23 had atypical carcinoid,with six in stage Ⅲ and 26 in stage Ⅳ.The common metastatic sites included the bones(18 cases),lungs(8 cases),pleura(7 cases),and liver(7 cases).The median length of the measurable primary tumor was 5.2 cm,which was mostly located centrally(22 cases).Five among the 16 patients who underwent somatostatin receptor(SSTR)imaging had high SSTR ex-pression.The initial symptoms mainly included respiratory symptoms,and none of them were combined with carcinoid syndrome.For the first-line treatment,19 patients were treated with chemotherapy,seven were treated with targeted therapy,four were treated with soma-tostatin analogs(SSAs),and two were treated with surgery.The best efficacy was evaluated as a partial response in one case(3.1%),stable disease in 23 cases(71.9%),and non-evaluable or unknown in eight cases(25%)in the first-line treatment.The median progression-free sur-vival(mPFS)of patients who received first-line treatment was 5.2 months(95%CI:0.0-13.9).The PFS of targeted therapy was the longest(11.0 months,95%CI:0.0-29.6),but there was no significant difference compared with the PFS of chemotherapy and SSA groups(P>0.05).The longest PFS(24.5 months,95%CI:0.0-58.7)was found in patients treated with chemotherapy combined with radiotherapy,but there was no significant difference compared to the PFS of the combined immunotherapy and combined anti-angiogenesis groups(P>0.05).The survival rates at 1,3,and 5 years were 79.1%,65.5%,and 58.9%,respectively.Cox regression analysis did not identify independent risk factors for prognosis.Conclusions:The initial symptoms of patients with locally advanced or metastatic NETs were mainly respiratory symp-toms but without specific manifestations.Some of them were accompanied by high SSTR expression,and there was generally no carcinoid syndrome.The first-line systemic therapy mainly included chemotherapy and target therapy,with relatively low objective response and high disease control rates.Targeted therapy and combined radiotherapy have longer PFS than that of chemotherapy.The overall survival of pa-tients with pulmonary NETs was good.

OBJECTIVE To explore the clinical characteristics of Mycoplasma pneumoniae pneumonia(MPP)after COVID-19 epidemic so as to offer help for early clinical diagnosis and treatment.METHODS The clinical data that were collected from the MPP patients who were treated in the fever clinic of the First Medical Center of Chinese PLA General Hospital from Jul.2023 to Aug.2024 were retrospectively analyzed.The results of laboratory tests for the different age groups of patients complicated with other pathogens were statistically analyzed.RESULTS Of totally 161 MPP patients who were enrolled in the study,78(48.85％)were male,and 83(51.55％)were fe-male;the average age was(32.98±14.35)years old,and the patients aged between 20 and 40 years old accoun-ted for 43.48％(70 cases).The enrolled patients were divided into the simple MPP group with 92(57.14％)ca-ses and the MPP+mixed group with 69(42.86％)cases according to the result of etiological test of sputum;the patients of MPP+mixed group were divided into the MPP+bacteria group with 42(60.87％)cases,the MPP+fungi group with 10(14.49％)cases,and the MPP+viruses group with 17(24.64％)cases.There was significant difference in the age among the groups(P＜0.05);there were no significant differences in the sex,white blood cell counts and percentage of mononuclear cells among the groups,the percentage of lymphocytes was highest in the simple MPP group,the levels of C-reactive protein(CRP)and interleukin-6(IL-6)were highest in the MPP+bacteria group,and there were significant differences(P＜0.05).All of the patients were divided into three groups:the ≤20-year-old group the＞20-40-year old group and the＞40-year-old group.There were no sig-nificant differences in the white blood cell counts,percentage of lymphocytes,percentage of mononuclear cells and IL-6 level among the three groups,and the CRP level was highest in the＞20-40-year old group(P=0.025).Ran-dom forest model analysis showed that the weight of CRP was highest(22.65％)among the clinical characteristics of the MPP patients,which played a key role in construction of model.As for other factors,the weight of age was 17.02％,the percentage of lymphocytes 15.34％,the white blood cells counts 14.86％,the percentage of mono-nuclear cells 14.39％,the IL-6 13.61％,the gender 2.13％.CONCLUSION MPP maintains common among the patients aged less than 40 years old after the COVID-19 epidemic,nearly half of the patients are complicated with the infections of other pathogens,and CRP is more helpful for the clinical diagnosis and treatment of the MPP in early stage.