Association of Anti-β 1 and Anti-M2 Antibodies with Autonomic Nervous System Modulation in Patients with Chronic Chagas Cardiomyopathy

Abstract Background: Different immune mechanisms of myocardial damage involved in the pathophysiology of Chagas disease coexist with high titers of autoantibodies induced by T. cruzi . There are few studies in the literature about the adaptive role of anti-β1 and anti-M2 antibodies in chronic Chagas cardiomyopathy (CCC). Objectives: To evaluate the association between anti-β1 and anti-M2 antibodies with heart rate variability (HRV) parameters on 24h Holter monitoring and the rate-pressure product (RPP) on cardiopulmonary exercise testing (CPET). Methods: Anti-β1 and anti-M2 antibody titers were measured by enzyme-linked immunosorbent assay (ELISA) in 64 patients affected by CCC. Analysis of HRV was performed through the time-domain indices NNs, mean NN, SDNN, SDANN, SDNN index, NNNs, RMSSD, and pNN50. Spearman's correlation coefficient was used to assess the association between antibody titers and numerical variables. The Mann-Whitney test was used for comparison between two groups. Multiple linear regression was used to identify independent variables capable of explaining anti-β1 and anti-M2 antibody titers at the 5% significance level. Results: On 24h Holter, during the period of greatest parasympathetic activation (2:00-6:00 a.m.), an inverse association was found between anti-β1 titers and SDNN (rs=-0.13, p =0.041, n=43), as well as a direct association between anti-M2 titers and SDANN ( r s=0.317, p =0.039, n=43). Regarding CPET variables, anti-β1 titers were directly associated with RPP (rs=0.371, p =0.005, n=56). The subgroup of patients with a normal chronotropic response showed higher anti-β1 titers than the subgroup with an impaired response (p=0.023). RPP was an independent explanatory variable for anti-β1 titers, although with a low coefficient of determination (R2=0.147). Conclusion: The findings of this study suggest that, in patients with CCC, anti-β1 and anti-M2 antibodies may affect HRV parameters. RPP was directly associated with higher anti-β1 titers.

The 493th case: recurrent edema of bilateral lower extremeties / 中华内科杂志

A 43-year-old male patient with onset of edema caused by nephrotic proteinuria and low titer of anti-M type phospholipase-A 2-receptor (PLA 2R) antibody was diagnosed as idiopathic membranous nephropathy by renal biopsy. Administrated with prednisone 40 mg once a day and cyclosporine 100 mg twice a day as front-line regimen, the patient relapsed after transient partial remission. When treatment was combined with cyclophosphamide 100 mg once a day, the 24-hour total urine protein and titer of anti-PLA 2R antibody were even elevated. Therefore, the patient received rituximab 1 g intravenously in April 2019, October 2019 and October 2020 respectively. CD19 positive B lymphocytes in peripheral blood were eliminated from 71/μl to zero. Immunosuppressants and corticosteroids were withdrawn successively. On the last follow-up in November 2020, the anti-PLA 2R antibody was negative, and the 24-hour total urine protein and serum albumin was 4.4 g and 34 g/L, respectively. This case suggested the potential efficacy of rituximab for refractory membranous nephropathy. Further studies should explore whether the titer of anti-PLA 2R antibody indicates the dose of rituximab.

Diagnosis and genetic analysis of severe neonatal anemia caused by α-Thalassemla combined with cold IgG anti-M / 中国输血杂志

【Objective】 To investigate the family inheritance of α-Thalassemla gene and the risk of severe anemia in neonates caused by cold IgG anti-M. 【Methods】 ABO, Rh, MN blood groups and the specificity of unexpected antibody were identified by blood group serology. The IgG subtype and antibody titer of anti-M antibody were detected. The etiology of neonatal hemolytic disease was identified by three tests and α-Thalassemla gene diagnosis. 【Results】 Family investigation showed that father was B, CCDee, MN with no α-Thalassemla gene detected; Mother B, CcDee, NN, carrying α-Thalassemla gene; both the proband and his brother were B, CCDee, MN, carrying α-Thalassemla gene. Cold IgG anti-M was present in plasma of both the mother and the proband. The titer of the mother was 128 and that of the proband was 64. The subtype of IgG anti-M was IgG1 and IgG3. The direct anti-globulin test, release test and free test of the proband and his brother were negative, and the diagnosis was severe anemia and hemolysis caused by α-Thalassemla combined with cold IgG anti-M. 【Conclusion】 The direct antiglobulin test of neonatal hemolytic disease caused by IgG anti-M can be negative or weakly positive, and α-Thalassemla gene could be hereditary in families. The presence of α-Thalassemla gene can cause anemia, hemolysis and splenomegalysis in neonates, which could be aggravated when accompanied by cold-type IgG anti-M. In the presence of high-valency IgG antibody in plasma, blood exchange combined with transfusion can improve the curative effect.

Anti-M induced severe haemolytic disease of foetus and newborn in a Malay woman with recurrent pregnancy loss

Haemolytic disease of the foetus and newborn (HDFN) is caused by maternal red blood cells (RBC) alloimmunisation resulted from incompatibility of maternal and foetal RBCs. However, only a few HDFN attributed to anti-M were reported, varying from asymptomatic to severe anaemia with hydrops foetalis and even intrauterine death. A case of severe HDFN due to anti-M alloantibody from an alloimmunized grandmultiparous Malay woman with recurrent pregnancy loss is reported here. The newborn was delivered with severe and prolonged anaemia which required frequent RBC transfusions, intensive phototherapy and intravenous immunoglobulin administration. Although anti-M is rarely known to cause severe HDFN, a careful serological work-up and close assessment of foetal well-being is important, similar to the management of RhD HDFN. Alloimmunisation with anti-M type can lead to severe HDFN and even foetal loss.

Expression of Serum Anti PLA2 R Antibodies in Idiopathic Membranous Nephropathy / 现代检验医学杂志

Objective To analyze the expression of serum anti M phospholipase A2 receptor (PLA2R)antibody in idiopathic membranous nephropathy (IMN),and to investigate its value in the diagnosis and evaluation of idiopathic membranous ne-phropathy.Methods One hundred and eighteen patients with biopsy-proved glomerular diseases were involved in this study, including 97 cases with IMN,21 cases with IgA nephropathy (IgAN)and 19 healthy people.ELISA was used to detect ser-um anti-PLA2R antibodies.Correlations of anti-PLA2R antibody level with laboratory parameters,including serum albumin, 24-hour urine protein of IMN patients were evaluated.Results The median of anti PLA2R antibody in IMN group,IgAN group and healthy group was 45.2(3.6~705.9)RU/ml,5.9(2.3~10.6)RU/ml and 1.2(0.6~9.3)RU/ml.The levels of serum anti PLA2R antibody in IMN group were higher than those in IgA nephropathy group and healthy control group.The difference was statistically significant (t=-5.027,-3.077;P=0.05).Among 97 cases with IMN,76 cases showed posi-tive anti-PLA2R antibodies (positive rate 78.35%).There was none patient showed positive anti-PLA2R antibody respec-tively in IgAN and healthy people.Furthermore,anti-PLA2R antibody level was negatively correlated with serum albumin (r=-0.453,P=0.000)and positively correlated with CREA,TC,ESR,24 hour urine protein (r=0.233,0.234,0.363, 0.586;P=0.004,0.217,0.021,0.000)in IMN patients.Conclusion Serum anti PLA2R antibody may be used as a IMN specific marker for the diagnosis of IMN,and it has important reference value for evaluating the severity of IMN.

Hemolytic Disease of the Newborn Caused by Anti-M in 2 Male Siblings / 대한주산의학회잡지

Hemolytic disease of the newborn (HDN) caused by anti-M is rare and clinical manifestations are variable ranging from mild anemia and hyperbilirubinemia to hydrops fetalis and intrauterine fetal death. There were few reports of HDN caused by anti-M in Korea but no case in siblings. We experienced a case of 2 male siblings, both of whom had anti-M induced HDN and prolonged anemia persisted for over a month. We report this case with a brief review of literature. This report documents the first case of HDN caused by anti-M in siblings in Korea.

Naturally occurring anti M complicating ABO grouping.

Anti M is considered a naturally occurring antibody that is usually active at temperatures below 37˚C and is thus of on clinical significance. This antibody, if present in an individual, can lead to a discrepancy between forward and reverse ABO grouping and thus creates diagnostic difficulties for blood bank staff. We report a case of a 58-year-old lady who had an unexpected reaction in reverse grouping due to anti M that posed a problem for us in the significance of such discrepancy in blood grouping.

The application of combined detection of autoantibodies in primary Sj(o)gren's syndrome / 中华内科杂志

Objective To compare the specificity and sensitivity of antibodies against SSA and SSB,anti-M3 receptor polypeptide antibodies,anti-α-fodrin(IgG)antibodies in primary SjSgren's syndrome (pSS).Methods One hundred and ten pSS patients(mean age was 49.2±14.8.mean disease duration was 5.6±4.6),80 systemic lupus erythmatosis(SLE)patients(mean age was 25.5 4-4.6,mean disease duration was 2.5±1.2)and 80 rheumatoid arthritis(RA)patients(mean age was 44.6±3.5.mean disease duration was 4.2±1.1)were studied.Enzyme-linked immunosorbent assay was used to measure these antibodies.Results The seropositive rates of anti-SSA,anti-SSB antibodies,anti-M3 receptor polypeptide antibodies and anti-α-fodrin(IgG)antibodies were 45.5%,30.9%,78.2%and 77.3%,respectivelv in pSS.They were much higher than those in RA and SLE patients(P<0.05).Specificities of SSA、SSB antibodies,anti-M3 receptor antibodies and anti-α-fodrin IgG were 83.8%,97.7%.92.0%and 90.O% respectively.With the combination of these antibodies in the diagnosis of pSS.the Sellsitivity can be increased at least to 88.2%and the specificity was not decreased significantly.Conclusion Combination of these antibodies can significantly improve the sensitivity of these antibodies in the diagnosis of pSS.Anti-SSA and SSB antibodies,anti-M3 receptor antibodies and anti-α-fodrin(IgG)antibodies are specific antibodies for the diagnosis of pSS.

The clinical significance of autoantibodies against acetylcholine muscarinic 3 receptor in primary Sj(o)gren's Syndrome / 中华内科杂志

Objective To detect anti-M3 receptor antibodies in primary Sj(o)gren's syndrome(pSS)patients and to explore its association with clinical manifestations.Methods Anti-M3 antibodies were tested in 70 patients with pSS,50 patients with systemic lupus erythematosus(SLE)and 76 normal controls with ELISA and Western blot.The correlation between anti-M3 antibodies and other clinical manifestations was analyzed.Results (1)The positive rate of anti-M3 antibodies in pSS Was 47.14% using ELISA and 60.00% using Western blot in SLE 4.00% using ELISA and 12.00% using Western blot and in normal controls 14.47% using ELISA and 15.79% using Western blot.(2)The incidence of sehirmer test,tear break-up time(BUT),whole saliva flow rate,punctate epithelial erosions(PEE)on the corneas and external eye examination were not significantly different between the anti-M3 positive and negative groups.(3)The incidences of IgG,rheumatoid factor,SSB and fluorescence index(FI)＞3 were higher in the positive group than in the negative group using EUSA.Conclusion The positive rate of anti-M3 antibodies is higher in pSS than in SLE and normal controls and in some degree it has correlation with the lesion in salivary gland.

Two Cases of Anti-M of Donated Bloods Confirmed at pH 6.5 / 대한수혈학회지

Anti-M is detected at room temperature and is often found in the sera of people who have never been exposed to human red cells. In a few cases, anti-M can be detected at 37 degrees C or at the antiglobulin phase, and these antibodies can cause hemolytic diseases in newborn or hemolytic transfusion reactions. Some examples of anti-M demonstrate stronger agglutination at low pH (pH 6.5), and when they react with the red blood cells of the MM type (dosage effect). An unexpected antibody test was carried out for the routine screening of donated blood and two cases that reacted to all panel cells at 5 degrees C were found, which indicated anti-M. We repeated the unexpected antibody identification test at pH 6.5 and confirmed the presence of anti-M. The reduction of the test system pH is a useful and simple method for detecting some cases of anti-M.

A Moderate Case of Hemolytic Disease in a Newborn Caused by Anti-M Antibody / 대한임상병리학회지

Anti-M antibodies are usually assumed to be naturally occurring and to consist of immunoglobulin M reacting at 4degrees C. They are not usually considered to be clinically significant, however, many of them have an immunoglobulin G component reacting at 37degrees C and can be correlated with hemolytic disease of the newborn (HDN). We report a moderate case of HDN by anti-M. A 2-days old baby born from a mother with preeclampsia as a second pregnancy was admitted due to anemia, hyperbilirubinemia and hypoxic encephalopathy. The blood type of mother was AB, ccDEE, NN, and the blood type of baby was A, D+, and MN. Antibody screening and identification identified anti-M antibody which was strong reactive at 37degrees C albumin and antiglobulin phase in both baby's and her mother's serum. The direct antiglobulin test of baby's red blood cells was negative. The infant was transfused with group O red cells which have negative to trace reaction with her mother's serum in antiglobulin phase. Two days later, the hemoglobin level elevated from 6.7 g/dL to 15.9 g/dL falled to below 11 g/dL quite soon. After all, newborn died of cardiac arrest due to her basic disease at age of 49 days; metabolic acidosis and hypernatremia.

Polymorphisms of PPARgamma2 gene in patients with type 2 diabetes mellitus and obesity / 대한내과학회지

BACKGROUND: Peroxisome proliferator activated receptor-gamma (PPAR-gamma) is a nuclear receptor that regulate adipocyte differentiation and modulate intracellular insulin-signaling events. As such, PPARgamma is a candidate gene for several human disorders including obesity and type 2 diabetes mellitus. The objective of our study was to examine the relationship between genetic variation of PPARgamma2 and diabetes and obesity in Korean subjects. METHODS: We studied 99 subjects with type 2 diabetes mellitus, 128 obesity patients and 97 controls. Screening for mutation at codon 12 and 115 of PPARgamma2 were carried out by PCR-RFLP analyses. Statistical significance was evaluated by Chi-square test. RESULTS: The allele frequency of the Pro12Ala PPARgamma2 variant were 0.05 in controls, 0.06 in type 2 diabetes group, and 0.07 in obesity group (p=0.47). Pro115Gln variant were only proline homozygote in all groups. Genotype frequencies were also similar and conformed to expectations of the Hardy-Weinberg rule. The presence of PPARgamma2 gene variant was no associated with concentrations of total cholesterol, triglyceride, HDL-cholesterol, and also with fasting glucose. CONCLUSION: We concluded that the Pro12Ala and Pro115Gln PPARgamma2 missense mutation may not be associated with type 2 diabetes mellitus and obesity in Korean patients.

A case of conventional antimitochondrial antibody test-negative primary biliary cirrhosis / 대한내과학회지

Primary biliary cirrhosis is a chronic progressive cholestatic liver disease of unknown cause that usually affects middle-aged women and eventually leads to cirrhosis and liver failure. It is characterized by the progressive destruction of small intrahepatic bile ducts, portal inflammation, and progressive scarring. The diagnosis is made by these characteristic pathologic findings and the presence of antimitochondrial antibody. Immunofluorescence, the most widely used method for determining antimitochondrial antibody, is less sensitive and specific than ELISA or immunoblotting and influenced by observer interpretation. Therefore, it is important to detect anti-M2 antibody, the most specific antibody of primary biliary cirrhosis, by ELISA or immunoblotting when antimitochondrial antibody is not detected by immunofluorescence method which can lead to the incorrect diagnosis as autoimmune cholangitis. We describe a case of primary biliary cirrhosis with antimitochondrial antibody negative by immunofluorescence, anti-M2 antibody positive by ELISA. We confirmed primary biliary cirrhosis by liver biopsy.

A Case of Successful Pregnancy in a Woman with Anti-M Isoimmunization after Intravenous Immunoglobulin Therapy / 대한산부인과학회잡지

Although severe hemolytic diseases of the newborn triggered by anti-M are very rare, anti-M alloantibodies have been known to be associated with a cause of multipie intrauterine death. Serological and hematological investigations have been reported on a woman who experienced four multiple intrauterine deaths due to anti-M. The mothers blood type was of group A, NN and the husbands cells were of group B, MN. In the serological examination at 9th week's gestation of the fifth pregnancy, anti-M antibodies were identified in her serum. The antibodies comprised IgM saline agglutinin at a titer of 16 at 4 degrees C and IgG agglutinin reacted in an indirect antiglobulin technique at a titer of 4 at 37 degrees C. She underwent high-dose immunoglobulin infusion therapy on a monthly program from 3rd month gestation and a total of 6 times of intravenous immunoglobulin was given. The anti-M titer did not rise during the pregnancy. She delivered a live girl by cesarean section at the 37th week because of a failure of induction. The childs blood type was of group O, MN. The child was discharged and developed normally.

Mood Group Serological Identification of Monocolonal Antibodies Anti-M and Anti-N / 中国输血杂志

The BALB/c mice were immunized with human O blood cells. Their spleen cells were fused with murine myeloma cells Ns-1 with PEG. The monoclonal antibodies were identified with human panelled cells. Two clones secreting monoclonal anti-M(2Al and 3F6)and another two clones secreting monoclonal anti-N(4E3 and 7G5)were identified. All these clones could consistently secrete IgM antibodies. In typing 300 different RBC samples,the specificity of antibodies were identical to those of commercial humen anti-M and anti-N typing sere reagent. Significantly, anti-N reagent 4E3 differed from anti-N reagent 7G5, which the former one couldn't be absorbed by M erythrocytes at all,while the latter one absorbed by M erythroeytes.