黄芪多糖对红斑狼疮小鼠6种抗磷脂抗体的影响

目的 :观察黄芪多糖 (PG2 )对红斑狼疮小鼠抗心磷脂 (anticardiolipin ,aCL)、抗磷脂酰胆碱 (antiphosphatidylcho line ,aPC)、抗磷脂酰丝氨酸 (antiphosphatidylserine,aPS)、抗磷脂酰肌醇 (antiphosphatidylinositol,aPI)、抗磷脂酸 (antiphosphatidicacid ,aPA)和抗磷脂酰乙醇胺 (antiphosphatidylethanolamine ,aPE) 6种自身抗体的影响。方法 :19只雌性NZB×NZWF1小鼠随机分为黄芪I组 (2 5mg kg) 7只 ,黄芪II组 (5 0mg kg) 6只及生理盐水组 (0 2ml d) 6只 ,日一次腹腔注射 ;雌性BXSB及C5 7BL 6小鼠作对照 ,用酶联免疫吸附 (ELISA)法测定各组小鼠的 6种抗磷脂抗体A值进行比较。结果 :NZB×NZWF1小鼠黄芪II组各种抗磷脂抗体A均值比生理盐水组明显降低 (P <0 0 5或P <0 0 1) ,与BXSB ,C5 7BL 6小鼠比无统计学差异 ;黄芪I组与生理盐水组比有所升高 ;黄芪I组及生理盐水组与BXSB、C5 7BL 6比明显升高 (P <0 0 5或P <0 0 1)。结论 :黄芪多糖低剂量有使抗磷脂抗体升高的趋势 ,高剂量可明显抑制抗磷脂抗体的产生     

广州市健康人群EB病毒感染情况的调查分析

目的了解广州地区健康人群中的EB病毒感染情况。方法采用ELISA法检测2007年1月至2011年12月本院体检的217935例健康人的EB—VCA—IgA抗体,统计对比男女阳性率、5年问阳性率及各年龄段（≤29岁、30,39岁、40～49岁和≥50岁5个组）阳性率的差异。结果EB—VCA-I酗抗体阳性4667例,总阳性率2．14％。其中男性135985例,阳性率1．87％（2547／135985）;女性81950例,阳性率2．59％（2120／81950）,男女阳性率差异有统计学意义（P：0．000）。5年间各年阳性率差异有统计学意义臼z=576．054,P=0．000）。EB—VCA．IgA抗体的阳性率随着年龄的增长而增高,各年龄段差异均有统计学意义（P=0．000）。结论广州地区健康人群中有一定比例的EB病毒感染者,且40岁以上健康人群感染率相对较高。     

广州地区健康儿童肠道病毒71型抗体水平调查

目的调查广州地区健康儿童肠道病毒71型抗体IgG（EV71-IgG）的水平,分析与EV71所致手足口病（HFMD）发病的关系。方法以来源于广州市妇女儿童医疗中心（我院）中心实验室分离到的EV71 C4亚型标本,制备EV71诊断抗原,建立EV71-IgG抗体诊断试剂盒方法,并进行实验室评价。收集2010年1~3月在我院儿保科抽血进行常规保健检测的标本,筛选出无发热、无HFMD症状的健康儿童血清标本,检测EV71-IgG抗体。选取我院2010年全年门诊及住院HFMD患儿的咽拭子标本进行EV71特异性核酸检测。结果①本研究建立的试剂盒EV71-IgG抗体检测临界值为0.148;与细胞中和实验方法阳性符合率为100%,阴性符合率为92%,与柯萨奇A16病毒抗体无交叉反应。②819名健康儿童血清标本中,男481名,女338名。〈1岁组（60%,60/100名）和~2岁组（39.3%,72/183名）EV71-IgG抗体阳性率显著高于其他各年龄组[~3岁、~4岁、~5岁和~14岁组分别为12.9%（15/116名）、27.1%（38/140名）、14.2%（16/113名）和22.8%（38/167名）]。EV71-IgG抗体阳性率无显著性别差异。③4 780例EV71阳性HFMD患儿中,男3 070例,女1 718例。〈1岁310例（6.5%）,~2岁1 157例（24.2%）,~3岁1 337例（28.0%）,~4岁1 094例（22.9%）,~5岁450例（9.4%）,~14岁432例（9.0%）。④各年龄组EV71-IgG抗体阳性率与EV71阳性年龄构成比呈相反趋势,〈1岁组EV71-IgG抗体阳性率最高,EV71阳性年龄构成比最低;~3岁组EV71-IgG抗体阳性率最低,EV71阳性年龄构成比最高。结论 〈1岁健康儿童EV71-IgG阳性率最高,EV71阳性年龄构成比与EV71-IgG阳性率呈相关现象。     

b型流感嗜血杆菌D蛋白原核可溶性表达研究

目的 通过原核表达系统可溶性表达重组D蛋白,为多糖结合疫苗的制备提供蛋白载体.方法 将Hib CMCC株基因组DNA中去除信号肽的hpd基因片段插入pET43.1a表达质粒,转化入感受态大肠埃希菌BL21 (DE3),IPTG诱导表达.表达的重组蛋白,经过硫酸铵沉淀和DEAE阴离子交换柱层析纯化后,用Western Blot的方法鉴定其免疫反应原性.结果 表达的重组蛋白以可溶性形式存在,表达量约占菌株总蛋白的44％,经过初步纯化后的重组蛋白可以和Hib抗血清发生特异性反应.结论 成功构建了D蛋白重组表达质粒,并在原核细胞中以可溶性形式表达出具有良好免疫反应原性的D蛋白.     

36854例普通住院患者梅毒血清学抗体阳性率及其分布状况调查

目的 了解住院患者梅毒(TP)血清抗体阳性率及其分布状况,为梅毒的预防工作提供参考依据.方法 采用酶联免疫吸附试验(ELISA)法对我院2012年1月至2014年10月共36854例普通住院患者血清进行梅毒抗体筛查,阳性标本用双孔复检后再用金标法进行确认试验,两种方法均为阳性病例列为本次统计范围,回顾性分析各科室、各年度及各年龄段阳性率.结果 在36854例住院患者血清中共检出639例梅毒抗体阳性,总体阳性率为1.73％,男性阳性率(2.10％,365/17402)显著高于女性(1.41％,274/19452)(P＜0.05);2012年至2014年年度检出率分别为1.78％、1.77％及1.66％,年度检出率无明显差异(P＞0.05),但呈下降趋势.在科室分布上,检出率排名前五位的科室分别为肿瘤内科(4.64％)、放疗科(3.9％)、内分泌科(3.03％)、心内科(2.86％)及泌尿外科(2.68％),其中肿瘤内科、内分泌科、心内科、泌尿外科及消化内科阳性率均高于总体阳性率(P＜0.05),产科阳性率(0.73％)低于总体阳性率(P＜0.05);各年龄组＜20、20～29、30～ 39、40～49、50 ～ 59、60～ 69、70～79及≥80岁的阳性率分别为:0.14％、0.68％、1.13％、2.14％、2.14％、2.15％、2.22％、3.42％,随着年龄的增加,阳性率呈上升趋势,其中≥40岁各年龄组均显著高于总体阳性率(P＜0.05).结论 三年来梅毒检出率未见上升趋势,梅毒血清抗体阳性在临床上占一定的比例,几乎分布各个科室,常规对住院患者进行梅毒血清学筛查很有必要,对保护医务工作者、减少医源性感染和传播、预防交叉感染以及避免不必要的医疗纠纷有着重要意义.     

脑梗死患者体液S-100b蛋白含量测定及其临床意义

目的　为了观察急性和恢复期脑梗死患者血液和脑脊液的S 10 0b蛋白含量变化 ,探讨其与神经功能缺损程度、脑梗死体积以及患者年龄等方面的相关性。方法　将 4 6例脑梗死住院患者作为观察组 ,2 5例与观察组相匹配的骨折、阑尾或胆囊摘除手术病人以及健康体检者作为对照组 ;采用双抗体夹心ELISA法 ,检测其血液及脑脊液S 10 0b蛋白的含量 ;并应用SPSS10 .0统计软件包进行统计学分析。结果　急性脑梗死 (ACI)患者血液和脑脊液S 10 0b蛋白显著高于恢复期患者和对照组 (P <0 .0 1) ;血液和脑脊液S 10 0b蛋白含量与梗死体积均呈显著正相关 (P <0 .0 1) ;与出院时神经功能缺损程度呈显著正相关 (P <0 .0 1)。结论　脑脊液或血清中的S 10 0b蛋白浓度 ,反映了神经胶质细胞的损害程度 ,也是脑组织破坏后较合适的生化标记物 ,有助于判断脑梗死病人梗死范围、监测病情变化、疗效观察。     

囊虫抗体检测中的方法学比较

本文采用五种不同改良的ELISA平行检测囊虫抗体,发现敏感性依次为ABC-ELISA(100.00％)、经典ELISA(95.65％)、SPA-ELISA(90.91％)、快速法ELISA(89.47％)和BA-ELISA(89.47％)。特异性依次为SPA-ELISA(100.00％)、经典ELISA(97.91％)、BA-ELISA(96.67％)、ABC-ELFSA(95.65％)、快速法ELISA(95.65％),结果显示各方法的敏感性和特异性在统计学上无显著性差异,方法学的选择主要依据习惯和实验的目的。     

麻疹IgM抗体行定量酶联免疫吸附试验检测应用效果分析

目的探讨对麻疹患者采用定量酶联免疫吸附试验测定IgM抗体的临床价值。方法回顾性分析在我院接种麻疹疫苗的100例儿童的临床资料,分别采用定量酶联免疫吸附试验和中和抗体试验测定血清IgM抗体水平,比较两者的符合率;同时统计ELISA与NT诊断的耗时、费用和阳性率。结果浓度≥200 IU/L样品ELISA检测与NT的符合率明显高于200 IU/L样品,其差异有统计学意义(P0.05)。两种检查手段阳性率无明显差异(P0.05),但ELISA法的耗时和费用明显低于NT法其差异有统计学意义(P0.05)。结论定量酶联免疫吸附试验在检测麻疹Ig M抗体时具有很高的准确性,且耗时和费用均较低,值得临床推广。     

非平衡法在乙型肝炎e抗体和核心抗体检测中的效果评价

目的 探讨酶联免疫吸附试验非平衡法对乙型肝炎e抗体和核心抗体检测结果的影响.方法 收集电化学发光免疫分析法（ECLIA）检测抗-HBe阳性标本44例和抗-HBc阳性标本57例,再用酶联免疫吸附试验法（ELISA）对阳性标本进行检测,样本加入反应孔中分别于0min、30min后加入酶标志物,余下步骤均严格按照说明书操作.结果 对ECLIA检测抗-HBe阳性标本44例、抗-HBc阳性标本57例进行ELISA复检后,平衡法抗-HBe的漏检率为52.3％,抗-HBc漏检率为40.4％;非平衡法抗-HBe的漏检率为34.1％,抗-HBc漏检率为24.6％.结论 竞争法检测抗-HBe和抗-HBc时应适当延迟加酶的时间,以降低漏检率.     

The acquisition of anti-pneumococcal capsular polysaccharide Haemophilus influenzae type b and tetanus toxoid antibodies, with age, in the UK.

Antibody levels specific for capsular polysaccharides of Streptococcus pneumoniae and Haemophilus influenzae type b (Hib) and to tetanus toxoid (TT), were measured in serum samples of 750 age-stratified subjects from the UK. The study subjects comprised healthy adult volunteers and hospitalized children undergoing elective surgery, excluding those with a history of infection or under investigation for immunological or haematological disorders. These antibody levels were calibrated by comparison with serum pool obtained from healthy adult volunteers, who were immunized with Hib polyribose-phosphate vaccine (Merieux). The data are intended to provide reference ranges to assist in the interpretation of specific antibody measurements in the clinical setting. Maternal IgG pneumococcal capsular polysaccharide (PCP) specific antibody levels, geometric-mean titre (GMT) 1/22, were lost by 6 months of age (GMT of 1/9). They remained low until 3-5 years (GMT of 1/20), and consisted principally of IgG1. Thereafter, IgG anti-PCP antibody titres increased steadily to adult levels (GMT of 1/275), of which 80% was IgG2. Anti-PCP antibody titres of the IgM isotype rose steadily from a GMT 1/21 (0-6 months) to 1/420 (3-5 years), a level which was maintained until adulthood. Anti-Hib antibody concentrations, determined by RABA, again demonstrated the decline in maternal antibody, from 0.18 micrograms/ml in the 0-6 month age cohort, to 0.09 microgram/ml between 6 and 12 months. Geometric-mean antibody concentrations remained below 0.2 micrograms/ml until 3-5 years, then increased with age, attaining the mean adult level of 1.02 micrograms/ml. Anti-TT antibody concentrations were measured in the same sera, by ELISA. Two peaks in anti-TT antibody levels were seen in children of 0.059 IU/ml and 0.166 IU/ml corresponding to the schedule of routine childhood immunization in the first year and at 5 years of age.     

Subclass distribution of IgA antibodies in saliva and serum after immunization with Haemophilus influenzae type b conjugate vaccines

IgA subclass distribution of antibodies against capsular polysaccharide (PS) of Haemophilus influenzae type b (Hib) was studied in saliva and serum samples of children vaccinated with two (n = 58) or three doses (n = 53) of Hib vaccine. One month after the second dose of Hib conjugate vaccine, at 7 months old, 40% of the children had IgA1 and 41% had IgA2 anti-Hib PS antibodies in saliva. One month after the third dose, at 15–25 months old, IgA1 was the predominating subclass; 72% of the children had IgA1, 26% had IgA2 anti-Hib PS in saliva. The mean concentration of IgA1 anti-Hib PS, expressed as optical density (OD) values, was significantly higher after three doses (OD 80.7) than after two doses (OD 18.9). The mean concentration of IgA2 did not change significantly after the third dose (OD 23.8 after two doses, OD 18.1 after three doses). In serum, IgA1 anti-Hib PS predominated both after two (17% had IgA1, none had IgA2) and three doses (72% had IgA1, 4% had IgA2) of Hib vaccine. In conclusion, both IgA1 and IgA2 anti-Hib PS were found in saliva of immunized children after two doses of Hib conjugate vaccine, whereas the third vaccine dose induced a shift towards IgA1 anti-Hib PS dominance in saliva.     

Immunogenicity of Haemophilus influenzae Type b Conjugate Vaccines in Korean Infants: A Meta-analysis

A meta-analysis was performed on the immunogenicity of Haemophilus influenzae type b (Hib) conjugate vaccines after 2 (2 and 4 months) and 3 doses (2, 4, and 6 months) in Korean infants. A database search of MEDLINE, KoreaMed, and Korean Medical Database was done. The primary outcome measure was the proportion of infants with anti-polyribosylribitol phosphate (PRP) concentrations ≥1.0 µg/mL. Eight studies including eleven trials were retrieved. One trial reported on the diphtheria toxoid conjugate vaccine (PRP-D) and 2 trials each on the mutant diphtheria toxin (PRP-CRM) and Neisseria meningitidis outer-membrane protein (PRP-OMP) conjugate vaccine. Heterogeneity in study designs between trials on PRP-CRM was noted and one trial reported on a monovalent and another on a combination PRP-OMP vaccine. Thus, a meta-analysis was conducted only on the tetanus toxoid conjugate vaccine (PRP-T). After a primary series of 2 doses and 3 doses, 80.6% (95% confidence interval [CI]; 76.0-85.1%) and 95.7% (95% CI; 94.0-98.0%) of infants achieved an antibody level ≥1.0 µg/mL, respectively. The immunogenic response to the PRP-T vaccine was acceptable after a primary series of 3 doses and also 2 doses. A reduced number of doses as a primary series could be carefully considered in Korean infants.     

Immunization with Haemophilus influenzae Type b Conjugate Vaccine in Children Given Bone Marrow Transplantation: Comparison with Healthy Age-Matched Controls

Forty-seven patients (age range, 7 months–18 years)with malignant (38 cases) and nonmalignant (9 cases)disorders given an allogeneic or an autologous bone marrowtransplantation (BMT) were immunized with Haemophilusinfluenzae type b (Hib) polysaccharide–diphtheriatoxoid conjugate vaccine administered in a single dose at different timepoints after transplantation. Results were compared with those of 13healthy children matched for age and sex who received the sameimmunization schedule. Serum and saliva samples for measurement of totalIgG subclass and specific antibody levels were obtained from patientsand healthy controls before and 3 weeks after vaccination. Twenty-fiveof the 47 patients (53%) had a specific anti-Hib IgGresponse, while an effective IgA and IgM response was mounted by 23(49%) and 11 (23%) children,respectively. In the control group, 13 of 13 subjects mounted a specificIgG antibody production (P < 0.005 in comparison to thepatients' response rate), while an IgA and IgM response wasdemonstrated in 12 (92%; P < 0.01compared to transplanted patients) and 7 (54%;P < 0.05 in comparison to BMT recipients) children,respectively. Lapse of time from BMT to immunization was the mostimportant factor predicting antibody response, as proved by an effectiveincrease in prevaccination specific IgG levels in the majority ofpatients vaccinated after 2 years from transplant. Our data demonstratethat BMT recipients have a reduced capacity to mount an antibodyresponse to polysaccharide antigens compared to normal controls, evenwhen a protein-conjugated vaccine is employed. Since time aftertransplant is the major factor influencing the recovery of immunereactivity to polysaccharide antigens, the ontogeny of the B cellrepertoire seems to follow a predetermined sequential program ofdevelopment.     

Expression of Haemophilus influenzae type b idiotype 1 on naturally acquired antibodies

The Chinese population in Hong Kong has a low incidence of invasive Haemophilus influenzae type b (Hib) disease, as well as carriage of the microorganism. Likely stimuli for the natural antibodies to Hib, which might protect against Hib infection, are cross-reactive antigens of bacteria like Escherichia coli K100. Our aim was to determine the isotype and idiotype distribution and cross-reactivity of natural antibodies against Hib capsular polysaccharide (CP) in healthy Hong Kong Chinese. Titration of 20 sera by ELISA showed IgG antibodies reacting with Hib CP in all individuals. The antibodies were mainly IgG2, and their avidity index ranged widely. Isoelectric focusing (IEF) combined with immunoblotting showed patterns of IgG2 antibody clones against the CP of Hib and E. coli K100 which were similar in 10 cases. Absorption with Hib CP only eliminated some bands in two sera. Absorption with K100 CP did not remove any anti-Hib CP bands. In three sera additional clones of antibodies reacting to K100 CP only, disappeared after absorption with this CP. Spectrotypic analyses of IgG antibodies reacting with anti-Hib idiotype 1 (Id-1) revealed stronger IEF patterns with bands in differing locations compared with anti-Hib CP antibodies. The strong reactivity of serum IgG, IgA and IgM antibodies with monoclonal anti-Hib Id-1 was confirmed by ELISA. This reactivity was not abolished after absorption of the sera with either Hib CP, or K100 CP. The data indicate a high prevalence of Id-1 among Hong Kong Chinese. However, only one individual had Id-1 antibodies specific for Hib CP, judging from absorption experiments. Others had much lower activity of Id-1 anti-Hib CP antibodies compared with the total IgG Id-1, suggesting that Hong Kong subjects have Id-1-positive antibodies in their serum which are not specific for Hib CP. This is consistent with the nature of Id-1, which is a marker of A2V_L region usage rather than a marker of a Hib CP paratope. We suggest that natural antibodies reacting with Hib CP in healthy Hong Kong Chinese are the product of exposure to some cross-reactive antigen(s), different from both Hib and E. coli K100 CP.     

Haemophilus influenzae type b opsonins of intravenous immunoglobulins

Immunoglobulin G may be prepared by different methods for intravenous infusion and administered as replacement therapy for hypogammaglobulinemia. Intravenous immunoglobulins prepared by different methods were comparedin vitro for their ability to opsonizeHaemophilus influenzae type b in the absence of complement and subsequently induce neutrophil chemiluminescence. While the antibody contents, measured by an enzyme-linked immunosorbent assay and radioimmunoassay, were equivalent, the immunoglobulin prepared by a non-molecular modifying method (ion-exchange chromatography) had the greatest ability to induce bacterial-neutrophil interaction, measured by chemiluminescence, while a reduced and alkylated immunolgobulin had the least. Thus, preparative methods may have a profound effect upon the function of intravenous immunoglobulins. The biological function of immunoglobulins for clinical use can be compared easily by neutrophil chemiluminescence.     

几株b型流感嗜血杆菌多糖结合物的免疫原性检定

目的 从分子水平检定b型流感嗜血杆菌,研究不同菌株荚膜多糖结合物的免疫原性.方法 提取基因组,通过型特异和荚膜型基因特异引物,利用PCR检定b型流感嗜血杆菌;不同纯化多糖分别与破伤风类毒素(TT)进行耦联结合,结合物原液经稀释免疫小鼠,通过两针免疫,采血进行免疫效力测定.结果 5株b型流感嗜血杆菌通过PCR法均能获得预期大小的型特异(482 bp)和荚膜型(343 bp)基因片段,BLAST分析显示,各菌之间型特异和荚膜型序列比对,其同源性均为100％,各菌型特异和荚膜型序列分别与GenBank X78559.1和M19995.1序列比对,同源性分别为99％和100％;ELISA检测显示,4株不同菌株来源的荚膜多糖结合物(PRP-TT)的小鼠免疫效力差异无统计学意义.结论 通过PCR法从分子水平检定b型流感嗜血杆菌,纯化的不同荚膜多糖结合物小鼠免疫原性基本一致.可供不同Hib多糖结合物免疫原性的研究参考数据.     

Characterization of the antibody response to a Haemophilus influenzae type b conjugate vaccine in children with recurrent lower respiratory tract infection

Children with recurrent lower respiratory tract infection (RLRI) may respond poorly to polysaccharide antigens. To examine how such children respond to a polysaccharide coupled to a protein carrier, we immunized 15 children with RLRI aged 8–69 months and 15 carefully age-matched healthy controls once with a Haemophilus influenzae type b (Hib) conjugate vaccine. Total IgG subclasses, total antipolysaccharide Hib antibodies, and antipolysaccharide Hib antibodies of IgM, IgG, IgA, and IgG 1–4 specificity were determined by ELISA. There were no significant differences between the two groups in any single total IgG subclass, but total IgG measured as the sum of all four subclasses was significantly lower in the children with RLRI than in the controls ( P = 0.036). Before vaccination, the children with RLRI had significantly less IgG antipolysaccharide Hib antibody than the controls ( P = 0.005), whereas 1 month later they had significantly more IgM antibody (P = 0.038). No other significant differences were found between the groups before or after immunization with respect to antipolysaccharide Hib antibodies. Since naturally occurring IgG antibodies are thought to be aquired partly as a consequence of antigenic stimulation on mucosal surfaces, we hypothesize that the low level of specific IgG found before immunization, as well as the low total IgG in the children with RLRI, may reflect an impaired ability to prime through mucosal surfaces. This is supported by our finding of an increased IgM response to Hib conjugate vaccine in these children, since this isotype predominates in the primary immune response, i.e., in the absence of immunologic memory. In conclusion, children with RLRI can be protected against invasive Hib infection as well as healthy children, but may have an immunodeficiency characterized by defective ability to respond to antigenic stimulation on mucosal surfaces.     

番禺区人群B型流感嗜血杆菌（Hib）疫苗接种情况及影响因素调查

目的了解番禺区人群Hib疾病免疫状况及影响因素，为预防和控制Hib疾病提供基础资料和科学依据。方法随机抽取番禺区一个城区疫苗接种门诊和两个乡镇疫苗接种门诊，对所有带儿童到接种点接种的监护人进行既往Hib疫苗免疫状况及影响因素的问卷调查。结果儿童监护人对Hib疾病的了解程度比较低．城区和乡镇均为35％左右；城区儿童监护人对Hib疫苗的了解明显比乡镇高（P=0．000），分别为65.3％和38．4％：城区的Hib疫苗接种率明显比乡镇接种率高（P=0．000），分别为72．4％和36．2％。影响Hib疫苗接种态度的因素主要为疫苗的效果，经医生介绍后儿童监护人对接种Hib疫苗的积极性都较好，城区和乡镇分别达到94．5％和80．4％。结论Hib疫苗的接种率比较低，主要是因为儿童监护人对Hib疾病和疫苗的认识不足，应加强宣传教育，提高儿童监护人接种Hib疫苗的意识。     

Characterization of the Impaired Antipneumococcal Polysaccharide Antibody Production in Immunosuppressed Pediatric Patients Following Cardiac Transplantation

We previously have demonstrated impaired pneumococcal polysaccharide IgG antibody responses in children immunosuppressed following cardiac transplantation in early childhood. We have further characterized the antibody defect. To further investigate the production of antibody, antipneumococcal polysaccharide (PPS) specific IgM, IgG, IgG subclasses, and IgA were measured in postvaccination sera by enzyme-linked immunosorbent assay. Two groups were studied: posttransplant children who made pneumococcal antibody in vivo following natural exposure or PPS immunization (R) and those with an impaired response (NR). There was no difference in IgM or IgA levels between R and NR. IgG and IgG2 levels were higher in R than NR (P = 0.002), even after adsorption of nonspecific common cell wall antigen antibody. Differences in anti-pneumococcal antibody levels suggest that immunoglobulin isotype switching from IgM to IgG and particularly IgG2 is impaired in patients immunosuppressed at a young age. These findings confirm data regarding the effect of immunosuppressive agents derived from animal models in humans.