Complete androgen insensitivity syndrome coexisting with müllerian duct remnants: a case report and literature review.

This study represents the first documentation of the coexistence of complete androgen insensitivity syndrome (CAIS) with Müllerian duct remnants (MDRs) in mainland China. Additionally, we provide a comprehensive review of the existing literature concerning CAIS with MDRs resulting from androgen receptor (AR) gene mutations. This study broadens the clinical spectrum of CAIS and offer novel insights for further exploration into Müllerian duct regression. A 14-year-old patient, initially raised as female, presented to the clinic with complaints of "primary amenorrhea." Physical examination revealed the following: armpit hair (Tanner stage 2), breast development (Tanner stage 4 with bilateral breast nodule diameter of 7 cm), sparse pubic hair (Tanner stage 3), clitoris measuring 0.8 cm × 0.4 cm, separate urethral and vaginal openings, and absence of palpable masses in the bilateral groin or labia majora. The external genital virilization score was 0 points. Serum follicle-stimulating hormone level was 13.43 IU/L, serum luteinizing hormone level was 31.24 IU/L, and serum testosterone level was 14.95 nmol/L. Pelvic magnetic resonance imaging (MRI) did not reveal a uterus or bilateral fallopian tubes, but nodules on both sides of the pelvic wall indicated cryptorchidism. The karyotype was 46,XY. Genetic testing identified a maternal-derived hemizygous variation c.2359C > T (p.Arg787*) in the AR gene. During abdominal exploration, dysplastic testicles and a dysplastic uterus were discovered. Histopathological analysis revealed the presence of fallopian tube-like structures adjacent to the testicles. The CAIS patient documented in this study exhibited concurrent MDRs, thus expanding the spectrum of clinical manifestations of AIS. A review of prior literature suggests that the incidence of CAIS combined with histologically MDRs is not uncommon. Consequently, the identification of MDRs in AIS cases may represent an integral aspect of clinical diagnosis for this condition.

Clinical characteristics of sitosterolemic children with xanthomas as the first manifestation.

BACKGROUND: Sitosterolemia (STSL) is an extremely rare genetic disease. Xanthomas as the first symptom are frequently misinterpreted as familial hypercholesterolemia (FH) in children. Inappropriate treatment may deteriorate the condition of STSL. OBJECTIVES: To present the clinical and laboratory characteristics of xanthomatous children diagnosed with sitosterolemia in comparison with childhood FH with xanthomas. METHODS: We summarized and compared the clinical characteristics of STSL and FH patients with xanthomas as the first manifestations and investigated the different indicators between the STSL and FH groups, as well as their diagnostic values for STSL. RESULTS: Two tertiary pediatric endocrinology departments contributed ten STSL cases. Five of the STSL patients (50%) experienced mild anemia, whereas two (20%) had vascular complications. The xanthomas of the STSL group displayed morphologies comparable to those of the FH group. There were ten cases of homozygous FH (HoFH) with xanthomas as the predominant symptom of the control group who had no anemia. The serum cholesterol (Chol) levels of the STSL and FH groups were 12.57 (9.55 ~ 14.62) mmol/L and 17.45 (16.04 ~ 21.47) mmol/L, respectively (p value 0.002). The serum low-density lipoprotein cholesterol (LDL-c) levels of the STSL and FH groups were 9.26 ± 2.71 mmol/L and 14.58 ± 4.08 mmol/L, respectively (p value 0.003). Meanwhile, the mean platelet volume (MPV) levels of the STSL and FH groups were 11.00 (9.79 ~ 12.53) fl. and 8.95 (8.88 ~ 12.28) fl., respectively (p value 0.009). The anemia proportions of the STSL and FH groups were 50% and 0%, respectively (p value 0.033). The AUC values of Chol, LDL-c, MPV, hemoglobin (Hb) for the diagnosis of STSL were 0.910, 0.886, 0.869, 0.879, respectively. Chol ≤ 15.41 mmol/L, LDL-c ≤ 13.22 mmol/L, MPV ≥ 9.05 fl., or Hb≤120 g/L were the best thresholds for diagnosing STSL with childhood xanthomas. CONCLUSION: The xanthoma morphology of STSL patients resembles that of FH patients. Xanthomas as the initial symptom of a child with Chol ≤ 15.41 mmol/L, LDL-c≤13.22 mmol/L, MPV ≥ 9.05 fl., or Hb≤120 g/L, he was most likely to have STSL.

[Genotypes and clinical features of 595 children with HbH disease in Guangxi, China].

OBJECTIVE: To investigate the genotypes and clinical features of children with HbH disease in Guangxi Zhuang Autonomous Region, China. METHODS: A total of 595 children from Guangxi were recruited. Single-tube multiplex polymerase chain reaction combined with agarose gel electrophoresis, as well as reverse dot blotting, were performed to detect the three α-globin gene deletion mutations (--(SEA), -α(3.7), and -α(4.2)) and three non-deletion mutations (Hb Westmead, Hb Constant Spring, and Hb Quong Sze) which are common in the Chinese population. RESULTS: Among the 595 cases, five common genotypes were identified, which were --(SEA)/-α(3.7) (232 cases), --(SEA)/α(CS)α (174 cases), --(SEA)/-α(4.2) (122 cases), --(SEA)/α(WS)α (35 cases), and --(SEA)/α(QS)α (24 cases). The genotype of THAI deletion associated with α-thalassemia-2 was detected in eight cases. Six ß-mutations including CD41-42, CD17-28, CD26, IVS-II-654, IVS-I-1, and CD27-28 were identified in 23 cases. All children with HbH disease had microcytic hypochromic anemia; children with HbH-CS disease had the most severe anemia, and those with HbH-WS disease had the mildest anemia. CONCLUSIONS: Deletional HbH disease is the main type in children with HbH disease in Guangxi, and some patients also have mild beta-thalassemia. Non-deletional HbH disease shows more severe phenotype than deletional HbH disease.

Therapeutic effects of growth hormone combined with low-dose stanozolol on growth velocity and final height of girls with Turner syndrome.

OBJECTIVE: Turner syndrome (TS), which is characterized by short stature and gonadal dysfunction, is managed by pharmacotherapy. This study aimed to investigate the therapeutic effects of recombinant human growth hormone (rhGH) combined with low-dose stanozolol on the growth and final adult height (FAH) of girls with Turner syndrome (TS). DESIGN: Prospective study. PATIENTS: A total of 44 girls with TS were treated with rhGH (47·6-52·4 µg/kg/day) and low-dose stanozolol (20-35 µg/kg/day), starting at a mean age of 12·65 ± 1·99 year. The control group consisted of 22 girls with TS, who did not receive treatment. MEASUREMENTS: Subjects' growth velocity (GV) was investigated. Height standard deviation score (HtSDS) was calculated relative to healthy Chinese girls (HtSDSN or ) as well as untreated Chinese girls with TS (HtSDSTS ). Post-treatment follow-up was performed until the subjects achieved FAH or near FAH. RESULTS: FAH was significantly higher in subjects receiving treatment compared to the untreated controls (151·42 vs 137·75 cm, P < 0·001). GV was significantly higher in the first to fourth years of treatment compared to baseline values (P < 0·001); it was significantly lower in the second to fourth years of treatment compared to the first year (P < 0·001). CONCLUSIONS: In girls with TS, 9-12 years of age, rhGH combined with low-dose stanozolol may effectively increase growth. At least a 2-year course of this treatment may effectively improve FAH with proper delay of oestrogen-induced development.

In vitro molecular evolution of AL NEIBMs improved immunoglobulin (Ig) binding and antibody detection.

AL (SpA A domain-PpL B3 domain), LD5 (PpL B3 domain-SpA D domain-PpL B3 domain-SpA D domain-PpL B3 domain, L-D-L-D-L) and LD3 (PpL B3 domain-SpA D domain-PpL B3 domain, L-D-L) are novel evolved Ig binding molecules (NEIBMs) derived from the in vitro molecular evolution of combinatorial phage libraries displaying randomly rearranged Ig-binding domains of protein A and protein L. These molecules all showed novel Ig-binding properties of double-site binding to the VH3 and Vκ regions of human Ig Fab and high affinity for human IgM, which enhanced IgM detection in the anti-HCV ELISA assay. In this double-site binding, the A domain binds to the VH3 chain with low affinity. Whether the appropriate mutations in the A domain could improve this binding remains unknown. In this study, four combinatorial phage libraries displaying AL mutants with random mutations at different amino acid positions in the A domain were constructed. Seven AL mutant phages with significantly improved Ig binding activity were obtained from the phage library displaying AL mutants randomly mutated at positions 27 and 34 through human IgM-directed in vitro evolution. Two of the seven prokaryotically expressed AL mutants, AL (VV) and AL (KA), exhibited IgM and IgG binding activities equivalent to those of wild-type AL, whereas other mutants showed attenuated binding. However, after labeling with HRP, AL (VV) and AL (KA) showed improved IgM and IgG binding activity, which significantly improved the detection in the anti-HCV assay. Thus, the present study demonstrates that the binding properties of AL were successfully improved through phage-based molecular evolution, which could substantially contribute to the use of AL in antibody detection, and provides an example of successful protein engineering through in vitro molecular evolution.

Associations between serum apelin-12 levels and obesity-related markers in Chinese children.

OBJECTIVE: To investigate possible correlations between apelin-12 levels and obesity in children in China and associations between apelin-12 and obesity-related markers, including lipids, insulin sensitivity and insulin resistance index (HOMA-IR). METHODS: Forty-eight obese and forty non-obese age- and gender-matched Chinese children were enrolled between June 2008 and June 2009. Mean age was 10.42 ± 2.03 and 10.86±2.23 years in obesity and control groups, respectively. Main outcome measures were apelin-12, BMI, lipids, glucose and insulin. HOMA-IR was calculated for all subjects. RESULTS: All obesity group subjects had significantly higher total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL-C), insulin levels and HOMA-IR (all P<0.05). In separate analyses, obese girls had significantly higher LDL-C, insulin and HOMA-IR than controls, and obese boys had significantly higher TC, TG, insulin and HOMA-IR than controls (all P<0.05). Apelin-12 levels were significantly higher in obese girls compared to controls (P = 0.024), and correlated positively with TG in all obese subjects. Among obese girls, apelin-12 levels correlated positively with TG, insulin and HOMA-IR after adjusting for age and BMI. In all boys (obese and controls) apelin-12 was positively associated with fasting plasma glucose (FPG). No significant correlations were found in either group between apelin-12 levels and other characteristics after adjusting for age, sex, and BMI. CONCLUSIONS: Apelin-12 levels are significantly higher in obese vs. non-obese girls in China and correlate significantly with obesity-related markers insulin, HOMA-IR, and TG. Increased apelin-12 levels may be involved in the pathological mechanism of childhood obesity.

[Effect of gonadotropin-releasing hormone analog combined with stanazolol on final height in girls with idiopathic central precocious puberty and apparent decrease of linear growth].

OBJECTIVE: To evaluate the effect of combined use of stanazolol (ST) on the final adult height (FAH) in girls with idiopathic central precocious puberty (ICPP) and apparently decreased linear growth during gonadotropin-releasing hormone analog (GnRHa) therapy. METHOD: Sixty-three girls with ICPP and decreased velocity of growth of height (HV<4 cm/yr) during GnRHa therapy were divided into 3 groups based on the following types of interventions:group 1 (n = 20), GnRHa+ST [25-30 µg/(kg·d) every 3-month followed by 3-month discontinuation], group 2 (n = 21), GnRHa+recombinant human growth hormone [rhGH, 1-1.1 U/(kg·w)], group 3 (n = 22), GnRHa alone.HV, the advancement of bone age (BA) for chronological age (CA) (ΔBA/ΔCA) and FAH were compared among groups. RESULT: (1)Total duration of ST combination therapy was (12.22 ± 3.62) months, while total duration of combination of rhGH was (13.22 ± 6.80) months. (2)HV increased significantly in both group 1 [ (2.79 ± 0.60) cm/yr vs. (6.27 ± 1.98) cm/yr, P < 0.01] and in group 2 [(2.80 ± 0.50) cm/yr vs. (6.25 ± 1.98) cm/yr, P < 0.01] during combined therapy, but maintained at low levels in group 3 [(3.95 ± 1.10) cm/yr vs. (3.34 ± 0.95) cm/yr, P > 0.05].No significant differences of ΔBA/ΔCA were found among the three groups [0.25(0.11∼0.28), 0.22(0.15∼0.31),0.19(0.10∼0.32), P > 0.05]. (3)FAH was significantly higher than predicted adult height (PAH) before combined therapy, as well as higher than target height (THt) in both group 1 [(156.25 ± 2.90) cm vs. (150.78 ± 3.70) cm, P < 0.01, (156.25 ± 2.90) cm vs. (153.94 ± 2.62) cm, P < 0.01], and in group2 [ (157.33 ± 4.69) cm vs. (152.61 ± 3.92) cm, P < 0.01, (157.33 ± 4.69) cm vs. (154.39 ± 4.72) cm, P = 0.01].In group 3, FAH was similar to PAH [(153.88 ± 2.6) cm vs. (152.54 ± 5.86) cm, P > 0.05], and was less than THt [(153.88 ± 2.6) cm vs. (155.60 ± 4.52) cm, P = 0.02]. (4)In girls treated with ST, no hirsutism, clitorism or hoarse voice was recorded.No polycystic ovary syndrome was found by B-mode ultrasound. CONCLUSION: Intermittent combined use of low dose ST therapy can increase HV and thus improve FAH in girls with ICPP and apparently decreased linear growth during GnRHa therapy.

[Determination of serum steroids in monitoring therapy of congenital adrenal hyperplasia].

OBJECTIVE: To assess the utility of serum steroids measurement in monitoring the treatment of children with congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency (21OHD). METHOD: Nineteen Patients with CAH 21OHD aged (3.67±1.54) years treated with hydrocortisone and fluorocortisone replacement were followed up at an intervals of 0.33 - 1.0 years over a period of (1.47±0.7) years. At each visit, roentgenograms of the hands and wrists were taken, fasting peripheral blood were collected to test serum dehydroepiandrosterone sulfate, progesterone, 17-hydroxyprogesterone (17-OHP), androstenedione (Δ4-A), testosterone, free testosterone, estrone, and estradiol concentrations at 8 AM in the morning before the first dose of glucocorticoid. Then the patients were classified as being in "Good Control" or in "Poor Control" based on clinical criteria including signs of androgen excess, growth velocity and bone age increment at each interval. Comparisons were carried out between the serum steroid concentrations of the two groups. The receiver operating characteristic (ROC) curves were used to determine the cut-off values for diagnosing "Poor Control". RESULT: Both of serum Δ4-A and 17-OHP concentrations were higher in "Poor Control" group than those in "Good Control" group [5.95 (2.23-11.2) nmol/L versus 1.05 (1.05-9.89) nmol/L, t=2.19; 13.85 (6.06-20) µg/L versus 3.67 (0.42-21.1) µg/L, t=2.17; P<0.05, respectively]. The ROC curves for serum Δ4-A concentrations, serum 17-OHP concentrations, serum Δ4-A in combination with 17-OHP concentrations were constructed with areas under the ROC curves (95%CI) of 0.76 (0.62, 0.90), 0.75 (0.62, 0.88), 0.69 (0.54, 0.84), P<0.05, respectively. Serum Δ4-A of 3.9 nmol/L had 0.78 of sensitivity and 0.75 of specificity in diagnosing "Poor Control". Serum 17-OHP of 7.1 µg/L has 0.67 of sensitivity and 0.71 of specificity in diagnosing "Poor Control". CONCLUSION: Each of serum 17-OHP or/and Δ4-A concentration was of significance in diagnosing "Poor Control" during the glucocorticoid replacement treatment of CAH 21OHD, with the diagnostic efficacy being serum Δ4-A concentration, serum 17-OHP concentration and serum Δ4-A in combination with 17-OHP concentration in descending order. Serum Δ4-A and 17-OHP concentrations may be used as the biochemical indicators to monitor the therapy of CAH 21OHD.

Phage-based molecular directed evolution yields multiple tandem human IgA affibodies with intramolecular binding avidity.

Affibodies are a group of affinity proteins that are based on a 58-amino-acid residue protein domain derived from one of the IgG-binding domains of staphylococcal protein A. A single human IgA affibody with high IgA affinity has been generated by directed evolution. It remains interesting whether tandem IgA affibody proteins could increase binding capacity. Here, we report the generation of multiple tandem IgA affibodies by directed evolution using a combinatorial phage library displaying the IgA affibody A1 and/or A2 linked with three random amino acids. These affibodies exhibited markedly increased IgA binding capacity, as shown by enzyme linked immunosorbent assay, immunoblotting and surface plasmon resonance assays. We further showed that these tandem IgA affibodies displayed preferential binding to intact IgA molecules compared to individual IgA chain, suggesting intramolecular binding avidity. Our data demonstrates that artificial multiple tandem human IgA affibodies with relevant biological binding avidity were successfully yielded by phage-based molecular evolution. These results have broad implications for the design and development of binding proteins that target important biological molecules.

Two cases of Fanconi-Bickel syndrome: first report from China with novel mutations of SLC2A2 gene.

Fanconi-Bickel syndrome (FBS) is a rare inherited disease caused by mutations in the glucose transporter 2 gene, SLC2A2. We reported the first two Chinese cases of FBS. Both cases presented typical clinical features of hepatomegaly, hypophosphatemic rickets, severely stunted growth, fasting hypoglycemia along with postprandial hyperglycemia, and proximal renal tubular dysfunction with disproportionately severe glucosuria. Genetic analysis of SLC2A2 gene revealed novel compound heterozygous mutations in both patients. The characteristics of being born as small for gestational age and apparent liver dysfunction in our cases have been seldom discussed in the literature. It seems FBS patients in general have lower birth weight than normal, but further data collection is still needed. Symptomatic treatments were effective, but the serum transaminase of patient 2 remained moderately increased, and he patient needed further follow-up. The present study will supplement the up-to-date clinical characteristic spectrum for FBS.

Clinical characteristics of adrenocortical tumors in children.

BACKGROUND: Adrenocortical tumors (ACTs) are rare in children. Because of the rarity and various manifestations of ACTs, patients of ACTs are not easily diagnosed. Some patients were misdiagnosed before surgery. OBJECTIVE: Identify the clinical, laboratorial, imaging and histopathological characteristics of adrenocortical tumors in children. Compare adrenalcortical adenoma with carcinoma. METHODS: A retrospective review of 34 identified patients who were younger than 15 years old with histologic confirmation of adrenocortical carcinoma (ACC) or adenomas from 1991 to 2010. RESULTS: In these 34 patients, 19 were adrenocortical adenoma (ACA) and 15 were ACC. The median age at diagnosis was 3.33 years (range, 0-16 years), and 70.6% of the patients were younger than five years. Girls slightly predominated over boys (1.4:1). For endocrine abnormality, 14 patients had isolated precocious puberty, five patients had isolated Cushing syndrome, 10 patients had precocious puberty plus Cushing syndrome, and five patients did not have any symptoms. The most frequent findings in laboratory tests were disturbance of the normal circadian rhythm of cortisol secretion (93.8%), followed by elevated serum level of testosterone (89.7%). Only 3.8% of ultrasound diagnosis and 12.1% of computed tomography (CT) diagnosis were consistent with pathologic diagnosis. CONCLUSION: Different from those in adult, the most frequent presentation in children with ACTs is peripheral precocious puberty with or without Cushing syndrome, and isolated Cushing syndrome. Few present with non-functional local mass. Laboratory tests usually reveal the discordantly elevated serum levels of sexual corticosteroid hormones, change of diurnal rhythm of cortisol or increase of morning cortisol. The differentiation of malignant from benign tumor cannot merely depend on imaging. Final diagnosis relies on comprehensive evaluation of clinical manifestations, laboratory data, imaging and pathology.

[Construction, expression and immunogenicity analysis of a Tat N-terminus-deleted mutant fusion protein of human immunodeficiency virus type 1].

In the study, a gene encoding Tat protein N terminal 1- 21 amino acid residues-deleted mutant (Tat22-101) was amplified by PCR from a full length Tat gene of human immunodeficiency virus type 1, and the prokaryotic expression plasmid pET32a-Tat22-101 was constructed. After identification by digestion with endonucleases and sequencing, the recombinant plasmid pET32a-Tat22-101 was transformed into E. coli BL21(DE3) and expressed with IPTG induction. The mutant fusion protein with deleted Tat N terminal was purified by an affinity chromatography column Ni(2+)-NTA and subsequently identified by SDS-PAGE and Western blotting. The results showed that the molecular weight of the mutant protein was approximately 26.9kD. Furthermore, BALB/c mice were immunized with the mutant protein and the anti-sera were collected. ELISA results showed that the mutant protein preserved its immunogenicity, particularly it could improve the production of antibodies to other epitopes in addition to the N terminal epitope of Tat protein, which might provide some valuable information for the study of Tat functions as well as for development of potential novel HIV Tat vaccine.

Activation of p38 MAPK pathway by hepatitis C virus E2 in cells transiently expressing DC-SIGN.

Dendritic cell-specific intercellular adhesion molecule 3-grabbing nonintegrin (DC-SIGN) is a cellular receptor for hepatitis C virus for the binding of viral envelope glycoprotein E2. Interaction of DC-SIGN with the E2 may evoke cellular signal transduction implicated in viral pathogenesis. We developed a cell model with DC-SIGN transient transfection to study p38 mitogen-activated protein kinase (MAPK) signaling pathway in response to the E2 treatment. HEK293T and HeLa were DC-SIGN-deficient cell lines. DC-SIGN was detectable at the surface of HEK293T and HeLa transfected with DC-SIGN, and the levels of DC-SIGN were high in transfected-HEK293T as compared with HeLa. The transfected-HEK293T displayed ability for the E2 binding. In the transfected-HEK293T, level of p38 MAPK phosphorylation was increased upon the E2 treatment and reduced following blockage of DC-SIGN with an antibody against DC-SIGN. Phosphorylation of downstream transcription factor activating transcription factor (ATF)-2 was also up-regulated by the E2 via DC-SIGN. Similar results were obtained with NIH3T3 cells stably expressing DC-SIGN and Huh7 cells. Our results indicate that DC-SIGN transient expression in HEK293T is a useful cell model for investigating p38 MAPK pathway triggered by the E2, which may provide information for understanding cellular receptors-mediated signaling events and the viral pathogenesis.

Persistent replication of the GBV-C subgenomic replicons in Huh7 cells.

Studies of GB virus type C (GBV-C) replication in vitro have been limited because of poor growth of GBV-C in cell culture. In order to address the infection of GBV-C, two GBV-C subgenomic replicons (GBCrepEGFP and GBCrepTNF) were developed from a GBV-C full-length genomic cDNA. The viral replication, protein expression and the production of virus-like particles were evaluated in human hepatoma cell line Huh7. The results showed that the established GBCrepEGFP and GBCrepTNF replicons could be replicated autonomously and expressed in cell culture for at least 2 months and 1 month respectively. The replicon RNA could assemble RNA-containing structures in the HuhEH cells expressing GBV-C structural proteins. It suggests that a cell line supporting the replication of GBV-C was established. This replicon system might be used to understand better the biology of GBV-C.

Evolutional selection of a combinatorial phage library displaying randomly-rearranged various single domains of immunoglobulin (Ig)-binding proteins (IBPs) with four kinds of Ig molecules.

BACKGROUND: Protein A, protein G and protein L are three well-defined immunoglobulin (Ig)-binding proteins (IBPs), which show affinity for specific sites on Ig of mammalian hosts. Although the precise functions of these molecules are not fully understood, it is thought that they play an important role in pathogenicity of bacteria. The single domains of protein A, protein G and protein L were all demonstrated to have function to bind to Ig. Whether combinations of Ig-binding domains of various IBPs could exhibit useful novel binding is interesting. RESULTS: We used a combinatorial phage library which displayed randomly-rearranged various-peptide-linked molecules of D and A domains of protein A, designated PA(D) and PA(A) respectively, B2 domain of protein G (PG) and B3 domain of protein L (PL) for affinity selection with human IgG (hIgG), human IgM (hIgM), human IgA (hIgA) and recombinant hIgG1-Fc as bait respectively. Two kinds of novel combinatorial molecules with characteristic structure of PA(A)-PG and PA(A)-PL were obtained in hIgG (hIgG1-Fc) and hIgM (hIgA) post-selection populations respectively. In addition, the linking peptides among all PA(A)-PG and PA(A)-PL structures was strongly selected, and showed interestingly divergent and convergent distribution. The phage binding assays and competitive inhibition experiments demonstrated that PA(A)-PG and PA(A)-PL combinations possess comparable binding advantages with hIgG/hIgG1-Fc and hIgM/hIgA respectively. CONCLUSION: In this work, a combinatorial phage library displaying Ig-binding domains of protein A, protein G, or protein L joined by various random linking peptides was used to conducted evolutional selection in vitro with four kinds of Ig molecules. Two kinds of novel combinations of Ig-binding domains, PA(A)-PG and PA(A)-PL, were obtained, and demonstrate the novel Ig binding properties.