Immunoglobulin K light chain deficiency: A rare, but probably underestimated, humoral immune defect

Human immunoglobulin molecules are generated by a pair of identical heavy chains, which identify the immunoglobulin class, and a pair of identical light chains, Kappa or Lambda alternatively, which characterize the immunoglobulin type. In normal conditions, Kappa light chains represent approximately 2/3 of the light chains of total immunoglobulins, both circulating and lymphocyte surface bound. Very few cases of immunoglobulin Kappa or Lambda light chain defects have been reported. Furthermore, the genetic basis of this defect has been extensively explored only in a single case. We report a case of a patient suffering of serious recurrent bacterial infections, which was caused by a very rare form of immunoglobulin disorder, consisting of a pure defect of Kappa light chain. We evaluated major serum immunoglobulin concentrations, as well as total and free Kappa and Lambda light chain concentrations. Lymphocyte phenotyping was also performed and finally we tested the Kappa chain VJ rearrangement as well as the constant Kappa region sequence. Studies performed on VJ rearrangement showed a polyclonal genetic arrangement, whereas the gene sequencing for the constant region of Kappa chain showed a homozygous T to G substitution at the position 1288 (rs200765148). This mutation causes a substitution from Cys to Gly in the protein sequence and, therefore, determines the abnormal folding of the constant region of Kappa chain. We suggest that this defect could lead to an effective reduction of the variability of total antibody repertoire and a consequent defect of an apparently normal immunoglobulin response to common antigen

Relationship Between Vascular Endothelial Growth Factor and Nuclear Factor-κB in Renal Cell Tumors

Aim To assess the relationship between protein and messenger RNA (mRNA) levels of vascular endothelial growth factor (VEGF) and subcellular localization of nuclear factor-kappa B (NF-κB), proliferation rate of tumor cells, and clinicopathological characteristics of renal cell tumors. Methods We analyzed 31 one renal cell tumors – 22 clear cell renal cell carcinomas (CCRCC) and 9 other histologic types (non-CCRCC). VEGF expression and subcellular localization of p65 member of NF-κB and Ki67 were immunohistochemically evaluated for the proliferation rate of tumor cells. Expression of VEGF mRNA was assessed using quantitative real-time polymerase chain reaction after total RNA extraction from snap-frozen tumor tissue samples. Results Cytoplasmic localization of VEGF protein in renal cell tumors showed a perimembranous and diffuse pattern, the former being more evident in CCRCC (27.1 ± 18.9 vs 3.3 ± 10 % tumors, P<0.001) and the latter in non-CCRCC type (71.7 ± 23.2 vs 31.1 ± 22.1 % tumors, P < 0.001). Heterogeneity in VEGF gene expression was more pronounced in CCRCC type than in non-CCRCC type (P = 0.004). In addition, perimembranous VEGF pattern was associated with higher VEGF mRNA levels (P = 0.006) and diffuse VEGF pattern with lower VEGF mRNA levels (P < 0.001). Nuclear and cytoplasmic staining of NF-κB/ p65 was observed in the majority of tumor cells. A significant association was recorded between cytoplasmic NK-κB/65 staining and VEGF staining of diffuse pattern (P = 0.026). Association between NF-κB/65 and proliferation rate of tumor cells was significant for cytoplasmic staining (P = 0.039) but not for nuclear NFkB/p65 staining (P = 0.099). Conclusion Higher but inhomogeneous expression of VEGF in tumor cells, especially in CCRCCs, is associated with NF-κB/65 activity. This indicates that both VEGF and NF-κB/65 may be important in renal carcinogenesis, representing a possible molecular target in the treatment of renal cell carcinoma

Investigation of endothelin-1 type A receptor gene polymorphism (-231 G>A) in preeclampsia susceptibility

none9OBJECTIVE: Preeclampsia is considered as a multifactorial disorder with a genetic predisposition. Alterations in the endothelin-1 (ET-1) system are considered to take part in triggering the vasoconstriction seen in preeclampsia. METHODS: In order to investigate the possible association of the -231 G > A polymorphism in the endothelin-1 type A receptor gene (EDNRA), previously shown to be associated with other conditions characterized by vasospasm, we examined 77 Caucasian preeclamptic women and 67 matched controls including normotensive subjects without history of thromboembolic event, abnormalities in blood pressure, proteinuria, edema and preeclampsia. The genotype was assessed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) on genomic DNA extracted from blood samples. Case vs. control allele frequencies and genotype distributions were compared. RESULTS: No significant differences were found when considering both genotype (chi(2) = 0.58, p = 0.75) and allelic frequencies (chi(2) = 0.08, p = 0.77). Furthermore, no significant genotype-related difference was found in relation to clinical features, such as gestational age at onset, systolic and diastolic blood pressure, proteinuria on admission and delivery week. CONCLUSIONS: No association between the -231 G > A polymorphism in the EDNRA gene and preeclampsia as well as any correlation with the main clinical features of the disorder were found, thus excluding a role for this polymorphism in susceptibility to preeclampsia.noneLISI V; PATERNOSTER DM; STECCA A; MICCICHE F; FANTINATO S; LEON A; DAMANTE G; FABBRO D; CLEMENTI M.Lisi, V; Paternoster, Dm; Stecca, A; Micciche, F; Fantinato, S; Leon, A; Damante, G; Fabbro, D; Clementi, Maurizi

Functional regulation of the apurinic/apyrimidinic endonuclease 1 by nucleophosmin: impact on tumor biology

Nucleophosmin 1 (NPM1) is a nucleolar protein involved in ribosome biogenesis, stress responses and maintaining genome stability. One-third of acute myeloid leukemias (AMLs) are associated with aberrant localization of NPM1 to the cytoplasm (NPM1c +). This mutation is critical during leukemogenesis and constitutes a good prognostic factor for chemotherapy. At present, there is no clear molecular basis for the role of NPM1 in DNA repair and the tumorigenic process. We found that the nuclear apurinic/apyrimidinic endonuclease 1 (APE1), a core enzyme in base excision DNA repair (BER) of DNA lesions, specifically interacts with NPM1 within nucleoli and the nucleoplasm. Cytoplasmic accumulation of APE1 is associated with cancers including, as we show, NPM1c + AML. Here we show that NPM1 stimulates APE1 BER activity in cells. We provide evidence that expression of the NPM1c + variant causes cytoplasmic accumulation of APE1 in: (i) a heterologous cell system (HeLa cells); (ii) the myeloid cell line OCI/AML3 stably expressing NPM1c + ; and (iii) primary lymphoblasts of NPM1c + AML patients. Consistent with impaired APE1 localization, OCI/AML3 cells and blasts of AML patients have impaired BER activity. Cytoplasmic APE1 in NPM1c + myeloid cells is truncated due to proteolysis. Thus, the good prognostic response of NPM1c + AML to chemotherapy may result from the cytoplasmic relocalization of APE1 and the consequent BER deficiency. NPM1 thus has an indirect but significant role in BER in vivo that may also be important for NPM1c + tumorigenesis

Functional interference between contacting amino acids of homeodomains.

AbstractIn a protein, the function of an amino acid at some position depends on the amino acids at other positions. Here we demonstrate a functional interference between base-contacting amino acids (at positions 50 and 54) of homeodomains. When, in the context of Antennapedia or Goosecoid homeodomains, Lys50 is paired to Tyr54 or Ala54 and Gln50 is paired to Met54, the resulting proteins efficiently discriminate among different DNA sequences. In contrast, in the presence of the pair Lys50-Met54, both homeodomains show a reduced capability to discriminate among different DNA sequences. Sequence selection experiments performed in the context of the Goosecoid homeodomain suggest that the presence of Met54 precludes the base-discriminating function of Lys50. These results may explain why the pair Lys50-Met54 is never found in natural homeodomains