[Killer cell immunoglobulin-like receptors and their ligands]

The Natural killer [NK] cells are a subset of lymphocytes comprising around 10% of total lymphocytes in peripheral blood. Due to their role in the innate response, NK cells provide a 'first line of defense' against infectious agents and cancer and are also thought to play a role in autoimmunity. The killer cell immunoglobulin-like receptors [KIR] are regulatory surface molecules, found on NK cells and on a subset of T lymphocytes. The genes for KIR are present on chromosome 19 in the leukocyte receptor complex and show a major difference for both the type and number of KIR genes present among different ethnic groups. They have been divided into two groups of 2D or 3D, depending on the number of external immunoglobulin domains. The presence of a long cytoplasmic tail with two immune tyrosine-based inhibitory motifs [ITIM] allows the transduction of inhibitory signals and characterizes the inhibitory KIRs [2DL and 3DL], whereas the presence of short cytoplasmic tails corresponds to the activating KIR receptors [2DS and 3DS]. These polymorphic receptors interact with specific motifs on human leukocyte antigen [HLA] class I molecules, modulate NK cytolytic activity. Some KIRs are known to interact with HLA-C molecules of target cells, HLA-Bw4 molecules and HLA-A3/11. For some KIRs the corresponding ligands are still unknown

[Antisperm antibody and the risk factors of its formation in infertile men]

Several studies have demonstrated that antisperm antibody [ASA] can interfere with fertilization. ASA can be detected in the serum or semen by different tests. In this study, the percentage of ASA-IgG was determined by the direct mixed antiglobulin reaction [MAR] test in men from infertile couples in Khorramabad city. Furthermore, the risk factors of formation of ASA were evaluated to determine the correlation between these factors and presence of ASA. 200 men were tested for ASA as a part of the infertility evaluation. Patients were grouped according to percentage of ASA of< 10% or >/= 10%. Risk factors for ASA [varicocele, hernia, and genitourinary infections] were considered for each group. Statistical analysis was performed using Fishers exact test. ASA was detected in 18.5% of the studied cases. Prior varicocele was significantly associated with presence of ASA detected by direct MAR. Prior hernia was not associated with presence of ASA detected by direct MAR. Prior genitourinary infections were significantly associated with presence of ASA detected by direct MAR. These findings suggest that manipulation of cord structures including vas deferens is not associated with formation of ASA; however, varicocele and prior genitourinary infections are significant risk factors for the development of ASA

Detection of antisperm antibodies by indirect flow cytometry: Comparison with direct mixed agglutination reaction test

The immunobead binding test [IBT] and the mixed agglutination reaction [MAR] are the most commonly used methods for detection of antisperm antibodies [ASA]. The detection of ASA by flow cytometry [FCM] was first described by Haas and Cunningham. Both assays can be performed as direct or indirect methods. In this study, indirect FCM was compared with the direct MAR for detection of ASA. Semen samples were obtained from 80 men [infertile couples] in Isfahan Fertility and Infertility Center. Seminal plasma samples were incubated with ASA-negative donor sperm. Then, surface-bound antibody was detected with FITC-labeled antihuman immunoglobulin directed against IgA and IgG in the indirect FCM assay. ASAs bound to the surface of patients' sperm were detected by direct MAR test. The indirect FCM correlates with direct MAR for detection of IgA antisperm antibodies [r=0.55 and P=0.006]. The indirect FCM, however, does not correlate with direct MAR for the detection of IgG antisperm antibodies [r=0.25 and P=0.25]. Some of the ASAs in seminal fluid bind to spermatozoa. Therefore, indirect tests to detect ASAs in seminal plasma are likely to miss the presence of IgG antisperm antibodies while they effectively detect IgA antisperm antibodies

[Correlation between in vitro fertilization with the level of antisperm antibody in seminal plasma measured by flow cytometry]

Antisperm antibodies [ASA] are present in%8-21 of infertile men. In vitro Fertilization [IVF] has been recommended as an effective procedure in couples with immunological male factor. Although this procedure has been found to bypass the inhibitory effect of antisperm antibodies on fertilizing ability of spermatozoa but the fertilization rate is reduced about%40 for ASA positive samples. The goal of present study was to investigate the correlation between anti-sperm antibodies measured by indirect flow cytometry and fertilization rate in infertile couples undergoing in vitro Fertilization [IVF]. Semen samples were collected from 80 infertile men undergoing IVF cycle in Isfahan fertility and infertility center. Couples were classified based on fertilization rate into high and low groups. 52 couples had high [>50%] and 28 couples had low fertilization rate [