Should laparoscopic lymph node biopsy be the preferred diagnostic modality for isolated abdominal lymphadenopathy?

Background: Isolated abdominal lymphadenopathy is frequently detected, but often challenging to diagnose. To obtain a tissue diagnosis, percutaneous biopsy (pb) or laparoscopic biopsy (lb) is often undertaken. The safety profiles and diagnostic accuracy of pb and lb within the abdomen are both poorly defined. Methods: In this retrospective analysis, we identified all patients who underwent lb or pb for isolated abdominal lymphadenopathy at our institute during 2008-2016. Results: Of 62 patients who underwent nodal biopsy for isolated abdominal lymphadenopathy, 33 underwent lb and 29 underwent pb. For the 33 patients who underwent lb, the procedure was diagnostic in 100% of cases; for the 29 who underwent pb, the procedure was diagnostic in 18 cases (62.1%). Both procedures were safe, with similar complication rates (6.0% for lb; 7.0% for pb). Conclusions: Our results establish that lb and pb are both safe and reliable in the setting of isolated abdominal lymphadenopathy. We also demonstrate that each procedure has situational advantages. A pb should be considered to be the upfront diagnostic modality, particularly when anatomic or disease factors favour its success. In situations in which it is felt that pb cannot safely access the lymphadenopathy or in disease states in which the yield of a core biopsy will be insufficient, lb should be strongly considered. Examples include extra-retroperitoneal lymphadenopathy and cases of suspected lymphoma.

Sex differences in immune responses and viral shedding following Seoul virus infection in Norway rats.

In the field, male rodents are more frequently infected with hantaviruses than females. This study examined whether patterns of immune responses against hantavirus differed between the sexes. Male and female Long Evans rats (Rattus norvegicus) were inoculated with Seoul virus, and antibody and cytokine responses, as well as virus shedding were assessed. Males were more likely to shed virus in saliva, to shed virus through multiple routes (saliva, urine, and feces), and to have viral RNA in the spleen than females. Anti-Seoul virus IgG responses were higher in males than females. In both sexes, splenic IFNgamma and IL-4 production increased following infection. After infection, males had higher Th1 immune responses (i.e., IgG2a, IFNgamma, and IL-2) than females; in contrast, Th2 immune responses (i.e., IgG1, IL-4, and IL-10) were similar between the sexes. These data suggest that immune responses to Seoul virus differ between the sexes.

Sex differences in Seoul virus infection are not related to adult sex steroid concentrations in Norway rats.

Field studies of hantavirus infection in rodents report that a higher percentage of infected individuals are males than females. To determine whether males were more susceptible to hantavirus infection than females, adult male and female Long Evans rats (Rattus norvegicus) were inoculated with doses of Seoul virus ranging from 10(-4) to 10(6) PFU. The 50% infective doses (ID(50)) were not significantly different for male and female rats (10(0.05) and 10(0.8) PFU, respectively). To determine whether sex differences in response to infection were related to circulating sex steroid hormones, sex steroid concentrations were manipulated and antibody responses and virus shedding were assessed following inoculation with the ID(90). Regardless of hormone treatment, males had higher anti-Seoul virus immunoglobulin G (IgG) and IgG2a (i.e., Th1) responses than females and IgG1 (i.e., Th2) responses similar to those of females. Males also shed virus in saliva and feces longer than females. Manipulation of sex steroids in adulthood did not alter immune responses or virus shedding, suggesting that sex steroids may organize adult responses to hantavirus earlier during ontogeny.