Exploring human splenic red pulp vasculature in virtual reality: details of sheathed capillaries and the open capillary network

Pregnancy With Massive Splenomegaly and Pancytopenia: A Case Report

Massive splenomegaly complicating pregnancy is a rare clinical entity that poses special difficulties, such as anemia, thrombocytopenia, ascites, and jaundice. This case report of a pregnant woman with large splenomegaly and pancytopenia highlights the value of prompt diagnosis and effective treatment. Splenomegaly can have a number of causes, including viral infections, hematological problems, portal hypertension, and metabolic abnormalities. A 29-year-old gravida 3 woman at 37 weeks of gestation who had massive splenomegaly was admitted and underwent a cesarean section to avoid complications of splenomegaly. The case report discusses the difficulties in obstetric management caused by enormous splenomegaly during pregnancy, including the choice of delivery method. Significant complications include splenic rupture and bleeding, particularly when pancytopenia is present. The need for several transfusions, the potential side effects of transfusion therapy, and factors related to the origin of splenomegaly when assessing maternal-fetal outcomes are discussed in this case report. The study concludes that in cases with pancytopenia splenomegaly during pregnancy, vigilant monitoring, prompt intervention, and a multidisciplinary approach are crucial to achieve positive outcomes for both the mother and the fetus.

Age-related changes of the human splenic marginal zone B cell compartment

In this review, we will summarize the growing body of knowledge on the age-related changes of human splenic B cell composition and molecular evidence of immune maturation and discuss the contribution of these changes on splenic protective function. From birth on, the splenic marginal zone (sMZ) contains a specialized B cell subpopulation, which recruits and archives memory B cells from immune responses throughout the organism. The quality of sMZ B cell responses is augmented by germinal center (GC)-dependent maturation of memory B cells during childhood, however, in old age, these mechanisms likely contribute to waning of splenic protective function.

Outcome of pregnancy in women with splenomegaly

BACKGROUND

The spleen is a lymphopoietic organ, contains almost one quarter of the body's lymphocytes.

METHOD

This was a prospective cross sectional study, carried out at Kassala hospital, Sudan between 1st of May 2019 to 30th of April 2020. The objective of this study was to investigate the outcome of pregnancy in women with splenomegaly. A total coverage of 57 women with splenomegaly were approached among all pregnant women attending the hospital and asking for care. An enlarged spleen detected by palpation and subcategorized into mild, moderate and severe one according to its length below the left costal margin using Ultrasound. Data was collected using structured questionnaire. Means and proportions were compared between the groups of the study-using student and x² test, and P < 0.05 was considered significant.

RESULTS

The most predominant type of splenomegaly was massive (50.9%) splenomegaly. The reported obstetric complications among the investigated women include: intrauterine growth restriction (19.3%), preterm labor ((17.5%), miscarriage (12.3%) and stillbirth (3.5%). Out of 50 patients their pregnancy progressed to delivery, three patients developed primary hemorrhage requiring blood transfusion with ≥ 2 units of blood. Respiratory distress syndrome (RDS), acute tachypnea of the newborn and stillborn babies were observed in 18%, 6% and 4% respectively. Higher proportion of women with poor obstetric outcomes was reported in cases of massive splenomegaly in comparison with other types.

CONCLUSION

The study showed significant association between adverse obstetric outcomes and massive splenomegaly. Thus, it is important to consider splenomegaly as one of the factors making the pregnancy high-risk one.

B cells in human lymphoid structures

Most B cells in the human body are present in tissues where they support immune responses to pathogens, vaccines, autoantigens, and tumours. Despite their clear importance, they are very difficult to study and there are many areas of uncertainty that are difficult to resolve because of limited tissue access. In this review, we consider the zonal structure of lymphoid tissues, the B cell subsets they contain, and how these are regulated. We also discuss the impact that methods of deep interrogation have made on our current knowledge base, especially with respect to studies of cells from dissociated tissues. We discuss in some detail the controversial B cells with marginal zone distribution that some consider being archived memory B cells. We anticipate that more we understand of B cells in tissues and the niches they create, the more opportunities will be identified to harness their potential for therapeutic benefit.

The human splenic microcirculation is entirely open as shown by 3D models in virtual reality

The human spleen is equipped with an organ-specific microcirculation. The initial part of the venous circulation is formed by spleen-specific large microvessels, the sinuses. Sinuses eventually fuse to form venules and veins. For more than 170 years there have been debates, whether splenic red pulp capillaries join sinuses, i.e., whether the microcirculation is closed or open-or even simultaneously closed and open. We have now solved this question by three-dimensional reconstruction of a limited number of immunostained serial sections of red and white pulp areas, which were visualized in virtual reality. Splenic capillaries have special end structures exhibiting multiple small diverging endothelial cell processes, which always keep a certain distance to the walls of sinuses. Only very few capillary ends were difficult to diagnose. Positive identification of these end structures permits to conclude that the human splenic microcirculation is entirely open. This is also true for the perifollicular capillary network and for capillaries close to red pulp venules. Follicles are supplied by a relatively dense open perifollicular capillary net, which is primarily, but not exclusively, fed by sheathed and few non-sheathed capillaries from the surrounding red pulp network.

Splenomegaly in Children and Adolescents

In contrast to other lymphoid tissues making up the immune system, the spleen as its biggest organ is directly linked into the blood circulation. Beside its main task to filter out microorganism, proteins, and overaged or pathologically altered blood cells, also humoral and cellular immune responses are initiated in this organ. The spleen is not palpable during a physical examination in most but not all healthy patients. A correct diagnosis of splenomegaly in children and adolescents must take into account age-dependent size reference values. Ultrasound examination is nowadays used to measure the spleen size and to judge on reasons for morphological alterations in associated with an increase in organ size. An enormous amount of possible causes has to be put in consideration if splenomegaly is diagnosed. Among these are infectious agents, hematologic disorders, infiltrative diseases, hyperplasia of the white pulp, congestion, and changes in the composition and structure of the white pulp by immunologically mediated diseases. This review attempts to discuss a comprehensive list of differential diagnoses to be considered clinically in children and young adolescents.