Patient description: The patients is a 25-year-old G1 P1 pregnant woman who is 24W3D gestational old who developed a sudden unset of fever and chills, accompany with nausea and vomiting. She also complains of dysuria, urgency and frequency. She also reports some severe pain in the flank. Her vital signs are: T = 39.7ºC, P = 117, R = 20, and BP = 113/74 mm Hg. Physical examination reveals tenderness on palpation of both costovertebral angles. She has no history of recurrent UTI prior to her pregnancy or any other underlying disease. The urine culture showed Gram-negative rod-shaped bacterial cells, leukocytes, and leukocyte casts. The blood culture is negative. A CBC shows Hb 12.9 g/dL, Hct 39%, MCV 76 fL, WBC count 14,120/µL.

Clinical trial eligibility criteria: eligible ages (years): 0.0-999.0,  Systemic Capillary Leak Syndrome Subjects with SCLS under 8 years of age are only eligible for components of this protocol that can occur Off Site and samples can be sent in to the NIH. All SCLS subjects must be at least 8 years old to participate in any other aspects of this protocol at the NIH. Subjects with SCLS may enter study while pregnant and remain on study after becoming pregnant. At the discretion of the investigator, some components of this protocol will not occur while subject is pregnant. Diagnosis or suspected diagnosis of Systemic Capillary Leak Syndrome by a physician or documented history of capillary leak as characterized by one or more of the following: 1. Hypotension (systolic blood pressure typically less than 90 mm Hg or diastolic blood pressure less than 60 mm Hg) or associated symptoms of hypotension (e.g., hypotonia [collapse], lightheadedness or syncope, incontinence, increased thirst) 2. Laboratory evidence of hemoconcentration (e.g., hemoglobin levels above the normal range [typically greater than17 g/dL], elevated leukocyte counts). 3. Clinical evidence of fluid extravasation (e.g. edema) and/or laboratory evidence of protein extravasation such as serum hypoalbuminemia (less than 3.5 g/dL) either chronically or during an acute hypotensive episode. Letter of referral, with copies of pertinent medical history and laboratory studies, from prospective study subject s referring physician. Patients may self-refer, but a letter of referral from primary physician is still required. Willing to donate blood for sample storage to be used for future research. FOR THE Willing to donate blood for sample storage to be used for future research. Relatives must be at least 3 years old. Healthy volunteers must be at least 18 years old. Relatives may be pregnant or become pregnant while participating in this protocol. At the discretion of the investigator, some components of this protocol will not occur while subject is pregnant. No skin biopsies or intradermal testing will be done on pregnant relatives. Bloodwork volumes may be decreased at the discretion of the investigator. Healthy volunteers may not be pregnant. Able to give informed consent  Presence of conditions which, in the judgment of the investigator or the referring physician, may put the subject at undue risk for travel (including frequent episodes of severe capillary leak, symptoms not preventable by pre-medication, acute infection, severe thrombocytopenia [minimum platelet count of 30,000/ (Micro)L], or significant cardiovascular disease). Any condition that in the view of the principal investigator would make the subject unsuitable for enrollment in this study (i.e., medically unstable, unstable to provide phlebotomy samples). There is an identified cause for hypotensive episodes and/or tissue swelling FOR THE Presence of conditions which in the judgment of the investigator may put the subject at undue risk (i.e., medically unstable, unstable to provide phlebotomy samples). Any condition that in the view of the principal investigator would make the subject unsuitable for enrollment in this study (i.e., medically unstable, unstable to provide phlebotomy samples)