Patient description: A 2-year-old boy is brought to the emergency department by his parents for 5 days of high fever and irritability. The physical exam reveals conjunctivitis, strawberry tongue, inflammation of the hands and feet, desquamation of the skin of the fingers and toes, and cervical lymphadenopathy with the smallest node at 1.5 cm. The abdominal exam demonstrates tenderness and enlarged liver. Laboratory tests report elevated alanine aminotransferase, white blood cell count of 17,580/mm, albumin 2.1 g/dL, C-reactive protein 4.5 mg, erythrocyte sedimentation rate 60 mm/h, mild normochromic, normocytic anemia, and leukocytes in urine of 20/mL with no bacteria identified. The echocardiogram shows moderate dilation of the coronary arteries with possible coronary artery aneurysm.

Clinical trial eligibility criteria: eligible ages (years): 4.0-13.0,  Obsessive-Complusive Disorder Children Anxiety Disorder Autoimmune Disease PANDAS Male and female children 4-13 years of age Presence of (Diagnostic and Statistical Manual of Mental Disorders Fourth Edition, Text Revision) DSM-IV TR OCD with or without a tic disorder Moderate or greater severity of symptoms, with a score of greater than or equal to 20 on the Children s Yale-Brown Obsessive-Compulsive Scale (CY-BOCS) and greater than or equal to 4 on the Clinical Global Impression Severity scale (CGI-S) The acute onset within the previous six months of symptoms in a child previously well, or the first acute recurrence within the previous six months, after a period of relatively complete remission of symptoms. The acuity of symptom onset/exacerbation is key and must be severe, dramatic in onset, and proceed from no/minimal symptoms to maximum severity within 24-48 hours Symptom onset or first exacerbation preceded within four months by a GAS infection, as documented by positive throat culture, exposure to documented GAS infection (in a close contact, such as a sibling sharing a bedroom), and/or documented two-fold rise in one or more anti-GAS antibody titers such as anti-streptolysin O, anti-streptococcal DNAaseB, anti-carbohydrate antibodies and others Onset/exacerbation of OCD is accompanied by at least three of the following 7 clinical signs and symptoms. The acuity of the comorbid symptoms must be similar to the OCD symptoms and occur in the same time interval Markedly increased level of anxiety, particularly new onset of separation anxiety Emotional lability, irritability, aggressive behavior and/or personality change Sudden difficulties with concentration or learning Developmental regression ("baby-talk," temper tantrums; behaviors atypical for actual chronological age)  History of rheumatic fever, including Sydenham chorea (the neurologic manifestation) Presence of symptoms consistent with autism, schizophrenia, or other psychotic disorder (unless psychotic symptoms have onset coincident with the possible and are attributed to OCD) Presence of a neurological disorder other than a tic disorder IQ < 70. Child subjects need to be able to contribute meaningfully to baseline and follow-up ratings, to report adverse effects, and to assent to participation Presence of serious or unstable medical illness or psychiatric or behavioral symptoms that would make participation unsafe or study procedures too difficult to tolerate IgA deficiency (< 20mg/dL). Intravenous immunoglobulin may contain trace IgA, which may very rarely lead to life-threatening anaphylaxis in IgA-deficient participants with anti-IgA antibodies (Misbah 1993) Hyperviscosity syndromes, which can increase risks associated with IVIG administration Need for live virus vaccine within six months after receiving IVIG (which may be 7.5 months from randomization) since IVIG can interfere with effectiveness of such vaccines. IVIG should not be administered sooner than two weeks after administration of a live virus vaccine, for the same reason Taking nephrotoxic drugs. Every concomitant medication will be subject to scrutiny and possible consultation with pediatric safety monitors before randomization to study drug. See below as well Recent (less than eight weeks) initiation of cognitive-behavior therapy (CBT)