Clinical examination
A 10-year-old boy was admitted for diagnostic lung biopsy in the setting of progressive chronic hypoxic respiratory failure and recurrent hyperinflammatory episodes. He was born at 7 pounds 3 ounces at estimated gestational age of 36 weeks via normal spontaneous vaginal delivery to a mother with a history of placental clots with a still birth at term. He was hospitalized at 4 months of age for respiratory syncytial virus (RSV) for 7 days, at 1 year old for hypospadias repair, and then again at age 3 years 8 months for what was thought to be mononucleosis due to positive Epstein-Barr virus (EBV) positive immunoglobulin M (IgM). During the latter episode, he was severely fatigued and had persistent fevers to 40 °C. Additionally, he had another RSV infection at 3 years and 4 months of age. He demonstrated mild gross motor developmental delay as he did not crawl and did not walk until 19 months of age. He was also fully vaccinated until 3 years of age.
At approximately 4 years of age, he presented with a one-month history of fatigue, intermittent fevers and dark urine. His fevers were daily reaching 40 °C with periods of defervescence. He then developed a cough with hypoxemia to 89% on room air and was admitted for viral bronchiolitis. Physical exam was notable for mild prognathism, slight frontal bossing, low-set and posteriorly rotated ears, mild pectus excavatum, bilateral undescended testes, and long fingers and toes with overlapping second and fourth toes over the third toes bilaterally were noted. His elbows and knees were hyperextensible and demonstrated moderate pes planus and out-toeing.
During hospitalization, hepatomegaly was found along with mild transaminitis (AST 301 U/L, ALT 74 U/L), direct antiglobulin test negative hemolytic anemia (hematocrit 24.7%) and hemoglobinuria without microscopic red blood cells. Abdominal CT scan revealed a small poorly perfused spleen which correlated well with the Howell-Jolly bodies and schistocytes on peripheral smear. Bilirubin was normal but lactate dehydrogenase (LDH) was dramatically elevated at 19,706 U/L. Normal renal function was present with creatinine 0.1 mg/d without evidence of proteinuria or myoglobinuria. Creatine kinase values were normal at 202 IU/L. Systemic inflammation was present with leukocytosis (peak 53.8 K/mm3), thrombocytosis (peak 914 k/mm3), elevated erythrocyte sedimentation rate (ESR, 87 mm/hr), hyperferritinemia to 1,980 ng/mL, but blood cultures and respiratory viral PCR panel was negative.
He had a liver biopsy that demonstrated mild sinusoidal fibrosis, mild microvesicular steatosis, and rare apoptotic hepatocytes, but ultimately was non-diagnostic. Work up for hypercoagulability, serum muscle enzymes and amino acid and organic acids from the urine and plasma were all normal. Serologies for antiphospholipid antibody syndrome, antineutrophil cytoplasmic antibodies, anti-nuclear antibody, anti RNP, and anti-SSA/SSB were all negative. Autoimmune hepatitis work-up yielded negative liver kidney microsomal and smooth muscle antibodies. Respiratory symptoms slowly resolved and hematologic findings improved, thus representing a flare that recurred regularly over the next 6 years.
During his next flare, the patient had anemia, leukocytosis, and thrombocytosis along with abdominal pain, hepatomegaly, and fevers. Further imaging with CTA abdomen demonstrated absent splenic veins and multiple collaterals to a small left kidney, implying that patient’s spleen had infarcted. A bone marrow biopsy demonstrated extensive histiocyte activation with phagocytosis of nucleated red blood cell precursors. There was normal cellularity but decreased trilineage hematopoiesis and increased megakaryocytes; no malignant cells were present. This flare was associated with HHV-7 viremia.
He was readmitted to the hospital multiple times for similar febrile episodes found to be triggered by viral and bacterial infections as well as Prevnar vaccination (Fig. 1). He had a prolonged four-month long flare following H1N1 infection complicated by pneumonia with pleural effusion. He received the Prevnar 13 vaccination and developed another hyperinflammatory episode lasting four months complicated by steroid responsive pericardial effusion and presumed inflammatory pneumonitis. He soon became oral corticosteroid-dependent as weaning resulted in hemolysis and dark urine. By the age of 8, the flares were characterized less by persistent febrile episodes but more by shortness of breath, chest discomfort and intermittent desaturations. His growth curve had started to plateau at age 4 despite being at the 50th percentile until the age of 3; he was less than the 10th percentile for weight and 20th percentile for height. He also began experiencing hip pain with unequal leg lengths, difficulty running, and decreased stamina. Mild knee swelling was noted accompanying myalgias and arthralgias with morning stiffness. Mild proteinuria developed as well. He was steroid responsive and therefore treated with oral prednisone 10 mg twice daily. Steroid sparing therapies, such as methotrexate and azathioprine, were introduced by discontinued because no benefit was observed.
Due to persistent and progressive respiratory symptoms exacerbated by an infection with RSV and mycoplasma, he was hospitalized at Seattle Children’s Hospital for further evaluation. Spirometry testing demonstrated a severely restrictive pulmonary pattern with a forced vital capacity (FVC) of 0.41 L (20%), forced expiratory volume in 1 second (FEV1) of 0.41 (22%), and FEV1/FVC 99%. He underwent a right thoracoscopic lung biopsy, which demonstrated extensive fibrotic nonspecific interstitial pneumonia (NSIP), patchy pleural fibrosis, and scattered cholesterol granulomas.
Following the procedure, he developed a right hemothorax and pneumothorax with respiratory distress and supplemental oxygen, requiring Pediatric Intensive Care Unit (PICU) admission. He had substantial fibrotic intrathoracic tissue and his pulmonary function continued to deteriorate, requiring consistent use of nasal cannula and increased use of BiPAP. In an attempt to treat his inflammatory state, corticosteroid dose was increased and gradually weaned while anti-IL-1R therapy (anakinra), was trialed for 10 days, overlapping with cyclosporine, and then switched to anti-IL-6 therapy (tocilizumab) with minimal benefit. He expired just prior to his eleventh birthday due to respiratory failure.
Patient Laboratory, Histopathology, and Radiologic Evaluation
During episodes, his baseline leukocytosis increased from about 20 K/mm3 to exceed 40 K/mm3. Hyposplenia, initially noted at age 4, was confirmed on serial abdominal imaging, contributed to baseline thrombocytosis, but platelet counts exceeded 1 million frequently during flares, requiring aspirin for coagulation prophylaxis. At baseline, he had mild anemia with hematocrit of high 30%/low 40s%. However, during flares, his hematocrit would nadir below 30%. LDH was elevated at baseline and episodically reached 28,000 U/L with uniformly elevated isoenzymes. His transaminitis largely remained within the mild range with corresponding mild elevation of GGT and INR (Table 1). Alpha-1 antitrypsin was normal at 245 mg/dL as was alpha fetoprotein (0.9 ng/mL). Metabolic etiologies were ruled out with plasma and urine amino acid levels as well as urine organic acid levels.
Table 1
Laboratory studies. ALT – alanine aminotransferase, AST – aspartate aminotransferase, CH50 – total hemolytic complement activity, GGT – γ-glutamyl transferase, HDL – high density lipoprotein, IgA – immunoglobulin A, IgD – immunoglobulin D, IgG – immunoglobulin G, IgM – immunoglobulin M, INR – international normalized ratio, LDH – lactate dehydrogenase, LDL – low density lipoprotein, NK—natural killer cell, PHA – phytohemagglutinin, PPSV23 – pneumococcal vaccine polyvalent, sIL-2R – soluble interleukin-2 receptor.
Test | Normal Values | Patient’s Values | Test | Normal Values | Patient’s Values |
Biochemical | | | Immunological | | |
ALT | 5–41 IU/L | 165–615 | IgG | 608–1572 mg/dL | 1050–1140 |
AST | 6–40 IU/L | 44–157 | IgA | 52–242 mg/dL | 262 |
GGT | 15–85 IU/L | 30–405 | IgM | 45–236 mg/dL | 89–108 |
Total bilirubin | 0.0-1.1 mg/dL | 0.2 | IgE | 0.98–570.6 mg/dL | 105 |
INR | < 1.0 | 1.2–1.6 | IgD | ≤ 10 mg/dL | 3 |
Fibrinogen | 230–450 mg/dL | 57–493 | PPSV23 | ≥ 8/21 (≥ 5/12) | 8/21 (5/12) |
D-dimer | ≤ 0.5 mg FEU/mL | > 20 | Tetanus | ≥ 0.01 IU/mL | 0.43 |
Ceruloplasmin | 29–56 mg/dL | 48 | C3 | 83–203 mg/dL | 186 |
Liver copper | 10–35 ug/g dry weight | 43 | C4 | 16–52 mg/dL | 24 |
Plasma copper | 56–191 mcg/dL | 191 | CH50 | > 32 unit/mL | 69 |
Triglycerides | 60–135 mg/dL | 95–503 | CD3 | 1,200-2,600/mm3 | 1465 |
LDL | < 110 mg/dL | 324 | CD4 | 650-1,500/mm3 | 3793 |
HDL | > 39 mg/dL | 58 | CD8 | 370-1,100/mm3 | 2117 |
Total LDH | 145–345 U/L | 5490-28,019 | CD4:CD8 | > 2:1 | 1.8:1 |
LDH 1 (%) | 17.5–28.3% (I, Heart) | 7.5–10 | CD16+CD56+ | 120–480/mm3 | 882 |
LDH 2 (%) | 30.4–36.4% (II) | 17.6–21 | CD19 | 270–860/mm3 | 1588 |
LDH 3 (%) | 19.2–24.8% (III) | 26.9 | PHA | > 30% | 24.70% |
LDH 4 (%) | 9.6–15.6% (IV) | 23.7 | anti-CD3 | > 30% | 21.50% |
LDH 5 (%) | 5.5–12.7% (V, Liver) | 24.3 | NK function | | |
Ferritin | 10–300 ng/mL | 555–4264 | 50:1 | > 20 | 11 |
sIL-2R | 45-1105 U/mL | 145 | 25:1 | > 10 | 9 |
| | | 12.5:1 | > 5 | 5 |
| | | 6.25:1 | > 1 | 5 |
| | | Lytic units | > 3.1 | 2.5 |
During two separate hospitalizations for flares, the diagnosis of hemophagocytic lymphohistiocytosis (HLH) and macrophage activation syndrome (MAS) were both considered based upon his laboratory features. Overall, two bone marrow biopsies were performed approximately one year apart and both demonstrated normal cellularity and markedly increased hemophagocytosis (Fig. 2). Natural killer (NK) cell function was assessed and was decreased (Table 1). CD107a could not be assessed due to insufficient NK cells. Soluble IL-2 receptor (sIL-2R, also known as soluble CD25) was normal and never elevated. Genetic testing for periodic fever syndromes and familial HLH were performed, but pathogenic variants in known genes were identified. Comparative genomic hybridization (CGH) revealed no structural variants, and he had a normal male karyotype.
Given his recurrent infections, an immune evaluation was performed revealing abnormal T cell proliferation to stimulation with both phytohemagglutinin (PHA) and anti-CD3 (Table 1). He had increased naïve CD45RA+CD27+CCR7+ population (65% of cells), few effector memory T cells, and likewise immature CD8+ population with > 65% of the cells naïve. He had normal quantitative immunoglobulin levels and robust vaccine responses, but B cell immunophenotyping was notable for absent immature and transitional B cells with reduced CD27+ memory B at 6% (normal > 8%). Class switched and BAFF receptor populations were normal. Further T cell analysis was not performed.