A 56-year-old Caucasian man complained of recurrent bilateral lower extremity cellulitis and ulcerations, requiring hospitalization and parenteral antibiotic administration. History included factor V Leiden mutation with recurrent lower extremity deep venous thromboses and recurrent MRSA urinary tract infections. He had undergone numerous abdominal procedures, with recurrent enterocutaneous fistulae and wall abscesses. Abdominal exam revealed wall ulceration with serosanguineous drainage and surrounding erythema. His lower extremities presented ochre dermatitis, bilateral +/4 edema below the knee; there were 2 ulcerations on the anterior portion of his left leg, measuring 1 × 1 cm and 2 × 3 cm (Figure ). A lower extremity ultrasound showed a left-sided nonocclusive chronic thrombus in the femoral and popliteal veins. Total levels of immunoglobulins were normal (except for a small decrease in IgG3), as were C2 and C4 (Table ). Anticardiolipin antibody was negative. The patient had a low level of MBL (<50 ng/ml), genotyping showing a LYPB/LYPB polymorphism for MBL and a wild-type MASP-2 (Table ). The patient's abdominal wall culture grew cephalosporin-sensitive Staphylococcus aureus; cultures from his lower extremity ulcerations were positive for Pseudomonas aeruginosa. The patient responded to antimicrobials, compression stockings and topical Tacrolimus©.
A 47-year-old woman presented with a pustular rash (Figure and ) on her skin (face, back, forearms and leg) and pustular inguinal eruptions; on one occasion she had developed a vulvar infection with abscess formation requiring drainage. Past medical history included recurrent rhinosinusitis and anxiety disorder. Biopsy of the lesion showed pustular changes with neutrophilic infiltration, but did not reveal lymphocyte infiltration. A culture from a lesion on her forearm was positive for Staphylococcus aureus. The patient responded to administration of cefadroxil and minocycline, with remission and frequent relapses. Laboratory workup revealed mild C4 deficiency and an undetectable IgE level (Table ). Assays were unremarkable for ANA, ESR, rheumatoid factor, hepatitis viruses, and HIV. The MBL level was exceptionally low at < 50 ng/ml, and her MBL functional pathway was impaired. MBL genotyping revealed a LYPB/HYPD haplotype, while MASP-2 was wild-type (Table ).