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 ).
A 39-year-old woman complained of recurrent pustular eruption of her upper extremities and chronic allergic rhinitis. Immunological evaluation demonstrated the following: IgG levels were slightly decreased, but IgG subclass levels were all normal. The patient had detectable/robust responses to 6/14 pneumococcal serotypes (Table ). Further work-up yielded a low level of MBL at < 50 ng/ml (reference: >100 ng/ml), as well as an impaired MBL pathway functional test using the C4b deposition assay. Genotyping showed the HYPD/HYPD variant of MBL2 and wild-type MASP-2 genotype (A/A) (Table ).